Conveying device having bellows and cooling device

Abstract

A conveying device, particularly in the form of a compressor, consisting of at least one housing (10) and a separation element movably arranged in the housing (10) and separating two fluid regions (14, 16) in the housing (10) from one another, the separation element being formed from a separation bellows (18) having individual bellows folds (20), a mechanical actuator is provided for controlling the movement of the separation bellows (18), and heat generated by the actuator via the movement of the separation bellows (18) can be at least partially dissipated from the housing (10) by a cooling device.

Description

[Technical field]

[0001] The invention relates to a conveying device, in particular in the form of a compressor, which consists of at least one housing and a separating element which is movably arranged in the housing and separates two fluid regions in the housing from one another. [Background technology]

[0002] Patent Document 1 discloses a conveying device for improving the energy efficiency of a hydraulic system, the conveying device having an actuator that functions as a consumer of hydraulic energy in one operating state and as a generator of hydraulic energy in the other operating state, and a hydraulic accumulator that can be charged by the actuator for energy storage in one operating state of the actuator and discharged for energy supply to the actuator in the other operating state. A discretely adjustable hydropneumatic piston-type accumulator, in which a number of pressure chambers adjacent to differently sized working surfaces on the fluid side of the accumulator piston are formed, serves as the hydraulic accumulator. Furthermore, an actuation arrangement is provided for connecting a selected pressure chamber or selected pressure chambers of the piston-type accumulator with the actuator depending on the respective pressure levels on the gas side of the piston-type accumulator and on the actuator.

[0003] This allows energy transport independent of the precharge pressure on the gas side of the accumulator and independent of the respective load pressure, since by selecting an appropriately sized working surface, each desired pressure level in the accumulator is available for charging or discharging. This allows optimal energy conversion under all operating conditions. Known multi-piston configurations for piston-type accumulators require seals, such as metal piston rings or rubber-elastic plastic seals, to seal the individual piston chambers from one another. Since high forces and pressures occur during operation, it is usually necessary to additionally use lubricants in order to keep frictional forces as low as possible, thus reducing wear and creating as leak-free a sealing as possible. Nevertheless, leakage is unavoidable and friction causes wear on the individual pistons and the associated seals. Although these wear particles are usually small, they nevertheless cause contamination of the transported gases and liquids, some of which are of high purity and can only be removed by very sophisticated filter means in the fluid flow. As long as heat is introduced into the gas side of the conveying device by friction during operation of the conveying device through a pre-determinable amount of trapped gas, excess heat is dissipated from the housing of the conveying device via the amount of fluid passing through the fluid side, so that undesirable further damage to the conveying device due to the introduction of heat does not occur. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2013 / 079222 Summary of the Invention [Problem to be solved by the invention]

[0005] The task of the present invention is based on this prior art and is to improve the known solutions and provide a leak-tight conveying device which also allows operation of the compressor with gases such as hydrogen gas. [Means for solving the problem]

[0006] The above problem is solved by a conveying device having the overall features of claim 1.

[0007] According to the characterizing feature of claim 1, the separating element is formed from a separating bellows with individual bellows folds, a mechanical actuating device is provided for controlling the movement of the separating bellows, and the heat generated by the actuating device through the movement of the separating bellows can be at least partially dissipated from the housing by a cooling device, thereby ensuring that no further leakage can occur under any circumstances. The separating bellows with individual bellows folds forms a medium-tight, in particular gas-tight, separation of the two fluid regions in the housing, so that any particles that have entered are not inadvertently exchanged between the fluid regions. In this respect, the separating bellows can be said to be medium-tight, and the conveying device can also be used as a compressor for gases, such as hydrogen gas.

[0008] When the separating bellows or the bellows is expanded, the volume of one of the fluid regions increases and the conveyed fluid flows into one of the fluid regions, while at the same time the volume of the other fluid region necessarily decreases. Conversely, when the separating bellows is contracted, one of the fluid regions simultaneously shrinks while the volume of the other fluid region increases, so that the conveyed volume previously accommodated in this one fluid region during the suction stroke is expelled from the conveying device in the course of one delivery stroke under the pressure effect of the contracting separating bellows. The separating bellows is preferably expanded by a delivery volume which flows at a defined pressure into the inlet side of the housing from a fluid supply circuit to which the conveying device is connected in a fluid-conducting manner.

[0009] Meanwhile, the separation bellows contracts under the action of a mechanical actuator which controls the separation bellows such that the amount of fluid previously taken up in one fluid region is expelled under pressure from the housing to the fluid supply circuit, with the supply of fluid downstream towards one fluid region being blocked.

[0010] However, the separating bellows may also be connected to a mechanical actuator, so that the mechanical actuator exclusively or at least predominantly causes both the expanding and contracting movements of the separating bellows. By means of the mechanical actuator, the moving steps for the movement of the separating bellows can then be started rapidly and continuously. More or less large amounts of liquid have to be first conveyed into or out of the housing by means of the movable piston, in contrast to the prior art, where the piston drive for conveying the liquid must first be controlled. In this way, the conveying device according to the invention can be used for conveying flowable fluids in the associated supply circuit. In addition to pure liquids, the transport of gases or mixtures of gases and liquids is therefore also possible.

[0011] In recent years, the use of hydrogen as an energy source has become increasingly important. In order to keep the volume of hydrogen transported low, it is effective not only to transport it in a connected supply circuit, but also to compress or condense it to high pressure during the transport stage. In this way, the amount of hydrogen transported can be reduced and hydrogen for later use can be made available at high pressure.

[0012] However, like any other gas, condensing hydrogen leads to a significant increase in temperature which, on the one hand, counteracts the desired compression that accompanies the expansion of the gas, and, on the other hand, this unwanted heat input can impair or damage the functioning of mechanical components of the conveying device, including possibly any remaining necessary sealing systems.

[0013] In any case, the separating bellows, preferably made of stainless steel, are particularly suitable as a reliable media separator for preventing undesirable particulate contamination arising from mechanical operating devices from reaching the gas side of the conveying device. In particular, when hydrogen is used during fuel cell operation, the gas stream must be free of particulates. Furthermore, the separating bellows made of stainless steel are suitable for effectively preventing embrittlement by very cold hydrogen gas. Thus, there is no equivalent in the prior art.

[0014] In a preferred embodiment of the conveying device according to the invention, it is provided that the actuating device comprises a drivable actuating rod which at least partially passes through the housing and can be brought into contact with the bellows base of the separation bellows in order to control the movement of the separation bellows. The actuating rod of the actuating device can be hydraulically controlled, for example by using a hydraulic actuating cylinder or, if necessary, by an electric motor which can be actuated in both directions by engaging a suitable intermediate gear. The actuating rod can be designed to be robust and can transmit high actuating forces to the separation bellows to be moved.

[0015] In a further preferred embodiment of the conveying device according to the invention, it is provided that the bellows base of the separation bellows can be controlled by the fluid pressure penetrating one fluid region on the side facing the actuation rod, so that the separation bellows is extended and the actuation rod, which is kept at least partially free from force in this respect, retracts. In this way, the separation bellows can be controlled by the pressure medium conveyed for the extension or filling procedure, while the actuation rod, acting pressure-wise on the opposite side for the discharge stroke, contracts the bellows in a volume-reducing manner, reducing the volume in one fluid region of the housing. Such actuation steps are performed in alternating succession, making it possible to move the separation bellows from the suction stroke to the discharge stroke and again from the suction stroke to the discharge stroke in succession. In particular, the conveyed working gas, such as hydrogen gas, can achieve a high compression ratio through the conveying device by the separation bellows, so that the conveying device can also operate as a compressor with conveying function.

[0016] In a further preferred embodiment of the conveying device according to the invention, in order to prevent interruptions in the operation when the bellows is expanded, it is provided that the fluid volume trapped in the other fluid region remains the same or substantially the same when the separating bellows is expanded, by retracting the actuating rod from this other fluid region.When the bellows is expanded, a volume of air is displaced in the other fluid region, and the actuating rod is retracted to the same extent as the bellows is expanded, at the same time extending partially outside the housing of the conveying device, so that an additional free volume is formed in the other fluid region, into which the separating bellows can displace air, allowing an unrestricted operation, despite the volume of air trapped in the further fluid region of the conveying device.

[0017] In a further preferred embodiment of the conveying device according to the invention, it is provided that the bellows holder is arranged inside the housing, and that the bellows folds, preferably facing each other, are stacked in the receiving space between the bellows holder and the housing, with the bellows base bearing on the bellows holder. Since the separate bellows with bellows folds are susceptible to buckling and expansion stresses, a reliable guidance of the folds through the receiving space is thus achieved, in particular in the contracted state of the separate bellows, which ensures that the individual folds do not buckle or expand until they butt up against each other. Furthermore, a space-saving receiving tray for the bellows folds is thus achieved in the housing of the conveying device. When the separate bellows with bellows folds are completely stacked in the receiving space, the bellows base lies flat on the bellows holder at least on the inside and faces towards the bellows holder at least in the circular edge region, so that a reliable and buckling-resistant support is also achieved in this respect, and the freely changing fluid volume for one fluid region of the conveying device is zero or almost zero at the maximum delivery stroke.

[0018] When the separation bellows extends during the suction stroke, the bellows base can rest with one of its free ends on the free end of the actuating rod, ensuring that the bellows folds do not undesirably overextend, which could otherwise render the bellows unusable.

[0019] At least one fluid line opening into one fluid region is preferably arranged in a bellows holder, with the suction stroke for the fluid volume to be conveyed and the discharge or delivery stroke for this volume from one fluid region of the conveying device being carried out via the respective fluid line.

[0020] In order to monitor the position of the separation bellows, a proximity sensor, e.g. in the form of a proximity switch, is preferably provided in the bellows holder, which, when activated, can control the extension movement of the actuating rod so that the separation bellows again performs an extension movement under fluid control.

[0021] According to a particularly preferred embodiment of the conveying device according to the invention, it is provided that the housing has a part of a cooling device on the outer periphery or that the cooling device is an integral part of the housing. The part of the cooling device essentially consists of a fluid guide for the cooling medium, or a receiving facility for this purpose, which is provided on the outer periphery of the housing of the conveying device. The part of the cooling device can thus consist of a cooling coil, which is arranged on the outer periphery of the housing and which can introduce cold cooling medium coming from a central cooling supply device on the input side for cooling and can discharge cooling medium heated by the operation of the conveying device on the output side to the central cooling supply point.

[0022] In a further preferred embodiment of the transport device according to the invention, it is provided that the cooling device has a cooling chamber through which the cooling medium flows, which is arranged concentrically so as to at least partially surround the housing on the periphery. Advantageously, it is further provided that the cooling chamber is bounded by the housing and by an additional housing part which together with the housing constitutes a tradeable structural unit. Alternatively, a number of separate cooling chambers can be arranged on the periphery of the housing of the transport device, or the housing is provided with cooling fins which are blown on from the outside, preferably via a fan device, for the purpose of dissipating heat from the housing. Furthermore, for the implementation of the cooling device, it is also possible to provide cooling ducts directly on the housing of the transport device, through which the cooling medium can flow from the cooling supply device.

[0023] The transport device according to the invention is explained in more detail below on the basis of the drawings, which are principle views and are not drawn to scale. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 shows a perspective view of one embodiment of the main components of the transport device in longitudinal section along line XX in FIG. [Diagram 2] FIG. 2 shows an end view of the transport device according to FIG. 1 in the direction of the arrow Y. [Diagram 3] FIG. 3 shows the main components of a coolant supply device for cooling the conveying device according to FIGS. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The conveying device shown in FIG. 1 has a pot-shaped housing 10 with a housing base 12. In the housing 10, preferably a hollow cylindrical housing 10, a separating bellows 18 is arranged as a separating element separating the two fluid regions 14, 16 from one another. The separating bellows 18 has in the usual way, according to the embodiment shown in FIG. 1, a plurality of individual interconnected bellows folds 20 which successively butt against one another when moving upwards. Such separating bellows systems are known in particular from bellows accumulators as a subgroup of hydraulic accumulators, as shown, for example, in DE 10 2009 060 852 A1. The last bellows fold 20 of the stacking sequence at the free end face is welded to a retaining ring 22, the other opposite bellows fold 20 is welded at this point further to a bellows base 24 on the free end face. The bellows base 24 is configured as a flat end plate and has on its outer periphery an annular groove 26 for receiving a sealing ring and / or a guide ring (not shown in more detail), via which the bellows base 24 is guided longitudinally movably along an inner periphery 28 of the housing 10.

[0026] According to the embodiment shown in FIG. 1, the bellows base 24 straddles a bellows holder 30, which is designed as a screwed part and is screwed flush into the free end of the housing pot, which is open towards one side. At the opposite side of the bellows base 24, at an axial distance, an actuating rod 32 is held as part of a mechanical actuating device. The actuating rod 32 can be moved back and forth over a given distance via an actuator device, not shown in more detail, for example in the form of a hydraulic actuating cylinder. Moreover, the actuating rod 32 passes through the otherwise closed housing base 12 at this point, viewed concentrically with respect to the longitudinal axis 34 of the housing 10. A further annular groove 36 is introduced in the housing base 12 for the purpose of receiving a guide and / or sealing device (not shown) for sealing the interior of the housing 10 from the environment in the form of a further fluid region 16 in any position of movement of the actuating rod 32. This further fluid region 16 is preferably filled with air, but if necessary, another filling gas, such as nitrogen gas, can also be introduced. Additionally, a cooling system component 38, generally designated 40 (FIG. 3), is mounted on the outer periphery of housing 10, as will be described in more detail below.

[0027] As can be further seen from Fig. 1, the bellows holder 30 is penetrated by a duct-like fluid line 42 which opens at one free end into one of the fluid regions 14 and is connected at the other free end via a corresponding connection point to a conventional fluid supply circuit 44, which should conform to the conventional prior art. Two non-return valves 46, 48, preferably of the same design, are connected to the associated circuit 44, which can also be held in their illustrated closed position under a spring load, if necessary. In this case, the non-return valve 46 is associated with a fluid inlet line 50 and the non-return valve 48 is associated with a fluid outlet line 52. The inlet line 50 and the outlet line 52 are part of a T-shaped connection piece which opens into the fluid line 42 in the bellows holder 30.

[0028] As the diagram in FIG. 2 shows, several, in the present embodiment three, fluid lines 42 can be arranged in the bellows holder 30, so that during both inflow and outflow of the fluid through one fluid region 14, the bellows base 24 is uniformly pressurized on its inside, for example during the inflow or outflow process. In this respect, too, the two further fluid lines 42 are also connected to the supply circuit 44 via corresponding line guidance. However, in an embodiment not shown in more detail, there is also the option of separating the inflow line 50 with the check valve 46 opening towards one fluid region 14 from the outflow line 52 via an independent fluid line 42 in the bellows holder 30, the check valve 48 to this end opening in the opposite direction to the check valve 46 as in the present embodiment. In this way, one fluid region 14 is provided with an independent inlet and an independent outlet via fluid paths independent of each other. The third fluid line 42 shown in FIG. 3 can be omitted accordingly. However, preferably, in each case, the respective fluid lines 42 form groups that are equally spaced around the longitudinal axis 34 of the housing 10 for space-saving accommodation, and further, the individual fluid lines 42 have the same radial distance from one another (FIG. 2).

[0029] When a pressurized fluid is introduced into one of the fluid regions 14 via the illustrated inlet channel 50 and the associated fluid line 42 with the non-return valve 46 open, the bellows base 24 is pressurized to this extent and performs an extension movement in which the individual bellows folds 20 are pulled apart. At this point, the bellows base 24 moves from right to left as viewed in the orientation of FIG. 1 and comes into contact with the free end face of the actuating rod 32 after a predefined path of movement. The actuating rod 32 is then locked in position and at this point can form a limit stop for the bellows base 24, although there is also the option that the actuating rod 32 is carried along in the left direction by the bellows base 24 so that it is pushed out of the further fluid region 16 of the housing 10 with as little force as possible. However, it is also possible that the actuating rod 32 faces the bellows base 24 from the start and in this range also performs a leftward displacement movement during the extension movement of the separating bellows 18 (not shown). During this suction stroke, the check valve 48 in the outlet passage 52 remains closed to prevent the inadvertent backflow of fluid already delivered from the supply circuit 44 .

[0030] According to the embodiment shown in Fig. 1, the bellows folds 20, which are susceptible to buckling and expansion, are accommodated in an annular receiving space 54 bounded towards the inside by an annular shoulder 56 of the bellows holder 30 and bounded towards the outside by the inner circumferential side surface 28 or inner wall of the housing 10. The bellows base 24 is likewise guided against the inner circumferential side surface 28 of the housing 10, so that there is no undesired bulging or buckling of the bellows folds 20 even when the bellows are extended, and in this respect, even when the separating bellows 18 is fully extended, the bellows folds 20 are guided stably in the receiving space 54 with their leg ends in the area of ​​the retaining ring 22. The retaining ring 22 is arranged on the outside with one of its free end faces resting on the annular shoulder 56 of the bellows holder 30 and with the other free end face resting on a protrusion 58 of the inner circumferential side surface 28 of the housing 10. In this way, the separation bellows 18 with its retaining ring 22 can be loosely placed on the shoulder 56 of the bellows retainer 30 for an assembly operation and, together with the latter, can be brought into position on the projection 58 of the housing 10 via the threaded portion 60 as part of a screwing operation. Between the bearing of the retaining ring 22 and the threaded portion 60 there is also a third annular groove 62 for receiving a sealing ring, not shown in more detail, for the purpose of sealing one of the fluid regions 14 from the environment of the housing 10.

[0031] 1 when the volume of fluid in one of the fluid regions 14 is at a minimum, the actuation rod 32 contacts the bellows base 24 and powers the bellows base 24 back to the initial position shown. During this powered displacement movement of the bellows base 24 from left to right, the volume of fluid previously stored in one of the fluid regions 14 during the intake stroke with the check valve 46 closed is thereby discharged from the delivery device under pressure via the outlet passage 52 with the check valve 48 open. If the delivery volume is a gas, such as hydrogen gas, it will be compressed to a higher pressure level during the associated delivery stroke movement. Thus, for example, in the course of stepwise pressure increase, the three conveying devices shown in FIG. 1 form a three-stage overall compressor in series, which makes it easy to increase hydrogen gas with an inlet pressure of 15 bar (15,00 kPa) to a pressure level of 500 to 600 bar (50,000 kPa to 60,000 kPa) in the last compressor stage and further use it.

[0032] In an embodiment not shown, there is also the option of rigidly connecting the actuating rod 32 directly to the bellows base 24, so that both the suction stroke and the delivery stroke are performed by the actuating rod 32 as part of a mechanical actuator. As can be further seen from Fig. 1, a proximity sensor in the form of a proximity switch 64 is arranged centrally in the bellows holder 30, concentric with the longitudinal axis 34 of the housing 10, which is capable of monitoring the position of the bellows base 24 or, respectively, the functional state of the separation bellows 18 associated therewith. Such position monitoring is necessary to enable the actuating rod 32 to be sensorily controlled by a central control device, not shown in more detail, in particular for performing the delivery stroke. The inside of the bellows base 24 rests in an outer peripheral region 66 on the associated protruding annular surface of the bellows retainer 30, and in this annular contact surface on the end face of the bellows retainer 30 a small valley-like depression 68 is provided in which residual fluid is retained so that during the extension movement of the isolation bellows 18 no vacuum is created between the bellows base 24 and the associated wall of the bellows retainer 30 which could impair the extension process.

[0033] The outer wall of the cylindrical housing is provided with a wall recess 70 in the circumferential direction, which is overlapped on the outer periphery by a thin-walled cylindrical housing part 72, which is part of a housing pot that is screwed at its base end to the housing base 12 by means of a threaded connection 74. Furthermore, the housing part 72 extends beyond the wall recess 70 on both sides, and in the region of this extension, the wall of the housing 10 each has a fourth recess 76, which serves to receive a ring seal, not shown, and in this respect isolates a cooling chamber 78 from the environment, which is bounded in this respect by the housing 10 and the housing part 72. This cooling chamber 78 is part of a cooling unit generally designated 40, as shown in more detail in FIG. 3.

[0034] Viewed from the orientation of Fig. 3, the conveying device according to Fig. 1 and Fig. 2 is only diagrammatically shown in the upper right corner with the housing 10 and the housing part 72 arranged above it, as well as the cooling chamber 78 located therebetween, which is connected to the cooling circuit 82 of the cooling device 40 via two fluid connection points 80. The cooling device 40 forms a kind of semi-closed cooling circuit 82, for which the storage tank 84 is sealed off from the atmosphere except for a specially constructed ventilation ventilation device. The presence of the storage tank 84 opens up the possibility of using an immersion pump 86 as a feed pump, the pump inlet of which is submerged below the liquid level 88 of the storage tank 84. The mentioned ventilation / ventilation device is formed by a valve, not shown in more detail, which is provided on the breather filter 90 and opens outwards at a given tank internal pressure and opens inwards at a given tank negative pressure.

[0035] The immersion pump 86 is driven by an electric motor 92, which, in operation, conveys the cooling medium as part of the cooling circuit 82 in the direction of the arrow through the flow path to the consumer, here in the form of a cooling chamber 78 for the conveying device. Conventional coolants can be used as the cooling medium, in this specific case a mixture of water and glycol is used. The heat of compression generated by the conveying device, in particular due to the characteristics of the compressor, is introduced into the cooling chamber 78 containing the cooling medium via the separating bellows 18 and the inside of the housing 10. There, it is heated and is returned to the tank 84 via the return line 94 and the heat exchanger 96 or 98. The heat exchanger can be a plate type heat exchanger 96, in which the heat exchange to the cooling medium is carried out by the liquid cooling medium, or a finned cooler 98, which is cooled by cooling air by a motor-operated fan 100. The cooling device 40 shown in FIG. 3 is only exemplary, and of course other suitable cooling devices can also be used here, for example cooling devices with a completely closed cooling circuit induction or an open cooling circuit induction.

[0036] It is still within the scope of the invention to replace the illustrated cooling chamber 78 with a cooling coil arranged to surround the outer periphery of the housing 10 of the transport device. In this respect, the connection points 80 form the fluid inlet and outlet, respectively, of the cooling medium guiding coil. The cooling chamber 78, which goes around the housing 10 like a jacket, can also be divided into small compartments or appropriately supplied cooling ducts can be introduced into the housing 10 itself (not shown).

Claims

**Claim 1** A conveying device, particularly in the form of a compressor, comprising at least one housing (10) and a separating element movably arranged within the housing (10) and separating two fluid regions (14, 16) within the housing (10) from each other, wherein the separating element is formed from a separating bellows (18) having individual bellows folds (20), a mechanical actuating device is provided for controlling the movement of the separating bellows (18), and heat generated through the movement of the separating bellows (18) by means of the actuating device can be at least partially dissipated from the housing (10) by a cooling device (40). **Claim 2** The conveying device according to claim 1, characterized in that the actuating device comprises a drivable actuating rod (32) that at least partially penetrates the housing (10) and can be brought into contact with the bellows base (24) of the separating bellows (18) in order to control the movement of the separating bellows (18). **Claim 3** The bellows base (24) of the separating bellows (18) can be controlled by fluid pressure on the side opposite to the actuating rod (32), and the fluid pressure extends the separating bellows (18) through one of the fluid regions (14), whereupon the actuating rod (32), which is held at least partially without force, retracts. The conveying device according to claim 2, characterized in that this is the case. **Claim 4** The conveying device according to claim 2, characterized in that the fluid volume enclosed in the other fluid region (16) is maintained the same or substantially the same when the separating bellows (18) is extended by the actuating rod (32) retracting from the other fluid region (16). **Claim 5** The conveying device according to claim 2, characterized in that within the housing (10), the bellows holder (30) is arranged in such a way that the bellows base (24) is supported by the bellows holder (30) and in the receiving space (54) between the bellows holder (30) and the housing (10), preferably, the bellows folds (20) adjacent to each other are stacked on top of each other. **Claim 6** The conveying device according to claim 5, characterized in that at least one fluid line (42) opening into one of the fluid regions (14) is arranged within the bellows holder (30). **Claim 7** The conveying device according to claim 5, characterized in that a proximity sensor, in particular a proximity switch (64), for monitoring at least one position of the separating bellows (18) is arranged in the bellows holder (30).

8. The conveying device according to claim 1, characterized in that the housing (10) has a part of the cooling device (40) on the outer peripheral side, or the cooling device (40) is an integral component of the housing (10).

9. The conveying device according to claim 1, characterized in that the cooling device (40) has a cooling chamber (78) through which a refrigerant circulates, and the cooling chamber at least partially concentrically surrounds the housing (10) on the outer peripheral side.

10. The conveying device according to claim 9, characterized in that the cooling chamber (78) is bounded by the housing (10) and an additional housing part (72) that forms a structural unit that can be transferred together with the housing (10).

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