WO2024104741A1

WO2024104741A1 - Compensation device

Info

Publication number: WO2024104741A1
Application number: PCT/EP2023/079640
Authority: WO
Inventors: Klaus Lang
Original assignee: Eagleburgmann Germany Gmbh & Co. Kg
Priority date: 2022-11-17
Filing date: 2023-10-24
Publication date: 2024-05-23
Also published as: DE102022130432A1

Abstract

The invention relates to a compensation device for compensating for movements in an axial direction X-X between two components, comprising a circumferentially closed bellows (2) and a spring device (3) which is connected to the bellows (2), wherein the bellows (2) provides a sealing function between an inner region (4) and an outer region (5) of the bellows, wherein the bellows (2) exerts a first pre-tensioning force F1 in a first axial direction X1, and the spring device (3) exerts a second pre-tensioning force F2 in a second axial direction X2 which is opposite the first axial direction X1. The absolute value of the first pre-tensioning force F1 differs from the second pre-tensioning force F2 such that a resulting pre-tensioning force F0 acting in the axial direction is produced.

Description

Compensation device

Description

The invention relates to a compensation device for compensating movements in an axial direction with a pre-tensioning function and a sealing function, for example in pipelines. Furthermore, the present invention relates to a pipe arrangement with a compensation device.

Compensation devices are known from the state of the art, for example as compensators in piping systems, in various designs. Compensation devices provide a flexible connection between two pipe ends in order to compensate for thermal changes in the length of the pipes in the pipe system, for example. Shaking or rattling movements or the like can also be exerted on the pipe system, which can lead to movements in the pipe system. Depending on the dimensions of the system, such compensation devices can have cross-sections of over one meter. Combined sealing and pre-tensioning functions must also be provided for other applications.

It is therefore an object of the present invention to provide a compensation device and a pipe arrangement which, with a simple structure and simple, cost-effective manufacture, enables a reliable compensation of axial movements, while at the same time a sealing function and a preloading function can be realized.

This object is achieved by a compensation device having the features of claim 1 and a pipe arrangement having the features of claim 10. The subclaims show preferred developments of the invention.

The compensation device according to the invention with the features of claim 1 combines a circumferentially closed bellows and a spring device to form a spring system. As a result, a bellows can have a large amount of freedom in terms of its properties, in particular with regard to the choice of material and its sealing properties. In addition to a pre-tension of the bellows, a pre-tension of the compensation device is also by means of a spring device. The spring device is connected to the bellows. The bellows provides a sealing function between an inner region of the bellows and an outer region of the bellows. The bellows has a first preload force F1 in a first axial direction and the spring device has a second preload force F2 in a second axial direction, opposite to the first axial direction. Absolute amounts of the first and second preload forces are different, so that the compensation device has a preload in one of the axial directions. Thus, after installation of the compensation device in a system, a sealing function and a preload function can be implemented at the same time. The different preload forces of the bellows and the spring device pointing in different directions enable a desired preload force to be set precisely in a relatively simple manner. The compensation device can be provided relatively inexpensively, whereby the bellows in particular can be optimized with regard to the sealing function and with regard to axial mobility, without the bellows boundary conditions relating to a preload force having an excessive influence on the design of the bellows. The resulting preload force of the compensation device can be provided by appropriate optimization of the spring device, so that the manufacture of the bellows in particular is subject to fewer potentially restrictive boundary conditions. This also makes it possible to seal media under high pressure, in particular greater than 200 x 10 ⁵ Pa and high temperatures, in particular greater than 550°C. The compensation device according to the invention therefore has a wide range of applications and can be used, for example, in power plants in pipelines or in gas pipelines.

Preferably, the amount of the first preload force F 1 of the bellows is smaller than the amount of the second preload force F2 of the spring device. This allows the bellows to be optimized in terms of its sealing function. The desired resulting preload force can then be provided by designing the spring device.

The spring device is preferably a spring element with negative stiffness at the operating point A (negative spring) and particularly preferably comprises at least one disc spring or at least one cylinder spring. However, the spring device can also be constructed from several disc springs, which are preferably each connected to a fold of the bellows. Alternatively, a plurality of cylinder springs can be arranged along the outer circumference of the bellows.

Further preferably, a spring characteristic curve FKO of the compensation device is provided such that in a maximum displacement range B of the compensation device, which defines a maximum axial displacement path of the compensation device, a maximum force variation of the resulting force is in a range of ± 10% of a force Fx at the operating point A of the spring characteristic curve FKO. As a result, the spring characteristic curve is very flat, especially in the area of the operating point A.

Particularly preferably, the compensation device is a pre-assembled unit which comprises the bellows and the spring device.

Preferably, the spring device is fixed directly to the bellows. The bellows is preferably a metal bellows, so that the spring device can preferably be attached to the metal bellows by means of a welding or soldering process. The spring device is further preferably fixed to fold end regions of folds of the bellows.

According to a preferred alternative embodiment of the invention, the spring device and the bellows are connected to one another by means of a connecting component. The connecting component is, for example, an annular disk or an annular flange or the like, to which the spring device is attached on the one hand and the bellows on the other.

Preferably, the spring device is arranged outside the bellows. Particularly preferably, the spring device is arranged completely radially outside the bellows. This results in a particularly compact structure, in particular in the axial direction of the compensation device.

The invention further relates to a pipe arrangement comprising a first and a second pipe and a compensation device according to the invention, which connects the first and second pipes to one another in a sealing manner. As a result, the pipe arrangement can compensate for thermally induced length changes or axial movements of the pipes caused by external influences, for example by shaking or rattling processes.

Preferred embodiments of the invention are described in detail below with reference to the accompanying drawing. In the drawing:

Fig. 1 is a schematic sectional view of a compensation device according to a first embodiment of the invention,

Fig. 2 is a schematic perspective view of the compensation device of Fig. 1,

Fig. 3 is a schematic representation of a diagram of a spring force F over a path X for the spring characteristics of the compensation device, and Fig. 4 is a schematic sectional view of a compensation device according to a second embodiment of the invention.

A compensation device 1 according to a first preferred embodiment of the invention is described in detail below with reference to FIGS. 1 to 3.

As can be seen from Fig. 1, the compensation device 1 comprises a circumferentially closed bellows 2 and a spring device 3 which is connected to the bellows 2. The compensation device is designed to compensate for movements in an axial direction X-X.

The compensation device 1 connects a first pipe 11 to a second pipe 12. The bellows 2 is connected to the first pipe 11 at one end and to the second pipe 12 at the other end by means of welded joints 6.

As can be seen from Fig. 1, the bellows 2 provides a sealing function between an inner region 4 of the bellows and an outer region 5 of the bellows.

The bellows has a first preload force F1 in a first axial direction X1. The spring device 3 has a second preload force F2 in a second axial direction X2. The second axial direction X2 is opposite to the first axial direction X1.

An absolute value of the first and second preload force F2, F1 is different. The first preload force F1 of the bellows is smaller than the second preload force F2 of the spring device 3. This results in a resulting preload force F0 in the second axial direction X2.

The spring device 3 comprises a plurality of spring rings 30, which are a type of disc spring (cf. Fig. 2), as well as a plurality of connecting webs 31, which connect the spring rings 30 to one another.

The spring device 3 is supported on a housing 9 and is directly connected to the bellows 2. Each spring ring is connected to a radially outwardly directed end 20a of a fold.

The bellows 2 and the spring device 3 can be connected at the ends 20a, for example by means of a welded connection.

The spring rings 30 are constructed in the same way and have two disc spring-shaped elements which are connected to one another by connecting webs 31. The spring rings 30 run along the entire outer circumference of the bellows 2. As can be seen in particular from Fig.

1, the spring device 3 is completely radially outside the bellows

2 arranged. Fig. 3 shows a diagram which schematically illustrates the composition of the preload force F0 of the compensation device. Fig. 3 shows the spring force F over the path X. A line FK1 is the spring characteristic curve of the bellows 2. A line FK2 is the spring characteristic curve of the spring device 3. The spring characteristic curve FK1 of the bellows 2 is a straight line and the spring characteristic curve FK2 of the spring device 3 is sinusoidal. A sum of the two spring characteristics FK1 and FK2 gives the resulting spring characteristic curve FKO, which defines the preload F0 in the axial direction of the compensation device 1. At an operating point A, the preload force of the compensation device 1 is positive in the second axial direction X2, so that a resulting preload force is exerted on the first tube 11. The spring device 9 is a spring element with a negative slope at the operating point A (negative spring).

As can also be seen from Fig. 3, the combined spring characteristic curve FKO of the compensation device 1 is very flat around the operating point A. In Fig. 3, a maximum displacement range B of the compensation device 1 is shown. The displacement range B defines a maximum axial displacement path of the compensation device. A maximum force variation of the resulting force lies in a range of ± 10% of a force Fx at the operating point A of the spring characteristic curve FKO. The spring characteristic curve FKO is therefore very flat and essentially horizontal in a wide range around the operating point A.

This ensures excellent axial mobility of the bellows 2, so that in addition to temperature-related changes in the length of the pipe system, shocks or similar that can be exerted on the pipe system can also be safely absorbed and cushioned. Due to the flat spring characteristic curve FKO in the area of the operating point A, a quick return to the starting position shown in Fig. 1, in which the resulting preload force F0 is present, can then take place after a deflection has taken place.

The bellows 2 is preferably made of metal. This allows the compensation device to be used in particular under extreme operating conditions, for example at very high temperatures > 550°C and very high pressures > 200 x 10 ⁵ Pa.

Furthermore, the compensation device according to the invention enables the use of a bellows in a compensation device, which was previously not possible in the prior art due to pressure, material strength, chemical compatibility and/or temperatures. In particular, the rigidity usually present when using metallic bellows, which impairs the axial mobility of the bellows, can be compensated by the additional integrated spring device 3. The compensation device 1 can therefore operate essentially wear-free. Using a metallic bellows, a particularly simple connection between the compensation device and the pipes 11, 12 can also be provided by the welded connection.

The compensation device 1 can also be provided as a pre-assembled unit, so that installation of the compensation device 1 is relatively quick and easy.

Fig. 4 shows a compensation device 1 according to a second embodiment of the invention. Identical or functionally identical parts are designated with the same reference numerals as in the first embodiment.

As can be seen from Fig. 4, the second embodiment essentially corresponds to the first embodiment. In contrast to the first embodiment, in the second embodiment a connecting component 7 is arranged between the bellows 2 and the spring device 3. As can be seen from Fig. 4, the connecting component 7 is annular and comprises a first, radially outward-facing leg 71 and a second leg 72 directed parallel to the axial direction XX. The two legs 71, 72 are arranged at a right angle to one another. The spring device 3 is connected to the first leg 71 and the bellows 2 is connected to the second leg 72. In this embodiment, the second leg 72 is only connected to one end 20a of a fold 20 of the bellows 2. However, it is also possible for the second leg 72 to be extended in the axial direction XX and to be connected to all ends 20a of the bellows. Thus, the bellows 2 and the spring device 3 are no longer connected directly to one another, but via the connecting component 7. Otherwise, this embodiment corresponds to the previous embodiment, so that reference can be made to the description given there.

List of reference symbols

1 compensation device

2 Bellows

3 Spring device

4 Interior

5 Outdoor area

7 Connecting component

9 Housing

11 first pipe

12 second pipe

20 folds

20a End of a fold of the bellows

30 Spring ring

31 Connecting bridge

A Operating point of the compensation device

B maximum axial displacement range

F0 combined preload force

F1 first preload force of the bellows

F2 second preload force of the spring device

FKO combined spring characteristic

FK1 spring characteristic of the bellows

FK2 Spring characteristic curve of the spring device

Fx force at operating point

X-X axial direction

X1 first axial direction

X2 second axial direction

Claims

Expectations

1. Compensation device for compensating movements in an axial direction X- X between two components, comprising a circumferentially closed bellows (2), and a spring device (3) which is connected to the bellows (2), wherein the bellows (2) provides a sealing function between an inner region (4) and an outer region (5) of the bellows, wherein the bellows (2) has a first preload force F1 in a first axial direction X1 and wherein the spring device (3) has a second preload force F2 in a second axial direction X2 which is opposite to the first axial direction X1, and wherein an absolute value of the first preload force F1 is different from the second preload force F2, so that a resulting preload force F0 results in the axial direction.

2. Compensation device according to claim 1, wherein the amount of the first preload force F1 of the bellows (2) is smaller than the amount of the second preload force F2 of the spring device (3).

3. Compensation device according to one of the preceding claims, wherein a spring characteristic curve FKO of the compensation device (1) describes an inflection point at an operating point A of the compensation device (1), wherein the spring device (3) is a spring system with a negative slope at the operating point.

4. Compensation device according to claim 3, wherein the spring characteristic FKO of the compensation device (1) in a maximum displacement range B, which defines a maximum axial displacement path of the compensation device, has a maximum force variation of a resulting force in a range of ± 10% of a force Fx in the operating point A of the spring characteristic FKO.

5. Compensation device according to one of the preceding claims, wherein the compensation device (1) is a pre-assembled unit which comprises the bellows (2) and the spring device (3).

6. Compensation device according to one of the preceding claims, wherein the spring device (3) is fixed directly to the bellows (2).

7. Compensation device according to one of claims 1 to 5, wherein the spring device (3) is connected to the bellows (2) by means of a connecting component (7).

8. Compensation device according to one of the preceding claims, wherein the

Spring device (3) is arranged outside the bellows (2).

9. Compensation device according to claim 8, wherein the spring device (3) is arranged completely radially outside the bellows (2).

10. Pipe arrangement comprising a first pipe (11), a second pipe (12) and a compensation device (1) according to one of the preceding claims, which connects the first pipe (11) to the second pipe (12).