The invention to which this application relates is apparatus of a type which is commonly known in the industry as a“hang off’ apparatus which is provided as an assembly for location with one or more cables so as to retain the cable in a substantially fixed position with respect to a structure in which the same is installed. In particular, although not necessarily exclusively, the hang off assembly is provided to be used as part of an installation of a wind turbine so as to locate and retain the cable in position with respect to an interior chamber of the wind turbine and in one embodiment, with respect to a floor of said interior chamber. Yet further, the invention is particularly, although not necessarily, exclusively for use in relation to wind turbines which are installed in an environment in which the cables can be adversely affected by corrosive environmental conditions such as in an offshore location.

The cables in question can be those which are required to be used to transfer power which is generated by the wind turbine to a remote location from which the electrical power can be distributed. Alternatively, or in addition, and as non-limiting examples the one or more cables can be used to transfer data (via fibre optics ) and/ or fluids such as oils and coolants. In environments where corrosion is a significant problem, the hang off assembly is required to be able to both locate and retain the cables in position and also prevent, or minimise, the ingress of air and/ or water which, if not restricted would cause corrosion of said cables and/or other components of the wind turbine.

The provision of hang off assemblies is well-known and conventionally, the hang off assembly comprises a plurality of components which, when located together, form a cavity in which a length of the cables are located and retained and, into said cavity, there is introduced a resin material which serves to seal the cavity with the cables therein and, in turn, seal the same from the corrosive environment. The resin in combination with the assembly effectively acts as a plug in the aperture in the floor of the wind turbine in which the hang off assembly is located and through which aperture the cables pass.

It will therefore be appreciated that when forming the assembly, the size of the aperture in the floor which is required to be formed both to receive the cable therethrough and the assembly therein, is greater than the area which is subsequently taken up by the cables once in position and so the resin is used to fill the gap between the exterior wall of the cables and the internal wall of the assembly which defines a channel through which the cables pass.

While this form of apparatus is known to provide a technical solution to the problem, the use of resin material is hazardous to the health of the personnel installing the apparatus, can be expensive to use due to the particular requirements of the resin in order for it to achieve the appropriate seal between the different environments, and can be difficult to apply at the location of installation of the hang off assembly. It is also typically required that the resin is stored in specialised storage conditions.

As such, the use of the resin is not particularly attractive to the installation teams and is not particularly environmentally friendly. However, conventionally, it is believed that this is the best way in which to achieve the required seal from the corrosive environment.

Other solutions which have been attempted include the removal of resin and one such assembly is disclosed in the patent application number GB1800939.9. However, in that patent application, as can be best understood, the hang off assembly which is used, comprises a number of split or half components which are required to be positioned on either side of the cables and then clamped together to pass around the cables. It is found in practice that the provision of the interface between the split halves, provide a pathway for the corrosive air to pass through the hang off assembly and hence an inefficient seal is formed and corrosion of the cables and/ or other components of the wind turbine structure such as relatively expensive switch and/ or control gear equipment, can occur.

Further problems can also be experienced with the conventional assembly in that the weight of the same is significant and the use of welding techniques to join parts together can cause further adverse effects on the apparatus.

The aim of the present invention is therefore to provide a form of hang off assembly which allows a substantially airtight seal to be provided by the assembly without the need for a resin material to be used. A further aim is to provide the hang off assembly in a form which can be installed efficiently and effectively so as to allow the use of the same to be attractive for installation personnel.

In a first aspect of the invention there is provided apparatus in the form of a hang off assembly for use in the location and retention of one or more cables with respect to a structure, the said one or more cables pass from a first side of the structure to a second side of the structure, said assembly including a first housing for location in an aperture, said housing having a channel through which one or more cables pass, a first plate arrangement which locates around the said one or more cables, a clamping arrangement which locates around the said one or more cables, a second plate arrangement which locates around the said one or more cables and said first and second plate arrangements are axially offset with respect to the longitudinal axis of the one or more cables and wherein a second housing is provided with a channel through which the one or more cables pass and which receives sealing elements to substantially seal the space between the external wall of the one or more cables and the interior wall of said second housing.

In one embodiment the first and second housing are engaged together to form a substantially continuous channel for the one or more cables to pass therealong.

In one embodiment the first and second housings are engaged by bringing flanges at the respective ends of the housings together.

Typically the second housing is formed as a one piece structure in as much that the wall of the channel passes around the one or more cables without a break in the wall thus avoiding the need for any seals or interfaces running substantially parallel with the longitudinal axis of said cables as they pass through the channels.

In one embodiment the walls of the respective channels of the first and/ or second housings are continuous around the circumference so that there are provided no joints or interfaces along the channel of the first housing and/ or the channel in the second housing.

In one embodiment the one or more cables are passed through the channel of the first housing, and then the outer wall of the cable is removed and the cores of each cable are splayed so that the cores are spaced apart as they pass through the channel in the second housing.

In one embodiment the sealing elements are provided in a number of dimensions and sizes to allow the same to be selected for the particular installation and then packed into the channel in the second housing to provide the required sealing effect.

In one embodiment one or both of the first and second plate arrangements comprise two plate parts which are brought together to lie around the one or more cables.

In one embodiment the clamping arrangement includes first and second clamp parts and securing means which allow the clamp parts to be brought together and clamped around the one or more cables.

In one embodiment, the first side of the structure to which the assembly is fitted includes corrosion causing particles such as salt and the second side of the structure is substantially sealed from the first side. In one embodiment the said structure and the hang off assembly in accordance with the invention form a barrier between the first side with the corrosion causing environment and the second side.

In one embodiment, the structure is part of a wind turbine and yet further is a wind turbine which has been installed in an offshore location.

In one embodiment the second housing is formed of a relatively low weight material such as a nylon based material.

Specific embodiments of the invention are now described with reference to the accompanying drawings wherein

Figure 1 illustrates in a schematic manner, a wind turbine in which the hang off assembly in accordance with the invention is installed.

Figure 2 illustrates a hang off assembly formed in accordance with the invention.

Figures 3a-i illustrate the steps of installation of a hang off assembly in accordance with one embodiment of the invention.

Referring firstly to Figure 1, there is illustrated a wind turbine structure 2 which is a form of a structure in which the hang off assembly 4 in accordance with the invention is most typically, but not necessarily exclusively, installed. The purpose of the hang off assembly is to allow a cable 8 or perhaps multiple cables, to pass from the wind turbine power generating unit 6 , (which can be of a conventional form and so is not described in detail here), to carry electrical power therefrom, through the wind turbine interior 10 and then to a remote location such as a distribution network and again which can be of a conventional form and which is not described in detail.

As the cable 8 passes through the interior 10 of the wind turbine it is required to pass through a floor structure 12 which serves to separate the relatively controlled environment 14, on the second or upper side of the floor structure from the environment of the first or lower side 16 of the floor structure.

Typically, the environment on the first side 16 of the structure 12, is exposed, particularly if the wind turbine is located offshore, to relatively harsh conditions such air containing salt particles, which are particularly corrosive and which are from the seawater 18. This means that if the cable interior is exposed to these conditions, then corrosion of the cable, switch gear, control gear and/ or other components of the wind turbine structure can occur which, in turn, can cause relatively rapid failure. There is therefore a need to be able to seal exposed portions of the cable as it passes through the floor structure 12, and in general, seal off the second side 14 from the first side 16 and this can be achieved by using an assembly known as a hang off assembly 4 and details of which, in accordance with the invention, are now provided.

Figure 2 illustrates a hang off assembly 4 in accordance with one embodiment of the current invention and illustrates the manner in which the cable 8 is introduced into the assembly at the first side 16 and then passes along the longitudinal axis 20 to exit at the second side 14 and in this embodiment, the cable 8, during the progression from the first to the second side has its cores 22,24,26 separated and splayed within the hang off assembly. The cable may include additional strands or components such as a fibre optic cable 25. There may also be separation of earthing components.

Thus, in order to install the assembly, then with reference to Figures 3a-i the cable 8 is passed through a first part or housing 30 which can be welded to the floor structure 12. The first part 30 includes a channel 28 formed therein and the cable passes along said channel so that the free end 32 of the cable protrudes through the same and it should be noted that there are no joins in the wall 34 of the channel. A first plate arrangement formed of parts 38,40, is then put into position and in one example the plates may be formed of stainless steel and positioned around the cable as shown in Figure 3b and held in position using fasteners 36.

A clamp arrangement is then installed above the first plate arrangement as shown in Figures 3c and d and clamp parts 42,44 are moved into position and securing means 46 are used to secure the clamp parts together. The inner faces of the clamp parts can be serrated to allow the removal of the outer collar of the cable so that armour wires or strands 50 are exposed and placed around a plate 49 located above the clamp parts 42, 44 with the parts 42, 44 are placed in position as shown in Figure 3d to support the cable 8 in a temporary position with respect to the first housing 30 and the first plate arrangement.

Once this has been achieved, a second plate arrangement is provided formed of first and second parts 52,54 as shown in Figures 3d and 3e which are moved into a position and retained in position by securing means 56 to lie around the exterior of the cable 8 as shown in Figure 3f and the first and second plate arrangements are offset by distance X, typically achieved by the provision of the securing means 56 being secured in apertures 58 in the clamp parts , to a sufficient height so that the clamp parts 42, 44 are effectively trapped between the first and second plate arrangements. Thus, the arrangement shown in Figure 3f is achieved. This also allows the first clamp, clamping force to be removed.

At this stage, the second housing 60, which may be formed of a relatively lightweight material such as nylon so as to reduce weight, is introduced in such a manner as to cause the cores of the cable 8 to pass-through the channel 62 formed in the second housing which, once again, is formed with a continuous channel wall. The first and second housings are then moved together as indicated by arrows 64,66 to bring the respective flanges 68,70 together and the flanges are secured together using securing means 72 to provide a condition as shown in Figure 3h and it will be noted that the cores 22,24,26 by this stage are stripped and located splayed apart in the second housing channel 62. It is also noted that the first and second plate arrangements and the clamping arrangement are also located in the second channel. Thus, at this point, the assembly is mechanically secured with the cable 8 and as shown in figure 3i a sealing assembly in the form of a number of plates 74,76 which are provided as part of a closure 78 lie to the periphery of the channel 62 and the closure 78 is secured in position in the channel 62 with a number of sealing elements 80 are selectively installed in the space between the cores 22,24,26 and the plates 74,76 so as to provide the sealed sealing assembly which seals off the channel 62 when in position as shown in Figure 2.

Thus, in accordance with the invention, there is provided a housing which allows the seal to be achieved at relatively high pressures between the first and second sides of the structure in which the assembly is formed and, at the same time, ensures the required mechanical connection of the cable with the assembly and hence the structure with no interfaces in the channel parallel to the path of the cable 8 along the channel formed by first and second channels 32,63 when the first and second housings 30,60 are joined together .