WO2007112979A1

WO2007112979A1 - Pressure compensation ring

Info

Publication number: WO2007112979A1
Application number: PCT/EP2007/002890
Authority: WO
Inventors: Franz Baumgartner
Original assignee: Franz Baumgartner
Priority date: 2006-04-01
Filing date: 2007-03-30
Publication date: 2007-10-11
Also published as: DE202006005297U1

Abstract

The invention relates to a pressure compensation ring to be inserted between faces (4a) of pipes when pipes (4) are advanced underground. Said pressure compensation ring (1) comprises one or several elastomeric pressure transducing elements (2) which are provided at least in part with reinforcements (8) on the contact surfaces (6) used for contacting the faces of the pipes (4), said reinforcements (8) largely preventing the pressure transducing elements (2) from expanding on the contact surfaces (6) on the plane of the pressure compensation ring (1), thus preventing transversal forces from being introduced into the faces of the pipes (4) and the mostly brittle material from breaking.

Description

Druckausαleichsrinα

The present invention relates to a pressure equalization ring for insertion between pipe end faces in the underground propulsion of pipes, wherein the pressure equalization ring has one or more pressure transmission elements of elastomeric material.

During the laying of pipelines in the pre-pressing process, a pipeline is formed from individual juxtaposed pre-compression pipes, which is driven by the fact that on its rear end a high axial pre-pressing force is exerted. At the pipe joints, the pipe end faces are consequently pressed together. In order to prevent damage due to uneven stress distributions, especially for pipes from relatively brittle Ma- materials, eg. As concrete, stoneware and the like, between the pipe end faces a flat, axial pressure equalization ring are inserted, which is often referred to as a pressure transmission ring. These pressure compensating rings made of flexible material compensate for punctual peak pressures, for example, due to unevenness and edge pressures in axial deviations from unwanted and intentional deflections, for example in curve pressing.

The pressure compensation rings must be able to absorb the entire axial Vorpresskraft without damage and thereby cause the most uniform pressure distribution on the pipe ends. In the prior art, these requirements have so far mostly been countered by the use of wood pressure compensation rings, which are either complete, or at least in the pressure-compensating rings.

BESTATJGUNGSKOPIE bearing areas made of wood. Such an embodiment results, for example, from DE 296 14 582 IM. The pressure transmission ring described therein has as the actual pressure transmission element made of a wood material core ring, which is surrounded in its radial outer region by an enveloping ring of elastic material. The relatively soft compared to wood material elastomer material, however, assumes only a sealing and adjustment function on the pipe wall, and no pressure transmission.

However, wood pressure compensation rings have the fundamental, material-related disadvantage that they are relatively strongly plastically deformed during pipe advance by the axial force acting and only have a low elastic resilience. In the permanently compressed state, which occupies the wood after the first compression, the desired pressure equalization and the uniform pressure distribution is no longer achieved.

In addition, over time wood pressure equalization rings entail an increased danger of germs. Removed wood particles and fibers also cause contamination and may damage the fittings, containers and other equipment. A check or repair of built-in wood pressure equalization rings is especially in non-walkable, d. H. Small-caliber lines after installation no longer feasible.

European Patent Application EP 1 079 064 A2 discloses a pressure compensation ring which has a plurality of pressure transmission elements made of elastomeric material, which are arranged at a distance from one another in the plane of the pressure equalization ring. Between the individual pressure transmission elements remain correspondingly cleared spaces. Since the elastomer materials used are incompressible, an axial compression of the pressure transmission elements has a transverse deformation in the plane perpendicular to the tube axis result. The pressure transmission elements behave resiliently in the axial direction and are elastically, ie reversibly deformed between the pipe end faces. However, as soon as for the pressure transmitting elements in the plane of the pressure equalization ring, ie the plane perpendicular to the tube axis, no escape space is available because the radially limited sealing surface is completely filled, the pressure compensation ring is incompressible against further compression in the axial direction. This results in a compact pressure plate as in a wooden pressure equalization ring. This means that the pressure equalization ring can be pressed together axially until the spaces between the individual pressure transmission elements are completely filled with elastic material by the transverse deformation occurring. If the contact pressure is increased beyond that, no further elastic deformation takes place, but the pre-pressing force introduced via a pipe end face is transferred directly to the opposite pipe end face.

An advantage of this pressure equalization ring is that is introduced by the initially elastic deformation of the pressure transmission elements of the contact pressure particularly evenly in the pipe end faces, even with unevenness in the pipe mirror or punctiform load on cornering when the socket gap on the pipe joint on the outside of the curve is greater as inside. The springback due to its elastic behavior ensures in this situation that the pressure transmission elements expand axially again in the enlarged sleeve gap and at the same time increase the contact pressure in the direction of the inner side of the cable through this elastic pressure transmission.

The elastic properties remain largely preserved even after multiple deformation by loading and unloading. Due to the incompressible behavior in the fully compressed state, d. H. at full pressure, the spring characteristic increases disproportionately, d. H. progressive, since the individual pressure compensation elements are pressed together in the manner described above to a closed flange parallel to the plane and behave like a compact pressure plate. In this state, the pre-pressing force acts until the mechanical material destruction, namely the pipe end or the elastomer material.

Due to the described elastic and elastohydraulic behavior, this pressure compensation ring provides an optimal, reversible pressure distribution. probably during the pipe jacking, as well as in later line movements guaranteed, which can be caused by damage or other movements of the ground. Incidentally, reference is made to EP 1 079 064 A2 with regard to the described pressure compensation ring.

However, a not yet completely solved in the pressure equalization ring described problem consists in that the transverse deformations occurring during compression of the pressure transmission elements can transmit forces to the material of the pipe end faces, which, in very strong compression, can lead to breakage of the brittle pipe material.

It is thus an object of the present invention to provide a pressure equalization ring which, on the one hand, incorporates the advantages of the above-described pressure equalization ring of EP 1 079 064 A2 and, moreover, does not introduce any transverse forces into the pipe end material in order to prevent breakage of this mostly brittle material.

This object is achieved by a pressure equalization ring for insertion between pipe end faces in the underground propulsion of pipes, wherein the pressure equalization ring one or more pressure transmission elements made of elastomeric material, wherein the pressure transmission elements at their intended for contact with the end faces of the tubes contact surfaces at least partially have a gain.

The reinforcement should be such that virtually no transverse expansion of the pressure transmission element occurs at the contact surfaces themselves, wherein transverse expansion is understood to mean an elongation perpendicular to the tube axis. Likewise, the plane of the pressure equalization ring is understood to mean the plane that is orthogonal to the pipe axis.

Advantageously, the pressure equalization ring on a plurality of pressure transmission elements, which are arranged spaced from each other in the plane of the pressure equalizing ring. Despite the built-in reinforcements in the contact surfaces, the pressure transmission elements are still able to deform elastically. Accordingly, they experience in the space between the contact surfaces themselves also a transverse deformation, wherein the individual pressure transmission elements can possibly be compressed so far 5, that spaces between the pressure transmission elements are completely filled, so that a compact pressure plate is formed. In this respect, the pressure equalization ring according to the invention corresponds to the above-described pressure equalization ring from EP 0 079 064 A2 when using a plurality of pressure transmission elements. The advantages of such a pressure compensation ring described in the introduction thus also apply to the new invention. Only in the region of the contact surfaces with the end faces of the pipes, the built-in reinforcements, that no or at most a minimal transverse strain of the pressure transmission elements, so that no transverse forces are transmitted to the end surfaces of the tubes 5. Accordingly, the pressure equalization ring according to the invention realizes all the advantages of the above-described prior art, but at the same time causes a breakage of the most brittle pipe material is practically excluded by the occurrence of shear forces.

Even in EP 1 079 064 A2, a reinforcement is already mentioned in the pressure transmission elements, but this is embedded in the entire elastomer body. For this reason, the elastomeric properties of the entire pressure transmission element are influenced accordingly, both in terms of the tensile strength in the longitudinal direction and in terms of transverse deformation. Although the properties of the elastomer body can be adjusted by means of such a reinforcement, it is not prevented that a transverse deformation occurs precisely at the contact surfaces with the tube end faces. In addition, the elastic properties o of the pressure transmission element itself are not adversely affected by the inventive use of reinforcements exclusively at the contact surfaces.

The reinforcements at the contact surfaces may be formed in various ways. In particular, it may be a fabric, with particular textile, steel, plastic, fiberglass, ceramic fiber, carbon fiber or aramid fiber tissue come into question. The fabric should be as strong as possible. The reinforcement serving tissue may be embedded in the contact region of the pressure transmission elements or be applied directly to the pressure transmission elements. Since the pressure transmission elements consist of an elastomeric material, it is particularly advisable to apply or vulcanize the fabric layers. However, it is also possible to use other types of attachment or embedding of the fabric, for example by gluing.

Other ways to perform the reinforcement are to attach strips lo of a material with a high modulus of elasticity to the contact surfaces of the pressure transmission elements or to embed them in the contact surfaces. The material should have a higher elastic modulus (modulus of elasticity) than the pressure transmission elements themselves, which are made of an elastomeric material. In particular, metals, for example steel, can be used. According to an advantageous embodiment of the invention, sheet steel strips are attached to or in the contact surfaces. The elastic properties of the remaining cross section of the pressure transmission elements are not affected. Particularly advantageous is the already mentioned above or vulcanization of reinforcing strips or Ver¬ 2o strengthening fabric.

Other ways to bring about a reinforcement at the contact surfaces are to embed fibers in the contact surfaces of the pressure transmission elements, which may in particular be glass fibers, steel fibers, plastic fibers, ceramic fibers, aramid fibers or carbon fibers. By embedding these reinforcing fibers, the elasticity of the pressure transmission elements at the contact surfaces is reduced so much that a transverse deformation virtually no longer occurs.

The pressure transmission elements can also have notches on at least one side, in particular on the inside and outside of the pressure equalization ring, in order to simplify the circular deformation. In particular, the reinforcements at the contact surfaces of the pressure-transmitting elements can also project radially beyond the elastic parts of the pressure-transmitting elements in the relaxed state. The reinforcements of the contact surfaces are correspondingly wider (with respect to the plane perpendicular to the tube axis) than the actual elastic pressure transmission elements. During compression during pipe jacking, the pressure transmission elements then likewise experience transverse expansion, so that reinforcements and elastic pressure transmission elements approach each other again in their radial expansion. Possibly. reaches the pressure transmitting element in the compressed state lo a radial extent, which corresponds to the reinforcement or even slightly beyond. An embodiment of the pressure compensation ring in this way that the reinforcements protrude radially beyond the pressure transmission elements is advantageous in that even with strong compression of the pressure transmission elements, the elastomer material is not pressed radially outward so far i5 that it transfers by contact with the pipe end faces transverse forces on them ,

The pressure transmission elements can also be provided with a press adhesive layer, whereby the pressure equalization ring can be fixed to the pipe end face of the vorzutreibenden tube. In this way, the insertion 20 and fixing the pressure equalization ring between the tubes is easier.

The pressure transmission elements preferably have parallel axial pressure surfaces. As a result, they can be installed in a defined manner between the frontal pressure surfaces of the pre-compression tubes and form a permanently elastic intermediate layer.

Particularly preferred are pressure transmission elements which form in cross section a parallel flattened section of a fictitious circular cross section. But also possible is a rectangular cross-section.

In the relaxed state, the pressure transmission elements can also radially have a concave curvature, so that there, where the pressure transmission o element experiences the strongest transverse strain, it has the smallest radial extent Has. Accordingly strong, the element can then be pressed without the elastomeric material bulging radially.

The shaping of the pressure transmission elements in the axial tube plane is in principle subject to no restrictions. However, it is particularly favorable, 5 that the pressure transmission elements are formed as elastomeric lamellae, either radially-fan-shaped running, or circumferential in the circumferential direction. The spaces between these slats also extend correspondingly radially-radially or circumferentially circumferentially.

The circumferentially extending elastomeric blades have the particular advantage that at the same time they effect a sealing of the sleeve gap due to their elastic properties. This may be particularly important in drinking and process water lines or for other special applications. The elastomeric slats can also be arranged in multiple rows.

Preferably, the elastomeric slats are interconnected by webs. As a result, an inventive pressure compensation ring forms an assembly unit which can be mounted particularly efficiently in the pipe joint.

It is also conceivable that the pressure transmission elements are mounted on a pipe end face. As a result, there is the possibility that, for example, elastomeric slats are already attached from the factory on one side to the frontal pressure surface of a prepressing tube, for example they are glued undetachably. The ease of assembly is thereby increased.

The invention will be explained in more detail by way of example with reference to the attached figures. Show it:

Figure 1 shows a 5 pressure compensation ring according to the invention in an axial view;

Figure 2 is a sectional view of a pipe joint with a pressure equalizing ring of the prior art; Figure 3 is a sectional view of a pressure transmitting element without reinforcement in the installed state;

FIG. 4 shows the pressure transmission element from FIG. 3 at full pressure;

Figure 5 is a sectional view of a pressure transmitting element with reinforcement;

Figure 6 is a sectional view of a pressure transmitting element according to another embodiment;

FIG. 7 shows the sectional view of the pressure transmission element from FIG. 6 at full compression;

Figure 8 is a sectional view of a pressure transmitting element according to another embodiment and

Figure 9 is a sectional view of

Pressure transmission element of Figure 8 at full pressure.

1 shows an axial view of a pressure equalization ring according to the invention düng, which is provided as a whole by the reference numeral 1 and a plurality of radially, fan or radially arranged protruding from the image plane pressure transmission elements 2 has. Between the lamellar pressure-transmitting elements 2 are intermediate spaces. 3

Figure 2 shows a pipe joint in a partial view in longitudinal section, wherein the ends of two abutting Vorpressrohre 4 are shown, between the frontal pressure surfaces 4a schematically a pressure equalization ring 1 is shown with pressure transmission elements 2 of the prior art. The pressure transmission elements 2 have a parallel flattened circular cross-section. The pressure transmission elements 2 are here partially compressed and practice one indicated by the arrows pressure in the axial direction of the tubes 4. The dashed outer lines the radial maximum transverse extent is characterized in which the pressure transmission elements 2 completely fill the gaps 3. As can be seen, the pressure transmission elements 2 undergo a considerable additional transverse expansion at full pressure, which exerts transverse forces on the pipe end faces 4a, which can lead to the formation of cracks or other damage to the pipes 4 there. In addition, a primary seal 5 is shown in this figure.

FIG. 3 shows a longitudinal section of a single pressure transmission element 2 without reinforcement from the prior art. FIG. 3 thus shows an enlarged detail of FIG. 2. The pressure-transmitting element 2 can be seen to have a width b at a distance h of the tubes 4, the pressure-transmitting element 2 and the tubes 4 abutting against the contact surfaces 6.

In Figure 4, the pressure transmission element 2 is shown in Figure 3 in full compression. The distance between the tubes 4 has decreased to h ', while the width of the pressure transmitting element 2 has increased to the width b'. By this additional radial transverse extension tensile stresses 7 are exerted on the pipe end faces.

FIG. 5 shows a representation corresponding to FIG. 3 of a pressure transmission element 2 made from a pressure compensation ring 1 according to the invention. The pressure transmission element 2 is also made of elastomeric material, but has at the contact surfaces to the tubes 4 in each case reinforcements 8, which extend radially outward than the Elasto body of the pressure transmission element 2 itself. In the case of compression of the pressure transmission element 2 takes place in In this case, at the contact surfaces to the tubes no radial transverse extent, so that no tensile stresses are exerted on the pipe end faces. The tubes 4 are thus preserved from damage. In this embodiment, the pressure transmission element 2 has the shape of a parallel flattened circular cross-section. FIG. 6 shows a further embodiment of a pressure transmission element 2, which has a rectangular profile.

The corresponding pressure transmission element 2 at full pressure can be seen in Figure 7, in which case it should be noted in particular that the reinforcements 8 remain unchanged in their radial extent c, c ', while the

Elastomer body of the pressure transmission element 2 itself clearly widened from b to b '. However, since the pipe end faces of not shown here

Tubes 4 come into direct contact only with the reinforcements 8, no tensile stresses are exerted on the pipe end faces by the transverse deformation of the pressure transmission element 2.

In the figures 8 and 9 further embodiments of a pressure transmission element 2 are shown, in which case a plane-parallel rectangular profile is used with concave radial faces. Also in this case, the radial extent of the reinforcements 8 is wider than the radial extent of the pressure transmission element 2 even in a relaxed state, so that even at full pressure, shown in Figure 9, the elastomeric part of the pressure transmission element 2 does not protrude radially beyond the reinforcements 8.

- Claims -

Claims

claims

1. pressure equalization ring for insertion between pipe end faces (4a) in the underground propulsion of pipes (4),

5 wherein the pressure equalization ring (1) has one or more pressure transmission elements (2) made of elastomeric material, characterized in that the pressure transmission elements (2) at their at least for the contact with the end faces of the tubes (4) contact surfaces (6) at least partially lo reinforcements (8 ), which largely prevent stretching of the pressure-transmitting elements (2) in the plane of the pressure-equalizing ring (1) at the contact surfaces (6).

2. pressure equalization ring according to claim 1, characterized in that the reinforcements (8) consist of a fabric.

3. pressure equalization ring according to claim 2, characterized in that the fabric is a textile, steel, plastic, glass fiber, ceramic fiber, carbon fiber or aramid fiber fabric.

4. pressure equalization ring according to claim 1, characterized in that the reinforcements (8) consist of strips of a material, the one

20 higher elastic modulus than the pressure transmission elements (2) itself.

5. pressure equalization ring according to claim 4, characterized in that the strips of metal, in particular made of steel.

6. pressure equalization ring according to one of claims 2 to 5, characterized in that the strips or the fabric on the contact surfaces (6) vulcanized onto the pressure transmission elements (2) or in the pressure transmission elements (2) is vulcanized.

5. Pressure equalizing ring according to claim 1, characterized in that the reinforcements (8) consist of fibers embedded in the contact surfaces (6) of the pressure transmission elements (2).

8. pressure compensation ring according to claim 7, characterized in that the fibers are glass fibers, steel fibers, plastic fibers, ceramic fibers, o aramid fibers or carbon fibers.

9. pressure equalization ring according to one of claims 1 to 8, characterized in that the pressure transmission elements (2) on at least one side notches.

10. pressure compensation ring according to one of claims 1 to 9, characterized 5 in that the reinforcements (8) protrude radially at the contact surfaces (6) via the elastic parts of the pressure transmission elements (2) in a relaxed state.

1 1. pressure compensation ring according to one of claims 1 to 10, characterized in that the pressure transmission elements (2) are provided with a press o adhesive layer.

12. pressure equalization ring according to one of claims 1 to 11, characterized in that the pressure equalization ring (1) has a plurality of pressure transmission elements (2), which are arranged in the plane of the pressure equalization ring (1) spaced from each other.

5 13. pressure compensation ring according to claim 12, characterized in that the pressure transmission elements (2) are formed as elastomeric lamellae.