Compression device and control mass flow separation method

Abstract

A device for compression of a gaseous fluid, in particular of a refrigerant. The device comprises a housing with a suction pressure chamber and a high pressure chamber, a compression mechanism as well as a configuration developed in the proximity of the high pressure chamber, for the separation of a control mass flow from a fluid-lubricant mixture for the control of the compression mechanism. The configuration is developed and disposed with a first flow duct for diverting a main mass flow of the compressed fluid-lubricant mixture from the device and a second flow duct for conducting the control mass flow within the device to the suction pressure chamber in such manner as to separate a mass flow of the gaseous fluid as a control mass flow. A method for the separation of a control mass flow is also provided.

Claims

1. A device for the compression of a gaseous fluid comprising a housing with a suction pressure chamber and a high pressure chamber, a compression mechanism as well as a configuration implemented in the proximity of the high pressure chamber for the separation of a control mass flow from a main mass flow comprising a fluid-lubricant mixture for the control of the compression mechanism, wherein the fluid lubricant mixture comprises a mixture of gaseous refrigerant and oil, and wherein the oil is a liquid, wherein the configuration comprises a first flow duct for diverting the main mass flow of the compressed fluid-lubricant mixture from the device and a second flow duct for separating a mass flow of the gaseous fluid, said gaseous fluid comprising the gaseous refrigerant, as the control mass flow from the main mass flow and conducting the control mass flow within the device to the suction pressure chamber, wherein the gaseous refrigerant is separated from the mixture of gaseous refrigerant and oil in the first flow duct and flows into the second flow duct; wherein a first expansion element is disposed downstream of the second flow duct, wherein the control mass flow comprises a gaseous refrigerant; wherein the liquid comprises an oil; wherein the gaseous refrigerant separated from the mixture of gaseous refrigerant and oil in the first flow duct flows into the second flow duct; wherein oil separated from the mixture of gaseous refrigerant and oil in the first flow duct is deposited in a lower region of the high-pressure chamber; and wherein the mixture of gaseous refrigerant and oil not separated in the first flow duct flows into a refrigerant circulation; wherein the second flow duct is developed to open out in the direction of flow of the control mass flow into a high pressure duct and at the outlet of the high pressure duct the first expansion element is disposed for relieving the control mass flow from a high pressure level to an intermediate pressure level, wherein the control mass flow is conducted into a region of the housing that is charged with gaseous fluid at the level of the intermediate pressure; wherein the region of the housing that is charged with gaseous fluid at the intermediate pressure level comprises a passage port to the suction pressure chamber and within the passage port a second expansion element is disposed for relieving the control mass flow from the intermediate pressure level to a low pressure level; and wherein the first expansion element and the second expansion element are configured to relieve their respective pressures simultaneously.

2. A device as in claim 1, wherein the second flow duct of the configuration, for the diversion of the control mass flow within a calm-flow region of the high pressure chamber, is disposed such that it opens out into the high pressure chamber.

3. A device as in claim 2, wherein the flow ducts within the configuration are developed isolated from one another and are oriented extending in a longitudinal direction of the configuration.

4. A device as in claim 2, wherein the configuration has a cylindrical shape.

5. A device as in claim 1, wherein the configuration is disposed in the proximity of an outlet from the high pressure chamber, wherein the second flow duct is developed in such manner that it diverges from the first flow duct and diverges at an angle (α) such that the control mass flow when flowing into the second flow duct is deflected by an angle (α) of at least 90°.

6. A device as in claim 1, wherein the compression mechanism as a scroll compressor comprises an immobile stator and a movable orbiter as well as an intermediate pressure chamber, wherein the stator and the orbiter are each developed with a spiral-shaped wall extending from the base plate, wherein the walls are disposed such that they interlock, and the intermediate pressure chamber is developed on a reverse side of the base plate of the movable orbiter and is charged with gaseous fluid at the intermediate pressure level.

7. A method for the separation of a control mass flow in a device for compressing a gaseous fluid with a configuration for the separation of the control mass flow as in claim 1, the method comprising the steps of: discharging a fluid-lubricant mixture compressed to high pressure into the high pressure chamber, diverting a main mass flow of the fluid-lubricant mixture through the first flow duct out of the device, as well as segregating a control mass flow from the main mass flow and diverting the control mass flow through the second flow duct within the device to a suction pressure chamber, wherein as the control mass flow gaseous fluid without solid particles is segregated, wherein the first expansion element is disposed downstream of the second flow duct, and wherein blocking and clogging of the first expansion element is prevented because the control mass flow is in the gaseous state.

8. A method according to claim 7, wherein the control mass flow during its flow through a first expansion element is relieved from a high pressure level to an intermediate pressure level and is conducted into a region of a housing that is charged with gaseous fluid at the intermediate pressure level, during its flow through a second expansion element is relieved from an intermediate pressure level to a low pressure level and is conducted into the suction pressure chamber.

Description

(1) Further details, characteristics and advantages of embodiments of the invention are evident in the subsequent description of embodiment examples with reference to the associated drawings. Therein depict:

(2) FIG. 1 a compressor, in particular a scroll compressor, with a configuration for separating a control mass flow, in sectional view as well as

(3) FIG. 2 schematically the flow of the control mass flow through an expansion element developed as a nozzle,

(4) FIG. 3 a detail view of a first alternative embodiment of the configuration for separating a control mass flow, in sectional view as well as

(5) FIG. 4 a detail view of a second alternative embodiment of the configuration for separating a control mass flow, in sectional view.

(6) FIG. 1 shows a compressor 1 with a configuration 10 for separating a control mass flow, in the following also denoted as separator 10, in sectional view. The compressor 1 comprises moreover a compression mechanism for drawing in, compressing and discharging of refrigerant as a gaseous fluid including the oil as lubricant for lubrication. The compression mechanism and the separator 10 are disposed within a housing 2.

(7) The compressor 1 is realized as a scroll compressor with a back housing element 2a, a middle housing element 2b as well as a front housing element 2c which, in the assembled state, form the housing 2. The compression mechanism of the compressor 1 comprises an immobile stator 3 as well as a movable orbiter 4, each with a base plate and a wall developed in the form of a spiral and extending from the base plate. The base plates are arranged with respect to each other such that the walls interlock. The immobile stator 3 is implemented within the housing 2 or as a constituent of the housing, the movable orbiter 4 is coupled by means of an eccentric drive to a rotating drive shaft 5 and is guided on a circular orbit. The drive shaft 5 is stayed with at least one radial bearing 7 on the middle housing element 2b and in a, not shown, second radial bearing on the front housing element 2c of the housing 2. The movable orbiter 4 is retained via a radial bearing 6 on the drive shaft 5.

(8) During the movement of the orbiter 4 the spiral-shaped walls of stator 3 and orbiter 4 come into contact at several sites and form within the walls several consecutive closed-off working volumes of different sizes with adjacently disposed working volumes delimiting capacities. As a reaction to the movement of the orbiter 4 relative to the stator 3 the capacities and the positions of the working volumes are changed. The capacities of the working volumes are increasingly smaller proceeding in the direction toward the center of the spiral-shaped walls. The gaseous fluid to be compressed, in particular the gaseous refrigerant with the oil, is aspirated, due to the pressure of the refrigerant, into the working volume as refrigerant-oil mixture through a suction chamber 8 also denoted as suction pressure chamber 8, it is compressed through the movement of the orbiter 4 relative to the stator 3 and discharged, due to the pressure of the refrigerant, into an ejection chamber 9 also denoted as high pressure chamber 9.

(9) The refrigerant-oil mixture, which in the high pressure chamber 9 is at high pressure level, is conveyed through a flow duct 11, that conducts the main mass flow of the gaseous refrigerant or the refrigerant-oil mixture, in the direction of flow 18 out of the compressor 1. The main mass flow of the refrigerant-oil mixture consequently flows from the high pressure chamber 9 through the flow duct 11, implemented in the configuration 10 for the separation, out of the compressor 1 into the refrigerant circulation. The flow duct 11 extends in the longitudinal direction of the preferably cylindrically developed separator 10 and opens out at a first end of separator 10 into a port developed in the back housing element 2a, which, due to the pressure level of the refrigerant, is also denoted as high pressure housing.

(10) The compressor 1 comprises, moreover, a region developed as a counter-pressure chamber 16, due to the pressure level within the compressor 1 also denoted as intermediate pressure chamber 16, which region is developed on the reverse side of the base plate of the movable orbiter 4 and presses the orbiter 4 against the immobile stator 3. The counter-pressure chamber 16 is charged with an intermediate pressure or a pressure intermediate between the suction pressure and the high pressure. The force resulting from the different pressures acts in the axial direction and the walls of the orbiter 4 as well as of the stator 3 are pressed at the axially adjacent face sides against one another and sealed against each other in order to minimize the radial transverse flow of the gaseous refrigerant.

(11) In addition to the first flow duct 11 for diverting the refrigerant-oil mixture out of the compressor 1 into the refrigerant circulation, the configuration 10 for the separation comprises additionally also a second flow duct 12 for the purpose of diverting within the compressor a control mass flow. The second flow duct 12 opens out perpendicularly and in such manner into a calm-flow region into the high pressure chamber 9 that in particular gaseous refrigerant flows in the orthogonal direction of flow out of the high pressure chamber 9 into the flow duct 12.

(12) The calm-flow region is for example disposed facing away from the outlet ports of the working volumes of the compression mechanism.

(13) The mouth of the flow duct 12 is, furthermore, developed in the direction of the force of gravity in the middle to upper region of the high pressure chamber 9 such that preferably exclusively gaseous refrigerants without any or only with minimal oil fraction and without any or only with minimal fraction of liquid refrigerant as well as without additional particles are conducted into the flow duct 12. The oil and possible suspended particles settle in the lower region of the high pressure chamber 9 and/or are conducted through the first flow duct 11 out of the compressor 1.

(14) The second flow duct 12 extends primarily in the longitudinal direction of the preferably cylindrically developed separator 10, wherein the mouth port into the high pressure region 9 is disposed perpendicularly to the longitudinal direction, and opens out into the high pressure duct 13 at a second end developed distally to the first end of separator 10. In the proximity of the mouth of the second flow duct 12 into the high pressure region 9 the gaseous refrigerant is deflected by 90° and flows in the direction of flow 19 through the second flow duct 12 into the high pressure duct 13 developed as a connection duct.

(15) In particular by disposing the port of the second flow duct 12 in the calm-flow region of the high pressure chamber 9 and by the deflections within the flow duct 12 mainly gaseous refrigerant reaches the high pressure duct 13 and arrives at a first expansion element 14 which, for example, is developed as a high pressure nozzle or a valve, in particular a control valve.

(16) Subsequent to the segregation or the separation of the control mass flow from the main mass flow of the refrigerant-oil mixture in separator 10, the control mass flow of gaseous refrigerant is relieved to an intermediate pressure level during its flow through the first expansion element 14 and is conducted through an intermediate pressure duct 15 into the intermediate pressure chamber 16. By means of the control mass flow the counterpressure for pressing the orbiter 4 onto the stator 3 is consequently ensured.

(17) During its flow through a second expansion element 17, which is developed for example as a low pressure nozzle or a valve, in particular a control valve, the control mass flow is relieved from the intermediate pressure level to the level of the suction pressure and returned into the suction pressure chamber 8. In the suction pressure chamber 8 the control mass flow is mixed with the refrigerant-oil mixture aspirated by the compressor 1 from the refrigerant circulation and aspirated into the working volume. The circulation of the control mass flow is closed.

(18) To operate the compressor 1 as efficiently as possible, the control mass flow should be minimal. When flowing through an expansion element 14, 17, such as the high pressure nozzle or the low pressure nozzle, the control mass flow is dependent on state variables, in particular the pressure difference Δp=p.sub.2−p.sub.1 of the fluid to be relieved before and after the expansion element 14, 17 as well as the density .sub.2 of the refrigerant and of the physical dimension of the cross section of the expansion element 14, 17, in particular the diameter d of the nozzle or of the valve. FIG. 2 shows schematically the streaming of the control mass flow through an expansion element 14, 17 developed as a nozzle. Since the pressure difference Δp and the density .sub.2 of the refrigerant cannot be influenced, the diameter d of the expansion element must be decreased. The control mass flow is herein the lesser the smaller the diameter d of the cross section of the expansion element 14, 17.

(19) However, the sensitivity of the blocking of the expansion element 14, 17 with particles increases with a decrease of the cross section or the diameter d. To avoid now the blocking, and therewith the clogging, of the expansion element 14, 17 over the entire service life, a particle-free control mass flow of gaseous refrigerant is segregated from the main mass flow by means of the separator 10 and the control mass flow is returned back to the suction side of the compressor 1 through the expansion elements 14, 17.

(20) In FIGS. 3 and 4 a detail view is shown in cross section of an alternative embodiment of compressor 1′, 1″, in particular of the configuration of separator 10′, 10″.

(21) The back housing element 2a of housing 2 comprises the high pressure chamber 9 and a separator 10′, 10″ for separating the control mass flow from the main mass flow. The first flow duct 11′, 11″ as the flow path of the main mass flow extends, starting from the high pressure chamber 9, to a port in housing 2. The refrigerant-oil mixture conducted as main mass flow is conveyed in the direction of flow 18 out of the compressor 1′, 1″ into the refrigerant circulation. The separator 10, 10″ is in each case developed as a portion of the back housing element 2a.

(22) In the embodiment according to FIG. 3 the second flow duct 12′ or the high pressure duct 13′ for conducting the control mass flow to the first expansion element 14 opens out perpendicularly, i.e. at an angle α of 90°, into the first flow duct 11′ of the main mass flow. The direction of flow 19 of the control mass flow and the direction of flow 18 of the main mass flow at the diversion of the control mass flow from the main mass flow are positioned with respect to one another at an angle α of 90°. The flow ducts 11′, 12′ are realized as two bores and oriented at an angle α of at least 90° with respect to one another.

(23) According to an embodiment not shown, the directions of flow of main mass flow and control mass flow are oriented in the proximity of the diversion at an angle of more than 90°. When the directions of flow are oriented at an angle of more than 90°, the control mass flow sweeps through an angle of more than 90° and the control mass flow is deflected by more than 90°.

(24) In the embodiment according to FIG. 4 the first flow duct 11″ of the main mass flow opens out obliquely to the port developed in housing 2 and a region of the diversion of the second flow duct 12″ of the control mass flow. According to an alternative embodiment, not shown, the first flow duct of the main mass flow opens out obliquely to the port developed in the housing and the region of the diversion of the second flow duct of the control mass flow. In the proximity of the diversion of the second flow duct 12″ of the control mass flow a separating sleeve 20 is disposed. In the configuration of the first flow duct 11″ and of the second flow duct 12″ at an angle of less than 90° the separating sleeve 20 serves for a forced flow conduction of the control mass flow. The separating sleeve 20 and the second flow duct 12″ are oriented with respect to each other such that the control mass flow is diverted and deflected substantially counter to the direction of flow 18 of the main mass flow into the second flow duct 12″. The control mass flow flows herein in the direction of flow 18 out of the first flow duct 11″ or the separating sleeve 20, is initially deflected by an angle α of more than 90° and, viewed overall, deflected by approximately an angle α in the range of 135° to 165° and flows subsequently into the second flow duct 12″ with a further deflection by 90°.

(25) In the segregation of the control mass flow as a particle-free, gaseous refrigerant mass flow, without or only with minimal oil fraction and without or only with minimal fraction of liquid refrigerant, from the main mass flow as a refrigerant-oil mixture with particles, the inertia of the particles as well as also that of the fluid is exploited, which is ensured through the deflection of the control mass flow by at least 90° according to the embodiments depicted in FIGS. 3 and 4 or by the diversion within a calm-flow region of the high pressure chamber 9 according to the embodiments depicted in FIG. 1.

LIST OF REFERENCE SYMBOLS

(26) 1, 1′, 1″ Device for compression, compressor 2 Housing 2a Back housing element 2b Middle housing element 2c Front housing element 3 Stator 4 Orbiter 5 Drive shaft 6 Radial bearing of orbiter 5 on drive shaft 6 7 Radial bearing of drive shaft 6 on housing 2 8 Suction chamber, suction pressure chamber 9 Ejection chamber, high pressure chamber 10, 10′, 10″ Configuration for separating, separator 11, 11′, 11″ First flow duct main mass flow 12, 12′, 12″ Second flow duct control mass flow 13, 13′, 13″ High pressure duct 14 First expansion element 15 Intermediate pressure duct 16 Counterpressure chamber, intermediate pressure chamber 17 Second expansion element 18 Direction of flow of main mass flow 19 Direction of flow control of mass flow 20 Separating sleeve α Angle d Diameter p.sub.1, p.sub.2 Pressure .sub.1, .sub.2 Density