DE29716233U1 - Centering, clamping and forming device for pipe sections to be welded together - Google Patents

Description

Description: G 97 144 Adolf Kandulla Winding Machines GmbH

12557 Berlin

Centering, clamping and forming device for pipe sections to be welded together

The innovation relates to a centering, clamping and forming device for straight and/or curved pipe sections that are to be butt-welded together, which can be inserted into the pipe sections.

The pipe sections are welded under protective gas - forming gas - especially in the case of steel pipes and stainless steel pipes.

With stainless steel pipes, particularly with diameters of 100 mm and over and with thin walls, for example from 2 mm, the problem arises that the pipe sections that are to be butt-welded together are deformed into an egg shape due to the low wall thickness and have to be centered. Furthermore, it is necessary to produce the weld seam under protective gas in order to avoid or reduce the formation of ferritic structural changes in the area of the weld seam on the pipe, since these areas of the pipes adjacent to the weld seam form weak points that are susceptible to corrosion and significantly impair the service life of the pipe.

The innovation is based on the task of creating a device for welding pipe sections, which at the same time takes over the centering while clamping the pipe sections and also enables the creation of a protective gas atmosphere on both sides of the pipe sections to be welded together. In addition, the device according to the innovation should also make it possible to weld not only straight pipe sections together

but also to weld pipe bends to each other and pipe bends to straight pipe sections.

This object is achieved with a device according to the innovation according to the features of claim 1. The device according to the innovation is characterized in that it has a pneumatically inflatable pressure and cooling part, and pneumatically inflatable clamping rings are arranged on both sides of the pressure and cooling part, which are movably connected to the pressure and cooling part.

According to the innovation, the device is divided into three parts, namely a middle clampable pressure and cooling part directly for the weld seam area and two separate outer clamping parts which, when inflated, fit snugly against the inner wall of the pipe sections to be connected. The movable connection of the outer clamping rings to the middle part, namely the pressure and cooling part, makes it possible not only to connect straight pipe sections to one another, but also to weld straight pipe sections to pipe bends. The movable connection between the clamping ring and the movable connection between the clamping ring and the middle part, i.e. the pressure and cooling part, is required at least on the side where the pipe bend connects. On the other part adjoining the straight pipe section, it is possible to fix the second outer clamping ring, which is movably connected to the middle part, by means of a locking device, running along one axis and connected to the middle part. This makes it possible to use the new device with the movably connected outer clamping rings with the middle pressure and cooling part with the help of the locking mechanism to weld both straight pipe sections together and straight pipe sections with a pipe bend.

Advantageous further developments of the innovation can be found in the characterising features of the subclaims.

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The movable connection between the inflatable tension rings and the inflatable middle pressure and cooling part is preferably made by means of a joint, such as a cardan joint.
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By inflating the clamping rings and the middle pressure and cooling part, it is possible to easily center and round even thin-walled pipes, which are usually egg-shaped or oval, by inflating them and to remove the deformation.

Inflation is carried out via a supply line for the supply of compressed gas to the pressure and cooling part and the clamping rings, whereby the compressed gas is in particular a protective gas or inert gas (forming gas) as is also used for gas shielded welding. Pressures of up to 10 bar and more are used here. This makes it possible to press the clamping rings, in particular the outer clamping rings, with some pressure onto the inner wall of the pipe sections to be connected, and to remove the deformation, restore the pipe roundness and at the same time enable very precise centering.

Furthermore, the device according to the invention makes it possible to use the compressed gas used for inflating the clamping rings and the middle pressure and cooling part at the same time as a protective gas inside the pipe sections in the area of the weld seam, so that the air inside the pipe sections is displaced by the compressed gas - forming gas - and no harmful side effects occur when welding on the steel parts in the weld seam area. The invention therefore makes it possible to use only a single gas, in this case forming gas, which also serves as a compressed gas for inflating the clampable parts of the device and as a forming gas during welding of the weld seam. According to the innovation, this is made possible in particular by the fact that when the gases are inflated and resting on the inner wall of the pipe sections to be connected to one another,

Clamping rings and pressure and cooling part, the clamping rings movably connected to the pressure and cooling part are spaced apart from the pressure and cooling part and the chamber formed between the respective clamping ring and the pressure and cooling part and the inner wall of the pipe sections can be filled with the pressure gas, i.e. protective gas, inert gas (forming gas).

An advantageous design of the inflatable pressure and cooling part, which is also designed as a clamping part, provides an expandable jacket made of an elastic material such as vulcanized rubber, which has a recess in the middle area on its jacket surface that rests against the inner wall of the pipe sections, into which cooling strips forming a ring are inserted and the cooling strips are traversed by channels that can be acted upon by a heating or cooling medium and the front sides of the pressure and cooling part are enclosed by metal covers.

By applying compressed gas to the elastic casing of the pressure and cooling part from the inside, it is pressed outwards, which enables a firm fit within the two pipe sections to be connected, whereby the weld seam, i.e. the butt-fitting ends of the two pipe sections, come to rest on the cooling strips, which are made of copper, for example. In order to enable particularly good centering, it is also proposed that the pressure and cooling part be designed to be straight or spherical only in the middle area on the outer circumference of the cooling strips and to slope slightly towards both ends, i.e. with a decreasing outer diameter of the casing.

An advantageous design of the clamping rings according to the innovation provides that they have an expandable casing made of an elastic material such as vulcanized rubber and that the material is applied to an annular carrier, which may be constructed in several parts, and the front sides of the clamping rings are covered by metal covers and the compressed gas can be introduced into the interior of the clamping rings in order to expand the elastic casing.

While for connecting straight pipe sections to one another the clamping ring usually has a uniform outer diameter, i.e. a straight outer surface, for connecting a pipe bend to a pipe section it is proposed that at least the outer surface of a clamping ring runs in a bevelled manner towards the end face facing away from the pressure and cooling part, i.e. with a decreasing diameter of the coat , which can then be inserted into the bent pipe section (pipe bend).

The centering, clamping and forming device according to the invention for welding butt-fitting metal pipe sections under protective gas can be manufactured as a simple operating unit with only one supply line for compressed gas for clamping and as forming gas. The clamping rings and the pressure and cooling part each form a tubular component that is connected to one another via joint connections. The stability of the clamping rings and the pressure and cooling part is achieved by means of a tubular support and the end-face covers, and the expandability by means of the elastic casing.

The innovation is explained below using the drawings as an example. They show

Fig. 1 is a schematic view of a device for centering, clamping and forming for the purpose of welding a pipe bend and a straight pipe section,

Fig. 2 a device for centering, clamping and forming in one-piece design for connecting straight pipe sections by butt welding,

Fig. 3 shows a partial cross-section through a device according to Fig. 2 to explain the structure,

Fig. 4 a cross-section through a structure of a pressure and cooling part,

Fig. 5a

and 5b two views of a cooling strip.

Fig. 1 shows a centering, clamping and forming device for producing a butt weld seam S between a pipe bend 6a and a straight pipe section 7, for example made of stainless steel. The device comprises a pneumatically inflatable pressure and cooling part 3 as the middle part and two inflatable clamping rings 1a, 1b, which are arranged at a distance on both sides of the middle part 3 and are each connected to the middle part 3 by means of the movable connection 2a, 2b. This movable connection of the clamping rings 1a, 1b to the middle part 3 can be made, for example, via an articulated connection such as a cardan joint. In this way, it is possible for one clamping ring to be used for centering and guiding a straight pipe section, here the clamping ring 1b, and the second clamping ring 1a, which can be bent accordingly via the movable connection, to be used for centering and clamping and guiding a pipe bend 6a, here a 90° bend. Assuming that the pipe bend 6a is already firmly welded to a pipeline at its other end, the clamping ring 1a of the device according to the innovation is inserted into the open end of the pipe bend 6a, so far that the free end of the pipe bend 6a rests approximately in the middle of the pressure and cooling part 3, i.e. in the area of the cooling strips 9, where the weld seam S is to be produced. Then the clamping ring 1a is inflated with the help of compressed gas, in particular a protective gas, fed through the supply line 8 and pressed against the inner wall of the pipe bend 6a while centering it. Pressures of up to 8 to 10 bar can be exerted here. In the case of thin pipes, the inflated clamping ring 1a simultaneously compensates for deformation and rounds the pipe. After the pipe bend 6a is on the

Device 3 is attached in the area of the clamping ring 1a, the straight pipe section 7 is pushed over the other clamping ring 1a onto the middle part 3 until it touches the end of the pipe section. Pipe section 7 and pipe bend 6a now rest approximately centrally on the pressure and cooling part 3 in the area of the weld seam S to be produced. Now the clamping ring 1b and the pressure and middle part can also be inflated so that they lie firmly against the inner wall of the pipe sections and perfect fixing, centering and clamping is achieved. Sealed chambers 4a, 4b are now formed between the clamping rings 1a and 1b and the pressure and cooling part 3 by the contact of these parts 1a, 1b and 3 against the inner wall of the pipe sections, which are also filled with the compressed gas, i.e. can be filled with the protective gas and thus with the same compressed gas with which the parts 1a, 1b and 3 are inflated. This compressed gas now fills the pipe sections from the inside and prevents the metallic structure of the pipe sections from changing in the weld area S to be produced. The clamping ring 1 b, which is connected to the middle part 3 in the longitudinal axis, is fixed by means of the locking mechanism 5 (not shown in detail).

In order to achieve the best possible fit and centering of the pipe sections with the aid of the device according to the innovation, it is provided that the pressure and cooling part 3 is slightly convex in the middle area and slopes down towards the sides, so that the weld seam S rests and is located in the convex area in the area of the cooling strips 9, which are made of copper, for example.
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The clamping ring 1a, which is inserted into the pipe bend 6a, is also spherical or bevelled, sloping towards the side facing away from the middle part 3, in order to enable a corresponding insertion into the pipe bend 6a.
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Fig. 2 shows how an inflatable device according to the invention for centering, tensioning and forming in the manufacture of

Butt welds between straight pipe sections 6, 7. Here, the clamping rings 1a and 1b are directly connected to the middle part 3, which carries the cooling strips 9, whereby the dashed lines L1, L2 indicate the separation lines for the three-part design of the device according to Fig. 1. The one-part device according to Fig. 2 is also closed on both ends and is supplied with compressed air via the supply line 8. The arrows in the clamping parts 1a, 1b and the middle part 3 show the direction of the expansion of the device to rest against the inner wall of the pipe sections 6, 7. It is shown schematically in an exaggerated manner that both the clamping rings 1a, 1b and the middle part are each spherical in the middle area and slope down towards the sides in order to enable the device to be centered and positioned as precisely as possible.

Fig. 3 shows a schematic of the structure of a pressure medium part 3 and the clamping rings 1 a and 1 b, starting from the one-piece version according to Fig. 2. The middle part 3, which serves as a pressure and cooling part, is tubular with a three-part support ring 33a, b, c, which forms a receiving groove 37 on the outside for an elastic, expandable material, such as vulcanized rubber, synthetic rubber for the casing 30. The parts 33a, b, c are connected to one another, for example by means of screws (not explained in more detail), and are made of metal. The casing 30 in turn has a groove 36 formed centrally in the middle area, into which the cooling strips 9 are inserted. The cooling strips are wedge-shaped segments, as shown in two views in Fig. 5a and 5b, which are made of copper and are formed with cooling channels 91 running around the circumference. The cooling strips 9 are designed in the middle area, which is not shown in detail in Fig. 3, to protrude spherically over the casing 30, so that the casing 30 slopes slightly towards both sides when viewed from the middle. Between the carrier ring, namely the middle part 33b and the elastic casing 30 on its inside, a groove 34a is left, which is connected to the interior 40 of the middle part via a bore 35.

is connected, through which the compressed gas G is introduced in the direction of the arrow for the purpose of inflating, whereby the elastic jacket 30 with the cooling strips 9 is expanded in the radial direction and can accordingly rest against the inner wall of the pipe sections. On both sides of the central part, a clamping ring 1a, 1b is provided, which in turn has a multi-part support ring made up of the parts 13a and 13b, respectively, which are connected to one another by means of screws not designated in more detail, and which has a groove on the outside into which the elastic expandable outer jacket 10a, 10b made of vulcanized rubber is inserted.

Through the middle area of the support ring 13a or 13b of the clamping rings 1a or 1b, a passage 15a, 15b is provided, which leads into a gap 14a, 14b on the inside of the casing 10a, 10b, and through which compressed air G can be introduced in the direction of the arrow from the interior 40 of the clamping rings in order to expand the clamping rings by inflating their outer casings 10a, 10b and to fix them to the inner wall of the pipe sections. If necessary, the cooling strips 9, which are made of copper, can be supplied with a cooling medium M in the area of their channels 9, which is supplied to the cooling strips 9 via the channels K.

In the one-piece design of the device with a middle part and clamping rings 1 a, 1 b, this is closed at the two end faces by means of cover plates 12 and 11, whereby the supply line with the compressed gas G is introduced into the interior 40 through one of these cover plates and from here is passed on via the openings 15b, 35 and 15a to inflate the elastic casing 10b, 30 and 10a. Cover plates and support ring serve to ensure the static strength of the device.

To form the three-part device according to the invention, the clamping rings 1a and 1b according to Fig. 3 are separated from the middle part 3 in the direction of arrow A1, A2 at the dividing line after loosening the screws and the side open end walls of both the clamping rings 1a, 1b

and the middle part 3 are closed by means of lids. The clamping rings 1 a and 1 b are then connected to the middle part 3 in the axial direction via movable joints, as shown schematically in Fig. 1. The supply line 8 now leads into each of the chambers formed inside the clamping rings 1 a, 1 b and the middle part 3 in order to introduce the compressed gas there and to inflate the clamping rings and the middle part, namely the pressure and cooling part 3. At the same time, the compressed gas is also introduced into the chambers formed between the clamping rings 1 a, 1 b and the pressure part 3 within the pipe sections, as already explained. This is one possible construction of the device according to the invention.

In Fig. 4, a pressure and cooling part 3 is again shown schematically in cross section. Here, the ring-shaped support part 33 is designed as a tube and is closed at the side by means of the covers 31, 32, which protrude outwards over the inner tube part 33 and thus form a receiving groove 37 for the elastic outer jacket 30. The outer jacket 30 in turn has the molded groove 36 in the middle, into which the cooling strips 9 are inserted. The compressed gas G for inflating the jacket 30 and tensioning the middle part 3 on the tube sections is introduced through the opening 34 into the interior of the middle part and from here is guided via holes (not shown) to the inside of the jacket 30 in order to press it radially outwards in the direction of the arrow P, together with the cooling strips 9.

If required, a cooling medium or heating medium M can be fed into the circumferential cooling channels 91 of the cooling strip 9 via the supply opening 35 in the cover 31 and the channel K in the jacket 30.

The new device is relatively light due to the use of inflatable tubular parts, namely the clamping rings and the pressure and cooling part.

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The design of the cooling strip 9 made of copper, which at the same time forms the weld seam base, enables the production of a very good, permanent weld seam, which can be produced from both sides under protective gas, namely from the outside by appropriate supply of protective gas and from the inside by introducing the protective gas into the inner chambers of the clamping rings 1a, 1b and the middle part 3 and additionally into the chambers 4a, 4b as explained in Fig. 1.

Claims (10)

Protection claims: G 97 144 1. Centering, clamping and forming device for straight and/or bent pipe sections to be butt-welded together, which can be inserted into the pipe sections, characterized in that it has a pneumatically inflatable pressure and cooling part (3) and pneumatically inflatable clamping rings (1a, 1b) arranged on both sides of the pressure and cooling part and movably connected to the pressure and cooling part. 2. Device according to claim 1, characterized in that the movable connection between the pressure and cooling part (3) and the clamping rings (1a) or (1b) is made by means of a joint, such as a cardan joint. 3. Device according to claim 1 or 2, characterized in that at least one of the two movable connections (2a, 2b) between the pressure and cooling part (3) and one of the clamping rings (1a) or (1b) is equipped with a locking device (5). 4. Device according to one of claims 1 to 3, characterized in that a supply line (8) for the supply of compressed gas for inflating the pressure and cooling part (3) and the clamping rings (1a, 1b) and a line for the supply of heating and cooling medium (M) is provided. 5. Device according to one of claims 1 to 4, characterized in that a protective gas or inert gas (forming gas) is provided as the pressure gas. 6. Device according to one of claims 1 to 5, characterized in that when inflated and on the inner wall of the pipe sections (6, 6b) and (7) to be connected to one another, the movable with the The clamping rings (1a, 1b) connected to the pressure and cooling part (3) are spaced apart from the pressure and cooling part (3) and the chamber (4a, 4b) formed between the respective clamping ring (1a) or (1b) and the pressure and cooling part (3) and the inner wall of the pipe sections can be filled with the compressed gas. 7. Device according to one of claims 1 to 6, characterized in that the pressure and cooling part (3) has an expandable jacket (30) made of an elastic material, such as vulcanized rubber, and the jacket has a recess (36) on its jacket surface which comes to rest on the inner wall of the pipe sections in the central region, into which cooling strips (9) forming a ring are inserted and the cooling strips (9) are traversed by channels (91) which can be acted upon by means of a heating or cooling medium (M), and the end faces of the pressure and cooling part (3) are covered by metal covers (31, 32). 8. Device according to claim 7, characterized in that the pressure and cooling part (3) is designed to be straight or spherical centrally in the middle area on the outer circumference of the cooling strips and is designed to slope slightly towards both end faces, ie with a decreasing diameter. 9. Device according to one of claims 1 to 8, characterized in that the clamping rings (1a, 1b) have an expandable jacket (10a, 10b) made of an elastic material such as vulcanized rubber and the jacket is applied to an annular carrier (13a, 14a; 13b, 14b) and the end faces are covered by metallic covers and the compressed gas can be introduced into the interior of the clamping rings (1a, 1b) for the purpose of inflating them. 10. Device according to one of claims 1 to 9, characterized in that the outer casing of a clamping ring (1a, 1b) slopes downwards towards the end face facing away from the pressure and cooling part (3), ie with a decreasing diameter of the outer casing.