Description

The invention lies within the technical field of devices for aligning and clamping contiguous tubes from the inside, which tubes are intended to be coupled in extension of one another in order to create tubular pipes. Devices of this kind, which are also referred to using the acronym ILUC (internal line-up clamp), are widely used in the laying of pipes to aid the process of joining contiguous tubes for welding, which tubes are intended specifically to form the pipe.

Traditionally, ILUCs comprise two contiguous and coaxial rings of radial expanders, which rings are spaced apart by a ring of welding support shoes. The rings of expanders are actuated by means of conical actuators or actuators having sloped surfaces which, after the relative mutual movement of the respective sloped profiles, act by expanding and, vice versa, retracting said radial expanders of each relevant ring in order to make them integral with one another from the inside and respectively free two contiguous tubes of the pipe in the joining process. The radial expanders are also designed to coaxially centre the two abutting tubes by eliminating possible local deformations, ovalizations and the like until the ends to be joined have been brought into mutual alignment.

The actuators of the radial expanders have the appreciable advantage of highly reliable functioning both when clamping and unclamping the radial expanders, but are disadvantageous in that they have large axial dimensions. Normally, therefore, the main disadvantage of these devices is their excessive length which is due, inter alia, to the actuator mechanisms which make it difficult to manoeuvre the ILUC for positioning, handling and possible recovery, in particular when laying vertical pipes.

Examples of similar devices produced according to the prior art are described in US4875615(A), US6662994(B2), US6779944(B2),

US7011244(B2) and US20170182605(A1).

W02014/056020 discloses an external aligner for flexible tubes made of a plastics material.

The possibility of using the teaching disclosed in WOO20 in an ILUC would lead to the motors of the actuators being radially arranged. This arrangement is possible in an external aligner, where there are no limits to the increase in radial dimensions, but it is clearly not possible in an internal ILUC aligner, in which the radial dimensions are strictly limited The problem addressed by the present invention is that of providing an ILUC device that is very compact and versatile. The device is also required to be suitably equipped to allow the tubes that are to be joined to be welded in a protective atmosphere, even in the presence of strong ventilation in the pipe.

Moreover, the device is required to be able to be modularly adapted to different requirements, for example to allow cables and tubes to pass therethrough or to be fitted with a motorisation module, a plasma arc welding module, visual inspection systems or the like. Not least, it is required that the device be provided with means which allow emergency braking if the winch and/or umbilical interface driving said winch fails. This problem is solved and these aims are achieved by a device produced in accordance with the accompanying claims.

In particular, the device is actuated by a system of electric motors and gears so as to reduce the longitudinal dimensions of the actuation mechanism with respect to traditional wedge actuation. There is also a mechanism for release of the expanders by means of a wedge system, which allows the machine to be extracted from the tube if the actuation mechanism fails.

The device is also provided with a dead-man-control emergency braking system which is actuated electropneumatically if the lifting or feeding system, in particular the umbilical which both supports the machine and feeds the braking system, fails, thereby preventing the device from falling uncontrollably into the pipe.

The features and advantages of the invention will become clearer from the following detailed description of a preferred but not exclusive embodiment thereof, shown by way of non-restrictive example and with reference to the accompanying drawings, in which:

- Fig. 1 is a side elevation of the device according to the invention;

- Fig. 2 is a sectional view along the line II-II in Fig. 1;

- Fig. 3 is a perspective view of the same device;

- Fig. 4 and 5 are a perspective view and sectional view, respectively, of a detail of the device of this invention;

- Fig. 6 to 8 are sectional views of the same detail in different operating phases;

- Fig. 9 and 10 are sectional views of another detail of the same device in two operating phases.

In the drawings, the reference numeral 1 indicates, as a whole, a device for aligning contiguous tubes Tl, T2, Tn for laying tubular pipes T.

The device 1 comprises four contiguous modules, respectively a front module 2, central module 3, rear module 4 and an emergency braking module 5. The front module includes a frame 6 that has a flange 7 to which an umbilical interface 71 connects that is used to hold the device 1 once inserted into the pipe T. The umbilical interface 71 is used to supply energy and working fluids, for example compressed air, to the device 1.

The front module 2 is connected to the central module 3 on the opposite side to the flange 7. The central module 3 comprises at least two contiguous modules 8 of radial expanders 9. The radial expanders each comprise a shoe 10 that is intended to be pressed against the internal wall of the tube Tn and Tn+1 and is each associated with a corresponding actuator in order to expand and, vice versa, retract the radial expanders towards and from the wall of the contiguous tubes of the pipe in the process of joining said tubes.

Each actuator comprises a screw 11 and female screw 12 device, the screw (or female screw) of which is translatably integral with the relevant shoe 10 by means of a clamping screw 17 while the corresponding female screw 12 (or screw) is actuated by a transmission 13 by means of at least one electric motor 14.

The transmission 13 comprises a gear 15 that has, on one side close to the front module 2 (on the same side in which the electric motors 14 are located), a cylindrical ring gear 16 with which respective pinions 18 of the electric motors 14 are meshingly engaged. A ring bevel gear 20 is formed on the side opposite the gear 15, with which ring bevel gear respective bevel pinions 21 are meshingly engaged, one for each screw and female screw actuator. The pinions 21 are integral with the screws of each actuator; alternatively, however, the reverse is possible.

All the screws 11 are rotationally synchronised by means of this meshing.

Each pinion 21 is in turn supported on a relevant pin 22 that extends radially from a runner 23. The assembly of runners 23 forms a contractible collar, the surface of which opposite the pins 22 is conical. Said collar of runners 23 is mounted on a conical wedge 24 such that the relative axial movement between collar and runners involves the radial expansion or retraction of the runners and the consequent engaging / disengaging of the shoes 10 from the wall of the pipe T.

The two wedges are interconnected by a right-hand/left-hand double- threaded screw 46 (as is often the case in turnbuckles for cables) which is actuated into rotation by a pneumatic motor 26 such that the wedges are pushed in opposite directions from one another for the emergency disengagement of the shoes 10 from the wall of the tubes T. Alternatively, it is possible to provide a system comprising a joint that holds the two central wedges in an overlapping position. When the machine is being driven by means of the umbilical, if a determined pulling force is exceeded, the disconnection of the joint causes the internal wedges to move apart on account of the expansion force which is exerted on the sloped surface, and therefore causes the disengagement of the shoes. The joint in question can be a breakaway screw joint or spring joint.

It is possible to insert a welding contact module 30 between the modules 8 of radial expanders, which module is produced by means of a plurality of welding shoes 31, generally made of copper, which are mounted so as to be radially contractible on a drum 32. The welding shoes 31 are secured on a piston 33 which is stressed radially outwards by springs 34 and pulled back radially inwards by means of the shoes 10 of the expanders. The welding shoes 31 move axially with respect to the machine in order to allow the shoes to be held in contact with one another, by means of sloped surfaces, and therefore to provide a continuous surface that contacts the tube over the entire expansion movement of the module.

An inflatable annular washer 35 is located close to each module of radial expanders on the two outermost sides of the central module. Once inflated inside the pipe to be welded, a discharge chamber is defined between the washers 35, in which chamber a protective atmosphere that has a low oxygen content is created by insufflation in order to prevent the metal from oxidising during welding. A third annular washer 36 is arranged on the rear module; the third washer 36 is used to isolate the welding region in the central module from the ventilation effect in the pipe.

Lastly, an emergency braking module is provided which is used to prevent the ILUC device from falling into the pipe if the umbilical interface fails.

The braking module comprises a wedge system 38, 39, the mutually contacting sloped surfaces of which actuate radially respective brake shoes 40. A series of compression springs 41 provides the resilient stress required to push the shoes 40 radially outwards. This stress is normally counteracted by a pneumatic cylinder 43 which is pressurised by means of the umbilical interface and therefore holds the brake shoes in a radially contracted position. The brake shoes are in turn individually disconnected from the control rods with which they interface by means of a sloped plane in order to guarantee the brake shoes further movement and the possibility of adapting to possible non-circularities of the tubes.

The brake shoes are held in the contracted position by means of springs, thereby avoiding dovetail machining in order to guarantee contact between the shoes 40 and the rods 39.

The wedge mechanism and the relative axial movement of the brake shoes with respect to the ILUC device during expansion involve an increase in expansion force caused by the mass of the device multiplied by the deceleration thereof, thus increasing the braking capacity, after the friction between the shoes and the surface of the tube has increased.

A quick release circuit 44 of the cylinder 43 is mounted on the module; this circuit 44 comprises a valve which is normally open and is controlled by means of two solenoid valves that are normally discharged and arranged in parallel; the valves control the discharge valve when excited by the power supply from the umbilical interface, thus controlling the closure of the controlled valve. Providing two valves in parallel increases the redundancy of the system by preventing accidental emergency braking. The valves are controlled by means of two separate electrical circuits so as to reduce undesired actuations caused by electrical failure. The braking module is terminated by a second flange 45 for possible connection to a plasma module (not shown).

Eight damped centring wheels are also provided which are distributed along the external casing of the ILUC and are used to keep the casing centred in the pipe in which it operates.

The invention designed in this way has numerous advantages over the devices produced in accordance with the prior art. These include the following :

- Longitudinal compactness due to the absence of longitudinal actuation pistons which have large longitudinal dimensions. The electric motors do not require the entire cross-sectional dimensions of the machine as is the case with pneumatic piston actuation, thereby allowing space for auxiliary devices or systems to be installed.

- Electrically actuating the expanders and the modular construction of the machine make it possible to prevent compressed air from being fed when the emergency braking module is not required (for example when used to lay S-shaped tubes).

- The braking device having an increased actuation speed with respect to the devices that are only pneumatically actuated and controlled by the pneumatic feed tube failing. The actuation speed is caused by discharging directly on the cylinder, which prevents the delay caused by the possible failure of the umbilical at a distance from the tube because it involves a delay in discharging that is caused by the presence of pressurised air in the cross section of the tube that remains connected to the machine. The presence of a redundancy on the brake control which decreases the possibility of undesired actuations of the brake itself. Wedge system for expanding the shoes which increases the braking force as a result of the action of the weight of the machine and of the deceleration thereof.

- The possibility of obtaining clear paths through the machine for tubes or cables to pass through which feed possible modules connected in series to the machine.