CN119404009A

CN119404009A - Compressor device and cooling device having the same

Info

Publication number: CN119404009A
Application number: CN202380047782.1A
Authority: CN
Inventors: 延斯·赫内
Original assignee: Pressure Wave Systems GmbH
Current assignee: Pressure Wave Systems GmbH
Priority date: 2022-06-23
Filing date: 2023-06-14
Publication date: 2025-02-07
Also published as: US20250129977A1; EP4544185A1; DE102022115715A1; WO2023247277A1; JP2025519781A

Abstract

The invention relates to a compressor device (2) comprising a cylinder (4), a piston (6) arranged in the cylinder (4), the piston defining a transfer chamber (16) filled with a transfer fluid and being able to periodically reciprocate by means of a drive device (26), a compressor element (8), in particular a (metal) bellows, arranged in the transfer chamber (16), the compressor element defining a working chamber/compression chamber (20) filled with a working gas, and a connector (10) via which the working chamber (20) can be connected to a working gas line (36) to form a Gifford-McMahon cooler or a pulse tube cooler (38), wherein the compressor element (8) and the working gas contained in the compressor element are periodically compressed indirectly by the transfer fluid discharged by the piston (6).

Description

Compressor device and cooling device with same

Technical Field

The present disclosure relates to a compressor device and a cooling device having a compressor device and a gifford-mcmahon cooler or pulse tube cooler.

Background

For cooling magnetic resonance tomography scanners, cryopumps, quantum computers, quantum communication devices, etc., pulse tube coolers or Gifford-McMahon-kuhler coolers are widely used. In this case, a gas compressor and in particular a helium compressor is used in combination with a rotary valve or rotary valve. The helium compressor is connected to the rotary valve via a high-pressure line and a low-pressure line. On the output side, the rotary valve is connected via a gas line to a cooling device in the form of a gifford-mcmahon cooler or a pulse tube cooler. The high-pressure side or the low-pressure side of the gas compressor is connected alternately to the pulse tube cooler or the gifford-mcmahon cooler via a rotary valve. The rate for introducing compressed helium into the cooling device and implementing again is in the range of 1-2 Hz. A disadvantage of such cooling systems or compressor systems is that the motor-driven rotary valve causes a loss of approximately 50% of the compressor input power.

Cooling devices with pulse tube coolers or gifford-maxwellian coolers are known from DE10137552C 1.

DE633104a discloses a compressor device having a compression mechanism in which a working medium is periodically compressed and again relieved by a reciprocating compressor element in the form of a piston. The driving means comprise a pressure cylinder with a reciprocating piston. The drive device is mechanically coupled to the compressor element. Both the drive means and the compressor element are formed with individual pressure cylinders in which the compressor piston or the compressor piston is supported. The drive means and the compressor element are mechanically connected in this case, wherein the lead-through formed by the pressure cylinder is sealed. This construction results in a relatively large space requirement for the apparatus, since the pressure cylinders are arranged in series. Furthermore, this construction necessitates the use of two pistons, and two penetrations, which are structurally too costly and susceptible to failure in terms of tightness.

Disclosure of Invention

It is an object of the present invention to obviate or at least mitigate the disadvantages of the prior art. It is an object of the present invention in particular to provide a compressor device and a cooling system which minimize losses and installation space.

This object is achieved by a compressor device according to claim 1 and by a cooling device according to the parallel claim.

In particular, this object is achieved by a compressor device having a cylinder, a piston arranged in the cylinder, the piston defining a transfer chamber filled with a transfer fluid and being able to be periodically reciprocated by means of a drive means, a compressor element, preferably a bellows, in particular a metal bellows, arranged in the transfer chamber, the compressor element defining a working chamber (compression chamber) filled with a working gas, and a joint through which the working chamber is connectable to a working gas line (pressure line) for a Cheng Jifu d-Maxwell or pulse tube cooler, in particular a two-stage 4K (four-Kelvin) cooler, wherein the compressor element and the working gas contained in the compressor element are periodically compressed/pressed indirectly by the transfer fluid discharged by the piston.

In other words, the compressor device comprises a cylinder having a cylinder travel path configured on the inside of the cylinder and a piston that runs in the cylinder, which has a piston skirt configured in the circumferential direction of the piston. The piston skirt sealingly slides on the cylinder path of the cylinder. Preferably, at least one annular seal/piston ring is formed between the piston skirt and the cylinder path. The piston also includes a piston crown that faces and defines a transfer chamber filled with a transfer fluid. The piston is arranged and configured to perform a periodic linear motion in a direction of a cylinder center line (cylinder center axis) extending in a cylinder length direction. A compressor element is formed in the transfer chamber, which comprises at least one preferably accordion-shaped wall. In other words, the compressor element is preferably configured as a bellows. The compressor element encloses a working chamber filled with a working gas. In other words, the compressor element defines a working chamber with respect to the transfer chamber. The working chamber is configured with a fitting that fixedly or detachably connects the working chamber with the working gas line. The connection is preferably formed on the side of the compressor element facing away from the piston. A working gas line is provided and configured to connect the working chamber with a gifford-maxwellian cooler or a pulse tube cooler or any other suitable cooler. The volume of the working chamber is variable due to the preferably accordion-shaped wall. By means of the linear movement of the piston, a force is exerted/transmitted to the compressor element by means of the transmission fluid and is periodically compressed/pressed and relieved by the working gas contained in the working chamber.

The core of the invention is thus the periodic compression and decompression of the working gas contained in the compressor element of the compressor device indirectly by means of the movement of the piston by means of the transfer fluid.

Furthermore, the core of the present invention is that a pressure generating site (force generating site) and a compression site are constructed in a cylinder.

A further core of the invention is that the piston and the compressor element are mechanically decoupled.

In other words, the piston and the compressor element are arranged within the cylinder such that they never contact each other. Furthermore, the forces acting on the piston or the forces to be transmitted by the piston are only transmitted hydraulically to the compressor element. In the present invention, the mechanical connection for force transmission between the piston and the compressor element is omitted.

By constructing the compressor device in this way, the rotary valve can be omitted and thus the losses can be reduced and thus the efficiency of the compressor device can be significantly increased. Furthermore, such a compressor device can be constructed more compactly, since a single-cylinder structure of the compressor device can be realized. A further advantage of such a compressor device is that the safety against malfunctions of the compressor device can be increased by reducing the number of components.

By constructing the working chamber in the compressor element, in particular by constructing the compressor element as a metal bellows, it is also possible to prevent water, transfer fluid, oil or other impurities from entering/diffusing into the working gas and contaminating/contaminating the working gas. Contamination of the working gas with impurities may cause the working gas to freeze and the seal to be damaged. In particular, the construction of the compressor element as a metal bellows has the advantage over, for example, a rubber construction of the compressor element that working gas cannot leak from the compressor element or through the compressor element into the transfer chamber.

In the first aspect, the volume of the space/fluid chamber enclosed by the piston, the compressor element and the cylinder may be constant.

In other words, the region of the transfer chamber outside the compressor element/working chamber may be completely filled with the transfer fluid, wherein the transfer fluid may be a substantially incompressible fluid.

In this way, it can be ensured that the force exerted by the piston on the transmission fluid can be transmitted to the bellows uniformly and without local force peaks. It is thereby ensured that the compressor element is compressed and expanded only in the manner and method provided, which considerably prolongs the service life of the compressor element and prevents premature failure of the compressor element. Furthermore, by completely filling the transfer chamber with the transfer fluid, foaming or foam formation of the transfer fluid during operation can be prevented.

Furthermore, the transfer chamber and the working chamber can be constructed completely and without a projection in the cylinder.

In another aspect, the pressure of the working medium in the working chamber may correspond to the pressure of the transfer fluid in the transfer chamber at any point in time.

In other words, at any point in time, the pressure in the compressor element corresponds to the pressure around the compressor element. In other words, the working medium in the working chamber and the transfer fluid in the transfer chamber are in pressure balance.

In this way, it can be ensured that the compressor element itself is not subjected or not subjected to large loads/forces and that the compressor element can be constructed thin-walled, which further reduces losses in the compression of the compressor element.

In another aspect, the pressure of the working medium and the pressure of the transfer fluid may be greater than an ambient pressure of an environment surrounding the compressor device.

In other words, the compressor device is preloaded such that in each position of the piston in the cylinder there is an overpressure of the working medium and the transmission medium relative to the surroundings.

In another aspect, the piston maximum stroke may be greater than the compressor element maximum stroke.

In other words, the amplitude of the piston implemented when it is periodically reciprocated in the piston movement direction may be larger than the maximum variation of the extension of the compressor element in the piston movement direction.

By means of a smaller maximum stroke of the compressor element, it is possible to keep the mechanical load on the compressor element small, in particular in the bending/folding of the compressor element, which increases the service life of the compressor element and reduces the risk of failure.

On the other hand, the piston may be periodically reciprocated by the connecting rod. A conventional electric motor may be used as the driving means by means of a connecting rod for moving the piston. Alternatively, the piston may be reciprocated by a threaded rod or the like.

On the other hand, the compressor element may be guided in the stroke direction.

In other words, the compressor device may comprise at least one guiding element configured to guide the compression element during compression and pressure relief and to prevent uncontrolled bending or collapse of the compressor element. The guide element can be configured, for example, in a rod-shaped or sleeve-shaped manner. Preferably, more than one guide element may be configured in the compressor device.

On the other hand, a closed displacement (tank element) can be formed in the working chamber.

In other words, the displacement element can be formed on the inner side of the compressor element facing the working chamber, preferably on the end side of the compressor element close to the pistonThe displacement element may be an element, in particular a cylindrical element, which is closed in a gas-tight manner, and which may be configured for a fixed connection with the compressor element.

The (gas) volume of the working chamber can be reduced by such displacement elements in the working chamber. It is thereby achieved that the working chamber has an approximately zero (dead/residual) volume in the compressed state, which reduces the deflection of the compressor element and thus the loading of the compressor element.

In another aspect, the maximum longitudinal extension of the compressor element in the stroke direction in the expanded state may be twice the minimum longitudinal extension of the compressor element in the stroke direction in the compressed state.

In another aspect, the transfer chamber and/or the working chamber can be connected to at least one equalization vessel, optionally via a valve, in order to pretension the compressor device and compensate for possible volume changes, in particular when the compressor device is running up or is started up.

In another aspect, the compression of the compressor element is reversible. This means that the volume of the compressor element changes only within a predefined range during operation and then resumes the original geometry.

In another aspect, the wall thickness of the compressor element may be constant. Preferably, the wall thickness of the compressor element may be less than 0.2mm.

In another aspect, the compressor element may be constructed from a plurality of membrane pairs. Preferably, the compressor element may be constructed from at least 30 membrane pairs. Particularly preferably, the compressor element can be constructed from at least 40 membrane pairs.

By configuring the compressor element with a plurality of membrane pairs, it can be ensured that each of the membrane pairs experiences only a small deflection during the stroke movement of the compressor element, which significantly reduces the mechanical load of the compressor element.

In another aspect, the transfer chamber may be configured with a multi-stage geometry, particularly a two-stage geometry. In other words, the transfer chamber may have a diameter jump, wherein the first diameter in the region of the piston may preferably be smaller than the second diameter in the region of the compressor element. In this way, the force to be applied by the piston for displacing the transmission fluid can be adapted to the driving force or driving torque of the driving means.

In a further aspect, the drive means may be configured with and/or connected to control means which control the compression/squeezing and pressure relief of the working medium in the working chamber by a periodical longitudinal movement of the piston, in particular by the rotational speed of the drive means.

On the other hand, the displacement volume displaced by the piston during the movement of the piston can be varied in relation to the working chamber volume, thereby significantly simplifying the control of the compressor device.

In another aspect, a filter may be connected downstream of the compressor device.

In another aspect, the working medium may be helium.

Advantageously, the movement profile of the piston is not a linear or sinusoidal profile, but follows a step function, in which the working gas is rapidly compressed, the pressure is maintained and then the working gas is rapidly depressurized again. The movement profile can be achieved by a correspondingly variable actuation of the drive means.

Alternatively, the drive means can be actuated in the same manner and the step-function movement of the piston is effected by means of a corresponding transmission element, such as a cam. In other words, the linear movement of the drive means can be converted into an almost step-function movement of the piston by means of a cam-shaped transmission element. In yet another words, the transfer element may be asymmetric about the rotational axis of the transfer element.

In another aspect, the drive means may drive more than one compressor device. In this configuration, the cylinders may preferably be arranged in a matrix-pair type (Boxerformation). In other words, for example, two cylinders can be configured diametrically opposite from the drive means, wherein the cylinders can be identically configured. Each cylinder may be configured with a piston and a compressor element.

In another aspect, the transfer fluid may (also) be used as a lubricant for the drive device. In other words, the transfer fluid can be configured as a lubricant on the side of the piston facing away from the transfer chamber. In particular, the transfer fluid may lubricate the motor link pairs and the link piston pairs. By configuring the transfer fluid as a lubricant, possible leakage of the transfer fluid through the piston towards the drive means can be prevented from negatively affecting the drive means.

In a further aspect, the compressor device may be designed for an operating frequency range between 0.1Hz and 10Hz and in particular for an operating frequency range between 0.5Hz and 5 Hz.

Furthermore, the object is achieved by a cooling device having a compressor device according to any of the above aspects and a gifford-maxwell or pulse tube cooler.

In other words, the cooling device comprises a compressor device according to any one of the above aspects and a gifford-mcmahon cooler or a pulse tube cooler connected via a joint. Alternatively, the heat exchanger for cooling the working gas may be configured between the cooling device and the gifford-mcmahon cooler or the pulse tube cooler, or the cooling device may be configured directly on the gifford-mcmahon cooler or the pulse tube cooler.

In this way, the rotary valve can be omitted and the pressure curve can be established directly with the compressor device. The gifford-maxwell cooler or pulse tube cooler may be directly connected to the compressor device. For operation of the gifford-mcmahon cooler or pulse tube cooler, extremely pure helium (6n=99.9999% helium) is required.

In one aspect, the compressor device and the gifford-mcmahon cooler or pulse tube cooler can be connected by a high pressure connection.

In another aspect, the cooling device or the compressor device may be preloaded at 16 bar. The operating range of the compressor device may be between 8 bar and 24 bar.

Further, the compressor refrigerator may be configured to have the compressor device, the evaporator, and the condenser according to any one of the above aspects.

Drawings

Fig. 1 is a schematic view of a compressor device according to the present invention in a general embodiment;

FIG. 2 is a schematic view of a compressor device according to the present invention in a particular embodiment;

Fig. 3 is a schematic view of the structure of a cooling device according to the present invention in a first embodiment;

fig. 4 is a schematic view of the structure of a cooling device according to the present invention in a second embodiment;

Fig. 5 is a schematic view of a compressor device according to the present invention in a first alternative embodiment;

fig. 6 is a schematic view of a compressor device according to the present invention in a second alternative embodiment;

Fig. 7 is a schematic view of a compressor device according to the present invention in a third alternative embodiment, and

Fig. 8 is a schematic view of a compressor device according to the present invention in a fourth alternative embodiment.

Detailed Description

Embodiments of the present disclosure are described below based on the drawings.

Fig. 1 shows a compressor device 2 according to the invention with a gas-tight cylinder 4, a piston 6 arranged in the cylinder 4, a compressor element in the form of a (metal) bellows 8 and a joint 10, wherein the compressor device 2 is arranged and configured to be coupled with or form part of a cooling device. The cylinder 4 comprises a (cylinder) working surface 12 configured on the inner side of the cylinder 4. The piston 6 comprises a piston skirt 14 formed on the outer circumferential surface of the piston 6, wherein the working surface 12 of the cylinder 4 and the piston skirt 14 of the piston 6 cooperate with one another in such a way that the piston 6 can move in a sealing manner in the cylinder 4 along the cylinder central axis ZM. The piston 6 and the cylinder 4 define a transfer chamber 16. The transfer chamber 16 is filled with a transfer fluid. The bellows 8 is arranged in the transfer chamber 16 and is surrounded by a (incompressible) transfer fluid. In particular, the transfer fluid is built in a fluid chamber 18 enclosed/enclosed between the cylinder 4, the piston 6 and the bellows 8. The volume of the fluid chamber 18 is substantially non-variable, wherein the geometry of the fluid chamber 18 may vary, however.

Bellows 8 contains/defines a working chamber 20. The working chamber 20 is filled with a working gas, preferably helium. In the embodiment shown here, the bellows 8 is configured as a bellows with an accordion-shaped wall 22. Bellows 8 separates transfer chamber 16 and working chamber 20 from each other in a gas-tight and fluid-tight manner. The joint 10 is formed on the side of the working chamber 20 facing away from the piston 6. Fitting 10 is provided and configured to connect compressor device 2 to a coldhead/cooler 38 (see fig. 3), such as a gifford-mcmahon cooler or a pulse tube cooler.

Fig. 2 shows a compressor device 2 in an embodiment, in which the piston 6 is linearly movable along a cylinder central axis ZM by means of a connecting rod 24.

The operation of the compressor device 2 according to the invention is described below with the aid of fig. 2. The actuation of the piston 6 by the connecting rod 24 is exemplary. Of course, other driving means of the piston 6 capable of periodically reciprocating the piston 6 along the cylinder center axis ZM are considered equivalent.

The drive means in the form of an electric motor 26, which is actuated by a corresponding control means (not shown), drives the disk 28 in rotation, on which the connecting rod 24 is mounted eccentrically in a first bearing position 30. In addition, the connecting rod 24 is supported/fixed on the piston 6 in the second support position 32. By means of the connecting rod 24, a linear movement of the piston 6 along the cylinder central axis ZM is formed by the rotational/circular movement of the disc 28. In other words, the force generated by the electric motor 26 is transmitted to the piston 6 via the disc 28 and the connecting rod 24.

When the piston 6 moves in the direction of the bellows 8 side along the cylinder center axis ZM, the force is transmitted to the transmission fluid in the fluid chamber 18. The transfer fluid surrounding the bellows 8 transfers force to the bellows 8 and compresses the working gas contained in the bellows 8. Because the transfer fluid is an approximately incompressible fluid, the force exerted by the electric motor 26 (minus possible friction losses) is substantially completely translated into the compression of the bellows 8 and the compression of the working gas in the working chamber 20. In other words, the working gas in the working chamber 20 is periodically compressed by the force of the electric motor 26. The working range of the bellows 8 is here between a first length L1 in the compressed state and a second length L2 in the depressurized state. The (maximum) length change al of the bellows 8 is much smaller than the first length L1 or the second length L2, which corresponds to the difference between the first length L1 and the second length L2.

Fig. 3 shows a cooling device 34 according to the invention with a compressor device 2 in a first embodiment. The working chamber 20 of the compressor device 2 is connected via a connection 10 to a pressure line 36. A pressure line 36 connects the compressor device 2 in a gas-tight manner to a cold head 38, which is embodied as a gifford-maxwellian cooler or pulse tube cooler. For operating such a cold head 38, the defined working gas volume is periodically compressed and relieved in a predetermined frequency range by the compressor device 2.

Fig. 4 shows a cooling device 34 according to the invention with a compressor device 2 in a second embodiment. The cooling device 34 of the second embodiment substantially corresponds to the cooling device 34 of the first embodiment. In the second embodiment, a heat exchanger 40 is provided between the connection 10 and the cold head 38 of the compressor device 2, said heat exchanger being provided and configured for cooling down the working gas, in particular after compression.

An alternative embodiment of the compressor device 2 is described below with reference to fig. 5 to 8. A description of elements corresponding to the general embodiment described in fig. 1 will be omitted hereinafter.

The first alternative embodiment of the compressor device 2 shown in fig. 5 comprises a tank element 42 in the bellows 8. The tank element 42 is formed in the working chamber 20 on the end face of the bellows 8 facing the piston 6. Tank member 42 reduces the gas volume/internal volume of working chamber 20. The tank element 42 is hermetically closed with respect to the working chamber 20.

Fig. 6 shows a second alternative embodiment of the compressor device 2 with a shaft-shaped or rod-shaped guide element 44. A rod-shaped guide element 44 is formed in the transfer chamber 16 on the end face of the bellows 8 facing the piston 6. The rod-shaped guide element 44 extends away from the bellows 8 toward the piston 6 and is supported in the piston 6. The rod-shaped guide element 44 is guided or supported linearly in the piston 6. Preferably, the rod-shaped guide element 44 is guided or supported in a bushing in the piston 6. Optionally, more than one rod-shaped guide element 44 is formed on the bellows 8. The rod-shaped guide element 44 prevents tilting of the bellows 8 relative to the piston 6.

Fig. 7 shows a third alternative embodiment of the compressor device 2 with a flat guide element 46. The flat guide element 46 is formed in the transfer chamber 16 on the end face of the bellows 8 facing the piston 6. The flat guide element 46 extends radially outwards towards the working surface 12 and guides the bellows 8 relative to the working surface 12. In the flat guide element 46, a bore 48 is formed, which ensures an unimpeded flow of the transfer fluid in the transfer chamber. The flat guide element 46 prevents tilting of the bellows 8 relative to the cylinder 4.

Fig. 8 shows a fourth alternative embodiment of the compressor device 2, wherein the cylinder 4 is constructed in two stages. The cylinder 4 comprises a first cylinder section 50, in which the bellows 8 is formed, and a second cylinder section 52, in which the piston 6 is formed. The first diameter of the first cylinder section 50 is greater than the second diameter of the second cylinder section 52. In other words, a pressure transition in the cylinder 4 is achieved by the first cylinder section 50 and the second cylinder section 52.

Of course, the features of all described embodiments may be combined arbitrarily in the claims, if technically feasible.

It is thus conceivable, for example, to configure the compression device 2 with a tank element 42 in the working chamber 20 and to additionally configure the bellows 8 with a rod-shaped guide element 44 and/or a flat guide element 46.

It is also conceivable for the compression device 2 to be configured with a cylinder 4 having a first cylinder section 50 and a second cylinder section 52 and a tank element 42.

It is furthermore conceivable for the compressor device to be configured with a cylinder 4, which has a first cylinder section 50 and a second cylinder section 52, a tank element 42 and a rod-shaped guide element 44 and/or a flat guide element 46.

List of reference numerals

2 Compressor device

4 Jar

6 Piston

8 Corrugated pipe

10 Joint

12 (Cylinder) working surface

14. Piston skirt

16. Transfer chamber

18. Fluid chamber

20. Working room

22. Wall with a wall body

24. Connecting rod

26. Electric motor

28. Disk

30. First support position

32. Second support position

34. Cooling device

36. Pressure pipeline

38. Cold head

40. Heat exchanger

42 Can element/displacement element

44. Rod-shaped guide element

46. Flat guide element

48. Hole(s)

50. First cylinder section

52. A second cylinder section

ZM jar central axis

L1 first length

L2 second length

Delta L length variation

Claims

1. A compressor device (2) having

Cylinder (4),

a piston (6) arranged in the cylinder (4), the piston defining a transfer chamber (16) filled with a transfer fluid and capable of periodic reciprocating motion by means of a drive means (26);

a compressor element (8), in particular a (metal) bellows, arranged in the transfer chamber (16), which defines a working chamber (20) filled with a working gas, and

A connector (10), through which the working chamber (20) can be connected to a working gas pipeline (36) to form a Gifford-McMahon cooler or a pulse tube cooler (38);

Therein, the compressor element (8) and the working gas contained therein are cyclically compressed indirectly by means of a transfer fluid expelled by the piston (6).

2. The compressor device (2) according to claim 1, wherein the volume of the (fluid) space (18) enclosed by the piston (6), the compressor element (8) and the cylinder (4) is constant.

3. The compressor device (2) according to claim 1, wherein the transfer chamber (16) and the working chamber (20) are completely formed in the cylinder (4).

4. The compressor device (2) according to any one of claims 1 to 3, wherein the pressure of the working medium in the working chamber (20) corresponds at any point in time to the pressure of the transfer fluid in the transfer chamber (16).

5. The compressor device (2) according to claim 4, wherein the pressure of the working medium and the pressure of the transfer fluid are greater than the ambient pressure of the environment surrounding the compressor device (2).

6. The compressor device (2) according to any one of claims 1 to 5, wherein the maximum piston stroke is greater than the maximum compressor element stroke (ΔL).

7. The compressor device (2) according to any one of claims 1 to 6, wherein the piston (6) can be periodically reciprocated by means of a connecting rod (24).

8. The compressor device (2) according to any one of claims 1 to 7, wherein the compressor element (8) is guided in the stroke direction.

9. The compressor device (2) according to claim 1, wherein a closed displacement element (42) is formed in the working chamber (20).

10. A cooling device (34) having a compressor device (2) according to any one of claims 1 to 9 and a Gifford-McMahon cooler or a pulse tube cooler (38).