EP2370724A1

EP2370724A1 - Device for centering adjacent pipes

Info

Publication number: EP2370724A1
Application number: EP09764614A
Authority: EP
Inventors: Erik Nicolaas Duin
Original assignee: Individual
Current assignee: Tecmission Bv
Priority date: 2008-11-26
Filing date: 2009-11-26
Publication date: 2011-10-05
Also published as: WO2010062177A1; NL1036246C2; RU2518705C2; NL1036246A1; RU2011125911A

Abstract

The invention concerns a device for centering adjacent pipes (18,19) comprising a number of clamps (4) with a mechanism for pressing a clamp surface in radial direction against the inside surface of a first pipe (18) and a guide (5) that has an inclined guide surface concentric with the clamp surfaces for positioning a second pipe (19). In accordance with the invention the guide comprises a number of guide pieces with a guide surface and the mechanism positions the guide surfaces in radial direction a slightly smaller radius than the clamp surface.

Description

Device for centering adjacent pipes

The invention relates to a device for centering adjacent pipes in accordance with the preamble of claim 1. Such a device is known from DE 4207375. The disadvantage of the known device is that the second pipe abuts on an inclined surface so that its position relative the first pipe is not stable. In order to overcome this disadvantage the device is in accordance with claim 1. In this way the second pipe is positioned around the guide sur- faces so that sideway movements of the pipes relative to one another are prevented.

In accordance with an embodiment the device is according to claim 2. In this way the guide surfaces always have the correct radial position relative to the clamp surfaces.

In accordance with an embodiment the device is according to claim 3. In this way the second pipe can rotate relative to the first pipe during and after centering. In accordance with an embodiment the device is according to claim 4. In this way it is easy to slide the second pipe that might rotate relative the first pipe on the guide pieces.

In accordance with an embodiment the device is ac- cording to claim 5. In this way it is easy to adjust the radial position of the clamp surface and the guide surface simultaneously.

In accordance with an embodiment the device is according to claim 6. In this way positioning and clamping the device in the first pipe simultenously positions the conical or elliptical rollers at the correct radial position . In accordance with an embodiment the device is according to claim 7. In this way by rotating the inner ring and the cam rings relative one another the number of clamps can be positioned simultaneously. In accordance with an embodiment the device is according to claim 8. In this way the cam surfaces are not subjected to wear and clamping takes place with little resistence .

In accordance with an embodiment the device is ac- cording to claim 9. In this way changes in the inner diameter of the first pipe for instance due to heating of the first pipe does not influence the tension between the clamps and the first pipe.

In accordance with an embodiment the device is ac- cording to claim 10. In this way before clamping the device in the first pipe the cam rings will be held in position .

In accordance with an embodiment the device is according to claim 11. In this way the inner ring is be- tween the pipes in a defined location.

The invention relates to a device for centering adjacent pipes. The centering device is internally fixed at the end of a first pipe, after which the centering device centers the end of a second pipe relative to the end of the first pipe. After centering the first pipe and the second pipe in an embodiment they can rotate relative to one another so that the often used name pipe coupling is misleading and will henceforth be avoided.

The centering device is used during coating of pipes with one or more layers while a conveyor transports successive pipes along a coating installation. During the coating process in the coating installation the pipes are transported in a longitudinal direction along the coating installation on the conveyor which comprises a series of wheel pairs that support the pipes. Each pipe is supported by a minimum of two wheel pairs. By putting the center line of the wheels at an angle not equal to 0 ° or 90 ° to the longitudinal direction of the pipes and driv- ing the wheels with a motor, a pipe on this conveyor will rotate and simultaneously move in its longitudinal direction .

The coating process is a continuous process, so that gaps and irregularities between the pipes have to be re- duced or avoided. For this reason adjacent pipes are joined together before the conveyor transports them along the coating installation. Because the pipes always have a slight curvature, the end of a first pipe will oscillate during transport relative to the front of a following pipe. This may create disturbances in the coating at the transition between two pipes. By using the centering device, the oscillating is eliminated and the coating process now takes place more evenly. There are several types of coating processes, in which different materials can be applied on the pipes. The centering device is suitable for all known coating processes.

In some situations when the length of a pipe is short, the distance between two consecutive wheel pairs is greater than half the length of the pipe, so that the pipe will tilt if it is not supported by another pipe. In these cases, the centering device provides this support and makes transportation of the pipes on the conveyor possible whereby the centering device in one pipe serves as support for the next pipe. The invention is further illustrated with the aid of several embodiments using the accompanying drawings, in which

Fig. 1 and 2 show a perspective view of both sides of a centering device, Fig. 3 shows a section of a pipe with the centering device of figures 1 and 2 in the position before tightening in the pipe,

Fig. 4 shows a section of a pipe with the centering de- vice of figures 1 and 2 in fixed position in the pipe, Fig. 5 shows a perspective view of detail of the centering device of figures 1 and 2,

Fig. 6 shows the centering device of figures 1 and 2, fixed in a pipe, a few moments before the centering of the pipes, and

Figure 7 shows a schematic detail of a section through the centering device of figures 1 and 2 between adjacent pipes .

Figures 1, 2, 3 and 4 show a centering device for centering an end of a first pipe relative to an end of an adjacent second pipe. The centering device comprises a centrally placed inner ring 1 which has a outer diameter that is preferably smaller than an outside diameter of a pipe in which the centering device is tightened and larg- er than an inside diameter so that the inner ring 1 cannot slide into the pipe. In another embodiment of the centering device the outer circumference of the inner ring 1 is provided with notches that together prevent the inner ring 1 sliding into the pipe. The inner ring 1 has slots 20 in radial direction; each slot 20 has a shaft 3 which can move radially in the slot 20. The center lines of the shafts 3 are parallel to the center line of the inner ring 1 and the pipes that have to be centered. The shaft 3 has on one side a flat roller 4 and on the other side an elliptic roller 5; the flat roller 4 and the elliptic roller 5 can rotate freely around the shaft 3. The maximum diameter of the elliptic roller 5 is a few millimeters less than the diameter of the flat roller 4. On either side of the inner ring 1 there is a cam ring 2. The outer circumference of the cam ring 2 has cams 13, whereby each cam 13 cooperates with a shaft 3 mounted in the slots 20 in the inner ring 1. For this the shaft 3 can have a cam roller 7 that can roll over the cam 13, the two cam rollers 7 that cooperate with the cams 13 on both cam rings 2 are mounted on the shaft 3. For axially positioning the cam rings 2 relative to the cam rollers 7, the flat roller 4 and the elliptic roller 5 on the shaft 3 there are washers at the ends of the shaft 3. Other solutions for axially positioning are possible such as grooved cam rollers 7.

Bolts 14 connect the cam rings 2 and spacers 15 keep the cam rings 2 at a fixed distance so that the cam rings 2 form a single part. The cam rings 2 can rotate together relative to the inner ring 1 around a rotation shaft that is approximate parallel to the shafts 3, whereby the cams 13 move over the cam rollers 7. The cams 13 are shaped such that the relative rotation of the inner ring 1 and the cam rings 2 forces the shafts 3 to move in a radial direction in the slots 20. The flat rollers 4 are located on the shafts 3 between the cam rings 2 so that the forces generated by the inner surface of a pipe on the flat rollers 4 are divided over the two cam rings 2. The elliptic rollers 5 extend outside the width of the cam rings 2 and the flat rollers 4 and the elliptic rollers 5 are on different sides of the inner ring 1.

An actuator 6 can force the inner ring 1 and the two cam rings 2 to rotate relative to one another. The actuator 6 as shown in figure 5 has a bracket 8 that is hinge- ably coupled to the cam rings 2. A pin 16 can slide through a hole in the bracket 8 and a fork 11 at the end of the pin 16 connects the pin 16 to the inner ring 1. The pin 16 is threaded, and a nut 10 can be screwed on the threaded end of the pin 16. A spring 9 is situated between the nut 10 and the bracket 8 for maintaining the tension in the pin 16 when there is a small relative rotation of the inner ring 1 and the cam ring 2.

Springs 12 press the shafts 3 in radial direction in the slots 20 towards the center of the inner ring, to ensure that the cam rollers 7 are pressed on the cams 13 against gravity when the centering device is not placed in a pipe. In the shown embodiment each shaft 3 has a spring 12. For centering the pipes using the centering device, the side with the flat rollers 4 is placed in front of an end of a first pipe 18. Then the centering device is pushed into the pipe 18 until the inner ring 1 rests against the outer end of the first pipe 18. Figure 3 shows the centering device in this position wherein the flat rollers 4 are free of a wall 21 of a pipe. By tightening the nut 10 on the threaded end of the pin 16 the two cam rings 2 are rotated relative to the inner ring 1, forcing the shafts 3 to move radially outward and the flat rollers 4 are pushed against the wall 21 of the first pipe 18 until the centering device is fixed in the first pipe 18, see figure 4. It is necessary to maintain an outwardly directed force on the shafts 3 during the coating process. During coating the pipes can be heated to a temperature between 200⁰C and 250⁰C and the high temperature causes the pipes to expand, which might cause the flat rollers 4 to lose contact with the inside of the first pipe 18. To maintain the outwardly directed force of the cams 13 onto the shafts 3 a spring 9 is applied between the nut 10 and the bracket 8, which ensures that the clamping force is maintained.

After applying the centering device at the rear end of the first pipe 18, see figure 6, the first pipe 18 is placed on the wheels of the conveyor and transported. Af- ter the first pipe 18 has passed a certain point, a second pipe 19 is placed on the wheels of the conveyor. The second pipe 19 is accelerated until it catches up and collides with the first pipe 18. During the last moments of the catching up process the second pipe 19 slides over the elliptic rollers 5 which stick out of the first pipe 18, until the second pipe 19 is pushed against the inner ring 1 of the centering device and the elliptic rollers 5 force the second pipe 19 to center with the first pipe 18. As the elliptic rollers 5 have a slightly smaller diameter than the flat rollers 4 a bit of play will remain between some of the elliptic rollers 5 and the inside of the second pipe 19. This might cause a negliable deviation in the centering, which will not disturb the coating process.

In the described embodiment of the centering device it remains possible that the first pipe 18 and the second pipe 19 rotate relative to one another, whereby the elliptic rollers 5 rotate around the shafts 3. In situa- tions wherein any process to which the pipes 18, 19 are subjected to, such as the coating process, requires that the pipes 18, 19 have the same rotation speed it can be advantageous to use static elliptic rollers 5 that cannot rotate. In stead of static elliptic rollers 5 an inclined guide piece can be used over which the second pipe 19 slides until the second pipe 19 is located against the inner ring 1.

After the first pipe 18 is coated and the first pipe 18 has moved past the coating installation, the first pipe 18 is pulled from the second pipe 19 by accelerating the first pipe 18, meanwhile the centering device remains fixed in this first pipe 18. After that the first pipe 18 is removed from the conveyor and the centering device is removed from the pipe. For this the nut 10 is loosened so that the cam rings 2 can be rotated relative to the inner ring 1, the springs 12 press the shafts 3 radially towards the center of the inner ring 1 and the centering device is removed from the first pipe 18. With the above described centering device a high clamping force in the pipe can be realized, since most of the forces that occur as a result of the clamping and the centering of the pipes are directed as normal forces onto the two cam rings 2, thus creating only a limited force on the actuator 6 and the pivot points. For each pipe diameter a different centering device is needed, where the number of shafts 3 depend on the diameter of the pipes.

In further embodiments of the centering device other constructions can be applied. In a centering device for heavy pipes large forces occur onto the elliptic rollers 5 which might lead to deformations. To reduce the applied forces on the elliptic rollers 5 a relief roller 17 (indicated in figure 7 with interrupted lines) is mounted between the cam ring 2 and inner ring 1 on the side of the elliptic rollers 5. The elliptic roller 5 is used to center the second pipe 19 during the moment the second pipe 19 approaches the first pipe 18. After this the relief rollers 17 and not the elliptic rollers 5 support the second pipe 19 during the coating process. The figure 7 shows bearings between the rollers 4, 5 and 7 and the shaft 3. In other embodiments the shaft 3 be a part of or may rotate with one of the rollers.

In the earlier described embodiment flat rollers 4 form a clamping element against the inside surface of the first pipe 18, while they are pressed against the pipe wall during the fixing of the centering device. In a further embodiment it is not necessary that the clamping elements are round, they may have another form, as long as they do not damage the insides of the pipe. They also do not have to rotate around the shafts 3. In a further embodiment the elliptic rollers 5 and if applicable the relief rollers 17 are rotatable around the shafts 3 as the first pipe 18 and the second pipe 19 may have differ- ent rotation speeds.

The material of rollers 4, 5 and 17 which interact with the pipes 18, 19 is preferably steel with a hard surface to prevent deformations, but other materials are possible. This depends on the surface condition of the inside of the pipe. For example, if the inside of the pipes is coated it may be desirable that the rollers are made out of plastic or rubber, to prevent the coating from being damaged when using the centering device.

In the earlier described embodiment the actuator 6 for the rotating and positioning of both cam rings 2 relatively to inner ring 1 comprises the nut 10 on one side and the pin 16 with a fork 11 fixed on the inner ring 1 on the other side. In another embodiment the pin 16 comprises a hook which is fixed in a toothed strip on the inner ring 1. Other embodiments of the actuator 6 might comprise a rack and pinion, where the cam rings 2 are rotated by changing the position of the pinion. Also the usage of a lever is possible, where pulling the lever makes the cam rings rotate relatively to the inner ring. The actuator 6 can be actuated manually, other means of activation might be electric or hydraulic drives that can be coupled to an energy source when the centering device is fixed in the end of the first pipe 18.

As described earlier the elliptic rollers 5 force the pipes 18, 19 to center relative to each other. In a further embodiment to achieve the same effect, the rollers 5 do not necessarily have to be elliptic, for example, the centering can also be achieved with conical rollers or rollers with a different form, as long as the pipes are forced to center when they are joined.

In the earlier described embodiment while rotating the cam rings 2, the cams 13 press against the cam roll- ers 7, forcing the shafts 3 outwards. In a further embodiment it is also possible to replace the cam rollers 7 with other elements, such as sliding blocks. These sliding blocks need not be rotatable around the shafts 3.

Claims

1. Device for centering adjacent pipes (18,19) comprising a number of clamps (4) with a mechanism for pressing a clamp surface in radial direction against the inside surface of a first pipe (18) and a guide (5) that has an inclined guide surface concentric with the clamp surfaces for positioning a second pipe (19) characterized in that the guide comprises a number of guide pieces (5) with a guide surface and the mechanism positions the guide surfaces in radial direction a slightly smaller radius than the clamp surface.

2. Device in accordance with claim 1 wherein each guide piece (5) is coupled to a clamp (4) forming a combined part and the mechanism positions the combined part in radial direction.

3. Device in accordance with claim 1 or 2 wherein the guide surfaces (5) can rotate around rota- tion shafts (3) parallel to the pipes (18,19) .

4. Device in accordance with one of the previous claims wherein the guide pieces comprise conical or elliptical rollers (5) with rotation shafts parallel to the pipes (18,19) .

5. Device in accordance with claim 4 wherein the conical or elliptical rollers are mounted on or rotate with a shaft (3) and the shaft supports a clamp (4) .

6. Device in accordance with claim 5 wherein the clamp comprises a cylindrical ring (4) mounted on or rotable with the shaft (3) .

7. Device in accordance with one of the previous claims wherein the mechanism comprises a number of shafts (3) each supporting a clamp (4) wherein each shaft is movable in radial direction in a slot (20) in an inner ring (1) and two cam rings (2) with cam surfaces (13) act on the shaft on either side of the clamp.

8. Device in accordance with claim 7 wherein cam rollers (7) are mounted on or rotate with the shaft (3) and the cam surfaces (13) act on the cam rollers.

9. Device in accordance with claim 7 or 8 wherein an actuator (6) that can be manually or mechanically driven can rotate the inner ring (1) relative to the cam rings (2) and the actuator has a spring (9) for maintaining a torque between the inner ring and the cam rings .

10. Device in accordance with claim 7, 8 or 9 wherein the inner ring (1) has springs (12) for pushing the shafts (3) onto the cam surfaces (13) .

11. Device in accordance with one of the claims 7, 8, 9 or 10 wherein the inner ring (1) has a diameter that is at least locally larger than the inner diameter of the first pipe (18) or the second pipe (19) .