The present invention relates to power plants in which heat is used to heat water to generate steam, and in particular to methods of and systems for fitting tube restraints to tubes that carry the water/steam to be heated in such power plants.

Power plants typically heat water to generate steam, with the steam then being used to drive a steam turbine which generates electricity. The water/steam may be heated by means of heat from a combusted fuel (e.g. biomass, waste, coal) and/or by waste heat, e.g. from a combustion process (such as the gas turbine exhaust on a combined cycle gas turbine (CCGT) power plant). The part of a power plant where waste heat is used to heat water/steam may be referred to as a heat recovery steam generator (HRSG), with the part of a power plant in which heat from a combusted fuel is directly used to heat water/steam being referred to as a boiler. However, “boiler” and “HRSG” can be used interchangeably in the power industry, and the present invention is generally applicable wherever water/steam is being heated in a power plant, irrespective of the source of the heat (e.g. whether it is waste heat or otherwise).

In such power plant arrangements, the water and/or steam being heated is usually contained within arrays of metal, pressurised tubes, which are arranged within the “gas path” of the boiler/HRSG such that the hot combustion products/waste heat gas flow can be directed over the tubes. The arrays of tubes are typically referred to as tube “modules” or “bundles”. For convenience herein, the terms “tube module” and “tube modules” will be used, but this should be understood to encompass all equivalent and corresponding tube arrays and constructions that are used to contain water and/or steam being heated in a heated gas path (flow). A tube module may carry water only, a mix of water and steam, or steam only.

A typical power plant tube module will contain a large number of parallel tubes arranged in a two dimensional array (in the plane perpendicular to the length of the tubes), with the tubes being appropriately spaced in the array so as to allow the heating gas to flow between the tubes (and thereby heat the water and/or steam within the tubes). ln general the tubes of a tube module will extend in a vertical direction (and will be substantially parallel in that vertical direction) within the gas path chamber, with the tube module then extending in two dimensions generally perpendicularly to the axis (length) direction of the tubes (and correspondingly in the direction of (generally parallel to), and perpendicular to, the (general) direction of the gas flow in use). (In other arrangements, the tubes may be orientated in a horizontal direction.)

For convenience herein, the direction along the length of the tubes of a tube module (the axial direction of the tubes) will be considered to be the length direction and dimension of the tube module (and will normally be the height/vertical direction and dimension of the tube module when in situ in a power plant), with the width direction and dimension of the tube module then being a direction perpendicular to the length (and that extends in a direction perpendicular to the intended gas flow when the tube module is in situ in a power plant), and the depth direction and dimension of the tube module then being the direction that is perpendicular to the width and the length (and that extends in the direction of the gas flow when the tube module is in situ in a power plant).

It will be appreciated here that these dimensions are intended to be and are defined with reference to the orientation of the tube module and the length direction (axis) of the tubes, and so while it may generally be the case that the tube module will be arranged such that the longitudinal axes of the tubes extend in a vertical direction when installed in a power plant, it could be the case that the longitudinal axes of the tubes extend in a horizontal direction and in that case the terms “height”, “vertical”, “width” and “depth”, etc. should be interpreted accordingly (and the present invention is intended to encompass such arrangements).

The tubes within a tube module are typically held in place by a plurality of tube restraints which are fitted at various positions within the tube modules to, for example, maintain the intended tube spacing and alignment, and prevent vibration and oscillation in the heated gas flow. Other terms that are used for such tube restraints are tube ties, wraparounds, etc.. Again, for convenience herein, the terms “tube restraint” and “tube restraints” will be used, but this is intended to encompass all equivalent and corresponding terms and constructions.

When initially fabricating a tube module, the tube restraints are fabricated and installed on the tube module as the tube module is being built. Completed tube modules including restraints are then erected at the power plant site with the gas path construction (chamber) then being completed around them. Tube module tube restraints can be damaged in various ways during the operational life of a power plant, for example through erosion, oxidation, corrosion, mechanical failure, etc.. This can result in the need for tube restraint repair or replacement. However, this can be very difficult to achieve when the tube modules are in situ within the gas path, for example due to inaccessibility within the depth of the tube modules.

The Applicants believe therefore that there remains scope for improvements to the fitting of tube restraints to tube modules in power plants, and in particular to the retrofitting of tube restraints to tube modules in power plants after initial installation of the tube modules.

According to a first aspect of the present invention, there is provided a method of fitting tube restraints to a tube module for a power plant, the tube module comprising a plurality of parallel tubes for carrying water and/or steam arranged in a two-dimensional array in the plane perpendicular to the length of the tubes, the tubes being spaced-apart in the plane perpendicular to the length of the tubes to allow heated gas to pass through the tube module to heat water and/or steam in the tubes of the tube module; the method comprising: inserting an assembly comprising an elongate base plate to which a plurality of spaced apart elongate tube restraint plates are mounted, the tube restraint plates extending in a direction that is perpendicular to the length of the base plate, into the tube module, by: aligning the tube restraint plates of the base plate and tube restraint plate assembly with the longitudinal axis direction of the tubes of the tube module; inserting the base plate and tube restraint plate assembly when so-aligned into the tube module; and once the base plate and tube restraint plates have been so-inserted into the tube module, rotating the base plate and tube restraint plate assembly about an axis parallel to the longitudinal axis of the base plate such that the base plate of the base plate and tube restraint plate assembly extends into the tube module in a first axis direction in the plane perpendicular to the length of the tubes of the tube module, and the tube restraint plates extend between tubes of the tube module in a second axis direction in the plane that is perpendicular to the length of the tubes of the tube module. According to a second aspect of the present invention, there is provided a system for fitting tube restraints to a tube module of a power plant, the tube module comprising a plurality of parallel tubes configured to carry water and/or steam arranged in a two-dimensional array in the plane perpendicular to the length of the tubes, the tubes being spaced-apart in the plane perpendicular to the length of the tubes to allow heated gas to pass through the tube module to heat water and/or steam in the tubes of the tube module; the system comprising: an assembly comprising an elongate base plate to which a plurality of spaced apart elongate tube restraint plates are mounted, the tube restraint plates extending in a direction that is perpendicular to the length of the base plate; the base plate and tube restraint assembly being configured such that it can be inserted into a tube module by: aligning the tube restraint plates of the base plate and tube restraint plate assembly with the longitudinal axis direction of the tubes of the tube module; inserting the base plate and tube restraint plate assembly when so-aligned into the tube module; and once the base plate and tube restraint plates have been so-inserted into the tube module, rotating the base plate and tube restraint plate assembly about an axis parallel to the longitudinal axis of the base plate such that the base plate of the base plate and tube restraint plate assembly extends into the tube module in a first axis direction in the plane perpendicular to the length of the tubes of the tube module, and the tube restraint plates extend between tubes of the tube module in a second axis direction in the plane that is perpendicular to the length of the tubes of the tube module.

The present invention relates to the fitting of tube restraints to a tube module for a power plant, in particular, and preferably, while the tube module is in place in the power plant (i.e. after initial installation and construction of the power plant). Thus the present invention in particular relates to methods and systems for “retrofitting” tube restraints to tube modules, for example where existing tube restraints have been damaged and so repairs or replacements are required.

In the present invention, an assembly comprising an elongate base plate on which a plurality of elongate tube restraint plates that extend in a direction perpendicular to the length of the base plate are mounted is used to provide tube restraints within the body (i.e. within the depth) of a tube module. In particular, and as will be discussed below, such a base plate and tube restraint plate assembly is inserted into the tube module from one side of the tube module, e.g. in the depth direction of the tube module, by aligning the tube restraint plates lengthwise relative to the tubes and then inserting the assembly into the tube module, with the assembly then being rotated, e.g., and preferably, through 90°, such that the tube restraint plates then extend perpendicularly to the length of the tubes, e.g. in a width direction, between tubes of the tube assembly.

This then facilitates, for example, and as will be discussed in more detail below, fitting tube restraints within the body of a tube module via only, for example, the front and/or rear side of the tube module, thereby facilitating retrofitting of tube restraints to a tube module in situ, notwithstanding the difficulty of accessing the interior of the tube module.

The present invention can therefore provide an improved method and system for retrofitting of tube restraints to in situ tube modules.

Furthermore, and as will be discussed in more detail below, the present invention can allow welding operations to only be required at the front and rear of the tube module, i.e. where there is “access”.

The tube module will comprise a plurality of parallel tubes arranged in a two-dimensional array in the plane perpendicular to the length of the tubes. The tubes may be arranged so as to be aligned along the perpendicular axes extending in the width and depth directions of the tube module, or the tubes may be staggered relative to each other along those axes. The tubes will be appropriately spaced so as to allow the heating gas to flow between the tubes.

When in place in a power plant, the tube module will be within an appropriate chamber for containing the gas flow path and the tube module, and thus will be arranged in a gas flow path via which heated gas will be conveyed through the tube module to heat water and/or steam in the tubes of the tube module. The tube module will be arranged such that the tubes extend in a lengthwise direction generally perpendicularly to the gas flow, with the width of the tube module also extending perpendicularly to the gas flow and the depth of the tube module extending generally in the direction of the gas flow. The tube module will correspondingly have an upstream side and a downstream side relative to the gas flow.

The tubes may, for example, have an outside diameter of 2” (50.8 mm). A tube module may, for example, be as small as 20 tubes wide and 2-8 tube rows deep, or as large as 80-120 tubes wide and around 12 tubes deep. Other configurations would, of course, be possible.

Within the gas flow path, the tubes of the tube module will extend parallel to each other. The ends of the tubes of the tube module will typically have appropriate connections (headers, collectors, manifolds, return ends, etc.) which either receive water and/or stream from an upstream part of the water/steam flow path for admission to the tubes, or collect the water and/or steam from the tubes for onward connection to a downstream part of the water/steam flow path.

The base plate and tube restraint plate assembly that is used in the present invention comprises an elongate base plate to which a plurality of spaced apart elongate tube restraint plates extending in a direction perpendicular to the length of the base plate are mounted.

The elongate base plate will generally comprise a flat, elongated plate that extends in a longitudinal direction. (In general, for the purposes of the present description, the elongate flat base plate (and all other elongate flat plates that are referred to herein, unless the context requires otherwise) will be considered to have a length direction and dimension extending in its length direction, a width direction and dimension extending in the plane of the plate that is perpendicular to the length direction/dimension, and a thickness or depth direction and dimension that is in the direction of the thickness of the plate (in the direction that is perpendicular to the plane of the plate). For simplicity and clarity purposes, references herein to the length, width and thickness/depth of a given plate should be interpreted accordingly, unless the context requires otherwise.)

The base plate should be, and is preferably, long enough so as to extend completely through the tube module in the direction in question (i.e. will extend through the entire depth of the tube module (in the direction of the gas flow perpendicular to the longitudinal axis of the tubes of the tube module)), i.e. such that it will protrude beyond the tube module at both ends when in position. It should, and preferably does, have a width such that it will fit through the spaces between the tubes in the tube module (and a thickness/depth that will fit through the spaces between the tubes of the tube module).

The elongate tube restraint plates that are mounted on the base plate correspondingly should, and preferably do, comprise appropriate (flat) elongated plates that extend in a lengthwise direction (from their proximal ends that are attached to the base plate to their distal ends (which will be free)). The tube restraint plates again should, and preferably do, have a width so as to be able to fit within the longitudinal spaces between the tubes of the tube module (and a thickness/depth that will fit through the spaces between the tubes of the tube module).

The tube restraint plates of a base plate and tube restraint plate assembly preferably have a length so as to extend across a plurality of tubes of the tube module when in position. They may all be the same length, or they could have different lengths. In a preferred embodiment they are all the same length.

The tube restraint plates could have a length such that they will extend across the entirety of the tube module (across the entire width of the tube module) when in position. In a preferred embodiment they extend across only a portion of the tube module in the direction in question (e.g. across only a portion of the width), such that a plurality of base plate and tube restraint assemblies can then be (and preferably are) arranged across the (e.g. width of) the tube module (e.g. for ease of handling and other practical considerations).

The base plates and tube restraint plates (and other plates) may be made of any suitable and desired material, such as a suitable grade of carbon steel or stainless steel, e.g. dependent on the temperature and chemical composition of the prevailing (heating) gas flow. The size of the plates will, as discussed above, be dependent on the tube to tube spacing and the desired arrangement and size of the base plate and tube restraint plate assembly or assemblies, but an exemplary size for the base plates would be, for example, around 860 mm long, 50 mm wide, and 8 mm thick, with the tube restraint plates being, for example, 660 mm long, 35 mm wide, and 8 mm thick. Other arrangements and other plate sizes and configurations would, of course, be possible.

The tube restraint plates are preferably mounted to the base plate such that the planes of the tube restraint plates are perpendicular to the plane of the base plate and preferably such that when in position (after being rotated) the plane of the base plate and the planes of the tube restraint plates are parallel to the longitudinal axis of the tubes of the tube module.

The number of tube restraint plates that are mounted to the base plate in a given assembly can be selected as desired. This should, and preferably does, correspond to, and is preferably based on, the number of tubes that there will be along the appropriate direction (e.g. along the depth dimension) of the tube module to which the tube restraint is intended to be fitted (along the base plate length). ln a preferred embodiment, the number of tube restraint plates (and the configuration of the tube restraint plates) is such that when the overall tube restraint system is in place, each tube will be restrained by at least one and in one preferred embodiment by (only) one respective tube restraint plate (in the direction in question) unless restrained on the side in question by another plate of the overall tube restraint system. Thus, in the case where, as will be discussed further below, there are outer surface support plates mounted on the outer surfaces of the tube module (which will thereby restrain the tubes that they engage), in one embodiment the number of tube restraint plates that are mounted to the base plate and tube restraint plate assembly comprises one less than the number of tubes along the tube module axis direction in question (e.g. along the depth direction of the tube module). Other arrangements would, of course, be possible, such as providing a tube restraint plate for every other tube, or providing a tube restraint plate on each of two sides (in the direction in question) of the tubes, if desired.

The tube restraint plates should correspondingly be spaced along the length of the base plate at a spacing (pitch) that is appropriate for the spacing (pitch) of the tubes in the relevant (e.g. depth) direction of the tube module to which the tube restraint is intended to be fitted.

The tube restraint plates are preferably appropriately welded to the base plate, although other forms of construction could be used, if desired. The base plate preferably comprises a plurality of notches (slots) that the tube restraint plates can be mounted in (and then welded in place).

The base plate and tube restraint plate assembly will be, and is preferably, pre-assembled before being installed in the tube module, e.g., “off site” or in the gas path chamber, and is installed in the tube module in its assembled form.

Depending upon the size of the tube module, a single base plate and tube restraint plate assembly may be used across the entire (e.g. width of the) tube module, or there could be a plurality of base plate and tube restraint plate assemblies installed across the (e.g. width of the) tube module.

It will also be appreciated that typically, and preferably, appropriate base plate and tube restraint plate assemblies are installed at a plurality of positions along the length dimension of the tube module (at a plurality of positions along the length of the tube module).

At least in the case where a plurality of base plate and tube restraint plate assemblies are arranged across, e.g. the width of, a tube module, then one or more of the base plate and tube restraint plate assemblies will be initially inserted (with the tube restraint plates aligned in the longitudinal direction of the tubes) between adjacent tubes of the tube module (by aligning the tube restraint plates with a gap between parallel tubes of the tube module), such that the base plate and tube restraint plate assembly will be inserted between tubes of the tube module and then once having being so-inserted between tubes of the tube module will be rotated into position.

In the case where a base plate and tube restraint plate assembly is being inserted at an (outer) edge of the tube module, then it may be that the base plate and tube restraint plate assembly will be inserted in the gap between the edge of the tube module and, e.g., a wall of the gas flow path chamber, and then rotated to position the tube restraint plates within and between the tubes of the tube module.

However, it may be that the gap between the wall and the end of the tube module is too small to permit insertion of a base plate and tube restraint plate assembly, in which case the “end” assembly can, for example, and preferably, be fed in (inserted) in the “opposite” orientation to other assemblies being installed across the width of the tube module (thus there may, for example, be a plurality of assemblies that are inserted in one direction (orientation), but with a final, end, assembly, then being inserted in the opposite direction (orientation)).

Thus, in a particularly preferred embodiment, the method of the present invention comprises (and the base plate and tube restraint plate assembly are configured correspondingly) inserting the base plate and tube restraint plate assembly into the tube module by: aligning the tube restraint plates of the base plate and tube restraint plate assembly with the longitudinal axis direction of the tubes of the tube module; inserting the base plate and tube restraint plate assembly when so-aligned into a gap between parallel tubes of the tube module; and once the base plate and tube restraint plates have been so-inserted into the tube module, rotating the base plate and tube restraint plate assembly about an axis parallel to the longitudinal axis of the base plate such that the base plate of the base plate and tube restraint plate assembly extends between tubes of the tube module in a first axis direction in the plane perpendicular to the length of the tubes of the tube module, and the tube restraint plates extend between tubes of the tube module in a second axis direction in the plane that is perpendicular to the length of the tubes of the tube module. In a preferred embodiment, the tube restraint plates are also supported at their distal ends (i.e. at the ends that are not mounted to the base plate). This can be done in any suitable and desired manner.

In a particularly preferred embodiment, this is achieved by also providing a support plate extending into (and preferably through) the tube module in the appropriate (e.g. depth) direction of the tube module that can (and will in use) support the distal (unsupported) ends of at least some of, and in one preferred embodiment of all of, the tube restraint plates of a base plate and tube restraint plate assembly (when they have been rotated into position).

In a particularly preferred embodiment, the support plate and the tube restraint plates are configured such that the distal ends of (at least some of, and in one embodiment all of) the tube restraint plates can engage the support plate (when the tube restraint plates have been rotated into position). Preferably the arrangement is such that the distal ends of the tube restraint plates will interlock with the support plate when rotated into position.

This can be achieved as desired. For example, the distal ends of the tube restraint plates could comprise appropriate notches so that the tube restraint plates can fit over and engage the support plate. In a preferred embodiment, the support plate comprises suitable notches (slots) for receiving the (distal) ends of the tube restraint plates, so that the tube restraint plates can be appropriately engaged with the support plate when in position. There could also be corresponding notches both in the ends of the tube restraint plates and in the support plate.

In the case where there is only a single base plate and tube restraint plate assembly across the, e.g. width of the, tube module, there will be only a single support plate arranged to engage with the other ends of the tube restraint plates. In the case where there are plural base plate and tube restraint plate assemblies arranged across the, e.g. width of the, tube module, then there should be, and is preferably, a corresponding number of tube restraint support plates, one for each base plate and tube restraint plate assembly.

A (and each) tube restraint support plate is preferably a separate, stand-alone (individual) support plate for its corresponding base plate and tube restraint plate assembly, that is then inserted individually into the tube module along the appropriate (e.g. depth) dimension of the tube module.

Thus, in a preferred embodiment there will be a sequence of base plate and tube restraint plate assemblies, interspersed with support plates, arranged in the, e.g. width direction of the tube module, with the distal ends of tube restraint plates of one assembly engaging appropriately with a respective support plate for that assembly, to thereby provide appropriate support to the distal ends of the tube restraint plates.

Subject to any notches, etc., for engaging with the distal ends of the tube restraint plates, a (and each) elongate support plate is preferably a similar size and configuration to, and preferably the same size and configuration as, the base plates of the base plate and tube restraint plate assemblies. In the case where the base plate has notches for receiving the tube restraint plates, the support plate preferably has a corresponding configuration of notches for receiving the tube restraint plates. In this case, the base plates and support plates may be cut to the same pattern, thereby reducing the number of patterns to be cut and easing fit up.

In some cases (discussed further below) wherein the overall tube restraint assembly comprises auxiliary tube restraint plates (as part of a further tube restraint plate and auxiliary tube restraint plate assembly), the support plate preferably supports both the tube restraint plates of the base plate and tube restraint plate assembly (at their distal ends, e.g. in the manner described above) and auxiliary tube restraint plates of the further tube restraint plate and auxiliary tube restraint plate assembly.

In a particularly preferred embodiment, the support plate has a first set of notches for receiving the tube restraint plates of the base plate assembly (at their distal ends, e.g in the manner described above), and a second set of notches for receiving the auxiliary tube restraint plates. The notches of the first set of notches are preferably interleaved with the notches of the second set of notches, such that successive notches when travelling along a longitudinal axis of the support plate belong to alternate sets of notches (e.g. with a first notch belonging to the first set of notches, a second notch belonging to a second set of notches, the third notch belonging to the first set of notches, etc. and so on).

The base plate and tube restraint plate assembly or assemblies and any corresponding support plate(s) for the distal ends of the tube restraint plates should be and are preferably appropriately mounted to the tube module once in position. This can be achieved in any suitable and desired manner.

In a particularly preferred embodiment, this is achieved by providing one or more (further) elongate support plates that are mounted to the outside of (on an outside surface of) the tube module which can then support the base plate and tube restraint plate assembly or assemblies and their corresponding support plate(s) for the distal ends of the tube restraint plates. Preferably, elongate support plates are mounted on both outside surfaces (e.g. the front and rear surfaces) of the tube module.

These outer surface support plates preferably extend in the same direction as the tube restraint plates (when rotated into position), and preferably have a length corresponding to the length of the tube restraint plates. An exemplary size for the outer surface support plates would be 675 mm long, 50 mm wide and 8 mm thick.

Thus in the case where the tube restraint plates extend (when rotated into position) in the width direction of the tube module, the outer surface support plates will correspondingly extend in the width direction of the tube module (and in that case at least will be mounted on the front and rear sides (relative to the gas flow) of the tube module).

Again, depending upon how many base plate and tube restraint plate assemblies are to be arranged across the, e.g. width of the, tube module, there may be a single pair of outer surface support plates arranged on the outer (e.g. front and rear) surfaces of the tube module across the, e.g. width of the, tube module, or, more preferably, a plurality of pairs of outer surface support plates will be arranged and mounted across the, e.g. width of the, tube module, corresponding to the number of base plate and tube restraint assemblies to be arranged across the, e.g. width of the, tube module.

The outer surface support plates are preferably appropriately mounted to, and preferably fixed to, the tube module (to thereby provide the means and mechanism for mounting and fixing the overall tube restraint structure to the tube module).

This is preferably done by mounting and fixing the outer surface support plates appropriately to tubes of the tube module.

The (outer surface) support plates can be mounted to tubes of the tube module in any suitable and desired manner. Preferably this is done by fixing, and preferably by welding, appropriate mounts, such as lugs or clips, to tubes of the tube module, which mounts (e.g. lugs) can then receive and support the outer surface support plates, so as to then mount (and fix) the outer surface support plates to the tubes of the tube module. Any suitable and desired configuration and number of mounts can be used for this purpose. For example, there could be a mount for each tube of the tube module, or mounts (e.g. lugs) could be fixed to every other or every third, etc., tube across the (width of the) tube module. This may depend, for example, upon features such as allowable clip loading.

The outer surface support plates are preferably then mounted on the mounts that are fixed to tubes of the tube module, so as to thereby mount the outer surface (front and rear) support plates on the tube module. The mounts (e.g. lugs) are preferably configured so as to retain the outer surface support plates in position without the need for welding them to the mounts.

In a preferred embodiment, the outer surface support plates have appropriate notches for engaging with and fitting over the mounts that are fixed to the tubes of the tube module. This will help to improve stability during fit-up and reduce the overall height of the finished assembly (which is preferable to reduce vortexing in the gas flow, consequent erosion damage, etc.).

The outer surface support plates, the base plates of the base plate and tube restraint plate assemblies, and the support plates for the distal ends of the tube restraint plates are preferably appropriately configured and arrangeable such that the base plate and tube restraint plate assemblies and the support plates for the distal ends of the tube restraint plates of the assemblies can be, and will be, supported by the outer surface support plates in use (when in position).

This can be achieved in any suitable and desired manner. Most preferably the various plates are arranged such that the ends of the base plates and the ends of the support plates for the distal ends of the tube restraint plates can engage with, and preferably interlock with, the outer surface (front and rear) support plates that are attached to the tubes of the tube module, so as to be supported by those outer surface support plates at their ends.

This can be achieved as desired. Again, this is preferably achieved by providing appropriate notches (slots) in one or both of the base plates of the base plate and tube restraint plate assemblies and the corresponding support plates for the distal end of the tube restraint plates, and the outer surface support plates, so that the base plates and tube restraint plate distal end support plates can be mounted on and interlock with the outer surface support plates in use (when fitting the tube restraints). For example, the ends of the base plates and of the support plates for the distal ends of the tube restraint plates could comprise appropriate notches so that the base plates of the base plate and tube restraint plate assemblies, and the corresponding support plates for the distal ends of the tube restraint plates, can fit over and engage and interlock with the outer surface support plates.

Additionally or alternatively, the outer surface support plates that are attached to the tubes of the tube module could comprise suitable notches for receiving the base plates of the base plate and tube restraint plate assemblies and the support plates for the distal ends of the tube restraint plates, e.g., and preferably, their ends.

There could also be corresponding notches in the base plates, the support plates for the distal ends of the tube restraint plates, and the outer surface support plates, so that the various plates can be appropriately engaged and interlock when in position.

In a preferred embodiment, the interlocking, e.g. notches, between the outer support plates and the base plates and the distal end support plates is such as to permit some (limited) relative movement between the base plates and the distal end support plates and the outer surface support plates (in contrast to the interlocking between the distal end support plates and the tube restraint plates of the base plate and tube restraint plate assemblies which, as discussed above, preferably does not permit any relative movement between the distal end support plates and the tube restraint plates of the base plate and tube restraint plate assemblies when interlocked, at least in the length direction of the distal end support plates). This will then permit, as will be discussed further below, some adjustment of the position of the base plate and the distal end support plates relative to the outer surface support plates when mounted on the outer surface support plates.

Preferably the interlocking is such as to permit (some) relative movement in at least one axial direction, and preferably in two (both) axial directions, in the plane perpendicular to the length of the tubes of the tube module.

Thus, in a particularly preferred embodiment, one or more sets of respective outer surface support plates are mounted to the (e.g. front and rear) of the tube module, and for each set of outer surface support plates, a tube restraint plate distal end support plate is inserted into the tube module and mounted on the outer surface support plates, and then a base plate and tube restraint plate assembly is inserted into the tube module and rotated into position in the manner of the present invention, and then the base plate is mounted on the outer surface support plates, and the distal ends of the tube restraint plates are engaged with the tube restraint plate distal end support plate.

It will be appreciated from the above that the tube restraint plates of the base plate and tube restraint plate assemblies that are used in the present invention will extend between tubes of a tube module in one direction only (along one axis only) in the plane that is perpendicular to the length direction of the tubes of the tube module (e.g. along the width direction of the tube module) when rotated into position.

In a particularly preferred embodiment, elongate tube restraint plates extending between the tubes of the tube assembly in the other axis direction of the plane that is perpendicular to the length of the tubes of the tube assembly (i.e. in a direction that is in the plane that is perpendicular to the length of the tubes of the tube assembly and in a direction that is perpendicular to the length direction of the tube restraint plates of the base plate and tube restraint plate assembly or assemblies) are also inserted into the tube module.

In other words, if the tube restraint plates of the base plate and tube restraint plate assemblies extend along the width direction of the tube module, there are preferably also tube restraint plates extending between the tubes along the depth direction of the tube module.

These further (e.g. depth direction) tube restraint plates are preferably inserted in the vertical spaces between the tubes of the tube module individually, and preferably extend the full length of the tube module in the relevant direction (e.g. in the depth direction).

These further (e.g. depth direction) tube restraint plates thus preferably extend parallel to the length of the base plates of the base plate and tube restraint plate assemblies (and parallel to length of the tube restraint plate distal end support plates, and perpendicularly to the length of the outer surface support plates that are fixed to the tubes of the tube module).

The number of further (e.g. depth direction) tube restraint plates that are used (for a given base plate and tube restraint plate assembly) can be selected as desired. Preferably at least as many further tube restraint plates are used such that each tube of the tube module in the relevant direction (that is not otherwise constrained by another plate in the direction in question) has a corresponding further tube restraint plate that can be arranged against the tube in question. Thus, there is preferably at least one further (e.g. depth direction) tube restraint plate for plural tubes of the tube module along the direction in question, and preferably for each tube of the tube module along the direction in question, except for at the outer sides of the assembly where the base plate and distal end support plate will already provide restraint on the outboard sides of the tubes.

In a particularly preferred embodiment, two further (e.g. depth direction) tube restraint plates are provided for plural tubes, and preferably for each tube in the relevant direction (except for at the outer sides of the assembly where the base plate and distal end support plate will already provide restraint on the outboard sides of the tubes), such that there will be a further tube restraint plate on each side of those tubes in the relevant direction. Preferably the overall arrangement is such that each tube of the tube module will have tube restraint plates on (at least) three sides.

These further (depth direction) tube restraint plates are also preferably appropriately mounted to and supported by the overall tube restraint construction.

Preferably, these further tube restraint plates are appropriately configured and arrangeable such that the further tube restraint plates can be, and will be, supported by the tube restraint plates of the base plate and tube restraint plate assemblies in use (when in position).

This can be achieved in any suitable and desired manner. Most preferably the further tube restraint plates and the tube restraint plates of the base plate and tube restraint plate assemblies are arranged such that the further tube restraint plates can engage with, and preferably interlock with, the tube restraint plates of the base plate and tube restraint plate assemblies, so as to be supported by the tube restraint plates of the base plate and tube restraint plate assemblies.

This can be achieved as desired. Again, this is preferably achieved by providing appropriate notches (slots) in one or both of the further tube restraint plates and the tube restraint plates of the base plate and the tube restraint plate assemblies, so that the further tube restraint plates can be mounted on and interlock with the tube restraint plates of the base plate and tube restraint plate assemblies in use (when fitting the tube restraints).

In a preferred embodiment the further tube restraint plates comprise appropriate notches so that they can fit over and engage the tube restraint plates of the base plate and tube restraint plate assemblies. Additionally or alternatively, the tube restraint plates of the base plate and tube restraint plate assemblies could comprise suitable notches for receiving the further tube restraint plates.

There could also be sets of corresponding notches in both the further tube restraint plates and the tube restraint plates of the base plate and tube restraint plate assemblies, so that the various plates can be appropriately engaged and interlock when in position.

In a preferred embodiment, the interlocking of the further tube restraint plates and the tube restraint plates of the base plate and tube restraint plate assemblies provides a (tight) fit at least in respect of relative movement in the lengthwise direction of the further tube restraint plates such that any movement of the base plate and tube restraint plate assemblies in the lengthwise direction of the further tube restraint plates will correspondingly move the further tube restraint plates (i.e. such that the further tube restraint plates and the tube restraint plates of the base plate and tube restraint plate assemblies are interlocked in such a manner that they will move together (as one) in the lengthwise direction of the further tube restraint plates).

The interlocking of the further tube restraint plates and the tube restraint plates of the base plate and tube restraint plate assemblies could also provide a (tight) fit in respect of relative movement in the lengthwise direction of the tube restraint plates of the base plate and tube restraint plate assemblies (such that any movement of the base plate and tube restraint plate assemblies in the lengthwise direction of the tube restraint plates of the base plate and tube restraint plate assemblies will correspondingly move the further tube restraint plates in that direction).

This would mean that the further tube restraint plates could not be moved along the length of the tube restraint plates of the base plate and tube restraint plate assemblies when mounted on the tube restraint plates of the base plate and tube restraint plate assemblies, but rather that the further tube restraint plates and the tube restraint plates of the base plate and tube restraint plate assemblies will move together (as one) in the lengthwise direction of the tube restraint plates of the base plate and tube restraint plate assemblies.

Alternatively, the interlocking of the further tube restraint plates and the tube restraint plates of the base plate and tube restraint plate assemblies could permit relative movement in the lengthwise direction of the tube restraint plates of the base plate and tube restraint plate assemblies. This would then mean that the further tube restraint plates could be moved along the length of the tube restraint plates of the base plate and tube restraint plate assemblies when in position (at least to a limited extent).

In the case where further tube restraint plates are provided for each side of the tubes of the tube module, the set of further tube restraint plates for one side of the tubes of the tube module may be interlocked with the tube restraint plates of the base plate and tube restraint plate assemblies such that there is no relative movement between them in the lengthwise direction of the further tube restraint plates, with the set of further tube restraint plates for the other side of the tubes of the tube module then being interlocked with the tube restraint plates of the base plate and tube restraint plate assemblies such that relative movement in the lengthwise direction of the tube restraint plates of the base plate and tube restraint plate assemblies is possible. This will then allow one set of the further tube restraint plates to be moved by moving the base plate and tube restraint plate assemblies, with the other set of further tube restraint plates then being individually adjustable in the lengthwise direction of the tube restraint plates of the base plate and tube restraint plate assemblies.

In a particularly preferred embodiment, the configuration and interlocking of the further tube restraint plates and the tube restraint plates of the base plate and the tube restraint plate assemblies is such that relative movement in the length wise direction of the tube restraint plates of the base plate and tube restraint plate assemblies of the further tube restraint plates is possible, i.e. such that the positions of the further tube restraint plates can be adjusted (on both sides of the tubes where appropriate) by moving them relative to the base plate and tube restraint plate assemblies, etc. (i.e. with the base plate and tube restraint plate assemblies, etc., being kept stationary (rather than fixing the further tube restraint plates to the base plate and tube restraint plate assemblies and then moving the whole assembly to adjust the position of further restraint plates)).

Preferably, the further tube restraint plates are (also) appropriately configured and arrangeable such that the further tube restraint plates can be, and will be, supported by the outer surface support plates in use (when in position).

This can be achieved in any suitable and desired manner. Most preferably the various plates are arranged such that the ends of the further tube restraint plates can engage with, and preferably interlock with, the outer surface (front and rear) support plates that are attached to the tubes of the tube module, so as to be supported by those outer surface support plates at their ends.

This can be achieved as desired. Again, this is preferably achieved by providing appropriate notches (slots) in one or both of the further tube restraint plates and the outer surface support plates, so that the further tube restraint plates can be mounted on and interlock with the outer surface support plates in use (when fitting the tube restraints).

In a preferred embodiment the ends of the further tube restraint plates comprise appropriate notches so that they can fit over and engage the outer surface support plates.

Additionally or alternatively, the outer surface support plates that are attached to the tubes of the tube module could comprise suitable notches for receiving the further tube restraint plates.

There could also be sets of corresponding notches in both the further tube restraint plates and the outer surface support plates, so that the various plates can be appropriately engaged and interlock when in position.

In a preferred embodiment, the interlocking, e.g. notches, between the outer support plates and the further tube restraint plates is such as to permit some (limited) relative movement between the further tube restraint plates and the outer surface support plates. This will then permit, as will be discussed further below, some adjustment of the position of the further tube restraint plates relative to the outer surface support plates when mounted on the outer surface support plates.

Preferably the interlocking is such as to permit some movement of the further tube restraint plates relative to the outer surface support plates when mounted on the outer surface support plates in at least one of, and preferably in both of: the lengthwise direction of the further tube restraint plates and the lengthwise direction of the outer surface support plates.

Thus, in a particularly preferred embodiment, a plurality of further elongate tube restraint plates are inserted between tubes of the tube module extending in a direction parallel to the longitudinal axis of the base plate(s) of the base plate and tube restraint plate assembly or assemblies, and mounted on the tube restraint plates of the base plate and tube restraint plate assemblies and on outer surface support plates.

As will be understood, in the embodiments described above wherein further elongate tube restraint plates are inserted between the tubes of the tube module, tubes of the tube module may be constrained by tube restraint plates on three sides (for example by a (e.g. width direction) tube restraint plate of a base plate and tube restraint plate assembly on a first side, and by two further (e.g. depth direction) tube restraint plates on two other (parallel) sides that are perpendicular to the first side).

In a particularly preferred embodiment, at least some, and preferably plural, and preferably all, of the tubes of a tube module are constrained by respective plates on (all) four sides (in the plane perpendicular to the length of the tubes), since this may further reduce the risk of tube vibration in the prevailing gas flow and also reduce the risk of tube deformation out of the plane at the elevation of the tube restraint system.

Thus, in a preferred embodiment, some, preferably plural, and preferably all, of the tubes of the tube module are constrained on an additional (fourth) side (such that all four sides of the tube are constrained).

This can be achieved as desired. For example, this could be done by providing additional tube restraint plates on the base plate of the base plate and tube restraint plate assemblies such that some or all of the tubes of the tube module are constrained by two tube restraint plates of the base plate and tube restraint plate assembly (i.e. by one (e.g. width direction) tube restraint plate of the base plate and tube restraint plate assembly on a first side and by another (e.g. width direction) tube restraint plate of the tube restraint plate assembly on a second side (parallel to the first) side).

In preferred embodiments, this is done using yet further elongate tube restraint plates (hereafter referred to as “auxiliary” elongate tube restraint plates) mounted on (at least one of) the further elongate tube restraint plates that are inserted between the tubes of the tube module (to thereby form a further tube restraint plate and auxiliary tube restraint plate assembly), the auxiliary elongate tube restraint plates extending in a direction that is perpendicular to the length of the further elongate tube restraint plates.

Such a further tube restraint plate and auxiliary tube restraint plate assemblies can preferably be and are preferably inserted into the tube module from one side of the tube module, e.g. in the depth direction of the tube module, by aligning the auxiliary tube restraint plates lengthwise relative to the tubes and then inserting the assembly into the tube module, with the assembly then being rotated, e.g., and preferably, through 90 degrees, such that the auxiliary tube restraint plates then extend perpendicularly to the length of the tubes, e.g. in a width direction (in a similar manner to the way in which the base plate and tube restraint plate assembly is inserted into the tube module according to the method of the present invention as described above).

By inserting such an assembly of a further elongate tube restraint plate and auxiliary tube restraint plates between the tubes of the tube module, a tube of the tube module may be constrained on all four sides (for example, by a (e.g. width direction) tube restraint plate of a base plate and tube restraint plate assembly on a first side, by an (e.g. width direction) auxiliary tube restraint plate of the further elongate tube restraint plate and auxiliary tube restraint plate assembly on a second side parallel to the first side, by the (e.g. depth direction) further elongate tube restraint plate of the further elongate tube restraint plate and auxiliary tube restraint plate assembly on a third side perpendicular to the first and second sides, and by a further (e.g. depth direction) elongate tube restraint plate on the fourth side parallel to the third side).

Thus in a preferred embodiment of the present invention, a plurality of spaced apart auxiliary elongate tube restraint plates are mounted on at least one of the further elongate tube restraint plates that are inserted into the tube assembly, thereby providing a further tube restraint plate and auxiliary tube restraint plate assembly that is inserted into the tube assembly by: aligning the auxiliary tube restraint plates of the further tube restraint plate and auxiliary tube restraint plate assembly with the longitudinal axis direction of the tubes of the tube module; inserting the further tube restraint plate and auxiliary tube restraint plate assembly when so-aligned into the tube module such that the further elongate tube restraint plate of the assembly extends in a direction parallel to the longitudinal axis of the base plate; and once the further tube restraint plate and auxiliary tube restraint plates of the further tube restraint plate and auxiliary tube restraint plate assembly have been so- inserted into the tube module, rotating the further tube restraint plate and auxiliary tube restraint plate assembly about an axis parallel to the longitudinal axis of the further tube restraint plate such that the further tube restraint plate of the further tube restraint plate and auxiliary restraint plate assembly extends into the tube module in the first axis direction in the plane perpendicular to the length of the tubes of the tube module, and the auxiliary tube restraint plates extend (between tubes of the tube module) in the second axis direction in the plane that is perpendicular to the length of the tubes of the tube module, parallel to the tube restraint plates of the base plate and tube restraint plate assembly.

Thus, as will be understood, in these embodiments of the present invention, the further tube restraint plate of the further tube restraint plate and auxiliary tube restraint plate assembly (when in position) extends parallel to the length of the base plates of the base plate and tube restraint plate assemblies (and parallel to length of the tube restraint plate distal end support plates, and perpendicularly to the length of the outer surface support plates that are fixed to the tubes of the tube module, if any), whilst the auxiliary tube restraint plates of the further tube restraint plate and auxiliary tube restraint plate assembly (when in position) extend parallel to the lengths of the tube restraint plates of the base plate and tube restraint plate assemblies.

The auxiliary tube restraint plates are preferably mounted to the further tube restraint plate such that the planes of the auxiliary tube restraint plates are perpendicular to the plane of the further tube restraint plate and preferably such that when in position (after being rotated) the plane of the further tube restraint plate and the planes of the auxiliary tube restraint plates are parallel to the longitudinal axis of the tubes of the tube module.

The auxiliary tube restraint plates that are mounted on the base plate preferably comprise appropriate (flat) elongated plates that extend in a lengthwise direction. In some embodiments, the auxiliary tube restraint plates are attached at a proximal end to the further tube restraint plate, extending in a lengthwise direction to their distal ends (that are free). In other embodiments, the auxiliary tube restraint plates are attached to the further tube restraint plate at a point along their length, with both ends of each auxiliary tube restraint plate being free.

The auxiliary tube restraint plates should, and preferably do, have a width so as to be able to fit within the longitudinal spaces between the tubes of the tube module (and a thickness/depth that will fit through the spaces between the tubes of the tube module).

The length of the auxiliary tube restraint plates that are mounted to the further tube restraint plate can be chosen as desired. They may all be of the same length, or they could have different lengths.

The auxiliary tube restraint plates could have a length such that they will extend across the entirety of the tube module (across the entire width of the tube module) when in position. In preferred embodiments they extend across only a portion of the tube module in the direction in question (e.g. across only a portion of the width), such that a plurality of further tube restraint plates and auxiliary tube restraint plate assemblies can then be (and preferably are) arranged across the (e.g. width of) the tube module (e.g. for ease of handling and other practical considerations).

In one preferred embodiment, the auxiliary tube restraint plates have a length so as to extend across only a single tube of the tube module (such that they do not extend across more than one tube of the tube module) when in position. In these embodiments, preferably a plurality of further tube restraint plates and auxiliary tube restraint plate assemblies are installed at a plurality of positions along the width dimension of the tube module, with each auxiliary tube restraint plate of each assembly extending across and restraining a (single) tube of the tube module it extends across (when in position).

In another preferred embodiment, the auxiliary tube restraint plates have a length so as to extend across a plurality of tubes of the tube module when in position. In these embodiments, preferably a plurality of further tube restraint plates and auxiliary tube restraint plate assemblies are installed at a plurality of positions along the width dimension of the tube module, with each auxiliary tube restraint plate of each assembly extending across and restraining a plurality of tubes of the tube module it extends across (when in position). In this case each auxiliary tube restraint plate preferably externds as far as a tube restraint plate of a (corresponding) base plate and tube restraint plate assembly.

The number of auxiliary tube restraint plates that are mounted to the further tube restraint in a given assembly can be selected as desired. This should, and preferably does, correspond to, and is preferably based on, the number of tubes that there will be along the appropriate direction (e.g. along the depth dimension) of the tube module to which the tube restraint is intended to be fitted (along the further tube restraint plate length).

Preferably, the number of auxiliary tube restraint plates (and the configuration of the auxiliary tube restraint plates) is such that when the overall tube restraint system is in place, each tube will be restrained by a respective auxiliary tube restraint plate (in the direction in question) unless restrained on the side in question by another plate of the overall tube restraint system. Thus, in the case where, as discussed above, there are outer surface support plates mounted on the outer surfaces of the tube module (which will thereby restrain the tubes that they engage), the number of auxiliary tube restraint plates that are mounted to the further tube restraint plate comprises one less than the number of tubes along the tube module axis direction in question (e.g. along the depth direction of the tube module). Other arrangements would, of course, be possible, such as providing an auxiliary tube restraint plate for every other tube.

The auxiliary tube restraint plates should correspondingly be spaced along the length of the further tube restraint plate at a spacing (pitch) that is appropriate for the spacing (pitch) of the tubes in the relevant (e.g. depth) direction of the tube module to which the tube restraint is intended to be fitted.

The auxiliary tube restraint plates are preferably appropriately welded to the further tube restraint plate, although other forms of construction could be used, if desired. The further tube restraint plate preferably comprises a plurality of notches (slots) that the auxiliary tube restraint plates can be mounted in (and then welded in place).

The further tube restraint plate and auxiliary tube restraint plate assembly will be, and is preferably, pre-assembled before being installed in the tube module, e.g., “off site” or in the gas path chamber, and is installed in the tube module in its assembled form.

The further tube restraint plates in the further tube restraint plate and auxiliary tube restraint plate assemblies in these embodiments of the present invention may, and preferably do, include any one or more or all of the preferred and optional features of the further tube restraint plates described above, as appropriate.

For example, the further tube restraint plates of the further tube restraint plate and auxiliary tube restraint plate assemblies are preferably appropriately configured and arrangeable such that the further tube restraint plates can be, and will be, supported by the tube restraint plates of the base plate and tube restraint plate assemblies in use (when in position), e.g. by providing appropriate notches (slots) in the further tube restraint plates, so that the further tube restraint plates can be mounted on and interlock with the tube restraint plates of the base plate and tube restraint plate assemblies in use (when fitting the tube restraints), in the manner described above.

Thus, as will be understood, the further tube restraint plates of the further tube restraint plate and auxiliary tube restraint plate assemblies may (and preferably do) comprise a first set of notches that the auxiliary tube restraint plates can be (and preferably are) mounted in, and a second set of notches provided for engaging (and preferably interlocking with) the tube restraint plates of the base plate and tube restraint plate assemblies, such that the further tube restraint plates can fit over (and thus engage) the tube restraint plates of the base plate and tube restraint plate assemblies.

In these preferred embodiments, the notches of the first set of notches are preferably interleaved with the notches of the second set of notches, such that successive notches when travelling along the length of the further tube restraint plate belong to alternate sets of notches (e.g. with a first notch along the length of the further tube restraint plate belonging to the first set of notches, a second notch belonging to a second set of notches, the third notch belonging to the first set of notches, etc. and so on).

In addition to these two sets of notches, the ends of the further tube restraint plate in the further tube restraint plate and auxiliary tube restraint plate assembly may also include appropriate notches so they can fit over and engage the outer surface support plates (e.g. in the manner described above), once the further tube restraint plate and auxiliary tube restraint plate assembly has been inserted into tube assembly and rotated (in the manner described above).

Thus, in a particularly preferred embodiment, the further tube restraint plate of the further tube restraint plate and auxiliary tube restraint plate assembly is mounted on the tube restraint plates of the base plate and tube restraint plate assemblies and on outer surface support plates (once rotated).

In preferred embodiments, the auxiliary tube restraint plates (that are mounted to the further tube restraint plates in the assembly) are supported at some point along their length, for example at their distal ends and/or at other points along their lengths. This can be done in any suitable and desired manner.

In a particularly preferred embodiment, the auxiliary tube restraint plates are supported along their length by one or more other further (e.g. depth direction) tube restraint plates that are inserted into the tube module (and mounted) (e.g. in the manner described above), wherein these one or more other further tube restraint plates are preferably not part of an assembly with auxiliary tube restraint plates. These other further tube restraint plates are preferably inserted into the tube module after the further tube restraint plate and auxiliary tube restraint plate assembly has been inserted into the tube assembly and rotated (in the manner described above), and preferably also after the further tube restraint plate of the further tube restraint plate and auxiliary tube restraint plate assembly is mounted on the tube restraint plates of the base plate and tube restraint plate assemblies and on outer surface support plates.

Thus, in these preferred embodiments, (at least one) other further tube restraint plates are inserted into the tube module in a direction parallel to the longitudinal axis of the base plate of the base plate and tube restraint plate assembly (and mounted on the tube restraint plates of the base plate and tube restraint plate assemblies and on outer surface support plates), with these other further tube restraint plates providing support for the auxiliary tube restraint plates (e.g. which extend in the width direction when in position) of the further tube restraint plate and auxiliary tube restraint plate assembly or assemblies.

Preferably the arrangement is such that that the auxiliary tube restraint plates will interlock with the one or more other further tube restraint plates once rotated into position.

This can be achieved as desired. For example, the auxiliary tube restraint plates could comprise one or more notches along their length so that the auxiliary tube restraint plates can engage with the one or more further tube restraint plates.

In a preferred embodiment, the one or more further tube restraint plates comprise a set of suitable notches for the auxiliary tube restraint plates, so that the further restraint plate can be appropriately engaged with the auxiliary tube restraint plates when in position (wherein this set of notches is separate from the set of notches on the further tube restraint plates that engage with the tube restraint plates of the base plate and tube restraint plate assemblies in use, as described above).

In embodiments (discussed above) wherein the auxiliary tube restraint plates have a length so as to extend across only a single tube of the tube module when in position, each auxiliary tube restraint plate preferably only engages with one other further tube restraint plate when in position. However, in embodiments (discussed above) wherein each auxiliary tube restraint plate has a length so as to extend across plural tubes of the tube module when in position, each auxiliary tube restraint plate preferably engages with plural other further tube restraint plates when in position.

In some embodiments, the auxiliary tube restraint plates of one or more of the assemblies that are inserted into the tube assembly are supported at their distal end by the tube restraint distal end support plate. Preferably the arrangement is such that that the auxiliary tube restraint plates will interlock with the support plate when rotated into position.

This can be achieved as desired. For example, the auxiliary tube restraint plates could comprise one or more notches at their distal ends so that the auxiliary tube restraint plates can engage with the support plate. In a preferred embodiment, and as discussed above, the support plate comprises a set of suitable notches that receive the auxiliary tube restraint plates, so that auxiliary tube restraint plates can be appropriately engaged with the support plate when in position (wherein this set of notches is separate from the set of notches on the support plate that engage with the tube restraint plates of the base plate and tube restraint plate assemblies in use, as described above).

It will be appreciated from the above, that in embodiments, there may be, and is preferably, one or more (and preferably plural) base plate and tube restraint plate assemblies, one or more (and preferably plural) distal end support plates, one or more (and preferably plural) further tube restraint and auxiliary tube restraint plate assemblies, and one or more (and preferably plural) further tube restraint plates (without auxiliary tube restraint plates), arranged across (e.g. the width of) a tube module (in use).

Correspondingly, when in place on a tube module, the complete tube restraint assembly will comprise a base plate and tube restraint plate assembly or assemblies, distal end support plate(s), and the further tube restraint plates including any further tube restraint plates and auxiliary tube restraint plate assemblies (if any), appropriately inserted into the tube module and mounted on and engaged with the outer surface support plates that are mounted to the tubes of the tube module.

In a preferred embodiment, the tube restraint plates of the base plate and tube restraint plate assemblies, and the further tube restraint plates, if any, and auxiliary tube restraint plates, if any, are positioned so that they will engage (contact) (abut) respective tubes of the tube assemblies (to thereby constrain the tubes more firmly in place). Preferably, the positions of (at least some of) the tube restraint plates can be, and are, adjusted so as to achieve this.

This is preferably done by adjusting the positions of the base plate and tube restraint plate assemblies (and their corresponding distal end support plates), and/or of the further tube restraint plates, on the outer surface support plates, for example by moving them in one axial direction or the other so as to move the tube restraint plates of the base plate and tube restraint plate assemblies, and/or the further tube restraint plates, into appropriate contact with tubes of the tube module. Once positioned, the base plate and tube restraint plate assemblies (and their corresponding distal end support plates), and/or the further tube restraint plates, can be, and are preferably, fixed in place, preferably by fixing them to the outer surface support plates.

Thus the base plates of the base plate and tube restraint plate assemblies and the corresponding distal end support plates once in position and engaged with the outer surface support plates, can be, and are preferably adjusted and moved in the direction of the length of the base plates of the base plate and tube restraint plate assemblies so as to bring the tube restraint plates of the base plate and tube restraint plate assemblies into contact with tubes of the tube module.

Once a base plate and corresponding distal end support plate have been moved in a lengthwise direction to adjust the positions of the tube restraint plates of a base plate and tube restraint plate assembly in this way, then the base plate and corresponding distal end support plate can be, and are preferably, fixed in place (on the outer surface support plates), so as to thereby correspondingly hold and fix the tube restraint plates in their (adjusted) positions.

In the case where only further tube restraint plates without auxiliary tube restraint plates are to be (or have been) inserted and mounted on the outer support plates and tube restraint plates of a base plate and tube restraint plate assembly, this adjustment of the base plate and the corresponding distal end support plates in the direction of the length of the base plates and subsequent fixing in place can be carried out either before or after the further tube restraint plates are inserted and mounted on the outer support plates and tube restraint plates of a base plate and tube restraint plate assembly.

However, in the case wherein (at least one) further tube restraint plate and auxiliary tube restraint plate assembly is to be inserted, this adjustment of the base plate and the corresponding distal end support plates in the direction of the length of the base plate and subsequent fixing is preferably carried out before any further tube restraint plate and auxiliary tube restraint plate assembly or assemblies is inserted and mounted on the outer support plates and tube restraint plates of a base plate and tube restraint plate assembly.

The base plate and tube restraint plate assemblies and distal end support plates can be fixed in place in any suitable and desired manner. For example, this can be done by shimming (and using appropriate shims). In a particularly preferred embodiment, this is done by welding (with or without shimming) the base plates of the base plate and tube restraint plate assemblies and the tube restraint plate distal end support plates, to the outer surface support plates that are mounted to the tubes of the tube module once the tube restraint plates of the base plate and tube restraint plate assemblies have been moved into position. This will then allow the tube restraint plates of the base plate and tube restraint plate assemblies to constrain movement of the tubes of the tube module in the relevant direction.

In a preferred embodiment the further tube restraint plates once in position and engaged with the outer surface support plates, correspondingly can be, and are preferably, adjusted and moved in the direction of the length of the outer surface support plates so as to bring the further tube restraint plates into contact with the tubes of the tube module.

Again, once a further tube restraint plate has been moved in a direction along the length of the outer surface support plates to adjust the position of the further tube restraint plate in this way, then the further tube restraint plate is preferably fixed in place (on the outer surface support plates), so as to thereby correspondingly hold and fix the further tube restraint plate in its (adjusted) position.

Again, in the case where only further tube restraint plates without auxiliary tube restraint plates are to be (or have been) inserted and mounted on the outer support plates and tube restraint plates of a base plate and tube restraint plate assembly, this adjustment of the further tube restraint plates in the direction of the length of the outer surface support plates (and subsequent fixing in place) can be carried out either before or after the base plate and the corresponding distal end support plates have been adjusted in the direction of the length of the base plates and subsequent fixed in place (as described above).

However, in the case wherein (at least one) further tube restraint plate and auxiliary tube restraint plate assembly is to be inserted, adjustment of further tube restraint plate and auxiliary tube restraint plate assemblies in the direction of the length of the outer surface support plates (and subsequent fixing in place) is preferably carried out after the base plate and the corresponding distal end support plates have been adjusted in the direction of the length of the base plates and fixed in place.

Again, the further tube restraint plates can be fixed in place in any suitable and desired manner, for example by shimming. Again, in a particularly preferred embodiment this is done by welding the further tube restraint plates to the outer surface support plates once the further tube restraint plates have been moved into position.

In a particularly preferred embodiment, each further tube restraint plate is adjusted and then fixed individually in this manner. Thus in a particularly preferred embodiment, a base plate and tube restraint plate assembly and its corresponding distal end support plate is adjusted such that the tube restraint plates of the assembly engage the tubes of the tube module appropriately and is then fixed in place, with the corresponding further tube restraint plates that lie crosswise across the tube restraint plates of the base plate and tube restraint plate assembly then being individually adjusted to constrain the tubes from the relevant side with the base plate and tube restraint plate assembly and its corresponding distal end support plate stationary, and then fixed in place.

Alternatively, as discussed above, in the case where only further tube restraint plates without auxiliary tube restraint plates are to be mounted on the outer support plates and tube restraint plates of a base plate and tube restraint plate assembly, the further tube restraint plates could be interlocked with the base plate and tube restraint plate assembly in question in such a way that movement of the base plate and tube restraint plate assembly in the relevant direction (in a direction along the length of the outer surface support plates) moves the further tube restraint plates correspondingly. In this case therefore the entire assembly of the further tube restraint plates and the base plate and tube restraint plate assembly can be moved together in a direction along the length of the outer surface support plates to adjust the positions of the further tube restraint plates in the desired manner. In such an arrangement, it may then only be necessary to fix the base plate and tube restraint plate assemblies and the corresponding distal end support plates in place to the outer surface support plates, rather than also having to fix the further tube restraint plates to the outer surface support plates.

In the case where further tube restraint plates are arranged on both sides of the tubes (in the relevant, e.g. width) direction, then, as discussed above, the set of further tube restraint plates on one side of the tubes may be interlocked with the base plate and tube restraint plate assemblies so as to be fixed relative to those assemblies in this manner, with the other set of further tube restraint plates (for the other sides of the tubes) then being individually movable and adjusted and fixed in place. In the case where a further tube restraint plate of a further tube restraint plate and auxiliary tube restraint plate assembly is arranged on one side of a tube, and another further tube restraint plate (without auxiliary tube restraint plates) is arranged on the other side of the tube, the further tube restraint plate of the further tube restraint plate and auxiliary tube restraint plate assembly may be interlocked with the base plate and tube restraint plate assembly so as to be fixed relative to that assembly (preferably once the adjustment of the base plate and tube restraint plate assembly in the lengthwise direction of the base plate has been carried out), with the further tube restraint plate (without auxiliary tube restraint plates) (for the other side of the tube) then being individually movable and adjusted and fixed in place.

It will be appreciated in this regard that all welding operations to fix the base plates of the base plate and tube restraint plate assemblies, the tube restraint plate distal end support plates and the further tube restraint plates once positioned can be achieved from the outer surface of the tube module, without the need for any access to the interior of the tube module. In a preferred embodiment, the overall tube restraint construction (assembly) also includes (and uses) tabs at appropriate positions to set positions for welding.

It will be appreciated that in these arrangements, there may be a need to adjust the positions of the base plates, tube restraint plate distal end support plates, and the further tube restraint plates relative to the outer surface support plate so as to position the tube restraint plates appropriately. The engagement and locking mechanisms between the base plates, tube restraint plate distal end support plates, the further tube restraint plates, and the outer surface support plates (that are mounted to tubes of the tube assembly) are all preferably configured and arranged to allow for such adjustment when engaged and in use. This can be achieved in any suitable and desired manner.

For example, and preferably, the notches via which the respective plates engage each other (e.g. that receive (interlock) the ends of the base plates and the outer surface support plates, that receive (interlock) the ends of the tube restraint plate distal end support plates and the outer surface support plates, and that receive (interlock) the ends of the further tube restraint plates and the outer surface support plates) are preferably sized so as to allow some (appropriate) (relative) movement and adjustment of the position of the plates within the notches. Thus the notches may not provide a tight fit for receiving, e.g., the ends of the plates, but may be of a width to allow the plates to have some relative movement to each other in the appropriate direction or directions for adjustment purposes.

Correspondingly, the engagement of the distal ends of the tube restraint plates of a base plate and tube restraint plate assembly with a tube restraint plate distal end support plate is preferably so as to effectively fix the tube restraint plate distal ends in place relative to the tube restraint plate distal end support plate (i.e. with there being substantially no relative movement possible between the tube restraint plate distal ends and the tube restraint plate distal end support plate (in contrast to the engagement with the outer surface support plates that will allow some relative movement and adjustment)). This is so as to ensure that any movement of the tube restraint plate distal end support plate is transferred (directly) to the distal ends of the tube restraint plates (and vice-versa).

Thus, for example, the notches that facilitate engagement between the distal ends of the tube restraint plates of a base plate and tube restraint plate assembly and a tube restraint plate distal end support plate are preferably configured to have a much tighter fit (and to prevent relative movement within the notches, for example), as compared to the notches that interlock the base plates and the tube restraint plate distal end support plates with the outer surface support plates (for example) (which notches are then configured so as to allow some relative movement within the notch between the base plate and the other surface support plates, and correspondingly between the corresponding tube restraint plate distal end support plate and the outer surface support plates, in the desired (e.g. base plate lengthwise) direction or directions.

In one preferred embodiment, an elongate (and flat) shield plate is mounted to and fixed to the upstream ends (in terms of the gas flow direction) of the base plate (of a base plate and tube restraint plate assembly) and distal end support plate (once the tube restraint assembly has been fixed in place). These elongate shield plates are preferably configured so as to cover the outer surface support plates on the upstream side of the tube module (and any mounts for those outer surface support plates), so as to provide, for example, and preferably, further protection to the outer surface support plates, their mounts, and the tube restraint assembly from erosive constituents in the gas flow in use. Preferably these shield plates are appropriately welded to the upstream ends (in terms of the gas flow direction) of the base plate (of a base plate and tube restraint plate assembly) and distal end support plate. Such shields will only be required in some cases, for example when a gas flow contains a erosive constituents such as ash. For a HRSG receiving exhaust gas from a gas turbine, shields would not be required as there is no erosive component in the gas flow.

A number of preferred embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Figure 1 shows schematically a heat recovery steam generator that the embodiment of the present invention may be used in;

Figures 2 and 3 show schematically a tube module of a heat recovery steam generator that the present embodiment may be used for;

Figures 4 to 11 show the components of the tube restraint system of the present embodiment; and

Figures 12 to 22 show schematically the installation of the tube restraint system of the present embodiment.

Figures 23 to 25 show components of the tube restraint system in another embodiment.

Figures 26 to 28 show schematically the installation of the tube restraint system of the another embodiment.

Figure 29 shows a component of the tube restraint system in yet another embodiment.

Figures 30 to 31 shows schematically the installation of the tube restraint system of the yet another embodiment.

Like reference numerals are used for like components throughout the Figures, where appropriate.

Figure 1 shows schematically a heat recovery steam generator or boiler. As shown in Figure 1, hot gas 1 enters a gas path construction (chamber) 2 and flows over a sequence of tube modules 3 that carry water and/or steam to be heated by the hot gas 1. The steam exiting the tube modules 3 passes through a steam turbine 4 to generate electricity and is then condensed in a condenser 5 for returning to the tube modules for heating by the gas flow 1.

Each tube module 3 in the gas path comprises an array of parallel tubes, each containing water and/or steam (when in use). In the present embodiments, the tubes of the tube modules are arranged vertically in the gas path chamber 2. Figure 2 shows the cross section of one of the tube modules 3 in the plane perpendicular to the length of the tubes of the tube module. As can be seen from Figure 2, the tube module 3 comprises an array of tubes 20 having appropriate gaps 21 between them to allow the heated gas 1 to flow between the tubes and thereby heat the water/steam that is in the tubes.

As can be seen from Figure 2, the tube module 3 will have a width direction 22 extending perpendicular to the gas flow 1 and a depth direction 23 parallel to the gas flow direction 1, and will correspondingly have a front side 24 and a rear side 25 relative to the gas flow.

Figure 3 is a perspective view of the tube module 3 and shows the array of parallel tubes with the tubes extending in the vertical (height) direction 30.

Figure 3 also shows a tube restraint system 31 of an embodiment of the invention arranged on the tube module 3 to maintain the positions of the tubes in the tube module 3 and constrain movement of the tubes in the tube module 3 when in use.

The configuration and installation of the tube restraint system 31 of the present embodiment will now be described in more detail with reference to Figures 4 to 12.

In general, the tube restraint system 31 of the present embodiment provides a tube restraint system that can be retrofitted to in situ tube modules via and accessing only the front and rear surfaces of a tube module. This then facilitates retrofitting of tube restraints to the tube module, notwithstanding the restricted access to the interior of the tube module once the tube module is in place in a power plant. In general, and as will be discussed further below, the tube restraint system of the present embodiment provides an interlocked grid of tube restraints that can be assembled and fixed in place whilst requiring access only to and via the front and rear surfaces of the tube module.

Figures 4 to 11 show the individual components of the interlocking tube restraint system of the present embodiment.

The tube restraint system of the present embodiment comprises a number of components that can be individually inserted into a tube module and then interlocked together to provide an interlocked tube restraint system that can be arranged against the tubes of a tube module and fixed to the tube module.

The tube restraint system of the present embodiment comprises firstly one or more, and preferably a plurality of, base plate and tube restraint plate assemblies 40, each of which comprise an elongate flat base plate to which is mounted a plurality of spaced apart elongate flat tube restraint plates extending perpendicularly from the base plate.

Figure 4 illustrates this, and shows a base plate and tube restraint plate assembly 40, comprising a base plate 41 and a plurality of perpendicular tube restraint plates 42 that are mounted and fixed to the base plate 41 at a spacing corresponding to the pitch of the tubes in the tube module to which the tube restraint system is to be fitted.

As shown in Figure 5, in the present embodiments, the base plate 41 includes appropriate notches 44 for receiving the tube restraint plates 42. The tube restraint plates 42 are then welded to the base plate 41 to provide an integral base plate and tube restraint plate assembly 40.

Figure 6 correspondingly shows the profile of the tube restraint plates 42 attached to the base plate 41.

The system also comprises a corresponding number of elongate flat tube restraint plate distal end support plates 70, having the form shown in Figure 7, that are used to support the distal (the free) ends of the tube restraint plates 42 of the base plate and tube restraint plate assemblies 40 when in position in a tube module. As can be seen from Figure 7, the tube restraint plate distal end support plates 70 include a corresponding set of notches 71 for receiving the distal ends of the tube restraint plates 42 when in position in a tube module.

It can be seen that the distal end support plate 70 has the same profile, notch configuration, etc. as the base plate 41 of the base plate and tube restraint plate assemblies 40.

The tube restraint system of the present embodiment further comprises respective pairs of elongate flat outer surface support plates 80, of the form shown in Figure 8. These outer surface support plates are mounted on the front and back surfaces of the tube module, and are used, as will be discussed in more detail below, to support, inter alia, the base plate and tube restraint assemblies 40 and distal end support plates 70.

As shown in Figure 8, the outer surface support plates 80 have respective notches 81 at their ends for receiving the ends of the base plates 41 and the distal end support plates 70, and in particular for engaging with notches 43 in the ends of the base plates 41 , and the notches 72 in the ends of the distal end support plates 70, so as to thereby interlock the outer surface support plates 80 and the base plates 41 and distal end support plates 70 when in position within a tube module.

Each outer surface support plate 80 also includes a respective pair of notches 82 for fitting over and engaging with a tube lug or clip 90 (Figure 9) that can be fixed to a tube of a tube module for then mounting the outer surface support plate 80 on the tube of the tube module.

The tube restraint system of the present embodiment further comprises a plurality of elongate flat further tube restraint plates 100, of the form shown in Figure 10. These further tube restraint plates 100 are positioned, in use, across the tube restraint plates 42 of the base plate and tube restraint plate assemblies 40 so as to provide an interlocking grid of tube restraint plates within the tube module.

Accordingly, as shown in Figure 10, the further tube restraint plates 100 include a sequence of notches 101 that will receive the tube restraint plates 42 of the base plate and tube restraint plate assemblies 40 when in position within a tube module. The further tube restraint plates 100 also comprise appropriate notches 102 at their ends for engaging and interlocking the further tube restraint plates 100 with the outer surface support plates 80.

Finally, the system of the present embodiment optionally comprises one or more elongate flat shield plates 110 as shown in Figure 11 (depending on the gas flow constituents). These are mounted on the protruding ends of the upstream ends (relative to the gas flow direction) of the base plates 41 and distal end support plates 70 on the front side of the tube module once the system is in place, to provide protection to the support plates 80 and tube mounts 90 on the front side of the tube module.

All of the plates are constructed from appropriate flat plate material, such as carbon steel or stainless steel of suitable grade (e.g. depending on the prevailing gas temperature and constituents).

The method for installing the tube restraint system of the present embodiment in a tube module in situ (in a power plant) will now be described with reference to Figures 12 to 22.

Figure 12 shows a cross section of the tube module 3 in the plane perpendicular to the longitudinal axes of the tubes with the tube restraint system of the present embodiment installed.

As shown in Figure 12, in the present embodiment, the tube restraints are fitted to the tube module 3 by fitting four respective sets of base plate and tube restraint plate assemblies 120, 121, 122 and 123 across the width of the tube module. The respective base plate and tube restraint plate assemblies are installed in the directions shown by the arrows 124.

Each respective base plate and tube restraint plate assembly (and its corresponding additional support plates, etc.) is installed in the same manner in the tube module 3. This operation will now be described with reference to Figures 13 to 22.

Each of Figures 13 to 22 shows, as appropriate, cross-section, front side, perspective and/or detail views of the tube module and tube restraint system installation, as the installation proceeds.

The installation (fitting) process starts by fixing, preferably by welding, appropriate outer surface support plate mounts 90 to tubes 21 at the front and rear of the tube module 3 (Figure 13).

Appropriate outer support plates 80 are then mounted on the mounts 90 at the front and rear of the tube module (Figure 14).

A tube restraint plate distal end supporting plate 70 is then inserted between the tubes of the tube module from the front side (or the rear side) of the tube module 3, and mounted on and interlocked with the outer surface support plates 80 at the front and rear of the tube module using the respective sets of notches 81 , 72 (Figure 15).

The base plate and tube restraint plate assembly 40 is then inserted into the tube module. This is done by aligning the tube restraint plates 42 of the base plate and tube restraint plate assembly 40 vertically (parallel to the lengths of the tubes) and inserting them through (and in) the vertical gap between the tubes when so-aligned (Figure 16).

Once the base plate and tube restraint plate assembly 40 has been completely inserted through (into) the tube module 3 (in the depth (gas flow) direction), it is then rotated 160 through 90° (Figure 16) so that the tube restraint plates 42 of the base plate and tube restraint plate assembly 40 extend horizontally (in the width direction) between the tubes of the tube assembly and the ends of the tube restraint plates 42 engage and rest in the notches 71 of the distal end support plate 70 (Figure 17). The base plate 41 is correspondingly mounted on and interlocked with the outer surface support plates 80 at the front and rear sides of the tube module using the respective notches 43, 81. This is done for each base plate and tube restraint plate assembly across the width of the tube module (Figures 18 and 19).

Once each base plate and tube restraint plate assembly 40 and its corresponding distal end support plate has been installed in position in this manner, then the further tube restraint plates 100 are installed, by inserting those plates in the depth direction between the tubes of the tube module and interlocking them with the tube restraint plates 42 of the base plate and tube restraint plate assembly 40 and the outer surface support plates 80 using the appropriate notches 100, 102 and 81 (Figure 20). Again, this is done for each base plate and tube restraint plate assembly across the width of the tube module.

At this point, for each base plate and tube restraint plate assembly there will be an interlocking grid of the base plate 41, tube restraint plates 42 and distal end support plate 70, and further tube restraint plates 100 supported on the outer surface support plates 80. The base plate 41 and distal end support plate 70 of the interlocked assembly are preferably then moved in the depth direction (e.g. by pulling or pushing them from the front side of the tube module 3) so as to bring the tube restraint plates 42 of the base plate and tube restraint plate assembly 40 extending in the width direction into engagement with (into contact with) the appropriate side (which in Figure 12 is illustrated as being the rear side) of the tubes of the tube module. This then constrains the tubes of the tube module from that side.

As can be seen from Figures 5, 7 and 8, for example, the notches that support and engage the base plate 41 and the distal end support plates 70 (and the further tube restraint plates 100) on the outer surface support plates 80 are sized so as to permit some relative movement of the base plate 41 and distal end support plate 70 in the depth direction relative to the outer surface support plates 80 for this purpose.

Once the interlocking grid of the base plate 41, tube restraint plates 42 and distal end support plate 70 and further tube restraint plates 100 mounted on the outer surface support plates 80 has been positioned in this manner, then the base plate 41, tube restraint plates 42 and distal end support plate 70 assembly is fixed in place, by welding the ends of the base plate 41 and of the distal end support plate 70 to the outer surface support plates 80 at the front and rear sides of the tube module. Next, each further tube restraint plate 100 has its position adjusted in the widthwise direction so that it will abut the tubes from the appropriate side, and is then fixed in place by welding it (its ends) to the outer surface support plates 80 at the front and rear of the tube module.

Once this is done, as can be seen from Figure 20, each tube 21 will be constrained by tube restraint plates on three sides.

Once this is done, a shield plate 110 (if required) is mounted (welded) to the protruding ends 210, 211 of the base plate 41 and distal end support plate 70 at the front of the tube module (Figure 21). The width of the shield plate 110 (in the vertical direction when installed) is greater than the width of the outer surface support plates 80, so as to offer protection to the outer surface support plates and the tube mounts 90 at the front of the tube module.

Figure 22 shows the welding tabs where the various plates are welded together. (It should be noted that the tabs fixing the depthwise position of the the base plate, distal end support plate and further tube restraint plates are welded before the front shield is fitted and welded.)

This completes the installation of the tube restraint system.

The tube restraint system may be installed at a plurality of different positions along the length of the tube module 3 so as to provide appropriate restraint and support along the length of the tube module.

Figures 23 to 25 show components of the tube restraint system in another embodiment.

Figure 23 shows a tube restraint plate distal end support plate 70a according to the another embodiment. Similarly to the tube restraint plate distal end support plate 70 shown in Fig. 7, the tube restraint plate distal end support plate 70a of this embodiment includes the set of notches 71 for receiving the distal ends of the tube restraint plates 42 when in position in a tube module. However, the tube restraint plate distal end support plate 70a also includes a second set of notches 71a (interleaved with the first set of notches 71), for receiving distal ends of auxiliary tube restraint plates (described below).

Figure 24 shows a further tube restraint plate 100a. Similarly to the further tube restraint plate 100 shown in Fig. 10, the further tube restraint plate 100a includes a sequence of notches 101 that will receive the tube restraint plates 42 of the base plate and tube restraint plate assemblies 40 when in position within a tube module. However, the further tube restraint plate also includes a second set of notches 101a, interleaved with the sequence of notches 101, for mounting or interlocking with auxiliary tube restraint plates.

Fig. 25 shows a further tube restraint plate and auxiliary tube restraint plate assembly 250a comprising the further tube restraint plate 100a and plurality of perpendicular auxiliary tube restraint plates 101b that have been mounted and fixed to the further tube restraint plate 100a in slots 101a, at a spacing corresponding to the pitch of the tubes in the tube module to which the tube restraint system is to be fitted. The auxiliary tube restraint plates 101b have a relatively short length, so as to extend across only (not more than) a single tube of the tube module when installed (as described below).

The installation of the auxiliary tube restraint plate assembly 250a will now be described with reference to Figs. 26 to 28.

As shown in Fig. 26, the outer support plates 80, tube restraint plate distal end supporting plate 70a, and base plate and restraint plate assembly including tube restraint plates 42 have already been mounted onto the tube assembly (in the manner described above and shown in Figs. 12 to 17).

The further tube restraint plate and auxiliary plate assembly 250a is then inserted into the tube module (Figure 26). This is done by aligning the auxiliary tube restraint plates 101b of the further tube restraint plate and auxiliary tube restraint plate assembly 250a vertically (parallel to the lengths of the tubes) and inserting them through (and in) the vertical gap when so -aligned. Once the further tube restraint plate and auxiliary plate assembly 250a has been completely inserted through (into) the tube module 3 (in the depth (gas flow) direction) such that the further elongate tube restraint plate 100a of the assembly extends in a direction parallel to the longitudinal axis of the base plate 41, it is then rotated through 90° so that the further tube restraint plate 100a extends horizontally (in the depth direction) between the tubes of the tube assembly (parallel to the base plate 41) and the axillary tube restraint plates extend (in the width direction) parallel to the tube restraint plates 42. The auxiliary tube restraint plates 101b each extend across only a single tube.

The further tube restraint plate 100a of the further tube restraint plate and auxiliary plate assembly 250a is interlocked with the tube restraint plates 42 of the base plate and tube restraint plate assembly 40 and the outer surface support plates 80 using the appropriate notches 100, 102 and 81 (Figure 26). This process is repeated for each further tube restraint plate and auxiliary tube restraint plate assembly 250a being installed.

The leftmost and rightmost tube restraint plate and auxiliary tube restraint plate assemblies 250a are installed by the same process, whilst also interlocking the ends of the auxiliary tube restraint plates 101b with the tube restraint plate distal end supporting plate 70a via the notches 71a.

Once each further tube restraint plate and auxiliary tube restraint plate assembly 250a has been installed, other further tube restraint plates 100a are installed (Fig 27) by inserting those plates in the depth direction between the tubes of the tube module and interlocking them with the tube restraint plates 42 of the base plate and tube restraint plate assembly 40 and the outer surface support plates 80 using the appropriate notches 100, 102 and 81, and with the auxiliary tube restraint plates 101b of the further tube restraint plate and auxiliary tube restraint plate assembly 250a using the appropriate notches 101a.

The interlocking of the further tube restraint plates 100a with the auxiliary tube restraint plates 101b of the further tube restraint plate and auxiliary tube restraint plate assembly 250a is shown in more detail in Fig. 28. As can be seen in Fig. 27, once this has been done, each tube will be constrained by tube restraint plates on four sides.

Fig. 29 shows a further tube restraint plate and auxiliary tube restraint plate assembly 290a according to yet another embodiment of the present invention. Compared to the further tube restraint plate and auxiliary tube restraint plate assembly 250a (shown in Fig. 25), the auxiliary tube restraint plates 101c are longer, such that they extend across a plurality of tubes of the tube module when installed, and are mounted at a point along their length such that they include a back-extending portion 101 d.

The installation of the auxiliary tube restraint plate assembly 250a will now be described with reference to Figs 30 and 31.

As shown in Fig. 30, the outer support plates 80, tube restraint plate distal end supporting plate 70a, and base plate and restraint plate assembly including tube restraint plates 42 have already been mounted onto the tube assembly (in the manner described above and shown in Figs. 12 to 17).

The further tube restraint plate and auxiliary plate assembly 290a is then inserted into the tube module (Figure 30). This is done by aligning the auxiliary tube restraint plates 101b of the further tube restraint plate and auxiliary tube restraint plate assembly 250a vertically (parallel to the lengths of the tubes) and inserting them through (and in) the vertical gap when so -aligned. Once the further tube restraint plate and auxiliary plate assembly 250a has been completely inserted through (into) the tube module 3 (in the depth (gas flow) direction) such that the further elongate tube restraint plate 100a of the assembly extends in a direction parallel to the longitudinal axis of the base plate 41, it is then rotated through 90° so that the further tube restraint plate 100a extends horizontally (in the depth direction) between the tubes of the tube assembly (parallel to the base plate 41) and the auxiliary tube restraint plates extend (in the width direction) parallel to the tube restraint plates 42. The auxiliary tube restraint plates each extend across a plurality of tubes.

The further tube restraint plate 100a of the further tube restraint plate and auxiliary plate assembly 290a is interlocked with the tube restraint plates 42 of the base plate and tube restraint plate assembly 40 and the outer surface support plates 80 using the appropriate notches 100, 102 and 81.

The ends of the auxiliary tube restraint plates 101c, 101 d interlock with the tube restraint plate distal end supporting plate 70a via the notches 71a.

Once each further tube restraint plate and auxiliary tube restraint plate assembly 250a has been installed, other further tube restraint plates 100a are installed (Fig 31) by inserting those plates in the depth direction between the tubes of the tube module and interlocking them with the tube restraint plates 42 of the base plate and tube restraint plate assembly 40 and the outer surface support plates 80 using the appropriate notches 100, 102 and 81, and with the auxiliary tube restraint plates 101b of the further tube restraint plate and auxiliary tube restraint plate assembly 250a using the appropriate notches 101a.

As can be seen in Fig. 31 , once this has been done, each tube will be constrained by tube restraint plates on four sides

It will be appreciated from the above that the present embodiment and the present invention is particularly applicable to the retro-fitting of tube restraints to tube modules in a power plant (i.e. when the tube module is already installed in the power plant). However, the tube restraint system and installation method of the present embodiment and the present invention could also be used for new builds in a factory setting, if desired.

Also, although the present embodiment has been described primarily with reference to the tubes of the tube module being in a vertical orientation in the power plant, the present embodiment and present invention is equally (and correspondingly) applicable to arrangements where the tube modules are arranged horizontally (or otherwise) in the power plant.

It can be seen from the above, that the present invention, in its preferred embodiments at least, provides an improved system for retrofitting tube restraints to in situ tube modules, in particular in which installation and welding operations are only required at the front and rear of the tube module (i.e. where there is good access).

This is achieved, in the preferred embodiments of the present invention at least, by using interlocking slotted sections of flat plate to form an interlocked assembly, which when fitted, has adjustment in two planes (to ensure fit-up to the tubes), thereby facilitating tube alignment and restraint through the depth of the tube module, whilst requiring access only at and through the front and rear of the tube module.