WO2004076118A1

WO2004076118A1 - Internal clamp for use in welding pipelines with integrated elecrical power supply

Info

Publication number: WO2004076118A1
Application number: PCT/DK2004/000125
Authority: WO
Inventors: René GRØNMARK
Original assignee: Weld-Tech Aps
Priority date: 2003-02-26
Filing date: 2004-02-25
Publication date: 2004-09-10

Abstract

A clamp (1), and a method of using said clamp, of the kind arranged for, during welding together from the outside two abutting pipe sections (3), supporting the abutting end parts of said pipe sections (3) from the inside. The clamp of the current invention differentiates itself from the currently available clamps by being powered by an electrical power supply (13) contained within the body (2) of the clamp (1). In addition, the clamp can be equipped with a wireless link (15,16). The combination of wireless link (15,16) and self contained electric power supply (13) make it possible to operate the clamp (1) without any physical connections to the clamp (1).

Description

INTERNAL CLAMP FOR USE IN WELDING PIPELINES WITH INTEGRATED ELECTRICAL POWER SUPPLY

Field of the Invention

The present invention relates to a clamp of the kind arranged for, during the welding together of two abutting pipe sections, supporting the abutting end parts of said pipe sections from the inside, said clamp comprising a self propelled carrier having wheels for supporting the clamp on the inside of the pipe sections and for moving the carrier along the pipe sections, supporting members mounted on the carrier having a supporting position, where they abut the inside of one or both end parts of the pipe sections, and a retracted position, where they are free of said insides, an actuator mechanism coupled to the supporting members for moving the supporting members to and from their two positions, and at least one electrical power supply contained within the carrier for supplying the clamp with electrical energy. The current invention also relates to a method for using the clamp when welding together said pipe sections.

^' Background of the Invention

Pipelines are built by continuously welding individual pipe sections to the end of the pipeline. Clamps, of the type mentioned above, are used to ensure that the individual pipe sections are properly joined to the end of the pipeline. These types of clamps are usually placed inside the pipes and clamp the two pipe ends together from the inside, giving free access to the outside of the pipe. Hence, they are usually called internal pipe clamps.

Pipe clamps serve three main functions. The first is to hold the pipe ends together during the welding process. The second is to ensure that the pipes are aligned. The third is to ensure that the ends of the pipes are circular during welding. Pipe ends are often slightly deformed, either from manufacturing or from transport. Also the thermal effects during welding can deform the ends. The pipe clamp holds the pipe in the desired circular shape during the welding process to ensure a good fit between the ends of the two pipe sections.

Description of the Prior Art

From US 3,197,195, is known an internal pipe clamp of the type mentioned above, which uses electrical power supplied via an electrical cable to drive an electric motor connected to a hydraulic pump. The hydraulic power supplied by the pump is used to extend and retract the clamping mechanism via hydraulic linear cylinders. A second electric motor connected to wheels supporting the clamp in the pipe is used to drive the clamp axially in the pipe.

From US 3,633,813, is known a development of the internal pipe clamp, where a portable compressed air tank was attached to the clamp frame. The pipe clamp could therefore be driven for short distances and the jaws activated without any power supplies being connected. Current internal pipe clamps used in the industry are similar to the clamp presented in US 3,633,813.

The current state-of-the-art internal pipe clamp suffers from two main problems. Firstly, air tanks cannot store much air and therefore need to be recharged via a hose connected to an external air compressor after each weld. Secondly the pipe clamp is difficult for an operator to control since it is inside the pipe.

One common solution to the second problem is a man machine interface connected to the clamp via an electrical cable. However, each time a new pipe is brought into place, the cable needs to be disconnected, fed through the new pipe and then connected to the clamp again.

Another option used is to have the man machine interface mounted on a rod extending from the end of the clamp. The rod is longer than the pipe sections so that the man machine interface extends outside the new pipe section. However, this is a problem when setting a new pipe in place due to the length of the control rod.

As can be seen from, for example US 6,169,267 and US 5,148,000, some internal welding clamps use an onboard battery for the purpose of driving the clamp forward in the pipe without requiring an electrical connection to the clamp via a wire. Batteries have also been used to power the control elements in the clamp such as valves and motors. However, a technical prejudice has existed in this field in that it has been assumed that a battery is not strong enough to drive the clamping mechanism. All known internal welding clamps with on board batteries either have an onboard air power supply or require a connection via an electrical cable to an external power supply in order to power the clamping mechanism.

Summary of the Present Invention

A first aspect of the invention is to provide a clamp of the kind mentioned in the preamble having an electrical power supply, which does not need to be disconnected each time a new pipe section is to be welded onto the pipeline.

Another aspect of the invention is to provide a clamp of the kind mentioned in the preamble having a power supply, which does not need to be recharged after having performed only one or a small number of welds. A third aspect of the invention is to provide a clamp of the kind mentioned in the preamble having a power supply, which can be easily exchanged once discharged.

A fourth aspect of the invention is to provide a clamp of the kind mentioned in the preamble, which is easy to operate.

A fifth aspect of the invention is to provide a method of the kind mentioned in the preamble, where a number of welds can be completed without disconnecting the power supply or recharging the power supply after each or only a few welds .

The new and unique way in which the current invention fulfills the above mentioned aspects is by presenting a clamp according to the opening paragraph in which said at least one electrical power supply supplies the required electrical energy to both the propulsion system of the self propelled carrier and the actuator mechanism of the supporting members.

A clamp according to this invention is therefore much more convenient to use. It is not required to fill an air tank or to disconnect and reconnect a cable after each clamping operation. In this way, the clamp according to the invention results in higher production rates.

The electrical power supply can be advantageously placed at the front of the clamp in order to permit the power supply to be conveniently removed and replaced.

For preventing the electrical power supply from being damaged or having its efficiency impaired the electrical power supply according to the invention can be thermally insulated from the clamping section, which experiences high heat during the welding process. The electrical power source of the clamp according to the current invention can e.g. be chosen as an electrical accumulator or battery, a fuel cell, or a generator powered by a combustion engine. These electrical power supplies are all of compact form such that they can be easily carried by the carrier and easily replaced by a charged one when discharged. Another advantage is that the time between necessary recharging is relatively long.

In order to make the clamp easier to control and operate, the clamp according to the current invention can be equipped with a wireless link between the controller on the clamp and a control input device. The combination of the electrical power supply contained within the carrier and the wireless link makes the clamp completely tetherless which removes the problems of long control rods or control cables.

Brief Description of the Figures

The invention will be explained in greater detail below where further advantageous properties and example embodiments are described with reference to the drawings, in which

Fig. 1 shows schematically a clamp according to the invention,

Fig. 2 shows the clamp shown in fig. 1 in a start position,

Fig. 3 shows the same in a first operation step,

Fig. 4 shows the same in a second operation step,

Fig. 5 shows the same in a third operation step, and

Fig. 6 shows the same in a fourth operation step, Description of a Preferred Embodiment of the Invention

The internal pipe clamp of fig. 1 shows a schematic representation of an example embodiment of an internal pipe clamp according to the invention.

The clamp 1 shown in fig. 1 is comprised of a self propelled carrier 2 supportable on the inside of the pipe 3 by three sets of wheels 4', 4'' and 4'''. A first electric motor 5 connected to the rear wheels 4' is provided to drive the carrier 2 inside the pipe 3. On the carrier 2 is mounted a hydraulic fluid reservoir 6, a hydraulic pump 7 powered by an second electric motor 8, and a plurality of support members 9 which can, via a hydraulic cylinder 10 based actuator mechanism 11, assume any position between an extended position where they abut against the inside of the walls of the pipe 3 and a retracted position where they are free from the walls of the pipe 3. Hydraulic connections between said hydraulic pump 7 and said hydraulic cylinder 10 of the actuator mechanism 11 are high-pressure hoses 12. A battery 13 is used to supply power to the two electric motors 5 and 8.

When the actuator mechanism 11 is expanded, as shown in fig. 1, the support members 9 are pressed against the insides of the pipes 3 holding the two pipes 3 together. In this position, the clamp 1 is centred in the pipe 2 and the wheels 4 of the carrier 2 are not touching the walls of the pipes 3. When the actuator mechanism 11 retracts, the support members 9 retract inside the carrier 2 and the wheels 4 of the carrier 2 come into contact with the walls of the pipes 3. In the retracted position, it is possible to drive the clamp 1 forwards and backwards axially in the pipe 3 by applying electrical power to the electrical motor 5 connected to the driving wheels 4' . A microprocessor-based controller 14 mounted on the clamp 1 controls how the electrical and hydraulic power is distributed to the different components of the clamp. A wireless receiver 15 establishes a wireless link between the controller 14 and a wireless transmitter 16 mounted on a control input device 17. The electrical connections between the controller 14, the drive motor 5, the hydraulic pump motor 8 and the battery 13, are electrical wires 18.

The wireless link 15 and 16 consists of a radio data link. The wireless link 15 and 16 allows control of all the major functions of the clamp: forward, stop, and reverse axial motion in the pipe 3, fine axial position control to accurately place the clamp 1 at the end of the pipe 3 , and expanding and retracting the support members 9.

The battery 13 is placed at the front of the clamp 1 to conveniently permit the battery 13 to be changed with a fresh one when it has been discharged. A heat shield 19' separates the battery 13 from the welding section 20 to prevent the high heat developed at the welding section 20 during the welding process from damaging the battery 13. A second heat shield 19'' protects the drive motor 5, the hydraulic power supply 6,7, and 8, and the controller 14 from the welding section 20.

Fig. 2 - 6 shows the clamp 1 shown in fig. 1 used during the welding together from the outside of two abutting pipe sections 3'' and 3'''. In fig. 2 is shown the start position of the clamp 1 after the pipes 3' and 3'' have just been welded together.

Fig. 3 shows the position of the clamp 1 after the clamp 1 has released the pipes 3 ' and 3 ' ' by retracting its support members 9 and has moved to the end of the pipe 3 ' ' by powering its drive wheels 4'. The clamp 1 is controlled via the wireless link 15 and 16. Fig. 4 shows the clamp 1 at the end of the pipe 3 ' ' and a new pipe section 3 ' ' ' brought into position. Fig. 5 shows the clamp 1 engaged to pipes 3'' and 3'''. Fig. 6 shows the pipes 3'' and 3''' welded together. Once the pipes 3 are welded together, the procedure is repeated.

This procedure is repeated until the battery 13 is drained. When the battery 13 is discharged, the battery 13 is replaced with a fresh battery between the steps shown in fig. 3 and fig. 4. Since the battery 13 is placed at front of the clamp 1, it is easy to take out and put a new one in.

As an example of an internal pipe clamp according to the current invention, a prototype was built as described in Fig. 1. Tests on this prototype gave the surprising result that a single automotive style battery could supply power for between 50 and 100 welds. In contrast, the current pneumatic internal pipe clamps require recharging the air tank after each weld. In effect this means that the current invention can give a performance increase of up to 100 times in comparison to the state-of-the-art .

The above description mentioned a battery used to supply the clamp with electrical power. Within the scope of the invention the electrical power could also be _* supplied by a fuel cell or a generator powered by a combustion engine.

It should also be obvious to the person skilled in the art that different electrical power supplies could be used to power different components of the clamp. For example, a first battery could power the clamping mechanism and a second battery could power the propulsion mechanism.

Claims

1. A clamp of the kind arranged for, during the welding together of two abutting pipe sections (3), supporting the abutting end parts of said pipe sections (3) from the inside, comprising a self propelled carrier (2) having wheels (4) for supporting the clamp (1) on the inside of the pipe sections (3) and for moving the carrier (2) along the pipe sections (3) , supporting members (9) mounted on the carrier (2) having a supporting position, where they abut the inside of one or both end parts of the pipe sections

(3) , and a retracted position, where they are free of said insides (3), an actuator mechanism (6,7,8,10,11,12) coupled to the supporting members (9) for moving the supporting members (9) to and from their two positions, and at least one electrical power supply (13) contained within the carrier (2) for supplying the clamp (1) with electrical energy, characterized in that said at least one electrical power supply (13) supplies the required electrical energy to both the propulsion system (4', 5) of the self propelled carrier (2) and the actuator mechanism (6,7,8,10,11,12) of the supporting members (9) .

2. The clamp of claim 1, characterized in that the electrical power supply (13) is mounted at the front of the clamp (1) .

3. The clamp of claim 1 or 2 , characterized in that it comprises heat insulation, e.g. a heat shield (19'), adapted for at least partly heat isolating the electrical power supply (13) from the influence of the heat generated during the welding together of the two pipe sections (3) .

4. The clamp of claim 1 - 3, characterized in that the electrical power supply (13) is an electrical accumulator or a battery.

5. The clamp of claim 1 - 3, characterized in that the electrical power supply (13) is a fuel cell.

6. The clamp of claim 1 - 3, characterized in that the separate electrical power supply (13) is an electrical generator driven by a combustion engine .

7. The clamp of any of the claims 1 - 6, characterized in that said clamp further comprises a control unit (14) with .a wireless receiver (15) for by means of wireless signals controlling the operation of the clamp (1) .

8. A clamp of the kind arranged for, during the welding together of two abutting pipe sections (3), supporting the abutting end parts of said pipe sections (3) from the inside, comprising a self propelled carrier (2) having wheels (4) for supporting the clamp (1) on the inside of the pipe sections (3) and for moving the carrier (2) along the pipe sections (3) , supporting members (9) mounted on the carrier (2) having a supporting position, where they abut the inside of one or both end parts of the pipe sections

(3), and a retracted position, where they are free of said insides (3) , an actuator mechanism (6,7,8,10,11,12) coupled to the supporting members (9) for moving the supporting members (9) to and from their two positions, at least one electrical power supply (13) contained within the carrier (2) for supplying the clamp (1) with electrical energy, and a control unit (14) with a wireless receiver (15) for by means of wireless signals controlling the operation of the clamp (1) , characterized in that said at least one electrical power supply (13) supplies the required electrical energy to both the propulsion system (4', 5) of the self propelled carrier (2) and the actuator mechanism (6,7,8,10,11,12) of the supporting members (9) .

9. A method for welding together from the outside two abutting pipe sections (3) by using the clamp according to claim 1 - 8, comprising the steps of moving the clamp (1) along the inside of the pipe sections (3) to a welding position by applying power to the drive mechanism (4,5) of said clamp (1), said power being applied by the electrical power supply (13), stopping the movement of the carrier (2) at the welding position by stopping power from being applied to the drive motor (5), moving supporting members (9) mounted on the carrier (2) from their retracted free position to their supporting position, by applying power to the actuator mechanism (11) coupled to the supporting members (9) , said power being applied by said electrical power supply (13) , - welding the two pipe sections (3) together, retracting the supporting members (9) to their free position by stopping the power from being applied to said actuator mechanism (11) coupled to said supporting members (9) , and repeating the steps .

0. A method for operating a welding process for welding together from the outside two pipe sections (3) by using the clamp according to claim 7 or 8, comprising the steps of, commanding the clamp (1) to move along the inside of the pipe sections (3) to a welding position, by sending a move command via a wireless signal to the wireless receiver (15) of the control unit (14), which thereby applies power to the drive mechanism (4,5) of the clamp

(1) , said power coming from the electrical power supply

(13), commanding the clamp (1) to stop at the welding position by sending a stop command via a wireless signal to the wireless receiver (15) of the control unit (14) , which thereby stops applying power to said drive mechanism (4,5), commanding the actuator mechanism (11) to move supporting members (9) mounted on the carrier (2) from their retracted free position to their supporting position, by sending an expand command via a wireless signal to the wireless receiver (15) of the control unit (14) , which thereby applies power to move the actuator mechanism (11) , said power coming from said electrical power supply (13), commanding the welding to weld the two pipe sections (3) together, commanding the actuator mechanism (11) to retract the supporting members (9) to their free position by sending a retract command via a wireless signal to the wireless receiver (15) of the control unit (14), which thereby stops applying power to the drive mechanism

(4,5) , and - repeating the steps.