DE102013218430A1 - Scroll compressor - Google Patents

Abstract

One of the nested scrolls of the scroll compressor is fixed while the other scroll is eccentrically orbitally but rotationally driven by means of a positive guide gear. The positive drive gear is designed as an expansion machine with which the compressor can be driven in addition. Thus, a portion of the compressor work for an additional drive of the compressor can be withdrawn.

Description

In the refrigerant circuit of a heat pump, a compressor is connected on the input side to a low-pressure, relatively cold refrigerant region and connected on the output side to a high-pressure region of the refrigerant. During the compression of the refrigerant coming from the low-pressure region, its temperature increases, so that a comparatively high temperature is present at the high-pressure region and heat can be removed to the outside or for use in a process, the refrigerant under high pressure condensing in a condenser , The condenser is connected to the low-pressure side of the heat pump through an expansion path, so that the refrigerant flows from the high-pressure side to the low-pressure side with corresponding depressurization and temperature reduction. Due to the work of the externally driven compressor, the refrigerant flow in the circuit is constantly maintained, so that the refrigerant in the low pressure range can absorb heat at low temperature and deliver in the high pressure region at high temperature.

In order to keep the energy consumption of the compressor as low as possible, it is in principle desirable and generally known to use the pressure difference between the high pressure and low pressure side of the heat pump for generating mechanical energy, which can then be used for an additional drive of the compressor, so that of externally supplied drive power is reduced accordingly. For this purpose, the expansion distance between high-pressure and low-pressure region is formed by a working machine in which the refrigerant at the input of the working machine under high pressure refrigerant is released to produce mechanical work, so that at the output of the expansion machine, the low pressure side of the heat pump corresponding refrigerant pressure is present.

In this connection, it is known to make the compressor and the expansion machine similar and operate only in opposite directions of action, that is, the refrigerant is compressed in the compressor by supplying mechanical work and expanded in the expansion machine to produce mechanical work. Reference may be made to the following document: Yu Shiotani et al .: "Development of Dual Compressor System using Compressor Combined with Expander for CO2 Heat Pump Hot Water Heating System", Int. Compressor Engineering Conterence at Purdue, July 16-19, 2012 ,

This is where the invention comes in and sets itself the task of providing a compressor for use in the refrigerant circuit of a heat pump, which has a drivable by the pressure difference between the high pressure side and the low pressure side of the refrigerant circuit auxiliary drive, which can be produced with relatively little design effort ,

This object is achieved in that the compressor is designed as a scroll compressor, in which a relatively stationary first spiral surface with a arranged within the first spiral surface movable second spiral surface cooperates, the second spiral surface of the scroll compressor by means of a gear on a circular path positively driven and the Transmission is designed as a positive displacement unit, which is controllably connected via a valve arrangement with a high-pressure and a low-pressure region fluidly connected.

The invention is based on the recognition that in a scroll compressor, the second spiral surface must be moved relative to the first spiral surface in translation on a circular path and therefore requires a corresponding positive guidance. Here now the general idea of the invention is to ensure this forced operation by a transmission designed as a displacement unit. Thus, the guidance elements which are necessary anyway for positively guiding the movable second spiral surface have an additional function in that they form a drive machine suitable for utilizing the pressure difference between fluidic high-pressure and low-pressure regions. Serving for positive guidance of the second spiral surface gear can thus be used without further effort as an additional drive for the compressor work.

In principle, the transmission can be configured as desired for positively guiding the movable spiral surface. In any case, it is expedient to guide the movable spiral surface or a carrier part connected thereto by means of an eccentric on a circular path and to provide additional guides which prevent a rotational movement of the movable spiral surface or of the associated carrier part.

According to a particularly preferred embodiment, the gear for positively guiding the movable scroll surface comprises two radially superimposed rings, wherein the one ring is arranged stationary and the other ring is fixedly connected to the movable scroll surface. Between the inner circumference of the larger ring and the outer periphery of the smaller ring thrust levers are expediently arranged, which are each connected at one end about a pivot axis parallel to the pivot axes pivot axis with one ring and are coupled to the other ring via a respective sliding joint, which at the other ring is displaceable in the radial direction. In an axial view of the radially superimposed rings, the thrust levers divide the annular clearance between the inner circumference of the larger ring and the outer circumference of the smaller ring into arcuate sections, the cross section of each section being varied between maximum and minimum when the movable ring is from the eccentric is guided on a circular path. Now, if said radially superimposed rings between two orthogonal to the ring axes surfaces are arranged, which connect tightly to the end faces of the rings and the thrust levers are formed as transversely to the aforementioned surfaces extending wall parts, between the rings in the circumferential direction of the rings adjacent Chambers separated from each other, whose volume varies between a minimum and a maximum value, when the one ring is moved relative to the other ring by means of the eccentric on a circular path. By now these chambers are controlled connected to a high pressure area or a low pressure area, it is possible to actively move the movable ring relative to the stationary ring and thus the movable scroll surface relative to the stationary scroll surface and thus to drive the scroll compressor fluidly. Additionally or alternatively, it can be provided that the thrust joints of the thrust lever each have piston-like guide body, which are displaceable in associated cylindrical guides and complete there each a piston working space movable. By pressurizing or depressurizing this piston working spaces then a drive of the scroll compressor is also possible.

Incidentally, with regard to preferred features of the invention, reference is made to the claims and the following explanation of the drawing, are described in detail with reference to the particularly preferred embodiments of the invention.

In the drawing shows

1 an axial section of a scroll compressor;

2 a radial section of a transmission for translationally orbiting leadership of the movable scroll surface of the scroll compressor;

3 one of the 2 similar representation, with a control valve arrangement is also shown in the form of a circuit diagram, with which the displacement chambers formed in the positive guide transmission act on pressure medium or relieve the pressure medium;

4 3 a perspective sectional view of the scroll compressor, wherein the valve arrangement of the positive guidance gear is designed as a slide valve arrangement,

5 a diagram showing the pressure in a displacement working chamber and its volume as a function of the crank angle.

The in 1 illustrated scroll compressor 1 has a drive unit 2 , whose output shaft 3 with an eccentric 4 rotatably connected. On the eccentric 4 is a ring body 5 rotatably mounted. This ring body 5 is, compare too 2 radially within a stationary outer ring body 6 arranged firmly in the housing of the scroll compressor 1 is housed. The ring body 5 is fixed to a carrier body 7 connected accordingly, that of the eccentric 4 caused movements of the ring body 5 follows. The carrier body 7 carries the one, movable spiral surface 8th of the scroll compressor. This movable spiral surface 8th is inside a stationary spiral surface 9 arranged, in turn, on a stationary in the housing of the scroll compressor arranged carrier body 10 is arranged. By further explained below transmission elements between the ring bodies 5 and 6 ensures that the moving ring body 5 in one revolution of the eccentric 4 a purely translational movement on the eccentric 4 performs predetermined circular path. Accordingly also leads the movable spiral surface 8th a purely translational movement with respect to the stationary spiral surface 9 out. However, the spiral surfaces are formed so that between them from the outside to inwardly migrating, their volume constantly decreasing displacement chambers are formed, which at the outer region of the stationary spiral surface 9 via a ring channel formed in the housing 11 take a compressible gas or vapor medium, which then with increasing compression to the center of the spiral surfaces 8th and 9 promoted and there with increased pressure in a pressure line 12 is dissipated. The ring channel 11 thus represents the suction side of the scroll compressor 1 and the pressure line 12 forms the connection to a pressure side, not shown.

For a scroll compressor 1 It is essential that the movable spiral surface 8th is always moved translationally and, accordingly, on a rotation about the eccentric 4 or the axis of the output shaft 3 is prevented. To prevent such rotation may be between the inner circumference of the outer ring body 6 and the outer periphery of the inner ring body 5 according to 2 thrust lever 13 be arranged, whose one end with one of the ring body 5 and 6 , In the example shown with the outer ring body 6 only articulated, but immovable is connected, that is everyone the thrust lever 13 is on the outer ring body 6 mounted pendulum about a pivot axis parallel to the ring axis. With the other ring body, in the example shown with the inner ring body 5 , are the thrust levers 13 coupled via a trained as a sliding articulated joint. This is a correspondingly spherical shaped end of the respective push lever 13 piston-like in a cylindrical radial guide 14 on the inner ring body 6 taken up, so that said spherical end of the push lever 13 on the one hand in the radial direction of this annular body 5 can move and on the other hand can pivot about a pivot axis parallel to the ring axis.

Optionally, instead of the crowned end also in the radial guide 14 slidable piston be provided, with which the respective thrust lever 13 around the axis of the ring body 5 parallel axis is pivotally connected.

The illustrated arrangement of the thrust lever 13 ensures that the inner ring body 5 the movements of the eccentric 4 can only follow purely translational and thereby no rotation relative to the axis of the outer ring body 6 can perform. Thus, the movable spiral surface moves 8th passing over her carrier body 7 firmly with the inner ring body 5 is connected, purely translational.

Out 2 it can be seen that the inner ring body 5 during circulation of the eccentric 4 with correspondingly wandering outer peripheral zones from the inner periphery of the outer ring body 6 is maximally or minimally spaced. The zones of minimum and maximum distance thus move analogous to the circulation of the eccentric 4 ,

This is synonymous with the fact that each of two adjacent thrust levers 13 and from the extended between these thrust levers arc portions of the outer circumference of the inner ring body 5 and the inner periphery of the outer ring body 6 cyclically enlarge or reduce the bounded areas. If now the ring body 5 and 6 and the thrust levers 13 between spaced in the radial direction of the annular body and spaced from each other in the axial direction of the annular body walls are arranged so that adjacent thrust lever 13 and arc portions extending therebetween of the outer circumference of the inner ring body 5 and the inner periphery of the outer ring body 6 each enclosing a chamber sufficiently tight, so these chambers can be used as a fluidic displacement chambers, as it is based on the 3 is explained schematically.

The aforementioned chambers are in 3 With 15.1 to 15.7 designated. In the illustrated position of the eccentric 4 has the chamber 15.1 a minimal volume, while the almost diametrically opposed chamber 15.4 has (nearly) a maximum volume. If the eccentric 4 Turning clockwise, subsequently the chamber 15.2 reach their minimum volume and the chamber 15.5 their maximum volume, etc. By means of an in 3 only schematically illustrated valve arrangement 16 May the opportunity now be created, the chambers 15.1 to 15.7 selectively connect to a high pressure fluid source H or a low pressure fluid side N. This allows the chambers 15.1 to 15.7 circulating in their volume so as to change that caused by the movement of the movable ring body 5 the eccentric 4 is moved circumferentially.

Because of the eccentric 4 in turn, with the movable spiral 8th is connected, thus the possibility is given to the scroll compressor to be for translationally rotating movement of the movable scroll 8th to drive fluidly provided transmission.

Thus, when the scroll compressor is disposed in a heat pumping circuit between its low pressure side and its high pressure side, there is the possibility of returning the high pressure fluid to the low pressure side to produce mechanical work in which the fluid expands. Part of the compressor work can then be used to drive the compressor, with the result that correspondingly less energy is needed to maintain the heat pump cycle.

4 now shows the possibility of the valve assembly 16 of the 3 form as a slide valve arrangement, wherein the eccentric 4 the function of the valve spool takes over.

The 4 shows a perspective sectional view of the scroll compressor 1 as well as his drive. On the output shaft 3 of the drive unit 2 is in turn rotatably the eccentric 4 arranged on which the inner ring body 5 is rotatably mounted. This ring body 5 is radially inside the outer ring body 6 arranged, in 4 between the two ring bodies 5 and 6 one of the chambers 15 in the in 4 shown position of the eccentric 4 has a relatively large volume, it can be seen. Diametrically opposite is another of the chambers 15 , this additional chamber 15 in the illustrated position of the eccentric 4 (at least nearly) has a minimal volume. The ring body 5 and 6 are between axially spaced apart walls 17 and 18 movably arranged, these walls 17 and 18 the aforementioned chambers 15 on the front sides of the ring body 5 and 8th to lock. The eccentric 4 separates within the illustrated housing a high-pressure chamber 19 from a low pressure room 20 from. The high pressure room 19 may be part of the high pressure side of the scroll compressor 1 form the comprehensive heat pump and the low-pressure chamber communicates with the low-pressure side of this heat pump, the low-pressure chamber 20 further with the suction side of the scroll compressor 1 communicated. On the outer circumference of the eccentric 4 are two each extending only over an arc portion of the outer circumference circumferential grooves 21 and 22 arranged, with the circumferential groove 21 via a frontal recess on the eccentric 4 with the high pressure room 19 constantly connected while the circumferential groove 22 via a arranged on the opposite end face of the eccentric recess constantly with the low pressure space 20 communicated. Accordingly, the circumferential groove forms 21 a high-pressure groove and the circumferential groove 22 a low pressure groove. The two circumferential grooves 21 and 22 are in the inner ring body 5 radial bores 23 and 24 assigned, such that each of the radial bores 23 and 24 each with only one of the circumferential grooves 21 and 22 communicated. This forms the radial bore in the example shown 23 a high pressure bore and the radial bore 24 a low pressure hole. The arc lengths of the circumferential grooves 21 and 22 are sized so that each of the radial bores associated chambers 15 over the respective high-pressure bore 23 and the high pressure groove 21 only with the high pressure room 19 communicates when the volume of each chamber 15 upon rotation of the eccentric 4 enlarged in a predetermined working direction. As soon as the chamber volume with further circulation of the eccentric 4 again reduced, receives the respective chamber 15 about their low pressure drilling 24 and the low pressure groove 22 Connection with the low-pressure room 20 ,

The diagram of 5 now shows a typical operation. The curve K _{1 shows} the relative volume of a chamber 15 during a rotation of the eccentric 4 around 360 °. It can be seen that the chamber volume is initially minimal and upon rotation of the eccentric 4 reached by 180 ° its maximum value of 100%. Subsequently, the chamber volume decreases again to 0% as soon as the eccentric reaches its initial position.

The curve K2 now shows the chamber pressure in the chamber 15 , The circumferential grooves 21 and 22 may now be arranged with such a bow dimensions that the respective chamber 15 in an initial phase P ₁ with the high-pressure chamber 19 communicated. Accordingly, the chamber pressure in the phase P _{1 is} at the value p _{19 of} the high-pressure chamber 19 , In the following, may the chamber 15 in a phase P ₂ both with respect to the high-pressure chamber 19 as well as towards the low pressure room 20 be shut off, that is, the high pressure bore 23 has no overlap with the high pressure groove 21 , and the low pressure hole 24 has no overlap with the low pressure groove 22 , Since the chamber volume increases almost linearly in this phase P ₂ , the chamber pressure drops exponentially. With appropriate dimensioning of the arc length of the low pressure groove 22 then can the chamber 15 with the low-pressure room 20 come into contact as soon as the chamber pressure on the level p _{20 of} the low-pressure chamber 20 has dropped. For other dimensioning of the arc length of the low pressure groove 22 can also occur cases in the chamber when opening the connection between the chamber and low-pressure chamber 20 there is still a greater or lesser overpressure compared with the low pressure p ₂₀ , or that the chamber pressure even falls below the level of the low pressure p ₂₀ , with the result that upon insertion of the connection between the chamber 15 and the low-pressure room 20 Fluid from the low-pressure space 20 flows back into the chamber.

It can be seen that the fluid of the high-pressure chamber 19 in the phases P ₁ and P _2, the volume changes of the respective chamber 15 actively supported in a direction enlarging the chamber volume. In any case, in the subsequent phase P ₃ , the fluid in the chamber can no longer counteract the change in the chamber volume. The chamber 15 In the phases P ₁ and P ₂ supplied or located in the chamber pressure fluid thus acts in the sense of supporting the rotational movement of the eccentric 4 , with the result that the scroll compressor 1 generated pressure difference between the high pressure and low pressure side of a heat pump circuit can be used for an additional drive of the scroll compressor, which accordingly requires less drive power. Due to thermodynamic laws can be expected with a reduction of the necessary drive power for the scroll compressor by about 15% compared to the case that the refrigerant of a heat pump is expanded during the transition from the high pressure side of the heat pump to the low pressure side of the heat pump without generating mechanical work through an expansion valve.

The illustrated invention can be generalized as follows: Within the circuit of a compressible fluid in a heat pump, a positive displacement unit is arranged between the high pressure side and the low pressure side, which serves to expand the fluid on its way from the high pressure side to the low pressure side, so that the expanding fluid performed mechanical work by means of the positive displacement unit is used as an additional drive of the compressor of the heat pump. In particular, a scroll compressor is provided whose movable spiral surface or its carrier part fixedly connected to the movable spiral surface forms a guide transmission for must have translational orbiting guidance of the movable spiral surface. In such a transmission, their volume can be formed in the orbiting motion cyclically changing chambers, which are usable as displacement working chambers and by means of a corresponding valve assembly, controlled with the high pressure side or the low pressure side of the heat pump can be connected. These displacement working chambers form a working machine in which the fluid of the heat pump is expanded. In this way, the necessary for positive guidance of the movable scroll surface guide gear can be used as an additional drive for the scroll compressor.

LIST OF REFERENCE NUMBERS

1

 Scroll compressor

2

 power unit

3

 output shaft

4

 eccentric

5

 ring body

6

 ring body

7

 support body

8th

 movable spiral surface

9

 stationary spiral surface

10

 stationary carrier body

11

 annular channel

12

 pressure line

13

 thrust lever

14

 radial guide

15.1-15.7

chambers

16

 valve assembly

17

 wall

18

wall

19

 High-pressure chamber

20

 Low-pressure chamber

21

 high pressure groove

22

 low-pressure groove

23

 radial bore

24

 radial bore

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• Yu Shiotani et al .: "Development of Dual Compressor System using Compressor Combined with Expander for CO2 Heat Pump Hot Water Heating System", Int. Compressor Engineering Conterence at Purdue, July 16-19, 2012 [0003]

Claims (8)

Scroll compressor between low-pressure region and high-pressure region of a fluid circuit of a heat pump, wherein the scroll compressor a stationary spiral surface ( 9 ) and a cooperating movable spiral surface ( 8th ) and a guide gear for translationally orbiting forced guidance of the movable spiral surface or of a carrier part firmly connected thereto ( 7 ), characterized in that the guide gear chambers ( 15 ), which cyclically change their volume during the translatory orbiting motion of the movable scroll surface, and that these chambers can be used as displacer work spaces and by means of a valve arrangement ( 16 ) can be operated as between high-pressure and low-pressure side connected expansion section, so that the guide gear is used as an additional drive of the scroll compressor. Scroll compressor with a stationary first spiral surface ( 9 ) and a translatory orbiting second spiral surface cooperating therewith during compressor operation ( 8th ), characterized in that the second spiral surface ( 8th ) by means of a gear on a circular path positively driven and the transmission is designed as a positive displacement unit, which via a valve assembly ( 16 ) is controllably fluidically connected to a high pressure and a low pressure region. Scroll compressor according to claim 2, characterized in that each spiral surface is fixedly arranged on an associated support part, wherein the one support part has an inner peripheral surface which encloses an outer peripheral surface arranged on the other support part, that one of the support parts on an eccentric ( 4 ) is arranged, which rotates about the central axis of one of the peripheral surfaces, and that between the peripheral surfaces coupling elements ( 13 ) are arranged, which force relative to one another during rotation of the eccentric a translational relative movement of the support members. Scroll compressor according to claim 3, characterized in that the coupling elements between the peripheral surfaces in the circumferential direction successive and closed at the end faces of the peripheral surfaces by portions of the supporting parts Verdrängerkammern ( 15 ) separate from each other. Scroll compressor according to claim 3 or 4, characterized in that the coupling elements ( 13 ) are designed as thrust pendulum, which are pivotally arranged with its one end on the one peripheral surface about the central axis of the peripheral surface parallel axes and are coupled with its other ends to the other peripheral surface radially slidably and pivotally. Scroll compressor according to one of claims 3 to 5, characterized in that the outer peripheral surface on a rotatably mounted on the eccentric ring part ( 5 ) is arranged, which between circumferentially adjacent coupling elements ( 13 ) of radial channels ( 23 . 24 ) is interspersed, which in the circulation of the eccentric in temporary overlap with circumferential grooves ( 21 . 22 ) on the eccentric ( 4 ), which in each case extends over a predetermined arc range of the circumference of the eccentric and either with a high pressure port ( 19 ) or a low-pressure connection ( 20 ) are connected. Scroll compressor according to claim 6, characterized in that the low-pressure connection ( 20 ) with a low pressure input ( 11 ) of the scroll compressor. Scroll compressor according to claim 6, characterized in that the high-pressure connection with a high-pressure outlet ( 12 ) of the scroll compressor.

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