EP2795204B1 - Compressor - Google Patents

Description

The invention relates to a compressor according to the preamble of claim 1 and a refrigeration system according to claim 15.

Compressors, as they are known from the preamble of claim 1, have a drive device and a compression device. The drive device is often an electric motor, for example. The compression device is designed in one or more stages, which means that the compressor, for example, in a first stage compresses refrigerant from a low pressure (suction pressure) to an intermediate pressure, the refrigerant at intermediate pressure then being fed to a second stage in which it is applied to a High pressure (final pressure) is compressed. Such or similar compressors are for example from the JP 2002 106 989 A , of the U.S. 3,913,346 A , of the WO 2011/049 767 A2 , of the EP 1 562 012 A1 , of the US 2011/203304 A1 , as well as the DE 10 2005 009 173 A1 known.

However, the efficiency of two-stage compressors is often not optimal. This fact becomes increasingly important when "new, natural" refrigerants, for example R744 (CO ₂ ), are to be used, which place special demands on the conditions of the compression process.

On the basis of the prior art discussed above, it is accordingly the object of the present invention to specify a compressor which, compared to the compressors according to the prior art, has an increased degree of efficiency or, in terms of energy, for one Operation with all common refrigerants is suitable. Furthermore, it is an object of the present invention to specify a correspondingly designed refrigeration system

This object is achieved according to the invention by a compressor according to patent claim 1 and a refrigeration system according to claim 15.

According to the invention, a compressor has a compressor housing, a drive device and a compression device with one or more compression stages for compressing a refrigerant. The compressor also has at least one refrigerant supply device for supplying refrigerant to the compression device and at least one refrigerant discharge device for discharging refrigerant from the compression device, at least one section of the refrigerant supply device being arranged thermally separated from the refrigerant discharge device or the refrigerant discharge devices.

Such a construction ensures that there is no excessive heat transfer from the compressed refrigerant to be discharged, which has been heated by a preceding compression process, to the refrigerant flowing through a section of the supply device. In other words, such a construction largely prevents the heat transfer from a compressed refrigerant, which is heated by the compression process, to an uncompressed refrigerant. The better the respective sections of the refrigerant supply device (s) are thermally separated or decoupled from those of the corresponding refrigerant discharge device (s), the lower the heat transfer. Ideally, not only sections but in each case the entire devices, ie the devices over their entire extent, are completely thermally separated from one another, which leads to a minimal heat transfer. However, it should be pointed out at this point that individual points of contact or areas of contact (heat transfer surfaces) of the respective devices are structurally almost inevitable, but the amounts of heat transferred via this are relatively small and can therefore be tolerated. With regard to the size of the contact areas (heat transfer surfaces), the most economical concept in each case, which takes into account both the manufacturing costs and the operating costs, can be selected. It should also be mentioned at this point that, for example, by designing the surfaces of the refrigerant discharge device (s) as small as possible a minimal heat exchange with the environment of the refrigerant discharge device (s) can be achieved.

In the case of compressors that have several refrigerant supply devices, i.e. for example multi-stage compressors, at least sections of all refrigerant supply devices for supplying refrigerant to the compression device from one, several or preferably all of the existing refrigerant discharge devices (for example device for discharging under an intermediate pressure or under high pressure) are preferred or final compression pressure standing refrigerant) arranged thermally separated. This reduces the heat transfer for all refrigerant supply devices, i.e. for example for the supplies to all stages of the compressor.

In a further preferred embodiment, in compressors that have a plurality of refrigerant supply devices, that is to say for example in the case of multi-stage compressors, at least two or more of the refrigerant supply devices are each thermally separated from one another at least over sections of the same. In particular, when the refrigerant to be supplied to a compression stage is provided for cooling, for example, a drive device of the compressor, thermal decoupling from the other or the other refrigerant supply devices is often desired. In general, it can be stated that such a construction should always be considered when the corresponding refrigerant supply devices carry refrigerants of different temperatures.

In a further preferred embodiment, in compressors that have several refrigerant discharge devices, that is to say for example in the case of multi-stage compressors, at least two or more of the refrigerant discharge devices are thermally separated from one another at least over sections of the same. This is advantageous, for example, when the respective refrigerant discharge devices carry refrigerants at different temperatures. For example, a two-stage compressor is conceivable for this case, in which the refrigerant at the outlet of one compression stage can possibly have a temperature that is different from that at the outlet of the other compression stage (s). A transfer of heat to the colder refrigerant, which is discharged from the first compression stage, can thus be prevented. This contributes to increasing the efficiency of the system.

In summary, it can be stated that a compressor according to the invention in which at least sections of one or more refrigerant supply device (s) are thermally separated or decoupled from one or more of the one or more refrigerant discharge device (s) present in the compressor enables an increase in the efficiency of the compressor. An optional further (additional) thermal separation between the refrigerant supply devices and from the refrigerant discharge devices, as well as the refrigerant discharge devices from one another, can further improve the efficiency of the respective compressor designs, especially in the case of temperature differences in the individual devices.

At this point, the definition of the wording "thermally separated" as it is used in the present application is explained in more detail. Thermally separated in the context of the present application means thermally not coupled or thermally relatively weakly coupled, ie provided with the lowest possible heat transfer. This can be achieved, for example, by spacing corresponding components and / or designing them as separate components. It is also an alternative to separate the individual sections from one another with an insulating material. This can also be used when several of the supply devices and the discharge devices for refrigerant are to be designed as an integral component. It is conceivable that the entire component is made of a material with a low thermal conductivity, preferably lower than the thermal conductivity of C-45 steel, further preferably lower than a thermal conductivity of 20 W / mK, in particular preferably lower than a thermal conductivity of 10 W. / mK to produce. Wall thicknesses of a few mm are effective. Alternatively, it would also be conceivable to use two-component structures with, for example, insulating layers, in which case the components are again spaced apart from one another by the insulating layer. Possibilities for minimizing the heat transfer are therefore avoiding contact surfaces, minimizing existing or required surfaces, choosing a less conductive material for required surfaces, in particular contact surfaces, and thermal insulation of surfaces, in particular contact surfaces, using appropriate materials or substances (solid-state insulation , Gas insulation, if necessary insulation by liquid) and / or by a corresponding spacing from one another.

Although a compressor according to the invention is explained in the following description of the figures using the example of a multistage radial piston compressor, the construction according to the invention can be applied to any single-stage and multistage compressor regardless of its compression principle. In addition to radial piston compressors, axial piston compressors, scroll compressors, screw compressors, turbo compressors, rotary compressors, etc. may be mentioned as examples.

Further features of the invention are specified in the subclaims.

• Fig. 1 eine erste mögliche Ausführungsform eines erfindungsgemäßen Verdichters;
• Fig. 2 eine schematische Darstellung einer Kälteanlage, welche einen Verdichter gemäß der ersten möglichen Ausführungsform aufweist, sowie ein hierfür gültiges Enthalpie-Druck-Diagramm; und
• Fig. 3 eine schematische Darstellung einer Kälteanlage, welche einen Verdichter gemäß einer zweiten möglichen erfindungsgemäßen Ausführungsform, sowie ein hierfür gültiges Enthalpie-Druck-Diagramm aufweist;
• Fig. 4 eine weitere schematische Darstellung einer (dritten) Kälteanlage, welche eine abgewandelte Kälteanlage der Fig. 2, sowie ein hierfür gültiges Enthalpie-Druck-Diagramm darstellt;
• Fig. 5 eine schematische Darstellung einer (vierten) Kälteanlage, welche wiederum eine Abwandlung der Kälteanlage gemäß Fig. 2 ist, sowie ein hierfür gültiges Enthalpie-Druck-Diagramm;
• Fig. 6 eine schematische Darstellung einer (fünften) Kälteanlage, welche wiederum eine Abwandlung der Kälteanlage gemäß Fig. 2 ist, sowie ein hierfür gültiges Enthalpie-Druck-Diagramm;
• Fig. 7 eine sechste Kälteanlage in einer schematischen Darstellung, welche eine Abwandlung der Anlage gemäß Fig. 3 darstellt, sowie ein hierfür gültiges Enthalpie-Druck-Diagramm; und
• Fig. 8 eine Ansicht eines Triebwerks des Verdichters gemäß der ersten Ausführungsform, geschnitten senkrecht zur axialen Richtung; und
• Fig. 9 eine weitere Schnittdarstellung des Verdichters gemäß Fig. 8, geschnitten parallel zu der axialen Richtung;

The invention is described below by way of example with reference to the accompanying drawings on the basis of preferred embodiments. In the drawings show:

• Fig. 1 a first possible embodiment of a compressor according to the invention;
• Fig. 2 a schematic representation of a refrigeration system which has a compressor according to the first possible embodiment, as well as a valid enthalpy-pressure diagram; and
• Fig. 3 a schematic representation of a refrigeration system, which has a compressor according to a second possible embodiment according to the invention, as well as a valid enthalpy-pressure diagram;
• Fig. 4 a further schematic representation of a (third) refrigeration system, which is a modified refrigeration system of Fig. 2 , as well as a valid enthalpy-pressure diagram;
• Fig. 5 a schematic representation of a (fourth) refrigeration system, which in turn is a modification of the refrigeration system according to FIG Fig. 2 is, as well as a valid enthalpy-pressure diagram;
• Fig. 6 a schematic representation of a (fifth) refrigeration system, which in turn is a modification of the refrigeration system according to FIG Fig. 2 is, as well as a valid enthalpy-pressure diagram;
• Fig. 7 a sixth refrigeration system in a schematic representation, which shows a modification of the system according to Fig. 3 represents, as well as a valid enthalpy-pressure diagram; and
• Fig. 8 a view of an engine of the compressor according to the first embodiment, cut perpendicular to the axial direction; and
• Fig. 9 a further sectional view of the compressor according to Fig. 8 , cut parallel to the axial direction;

At the in Fig. 1 The illustrated first embodiment of a compressor according to the invention is a radial piston compressor 10 which has a drive device or drive unit in the form of an electric motor 12 and a compression device or compression unit 14. Both the electric motor and the compression unit 14 are arranged in a compressor housing 15, which is composed of two parts, namely a motor housing 15-1 and a pressure cover 15-2. The motor housing 15-1 is connected to the pressure cover 15-2 in a gas-tight manner. It is therefore a compressor of a hermetic type, in short a hermetic compressor. In the present embodiment, the two housing components are welded to one another, other thermal connection methods such as brazing etc. or other suitable gas-tight connection methods such as flanging, gluing etc. also being conceivable.

In the embodiment described here, the compression unit 14 has six pistons 18 which extend away from a central axis 16 in the radial direction and which are arranged in corresponding cylinders or cylinder bores 19 such that they can be displaced back and forth in the radial direction. The drive of the compression unit 14 takes place via a drive shaft 16 which is connected to the electric motor 12 in a rotationally fixed manner and which is in operative engagement with the piston 18 via an eccentric mechanism and a connecting rod. In alternative embodiments, any number of pistons other than six is conceivable. The number of pistons is determined on the basis of the desired specifications and the desired area of application. The functioning of the compression process itself is possible both for the radial piston compressor described here and for all others Compressor types are well known and will not be further described here.

The compressor 10 is a two-stage compressor, the compression unit 14 of which is designed to compress refrigerant in two stages. For this purpose, the compressor 10 is supplied with refrigerant for a first compression stage 14-1 via a low-pressure refrigerant supply device 20 which limits a low-pressure volume of the compressor 10 (suction volume) and is compressed in this to a predetermined intermediate pressure. It should be noted at this point that the compressor according to the invention can of course alternatively also be designed as a single-stage compressor and also as a different type of compressor (scroll compressor, etc., in a single-stage and multi-stage design). In the embodiment described, a reciprocating piston compressor is used because it can be used advantageously because of, among other things, its high degree of tightness, which is due to the use of cylinders (good sealing via the piston rings). Furthermore, the areas around the cylinder, that is, for example, some heavily loaded areas, are only thermally loaded during the compression moment, i.e. when the cylinder is filled with refrigerant and the piston is approaching top dead center (due to the heating caused by the compression of the refrigerant caused). Afterwards, cooling takes place immediately, for example by inflowing refrigerant, so that the material load is kept as low as possible.

The low-pressure refrigerant supply device 20 has a plurality of subregions. This is a first low-pressure refrigerant supply device sub-area 20-1 formed and defined by a tubular wall or a pipe, which extends outside the compressor housing 15 from the compressor housing 15 to a low-pressure connection 22, one in turn through a tubular wall or . By a pipe formed and defined second low-pressure refrigerant supply device sub-area 20-2, which extends within the compressor housing 15 from the compressor housing 15 to the compression unit 14, and a third, formed in the compression unit 14 low-pressure refrigerant supply device sub-area 20-3 on. In the embodiment described, the subregions are each formed by separate components which are each connected in a gas-tight manner at the ends to a corresponding end of one of the other components. It should be noted at this point that the entire low-pressure refrigerant supply device 20 can alternatively be formed in one piece or can have one of three different numbers of components. The extent of the above-mentioned sub-areas does not have to coincide with the extent of the components.

After being fed to the first compression stage 14-1, which is formed by four of the six cylinders, the refrigerant is compressed to an intermediate pressure in the first compression stage. After compression by the first compression stage 14-1, the refrigerant is ejected into an intermediate-pressure refrigerant discharge device 24, which in turn has three sub-areas: a first intermediate-pressure refrigerant discharge device sub-area 24-1, which is again delimited by a tubular wall or a pipe extends outside the compressor housing 15 from the compressor housing 15 to a first intermediate pressure connection 26; a second intermediate-pressure refrigerant discharge device sub-area 24-2, likewise bounded by a tubular wall or pipe, which extends within the compressor housing 15 from the compressor housing 15 to the compression unit 14, and a third intermediate-pressure refrigerant discharge device sub-area 24-3, which is formed in the compression unit 14 and serves to connect the second intermediate-pressure refrigerant discharge device section 24-2 to the cylinders, more precisely, to the outlets of the cylinders of the first compression stage 14-1. The intermediate pressure refrigerant discharge device sub-areas are in turn connected in a gastight manner to the first intermediate pressure connection 26 and the cylinders of the first compression stage 14-1 in a gas-tight manner analogous to the low pressure sub-areas at respective ends and at corresponding other ends. The statements for the low-pressure feed device 20 also apply analogously with regard to the number of components.

The intermediate pressure refrigerant is led out of the compressor via the intermediate pressure refrigerant discharge device 24 and made available at the first intermediate pressure connection 26 for transfer to an intermediate cooler 28 (see FIG Fig. 2 ). In an exemplary refrigeration system, which is shown in Fig. 2 is shown and which a compressor 10 according to Fig. 1 has, the compressor 10 is connected via the first intermediate pressure connection 26 by means of a first pipe 30 to the intermediate cooler, in which the intermediate pressure refrigerant is cooled. Via a further, second pipe 32, the cooled, intermediate-pressure refrigerant is then supplied via a second intermediate-pressure connection connected to the second pipe 32 34 brought into an intermediate pressure refrigerant supply device 36 of the compressor 10.

In the embodiment described, the intermediate pressure refrigerant supply device 36 has two sub-areas connected to one another in a gas-tight manner: a first intermediate-pressure refrigerant supply device sub-area 36-1, which is again tubular and which is arranged between the compressor housing 15 and the second intermediate pressure connection 34 and is connected to it in a gas-tight manner, a tubular second intermediate-pressure refrigerant supply device sub-area 36-2, which extends from the compressor housing 15 in a 90 ° curve towards the electric motor 12 and ends in the area of the electric motor 12. As a result, in the described possible embodiment, the electric motor 12 is cooled by the cooled refrigerant at intermediate pressure. Via a third intermediate-pressure refrigerant supply device sub-area 36-3 arranged in the compression unit 14, after flowing through and cooling the engine, the cooled refrigerant is then supplied to a second compression stage 14-2 consisting of two cylinders, in which it is fed to one high pressure (high pressure) is compressed. For this purpose, the cylinders of the second compression stage 14-2 are connected in a gas-tight manner on an inlet side to the third intermediate-pressure refrigerant supply device section 36-3. The intermediate-pressure refrigerant supply device 36 can also consist of any number of components that do not have to match the corresponding subregions.

After compression to high pressure, the refrigerant is then expelled from the cylinders (outlets) of the second compression stage 14 - 2 into a high pressure refrigerant discharge device 38. The high-pressure refrigerant discharge device 38 has five high-pressure refrigerant discharge device subareas, each connected to one another in a gas-tight manner: a first tubular high-pressure refrigerant discharge device subarea 38-1, which extends outside the compressor housing 15 from the compressor housing 15 to a high-pressure connection 40; a likewise tubular second high-pressure refrigerant discharge device sub-area 38-2, which extends within the compressor housing 15 from the compressor housing 15 to a third high-pressure refrigerant discharge device sub-area 38-3; the third high-pressure refrigerant discharge device section 38-3, which is roughly cuboid, that is, is designed with a rectangular cross-section and serves to dampen pulsations in the high-pressure volume 38; a fourth high pressure refrigerant discharge device section 38-4 extending from the third high pressure refrigerant discharge device section 38-3 to the compression unit 14; and a fifth high-pressure refrigerant discharge device sub-area 38-5 formed in the compression unit 14, which is connected to the cylinder outlets of the second compression stage 14-2 and serves to discharge refrigerant to high pressure or compression end pressure. Again, any number of components can be used, the number of subregions does not have to match that of the components and the subregion boundaries do not have to coincide with component boundaries, as is also the case for the other feed and discharge devices.

From the high pressure connection 40, the refrigerant is in the exemplary refrigeration system of Fig. 2 is fed via a third pipe 42 to a gas cooler 43 in which it is cooled. The cooled refrigerant, which is at high pressure, then flows via a fourth pipe 44 into a first expansion element 46, where it is expanded to a mean pressure which does not have to correspond to the intermediate pressure. The refrigerant then flows via a fifth pipe 48 into a collector 50, from where it flows via a sixth pipe 52 into a second expansion element 54, in which it is expanded to low pressure (suction pressure), and then via a seventh pipe 56 to an evaporator 58 arrives. The refrigerant then flows from the evaporator 58 via a further, eighth pipe 60 to the compressor 10, more precisely to the low-pressure connection 22 of the compressor 10.

For the compression of refrigerants and in particular for the compression of natural refrigerants such as CO2, which is used as a refrigerant in the embodiment described here, it is important that the (gaseous) refrigerant is not unnecessarily heated before entering the respective compression stage becomes. Since the permissible final compression temperature is limited, any heating before the actual compression means a limitation of the compression ratio that can be achieved and an increase in the workload per mass of compressed refrigerant.

Therefore, a portion of each refrigerant supply device 20, 36 is arranged to be thermally separated from the refrigerant discharge devices. It is in the present Embodiment here to sections which begin at respective connections for the refrigerant (low pressure connection 22, second intermediate pressure connection 34) and in the case of the low pressure refrigerant supply device comprises the first low pressure refrigerant supply device sub-area 20-1 and the second low pressure refrigerant supply device sub-area 20-2 . In the case of the intermediate-pressure refrigerant supply device 36, the first and the second intermediate-pressure refrigerant supply device sub-regions 36-1 and 36-2 are included.

In addition, the intermediate-pressure refrigerant discharge device 24 and the high-pressure refrigerant discharge device 38 are also thermally separated from one another. In the intermediate-pressure refrigerant discharge device 24, the corresponding section comprises the first and second intermediate-pressure refrigerant discharge device subareas 24-1 and 24-2, and in the high-pressure refrigerant discharge device 38 the first to fourth high-pressure refrigerant discharge device subareas 38-1 to 38-4 .

The respective sections, which are arranged thermally separated from one another, are arranged at a distance from one another and thermally separated or decoupled from one another by the respective ambient atmosphere (in the compressor refrigerant, either under intermediate pressure or under suction pressure, outside the compressor ambient atmosphere).

Furthermore, in Fig. 2 a corresponding pressure-enthalpy diagram for the refrigeration system is shown, with the states marked with single-digit numbers in the pressure-enthalpy diagram occurring at the single-digit points in the system in circles. The states in the respective pressure-enthalpy diagrams are analogous Figures 3 to 7 marked. In the following, reference is no longer made to this individually, but rather, as already explained, it is assumed that the respective in the Figures 3 to 7 The pressure-enthalpy diagrams shown represent the states in the refrigeration systems shown in the same figure. The states identified by a number are in each case at the point of the refrigeration system provided with a number in a circle.

In Fig. 3 a further exemplary refrigeration system is shown, which has a second possible embodiment of a compressor according to the invention. The compressor 110 is again designed in two stages, and essentially corresponds to the compressor 10 of FIG first described embodiment according to Fig. 1 . At this point, the differences to the compressor 10 are above all in accordance with Fig. 1 described. The compressor 110 has two compression stages 114-1 and 114-2.

In contrast to the first possible embodiment, the first compression stage 114-1 compresses a main coolant flow at low pressure (suction pressure), which is made available to the compressor 110 via a low-pressure connection 122 and a low-pressure volume that corresponds in structure and function to that of the first embodiment will, at high pressure. In parallel with this, the second compression stage 114-2 is arranged, which also compresses the intermediate pressure refrigerant of a secondary coolant flow to high pressure. The intermediate pressure refrigerant is supplied to the compressor 110 via an intermediate pressure connection 134, which corresponds to the second intermediate pressure connection 34 of the first embodiment, and an associated intermediate pressure volume, which corresponds in structure and function to the second intermediate pressure volume of the first embodiment. Here, too, the intermediate pressure refrigerant is used to cool the electric motor of the compressor.

In contrast to the compressor 10 of the first embodiment, in the compressor 110 the cylinders (cylinder outlets) of both compression stages 114-1 and 114-2 are connected to a common high-pressure sub-volume 138-5, which is the fifth high-pressure sub-volume 38-5 of the first embodiment, which is only connected to the Cylidern (cylinder outlets) of the second compression stage 14-2 is connected, replaced; The remaining partial volumes of the high pressure volume of the second embodiment are designed analogously to those of the first embodiment; A high pressure connection 140 corresponding to the first embodiment is also provided.

In the case of the compressor 110 of the second embodiment, the first intermediate pressure volume 24 via which the refrigerant compressed in the first compression stage 14-1 of the compressor according to the first embodiment was supplied to the intercooler without replacement is thus omitted.

The refrigerant flows from the high-pressure connection 140 (again via pipelines in each case) to a gas cooler 143, which corresponds to the gas cooler 43 in terms of structure and functionality and is cooled there. The refrigerant flow is then divided into the main flow H and the secondary flow N, the secondary flow passing through a first expansion element 146-1, where it is expanded to the intermediate pressure of the compressor. The secondary stream N is then fed to a heat exchanger 162. The main stream H initially does not pass through an expansion device but is fed directly to the heat exchanger 162, so that the main stream H is further cooled by the secondary stream N.

The secondary flow is then led to the second compression stage 114-2, more precisely to the intermediate pressure connection 134, while the main flow H passes through an expansion element 146-2, which expands the refrigerant of the main flow or the main flow to a mean pressure that is different from the intermediate pressure can. After passing through a collector 150, which corresponds in structure and function to the collector 50 of the first embodiment, and a further expansion element 154, which corresponds in structure and function to the expansion element 54 of the first embodiment, the refrigerant of the main flow H then returns to the evaporator 158 Low pressure connection of the compressor 110.

It should be noted at this point that in both of the described embodiments of a compressor according to the invention, the rotor of the electric motor 12 functions as an oil separator. In the described embodiments, the compressor housing 15 consists of two parts that are thermally connected to one another in a non-removable manner after the drive device and the compression unit have been introduced. This leads to a high level of stability of the compressor, since loosening of connections, for example due to vibrations, is unlikely. Alternatively, more than two parts can also be used to form the housing 15, which, in spite of a higher number of parts and slightly higher manufacturing costs, may increase the ease of assembly and thus ensure cost savings elsewhere.

A third refrigeration system based on the compressor 10, which is a modification of the in Fig. 2 refrigeration system shown is in Fig. 4 shown. In addition to the in Fig. 2 existing components, the third refrigeration system has a connecting line in the form of a pipe 64 between the collector 50 and the pipe 32, which is arranged between the intercooler 28 and the second intermediate pressure connection 34. This creates a secondary refrigerant flow from collector 50 to the second Compression level 14-2 allows.

Another (fourth) refrigeration system based on the compressor 10 is shown in FIG Fig. 5 shown. In this embodiment, the intercooler 28 and the pipelines assigned to it are omitted, but otherwise the fourth refrigeration system is identical to the third refrigeration system according to FIG Fig. 4 .

A fifth, in Fig. 6 The refrigeration system shown is based on the refrigeration system of Figure 2 (two-stage compressor with serially arranged compression stages), whereby the refrigerant flow after the gas cooler 43 (analogous to the refrigeration system, which in Fig. 3 is shown) divided into a main flow H and a secondary flow N, the secondary flow passing through a first expansion element 46-1, where it is expanded to the intermediate pressure of the compressor. The secondary stream N is then fed to a heat exchanger 62. The main stream H initially does not run through an expansion element but is fed directly to the heat exchanger 62, so that the main stream H is further cooled by the secondary stream N.

The secondary flow is then led to the second compression stage 14-2, more precisely to the intermediate pressure connection 34, while the main flow H passes through an internal heat exchanger 66 and then an expansion element 54, the refrigerant of the main flow H then passes via the evaporator 58, another collector 68 and the internal heat exchanger 66 back to the low pressure connection of the compressor 10.

In Fig. 7 Finally, another (sixth) refrigeration system is shown, which has a compressor 110 (ie a compressor with parallel compression stages 114-1 and 114-2). In contrast to the refrigeration system according to Fig. 3 however, the sixth refrigeration system does not have a heat exchanger which transfers heat from a main refrigerant flow to a secondary refrigerant flow. The total refrigerant flow passes through, similar to the refrigeration system Fig. 5 an expansion element 146 and then passes into a separator or collector 150. A connection in the form of a pipe 164 extends from the collector 150 to the inlet of the compression stage 114-2, whereby a secondary flow N is fed to the compression stage 114-2, whereas a main flow H is supplied is fed to the expansion element 154 and via the evaporator 58 arranged thereafter to the first compression stage 114-1.

As already indicated above, the described first embodiment of a compressor 10 is a compressor 10 with an eccentric mechanism. In the following, the corresponding engine will be discussed in more detail, although this is an example of a compressor according to the invention, which by no means has to be a reciprocating compressor, but may also be a scroll compressor, a screw compressor or any other known type of compressor. In particular, however, for cases in which radial piston compressors should or must be used due to technical specifications or also due to customer requests and the like, the drive unit described below is an advantageous variant.

How Fig. 8 and 9 can be removed, the compressor 10 (which can also be used as the compressor 110) has six pistons 18 which are arranged in corresponding cylinder bores or cylinder sleeves 216 such that they can be moved back and forth in a radial direction. The cylinder bores or cylinder liners 216 themselves are designed as corresponding recesses in a cylinder block 218. As already mentioned above, the pistons 18 are designed to be movable to and fro in the radial direction. A distinction is made between a disengaging movement and an engaging movement in this to-and-fro movement, the disengaging movement being directed in the radially outward direction (indicated by arrow 220) and the engaging movement in a radially inward direction (indicated by arrow 222) is. As already indicated above, the compressor 10 serves to compress R744 (CO ₂ ) as a refrigerant. It should be noted, however, that any other refrigerant (for example R134a, etc.) can also be used.

Furthermore, the compressor 10 has the drive device in the form of the drive shaft 16 (cf. for example FIG Fig. 9 ), by means of which the drive of the compressor 10 takes place. In the embodiment described, the drive shaft 16 is coupled to the electric motor 12, but in alternative embodiments it can also be coupled to a corresponding belt drive device or some other device. At this point it should be noted that, depending on the intended use, the axial extent of the drive shaft 16 can also be significantly shorter than in the embodiment shown in the figures, in which the drive shaft 24 is in operative engagement with the electric motor and extends through it.

During the disengaging and engaging movements of the pistons, refrigerant is sucked into the cylinder bores or cylinder sleeves 216 when the pistons 18 are engaged, compressed when the disengaging movement is carried out and then expelled.

The drive device in the form of the drive shaft 16 is in operative engagement with an eccentric 228. More precisely, the drive shaft 16 is formed eccentrically in a corresponding region (eccentric section of the drive shaft 16). The eccentric 228 is thus formed integrally and in one piece with and on the drive shaft 16. In alternative embodiments, the eccentric 228 can also be designed as a separate component and attached to the drive shaft 16, in particular articulated or supported accordingly.

The eccentric 228, cut perpendicular to the axial direction, has a circular cross section and radially outwardly directed eccentric surfaces 230 which are arranged in a region of an eccentric active section 232. The eccentric active section 232 serves to drive the pistons 18 and is in operative engagement therewith via a connecting rod 234 assigned to each piston 18. For this purpose, the connecting rods 234 are articulated to the piston 18 by means of connecting rod eyes 236, which are formed on the sides of the connecting rods 234 facing the pistons 18.

On the side facing the eccentric 228, the connecting rods 234 have an active connecting rod section 238 which is used for operative engagement with the eccentric 228. The eccentric 228 is in active engagement with the connecting rod active sections 238 via a bearing in the form of a needle bearing 240, which is arranged (fitted) on the eccentric active section 232 (circular cross section) and there on the eccentric surface 230. As an alternative to the needle bearing 240, other bearings, in particular plain bearings or roller bearings in any possible design, are conceivable.

The bearing 240 ensures a low-friction transfer and a conversion of the movement (rotary movement) of the eccentric 228 into a movement in the radial direction of a connecting rod active section receptacle 242, which is in operative engagement with the bearing by means of a corresponding fit. The corresponding movement in the radial direction is then correspondingly applied to the connecting rods 234 and the pistons 18 articulated thereon transfer. The connecting rod active sections 238 corresponding to the circular outer circumference of the bearing 240, which are configured in the manner of a segment of a circle on their side facing the bearing 240, have for this purpose a widened extension in the axial direction at their end facing the bearing, so that they can be expanded by means of two, im Cross-section of L-shaped shells 244, which form the connecting rod active section receptacle 242, are securely arranged on the bearing 240. The connecting rod active sections of all connecting rods 234 are arranged on a circular path around the eccentric 228 and thus also around the eccentric active section 232, which is concentric therewith.

Due to the fact that the pendulum point of the device is arranged eccentrically due to the use of the eccentric 228, the present construction, in which circular segment-like connecting rod active sections 238 are used and the connecting rods 234 are thus decoupled from one another in their movement, in the area of the respective pistons18 a different movement take place. If the connecting rods 18 were rigidly coupled, there would be an error in the stroke movement and thus an increased dead space in the area of the pistons 18, which are far from the pendulum point.

Although the invention is described on the basis of embodiments with fixed combinations of features, it also encompasses the further conceivable advantageous combinations as indicated by the subclaims.

List of reference symbols

10, 110

compressor

12th

Electric motor

14th

Compaction device

14-1, 114-1

first compression stage

14-2, 114-2

second compression stage

16

drive shaft

18th

piston

19th

cylinder

20th

Low pressure refrigerant supply device

22nd

Low pressure connection

24

Intermediate pressure refrigerant discharge device

26th

first intermediate pressure connection

28

Intercooler

30.32

Pipeline

34

second intermediate pressure connection

36

Intermediate pressure refrigerant supply device

38

High pressure refrigerant discharge device

40, 140

High pressure connection

42

Pipeline

43, 143

Gas cooler

44

Pipeline

46, 146

Expansion device

48

Pipeline

50, 150

Collector

52

Pipeline

54, 154

Expansion device

56

Pipeline

58, 158

Evaporator

60

Pipeline

62, 162

Heat exchanger

64

Pipeline

66

internal heat exchanger

68

Collector

216

Cylinder bores / cylinder liners

218

Cylinder block

220

arrow

222

arrow

228

eccentric

230

Eccentric surface

232

Eccentric effective section

234

Connecting rod

236

Connecting rod eye

238

Connecting rod effective section

240

(Needle) bearings

242

Connecting rod active section recording

244

Bowl

Claims (16)

1. A compressor (10, 110), having a compressor housing (15), having a drive device (12) and having a compression device (14) with one or more compression stages (14-1, 14-2) for compressing a refrigerant, wherein the compressor (10, 110) furthermore has one or more refrigerant feed devices (20, 36) for feeding refrigerant to the compression device (14) and one or more refrigerant discharge devices (24, 38) for discharging refrigerant from the compression device (14), wherein
   at least one section of the one refrigerant feed device or at least one section of at least one, in particular each of the multiple refrigerant feed devices (20, 36) is arranged so as to be thermally separate from the one refrigerant discharge device or at least one, in particular each of the multiple refrigerant discharge devices (24, 38) characterized in that
   the high-pressure refrigerant discharge device (38) has five high-pressure refrigerant discharge device sub-regions which are each connected to one another in gas-tight fashion, namely a first, tubular high-pressure refrigerant discharge device sub-region (38-1) which extends outside the compressor housing (15) from the compressor housing (15) to a high-pressure port (40); a second high-pressure refrigerant discharge device sub-region (38-2) which is likewise of tubular form and which extends within the compressor housing (15) from the compressor housing (15) to a third high-pressure refrigerant discharge device sub-region (38-3); the third high-pressure refrigerant discharge device sub-region (38-3) which is of approximately cuboidal form, that is to say has a rectangular cross section, and which serves for pulsation damping in the high-pressure volume; a fourth high-pressure refrigerant discharge device sub-region (38-4) which extends from the third high-pressure refrigerant discharge device sub-region (38-3) to the compression unit (14); and a fifth high-pressure refrigerant discharge device sub-region (38-5) which is formed in the compression unit (14) and which is connected to cylinder outlets of the compression stage (14-2) and which serves for the discharge of refrigerant at high pressure or compression end pressure.
2. The compressor (10, 110) as claimed in claim 1, characterized in that

   - the compressor has more than one refrigerant feed device,

   - is in particular of multi-stage design, and

   - at least one section of each refrigerant feed device (20, 36) is arranged so as to be thermally separate from the one or more refrigerant discharge devices (24, 38).
3. The compressor (10, 110) as claimed in claim 1, characterized in that

   - the compressor has more than one refrigerant feed device,

   - is in particular of multi-stage design, and

   - at least one section of each refrigerant feed device (20, 36) is arranged so as to be thermally separate from every other refrigerant feed device (20, 36) that is provided.
4. The compressor (10, 110) as claimed in in claim 1, characterized in that

   - the compressor has more than one refrigerant discharge device,

   - is in particular of multi-stage design, and

   - at least one section of each refrigerant discharge device (24, 38) is arranged so as to be thermally separate from every other refrigerant discharge device (24, 38) that is provided.
5. The compressor (10, 110) as claimed in one of the preceding claims,
   characterized in that
   the one or more sections that are arranged so as to be thermally separate from the other refrigerant feed device(s) (20, 36) or refrigerant discharge device(s) (24, 38), or separate from sections thereof, are formed separately from these and/or are arranged so as to have no contact surface or a minimized contact surface with respect to one another and/or so as to be spaced apart from these and/or so as to be separated from these by a thermally insulating material or a material that exhibits low thermal conductivity.
6. The compressor (10, 110) as claimed in one of the preceding claims,
   characterized in that
   one or more of the sections that are arranged so as to be thermally separate from other refrigerant feed device(s) or refrigerant discharge device(s) (24, 38) extend from the inner side of the compressor housing (15) to the compression device (14) .
7. The compressor (10, 110) as claimed in one of the preceding claims,
   characterized in that
   one refrigerant feed device (20, 36) opens out in the compressor housing, in particular in the region of or adjacent to the drive device (12).
8. The compressor (10, 110) as claimed in claim 7,
   characterized in that
   the refrigerant feed device that opens out in the compressor housing (15) is a refrigerant feed device (20, 36) for refrigerant which is at low pressure or for refrigerant which is at an intermediate pressure.
9. The compressor (10, 110) as claimed in one of the preceding claims,
   characterized in that
   at least one refrigerant discharge device (24, 38), in particular a refrigerant discharge device for refrigerant (24) which is at an intermediate pressure, is provided for connecting to an inlet of a refrigerant intercooler (28) of a refrigeration system or can be in fluid communication with an inlet of a refrigerant intercooler of the compressor (10, 110).
10. The compressor (10, 110) as claimed in one of claims 7 to 9,
    characterized in that
    the refrigerant feed device (36) that opens out in the compressor housing (15) is provided for connecting to an outlet of a refrigerant intercooler (28) of a refrigeration system or can be in fluid communication with an outlet of a refrigerant intercooler of the compressor (10, 110) .
11. The compressor (10, 110) as claimed in one of the preceding claims,
    characterized in that
    the drive device has an electric motor (12) with a rotor and a stator, wherein the rotor serves as an oil separator for refrigerant that is supplied thereto.
12. The compressor (10, 110) as claimed in one of the preceding claims,
    characterized in that
    the compressor (10, 110) is of two-stage design and has a refrigerant feed device (20) for refrigerant at low pressure and a refrigerant feed device (36) for refrigerant at intermediate pressure and a refrigerant discharge device (24) for refrigerant at intermediate pressure and a refrigerant discharge device (38) for refrigerant at high pressure, wherein in each case at least sections, in particular sections arranged within the compressor (10, 110), of each refrigerant feed device (20, 36) and of each refrigerant discharge device (24, 38) are arranged so as to be spaced apart from one another.
13. The compressor as claimed in one of the preceding claims,
    characterized in that
    the compressor (10, 110) is provided for R744 as refrigerant.
14. The compressor (10, 110) as claimed in one of the preceding claims,
    characterized in that
    the compressor (10, 110) has at least two housing components (15-1, 15-2) which are connected to one another in gas-tight and non-disassemblable fashion, and/or the compressor (10, 110) is of a hermetic or semi-hermetic type of construction.
15. A refrigeration system,
    characterized in that
    it has a compressor (10, 110) as claimed in one of the preceding claims.
16. The refrigeration system as claimed in claim 15,
    characterized in that
    it has an intercooler (28) for cooling refrigerant that is provided by a refrigerant discharge device (24, 38) of the compressor (10, 110).

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