WO2016141788A1

WO2016141788A1 - Scroll compressor

Info

Publication number: WO2016141788A1
Application number: PCT/CN2016/072773
Authority: WO
Inventors: 王贻任; 曾荡; 叶涛; 王蒙
Original assignee: 艾默生环境优化技术(苏州)有限公司
Priority date: 2015-03-12
Filing date: 2016-01-29
Publication date: 2016-09-15

Abstract

Disclosed is a scroll compressor (1; 100), comprising: a housing (10; 110) defining an internal space; and a compressing mechanism (CM) arranged inside the housing (10; 110) and comprising a static scroll member (30) and a moveable scroll member (40), wherein the static scroll member (30) and the moveable scroll member (40) each comprise an end plate (30a; 40a) and scroll teeth (30b; 40b) in the form of a double vortex ring, and the static scroll member (30) and the moveable scroll member (40) are engaged with each other to form a first compressing path (CP1) and a second compressing path (CP2) between a first air suction port (In1) and a first air exhaust port (Out1), and a third compressing path (CP3) and a fourth compressing path (CP4) between a second air suction port (In2) and a second air exhaust port (Out2). The scroll compressor (1; 100) further comprises a first air suction pipeline (52) leading to the first air suction port (In1) and a second air suction pipeline (54) leading to the second air suction port (In2), with a first main magnetic valve (MV1) for controlling the ON and OFF of the air suction pipeline (52) being provided on the air suction pipeline (52). The scroll compressor (1; 100) is capable of precisely adjusting the volume and reducing pressure fluctuations in the case of continuous operation of the compressing mechanism.

Description

Scroll compressor

This application claims Chinese Application No. 201510110237.X, entitled "Vortex Compressor", filed on March 12, 2015, and Chinese Utility Model Application No. 201520140650.6, entitled "Vortex Compressor", filed on the same day. The priority of these applications is incorporated herein by reference.

Technical field

The present invention relates to a scroll compressor, and in particular to a double scroll scroll compressor capable of adjusting the capacity of a compressor.

Background technique

The content of this section merely provides background information related to the present disclosure, which may not constitute prior art.

The Digital Scroll compressor utilizes the "axially flexible" technology, which allows the scroll to move a very small distance in the axial direction, ensuring that the scroll always works with optimum force. The control cycle of the digital scroll compressor includes a "load period" and a "unload period". During the load, the compressor works like a conventional scroll compressor, delivering full capacity and a compressor output of 100%. During the unloading, due to the flexible design of the compressor, the two scrolls have a slight separation in the axial direction, no more refrigerant passes through the compressor, and the compressor output is zero. By changing these two times, the output capacity of the compressor can be adjusted.

In the case of compressor adjustment, that is, during the engagement and disengagement of the orbiting scroll and the fixed scroll, large pressure fluctuations are generated. Therefore, there is a need for a double scroll scroll compressor that can precisely adjust capacity and reduce pressure fluctuations.

Summary of the invention

It is an object of one or more embodiments of the present invention to provide a twin scroll scroll compressor capable of accurately adjusting capacity and reducing pressure fluctuations.

In order to achieve the above object, according to an aspect of the invention, a scroll compressor includes: a housing defining an inner space; a compression mechanism located in the housing, the compression mechanism including a fixed scroll and a movable vortex The rotary member, the fixed scroll and the movable scroll respectively comprise an end plate and a vortex tooth in the form of a double vortex, and the fixed scroll and the movable scroll are engaged with each other to form a first suction. a first compression path and a second compression path between the port and the first exhaust port, and a third compression path and a fourth compression path between the second intake port and the second exhaust port. Wherein, the scroll compressor further includes a first suction line leading to the first suction port and a second suction line leading to the second suction port, and the first suction line is provided with controlling the suction The first main solenoid valve of the gas line is turned on and off.

Thereby, the capacity of the compressor can be adjusted in a state where the compression mechanism continues to operate without frequent start and stop. When the main solenoid valve is closed, the corresponding compression path does not compress the refrigerant, thereby avoiding unnecessary power consumption. The main solenoid valve can be pulse width modulated to achieve precise adjustment at a lower duty cycle. The capacity can be directly adjusted to 50% to avoid pulse width modulation and the resulting pressure fluctuations.

Alternatively, a lubricant passage is provided in the end plate of the movable scroll, and the lubricant is supplied to the respective compression paths in the first to fourth compression paths via the lubricant passage.

Thereby, the lubricant can be supplied to the compression path, thereby taking away the heat generated by the friction.

Optionally, in a state where the first main solenoid valve is closed and the first intake line is disconnected, when the temperature near the first exhaust port exceeds a predetermined threshold, the first main solenoid valve is opened for a predetermined time.

Thereby, the temperature of the compression mechanism can be lowered to prevent damage to the compressor.

Optionally, a main electromagnetic valve is not disposed on the second suction line, and a bypass line is formed in the end plate of the fixed scroll, and the bypass line is in a predetermined profile of the vortex of the fixed scroll The third compression path communicates with the portion of the scroll compressor at the suction pressure at the length, and a bypass solenoid valve is disposed on the bypass line to control the on and off of the bypass line.

Thereby, more adjustment of the fixed capacity can be provided, and fine adjustment can be achieved with a lower duty ratio.

Optionally, a bypass line is formed in the end plate of the fixed scroll, and the bypass line places the first compression path with the scroll compressor at a predetermined profile length of the vortex of the fixed scroll The portion of the suction pressure is connected, and a bypass solenoid valve is provided on the bypass line to control the on and off of the bypass line.

Optionally, the portion at the suction pressure is the first suction line.

Optionally, the connection point between the bypass line and the first suction line is located downstream of the first main solenoid valve.

Optionally, the bypass solenoid valve is configured to be in an open state when the first main solenoid valve is closed, such that a portion of the working fluid circulates in the first compression path via the bypass line.

Thereby, part of the working medium can be retained in the first compression path, avoiding a serious vacuuming phenomenon in the first compression path, thereby reducing the temperature of the compression mechanism.

Optionally, the bypass solenoid valve is configured to be switchable between an open state and a closed state when the first main solenoid valve is open, and at least part of the working fluid in the first compression path passes through the bypass pipe when in the open state The road is discharged to the first suction line.

Optionally, the point of connection between the bypass line and the location at the suction pressure is upstream of the first main solenoid valve.

Optionally, the bypass solenoid valve is configured to be in a closed state when the first main solenoid valve is closed.

Thereby, it can be avoided that the working medium bypasses the main solenoid valve and enters the bypass line when the main solenoid valve is closed.

Optionally, the bypass solenoid valve is configured to be switchable between an open state and a closed state when the first main solenoid valve is open, and at least a portion of the working fluid in the first compression path passes by when the bypass solenoid valve is opened The through line is discharged to a portion at the suction pressure.

Optionally, the bypass hole between the bypass line and the first compression path is disposed adjacent to the vortex tooth of the fixed scroll, and can be completely covered by the vortex tooth of the movable scroll, so that the bypass hole communication hole only passes To the first compression path.

Thereby, it is possible to prevent the bypass hole from opening to two adjacent compression paths and to avoid pressure release which may occur thereby.

Optionally, the bypass line leads to the first exhaust port, and a limited pressure valve is disposed in the bypass line to cover the bypass port between the bypass line and the first compression path, the pressure limiting valve The unidirectional opening is made toward the bypass line only when the pressure at the bypass port is greater than the exhaust pressure at the first exhaust port.

Therefore, when the bypass valve is closed, when the pressure in the compression path advances to the predetermined discharge pressure, the working fluid in the compression path can be discharged to the exhaust port via the bypass path, thereby realizing the effect of adjusting the pressure ratio. And reduce energy waste.

Optionally, a check valve is disposed downstream of the bypass port between the bypass line and the first exhaust port in the first exhaust port to prevent gas outside the compression mechanism from entering the first exhaust port.

Optionally, the bypass line communicates the first and second compression paths with the portion at the suction pressure, and the pressure limiting valve has two valve sheets that can be opened and closed independently of each other, the two valve sheets being respectively disposed at A bypass port between the bypass line and the first compression path and a bypass port between the bypass line and the second compression path.

Thereby, the applicable range of the bypass line can be enlarged, so that it can simultaneously adjust the output capacities of the two compression paths.

Optionally, the portion at the suction pressure is the first suction line.

Optionally, the bypass solenoid valve is configured to be open when the first main solenoid valve is closed such that a portion of the working fluid in the first and second compression paths circulate in the first compression path via the bypass line.

Optionally, the bypass solenoid valve is configured to be switchable between an open state and a closed state when the first main solenoid valve is open, and when the open state is open, the pressure limiting valve can be opened based on the differential pressure such that the first and the first At least part of the working fluid in the two compression paths is discharged to the first suction line through the bypass line.

Optionally, the vortex tooth of the fixed scroll is provided with a tooth top sealing groove and a sealing member located in the tooth top sealing groove, and a back pressure pipe is disposed in the vortex tooth of the fixed scroll and the end plate to be the first One of the suction line and the second suction line communicates with the addendum sealing groove, and a back pressure solenoid valve is disposed in the back pressure line to control the on and off of the back pressure line.

Thereby, the pressure in the relevant compression path can be adjusted by pulse width modulating the back pressure solenoid valve, thereby finely adjusting the capacity. In addition, the capacity adjustment can be realized by adjusting the position of the seal instead of the position of the movable and fixed scrolls, and the energy efficiency can be further improved.

Optionally, the scroll compressor is a high pressure side compressor, the first suction line and the first suction port are sealingly connected to each other, and the second suction line and the second suction port are sealingly connected to each other.

Alternatively, the scroll compressor is a low pressure side compressor, and the compression mechanism directly inhales through the first suction line and the second suction line instead of inhaling from the housing of the scroll compressor.

Thereby, the amount of the working medium entering the intake line can be precisely controlled.

Optionally, there is an opening between the first suction line and the first suction port and/or between the second suction line and the second suction port, and the opening (G) is made from the corresponding suction pipe The working medium of the road can partially enter the internal space of the casing.

Thereby, cooling of other components (such as a drive mechanism) in the internal space of the housing can be achieved.

DRAWINGS

The features and advantages of one or more embodiments of the present invention will become more <RTIgt; For the sake of clarity, the various parts are not necessarily drawn to scale, but may be exaggerated or omitted. In addition, some parts are shown in a schematic manner and do not represent the physical structure of the parts. In the drawing:

Figure 1 shows an overall longitudinal sectional view of a scroll compressor according to a first embodiment of the present invention;

2 and 3 are perspective views respectively showing a fixed scroll and an orbiting scroll of the scroll compressor shown in Fig. 1;

Figure 4 is a top cross-sectional view showing the compression mechanism of the scroll compressor shown in Figure 1;

Figure 5 is a longitudinal sectional view showing the compression mechanism of the scroll compressor shown in Figure 1;

Figure 6 is a plan sectional view showing a compression mechanism of a scroll compressor according to a second embodiment of the present invention;

Figure 7 is a longitudinal sectional view showing a compression mechanism of a scroll compressor according to a second embodiment of the present invention;

Figure 8 is a plan sectional view showing a compression mechanism of a scroll compressor according to a third embodiment of the present invention;

Figure 9 is a perspective view showing a pressure limiting valve in a scroll compressor according to a third embodiment of the present invention;

Figure 10 is a longitudinal sectional view showing a compression mechanism of a scroll compressor according to a third embodiment of the present invention;

11 and 12 are perspective views of a fixed scroll and an orbiting scroll of a scroll compressor according to a fourth embodiment of the present invention;

Figure 13 is a longitudinal sectional view showing a compression mechanism of a scroll compressor according to a second embodiment of the present invention;

14 and FIG. 15 are enlarged views showing the A portion of FIG. 13 in different states;

Figure 16 is a view showing an overall longitudinal sectional view of a scroll compressor according to a fifth embodiment of the present invention;

Figure 17 is a longitudinal cross-sectional view showing the compression mechanism of the scroll compressor shown in Figure 16.

detailed description

The following description of the preferred embodiments is merely exemplary and is in no way limiting The same reference numerals are used in the respective drawings to refer to the same components, and thus the construction of the same components will not be repeatedly described.

The basic configuration of the scroll compressor 1 to which an embodiment of the present invention can be applied will be described below with reference to Fig. 1 .

As shown in Fig. 1, a scroll compressor (hereinafter also referred to as a compressor) 1 includes a substantially sealed seal. Closed housing 10. A compression mechanism CM for compressing a working medium (such as a refrigerant) and a drive mechanism DM for driving the compression mechanism CM are housed in the casing 10. In the present example, the scroll compressor 1 is of a high pressure side design. In the art, a compressor in which a drive mechanism is in a discharge pressure zone (ie, a high pressure zone) is generally referred to as a high pressure side compressor, and a compressor in which a drive mechanism is in an intake pressure zone (ie, a low pressure zone) is referred to as a low pressure side. Compressor. The scroll compressor 1 is a high pressure side compressor, and both the drive mechanism DM and the compression mechanism CM are in the exhaust pressure zone. It will be understood by those skilled in the art that for so-called open compressor designs, the drive mechanism DM can also be disposed on the outside of the housing 10 without affecting the practice of the present invention.

The drive mechanism DM may include, for example, a motor composed of the stator 12 and the rotor 14. The stator 12 can be fixed relative to the housing 10 in any suitable manner. The rotor 14 is rotatable in the stator 12 and is provided with a drive shaft 16 therein. The drive shaft 16 is supported by a main bearing housing 18 and a lower bearing housing 20. One end of the drive shaft 16 is formed with an eccentric crank pin 16a. The eccentric crank pin 16a is fitted in the hub portion 40c of the movable scroll 40 to drive the compression mechanism CM. A lubricating oil (lubricant) passage 16b is also formed in the drive shaft 16.

The compression mechanism CM may include a fixed scroll 30 and an orbiting scroll 40. The fixed scroll 30 can be fixed relative to the housing 10 in any suitable manner, such as by bolts relative to the main bearing housing 18, while the main bearing housing 18 can be fixed relative to the housing 10 by any suitable means. Both the fixed scroll 30 and the movable scroll 40 have a double scroll type line structure, and therefore, the scroll compressor 1 is also referred to as a double scroll type scroll compressor. The movable scroll 40 can be driven by the drive mechanism DM to rotate normally with respect to the fixed scroll 30 (ie, the central axis of the movable scroll 40 rotates around the central axis of the fixed scroll 30, but the movable scroll 40 It does not rotate itself about its central axis to achieve fluid compression. The above translational rotation is achieved by a cross slip ring disposed between the fixed scroll 30 and the movable scroll 40 or between the movable scroll 40 and the main bearing housing 18 (not shown).

As shown in FIGS. 2 to 5, the fixed scroll 30 may include a fixed scroll end plate 30a and a fixed scroll vortex 30b formed on one side of the fixed scroll end plate 30a. A first intake port In1 and a second intake port In2 are formed at substantially diametrically opposed positions on the outer circumference of the fixed scroll 30. A first exhaust port Out1 and a second exhaust port Out2 are formed in a substantially radial central portion of the fixed scroll end plate 30a. The first exhaust port Out1 communicates with the first intake port In1, and the second exhaust port Out2 communicates with the second intake port In2. It should be understood that only one exhaust port may be provided in the fixed scroll 30. A check valve may be disposed in the first exhaust port Out1 and the second exhaust port Out2 or in the common exhaust port to prevent gas outside the compression mechanism CM from entering the row Air port. The movable scroll 40 may include an orbiting scroll end plate 40a, an orbiting scroll vortex 40b formed on one side of the movable scroll end plate 40a, and a hub formed on the other side of the movable scroll end plate 40a. 40c. The fixed scroll vortex 30b can intermesh with the orbiting scroll vortex 40b to form a series of compression paths CP together with the fixed scroll end plate 30a and the orbiting scroll end plate 40a. The pressure inside these compression paths gradually increases from the radially outer side to the radially inner side. Specifically, since each of the scrolls of the orbiting scroll vortex 40b separates two mutually uncompressed compression paths CP between adjacent fixed scroll worms 30b, the first intake port A first compression path CP1 and a second compression path CP2 are formed between In1 and the first exhaust port Out1, and a third compression path CP3 and a fourth compression path are formed between the second intake port In2 and the second exhaust port Out2. CP4.

Improvements in accordance with embodiments of the present invention are described in detail below. As shown in FIG. 4, in the scroll compressor 1, the main intake pipe 50 introduces the working fluid from the outside of the compressor 1 into the compression mechanism CM, and has two branches at the end 50a: leading to the first suction. The first suction line 52 of the port In1 and the second suction line 54 leading to the second suction port In2. The first suction line 52 is sealingly engaged with the first suction port In1, and the second suction line 54 is sealingly engaged with the second suction port In2 so that the working medium inside the compression mechanism CM and the outside of the compression mechanism The high pressure environment is isolated.

A first main solenoid valve MV1 is disposed on the first intake line 52, and a second main solenoid valve MV2 is disposed on the second intake line. The first main solenoid valve MV1 and the second main solenoid valve MV2 can be closed or opened simultaneously or separately. When closed, the working fluid on the corresponding pipeline cannot flow into the corresponding suction port, and the corresponding compression path cannot be compressed. The capacity of the compressor (ie, the amount of cooling) can be adjusted by pulse width modulation of the main solenoid valve. It is also possible to set only one of the first main solenoid valve MV1 and the second main solenoid valve MV2.

When a main solenoid valve (such as the first main solenoid valve MV1) is closed, as the compression mechanism CM operates, the working fluid in the compression paths CP1 and CP2 connected to the first suction port In1 is gradually discharged, that is, occurs. Vacuuming phenomenon. Since the fixed scroll 30 and the movable scroll 40 are rotated at high speed with respect to each other, and the cooling of the working medium is lacking in the compression path, the temperature of the compression mechanism CM is rapidly increased, thereby affecting the structural reliability of the compression mechanism CM. In order to prevent this, it is designed to periodically open the first main solenoid valve MV1, such as opening 1 s or less, to introduce a small amount of working fluid, thereby preventing the pressure in the compression path from being too low and preventing the compression mechanism CM. The temperature exceeds a predetermined threshold. Specifically, the exhaust gas near the first exhaust port Out1 can be detected, for example, by providing a temperature sensor at the exhaust port or at the end of the first and second compression paths. The temperature, and when the detected exhaust gas temperature exceeds a predetermined threshold, causes the first main solenoid valve MV1 to open for a predetermined time. Therefore, the "roughly closed" mentioned below is not completely closed, but includes such a short opening.

In addition, in order to avoid the above-mentioned lack of cooling, it is also possible to control the two main solenoid valves MV1 and MV2 so that they are alternately switched, thereby avoiding long-term lack of working medium entry in a certain intake port. Moreover, since there is inevitably a certain degree of leakage in the high-pressure side compressor, the working medium may enter the closed compression path from the adjacent compression path or the lubricant passage described below, so that the closed compression The temperature in the path does not rise excessively.

In order to avoid temperature rise in the compression path associated with the closed main solenoid valve, a lubricant passage 40d may be provided in the orbiting scroll end plate 40a, and the lubricant passage 40d will be corresponding in the vicinity of the suction ports In1 and In2. The compression path CP communicates with the movable scroll hub portion 40c and further communicates with the lubricant passage 16b. Since the pressure in the housing 10 is the exhaust pressure, which is higher than the pressure in the compression path CP, a large amount of lubricant enters the compression path via the lubricant passage 40d under the pressure difference, and is separated by the exhaust port after being compressed. , thus taking away the heat generated by the friction and preventing damage to the compressor.

According to this embodiment, during operation, for example, when the first main solenoid valve MV1 is substantially closed, no refrigerant enters the first intake port In1, and at this time, only the compression path associated with the second intake port In2 is used for compression. The working fluid, so the capacity of the compressor can be directly adjusted to about 50% of the rated capacity without frequent start-up and shutdown. When the main solenoid valve is closed, the corresponding compression path does not compress the refrigerant, thereby avoiding unnecessary power consumption.

In addition, it is also possible to adjust the capacity from 0% to 50% by performing pulse width modulation on the other main solenoid valve when one of the first main solenoid valve MV1 and the second main solenoid valve MV2 is substantially closed. . For example, to achieve a 25% capacity, the first main solenoid valve MV1 can be substantially closed and the duty cycle of the second main solenoid valve MV2 can be controlled to be 50%, for example, such that it is periodically turned off for 5 s after every 5 s. It is also possible to achieve an adjustment of the capacity from 50% to 100% by controlling the opening/closing time of the other main solenoid valve when one of the first main solenoid valve MV1 and the second main solenoid valve MV2 is opened. Since each of the main solenoid valves controls only a range corresponding to 50% of the capacity, more precise control can be easily realized.

With this adjustment mode, since the compressor is always in the normal working state during the capacity adjustment process, no unloading occurs, so there is no problem of pressure fluctuation. At the same time, 50% When the cooling capacity is adjusted, since an intake port can be closed directly, a high duty ratio is not required for adjustment. That is, the scroll compressor according to the present embodiment can achieve accurate capacity adjustment with the compression mechanism operating normally, and can easily achieve a fixed (50%) capacity.

Next, a second embodiment of the scroll compressor 1 will be described with reference to Fig. 6, which is an improvement made on the basis of the first embodiment, and therefore, the description of the same portions as those in the first embodiment will be omitted.

In the scroll compressor 1, at least one bypass line 32 may be provided in the fixed scroll end plate 30a, the bypass line 32 being at a predetermined profile length of the volute 30b of the fixed scroll 30 The predetermined compression path CP is communicated with one of the first intake line 52 and the second intake line 54.

Specifically, in the illustrated embodiment, at least one of the two

bypass lines

32a and 32b is provided with respect to the first intake line 52 and the first compression path CP1. Since the second suction line 54 is similar to the first suction line 52, the remaining compression paths CP2, CP3 and CP4 are similar to the first compression path CP1, so in the description only the first suction line and the first compression are combined. The path CP1 is described in detail. It will be appreciated that similar bypass lines can also be applied to other suction lines and other compression paths.

Wherein, the first bypass line 32a is in communication with the first compression path CP1 at the first bypass port 31a and downstream of the first main solenoid valve MV1 (relative to the working medium entering from the main intake pipe 50) The first connection point 52a is in communication with the first suction line 52. The second bypass line 32b communicates with the first compression path CP1 at the second bypass port 31b and with the first intake line 52 at a second connection point 52b upstream of the first main solenoid valve MV1. In other words, both the first bypass line 32a and the second bypass line 32b communicate the first compression path CP1 with the first suction line 52, only the difference between the two and the first suction line 52. Connection points 52a and 52b are located downstream and upstream of the first main solenoid valve MV1, respectively.

In the present embodiment, in order to make both the first bypass line 32a and the second bypass line 32b open to the first compression path CP1, and not to the second compression path CP2 (which is driven by the first compression path CP1) The scroll teeth 40b of the scroll are spaced apart, and the first bypass port 31a and the second bypass port 31b may be disposed in the vicinity of the fixed scroll wrap 30b such that the orbiting scroll wrap 40b is at the bypass. When the mouth is engaged with the fixed scroll vortex 30b, the orbiting scroll vortex 40b can completely cover the bypass ports, whereby each of the bypass holes is connected only to one compression path. It should be understood that The above settings are only for convenience of control, and if desired, these bypass ports may be disposed to span the two compression paths CP1 and CP2 to connect the two compression paths from the first intake port In1. To the first suction line 52. It even traverses compression paths from different suction ports, such as CP1 and CP3, to connect them all upstream of the corresponding solenoid valve in the first suction line 52 or the second suction line 54.

On each of the

bypass lines

32a and 32b, for example, at the connection points 52a and 52b of the respective bypass lines and the intake line, a first bypass solenoid valve BV1 and a second bypass solenoid valve BV2 are provided. Independently control the on and off of the corresponding bypass line.

The operation of each bypass line will be described below with respect to the case when the first main solenoid valve MV1 is opened and closed.

1. The first main solenoid valve MV1 is open

When the first main solenoid valve MV1 is opened, the functions of the first bypass line 32a and the second bypass line 32b are similar for the working medium, and thus will be uniformly described.

1.1 The first bypass solenoid valve BV1 or the second bypass solenoid valve BV2 opens

At this time, the working medium enters the corresponding first compression path CP1 from the first intake port In1, and when passing through the first bypass port 31a, the partially compressed working fluid flows back to the first through the first bypass line 32a. Suction line 52. That is, the pressure is lowered at the first bypass port 31a. In an ideal case, the pressure at the first bypass port 31a can be lowered to the suction pressure. At this time, only the vortex profile line (also referred to as the remaining vortex profile line) downstream of the first bypass port 31a functions as a compression medium, which is equivalent to arranging the vortex profile of the first bypass line 32a at a predetermined time. The length of the profile is "truncated".

It is assumed that when the second main solenoid valve MV2 is closed, the output capacity of the remaining vortex profile is M% of the full capacity. Then, when the second main solenoid valve MV2 is also opened, the output capacity of the remaining vortex profile is 50%+0.5×M% of the full load capacity. For example, when the second main solenoid valve MV2 is closed, the output capacity is 34% of the full load capacity, and when the second main solenoid valve MV2 is open, the output capacity is 67% of the full load capacity. Thereby, accurate capacity adjustment can be realized under normal operation of the compression mechanism, and multi-speed capacity (such as 34%, 50%, 67%) can be easily realized, and in some application environments, only the fixed capacity is adopted. This is sufficient to avoid pulse width modulation of the solenoid valve and to avoid the resulting pressure fluctuations. Of course, more precise stepless adjustment can be achieved by pulse width modulation of the main solenoid valve and the bypass solenoid valve without requiring a high duty cycle.

Similarly, for the second bypass line 32b, when the second bypass solenoid valve BV2 is opened, the vortex profile can be "truncated" at different predetermined profile lengths to achieve similar precision adjustments, The description will not be repeated here.

In addition, when one of the first suction line 52 and the second suction line 54 is not provided with the main solenoid valve on the second suction line 54, a similar bypass tube may be provided. The bypass line allows, for example, the third compression path CP3 to communicate with the second suction line 54. The bypass line will operate in a manner similar to that described in 1.1 above, ie the bypass solenoid valve can be switched between an open state and a closed state, and when in the open state, the partially compressed working fluid passes by The through line is discharged to the corresponding suction line.

1.2 The first bypass solenoid valve BV1 or the second bypass solenoid valve BV2 is closed

In this case, the first bypass line 32a or the second bypass line 32b does not function, and the working medium entering the first compression path CP1 or the second compression path CP2 from the first intake port In1 is normally compressed. .

2. The first main solenoid valve MV1 is closed

At this time, the second bypass solenoid valve BV2 is also closed, so the second bypass line 32b does not function to prevent the working medium from entering the first compression path CP1 via the second bypass solenoid valve BV2 and being compressed. Of course, it may be provided, if desired, to allow the working fluid to enter the compression path via the second bypass line 32b, without departing from the scope of the invention.

Only the operation of the first bypass solenoid valve BV1 will be discussed below.

2.1 The first bypass solenoid valve BV1 opens

In this case, during the compression of the first compression path CP1, the pressure at the first bypass port 31a is higher than the pressure at the first connection point 51a, and therefore, the working medium passes through the first bypass. At the time of the port 31a, it returns to the first connection point 51a due to the pressure difference between the two sides of the first bypass line 32a. Thereby, at least part of the working fluid circulates in the first compression path CP1 without being discharged from the first exhaust port Out1. In this way, the evacuation phenomenon in the first compression path CP1 can be alleviated, thereby suppressing the temperature increase tendency of the compression mechanism CM, and facilitating the balance of the movable scroll 40.

2.2 The first bypass solenoid valve BV1 is closed

In this case, the first bypass line 32a does not function, and the compression process in the first compression path CP1 is as described in the first embodiment above. For example, the first main solenoid valve MV1 may be intermittently opened briefly to prevent an excessive rise in temperature in the first compression path CP1.

The above only describes the functions of the respective bypass lines in the on and off states when the main solenoid valve is opened and closed. It should be understood that the main solenoid valve and the bypass solenoid valve may be pulse width modulated as needed to achieve more complex and precise adjustments.

The positions of the first bypass port 31a and the second bypass port 31b may be appropriately selected, that is, a predetermined profile length provided with a bypass port (the bypass pipe communicates with the compression path through the bypass port) is appropriately selected, so that The length of the active vortex profile remaining after the "cut" of the bypass port has an appropriate value. Preferably, the bypass port is disposed on the intermediate portion of the vortex, that is, at a distance from the intake port and the exhaust port. This is because, on the one hand, the bypass port should not be too close to the suction port, that is, the length of the remaining vortex line should not be too long, otherwise the effect of capacity adjustment is not obvious; on the other hand, the bypass port should not be too close to the exhaust port, ie The length of the remaining vortex line should not be too short, otherwise the force of the orbiting scroll is difficult to balance in the case where the corresponding bypass solenoid valve is opened and closed, for example, because the length of the profile is too short, the pressure in the compression path Too small, axial flexibility may not be achieved. Preferably, the predetermined profile length (measured from the air inlet) provided with the bypass port is between 90° and 200°.

The bypass line shown in the above figure is merely for exemplifying the function of the solenoid valve at each position and the function when combined. In practice, it is not limited to the provision of the number of bypass lines in each compression path, and the connection point of the bypass line to the suction line may be upstream or downstream of the main solenoid valve.

A third embodiment of the scroll compressor 1 will be described below with reference to Figs. 8 to 10, which is an improvement made on the basis of the first embodiment, and therefore, the description of the same portions as those in the first embodiment will be omitted. .

A third bypass line 32c is provided in the end plate 30a of the fixed scroll. The third bypass line 32c is in communication with the first intake line 52 at a third connection point 52c located upstream of the first main solenoid valve MV1. And, the third bypass line 32c communicates with the first compression path CP1 and the second compression path CP2 at the third bypass port 31c and the fourth bypass port 31d, that is, the third bypass port 31c and the fourth The bypass port 31d is disposed close to the fixed scroll vortex 30b such that when the meshing point of the orbiting scroll vortex 40b and the fixed scroll vortex 30b passes through the bypass ports, the orbiting scroll vortex 40b can be completely Cover these bypass ports. Therefore, each bypass port leads only to one Compressed path. It can be understood that only one of the third bypass port 31c and the fourth bypass port 31d may be provided to adjust its corresponding compression path. It should be understood that in these cases, the structure of the limit valve described below will also be Make adaptive modifications.

In the third bypass line 32c, for example, at the third bypass line 32c and the third connection point 52c of the first intake line 52, a third bypass solenoid valve BV3 is provided to control the third bypass The line 32c is turned on and off. For the sake of simplicity of the description below, the third connection point 52c is shown located upstream of the first main solenoid valve MV1.

According to the above description of the second embodiment, those skilled in the art can understand that when the first main solenoid valve MV1 is closed, the third bypass solenoid valve BV3 can also be closed together to avoid entering through the third bypass line 32c. gas. When the first main solenoid valve MV1 is opened, the third bypass solenoid valve BV3 can be switched between an open state and a closed state. Similarly, in the case where the third connection point 52c is disposed downstream of the first main solenoid valve MV1, when the first main solenoid valve MV1 is closed, the third bypass solenoid valve BV3 is opened to enable the partial working medium to be in the first compression path. The CP1 circulates, and when the first main solenoid valve MV is opened, the third bypass solenoid valve BV3 can be switched between an open state and a closed state. The description will not be repeated below, but the differences between the third embodiment and the second embodiment will be mainly described.

The third bypass line 32c is further in communication with the first exhaust port Out1 at the fifth bypass port 31e. Therefore, in the case where the third bypass solenoid valve BV3 is closed, the pressure in the third bypass line 32c is the exhaust pressure of the first exhaust port Out1. A check valve 30f is further provided on the exhaust port Out1 of the fixed scroll 30 downstream of the fifth bypass port 31e to prevent external pressure from entering the first exhaust port Out1 and the third bypass line 32c. in.

A finite pressure valve RV is provided at a bypass port between the third bypass line 32c and the compression path, and the pressure limiting valve RV is set to open only when the pressure at the bypass port is greater than the exhaust pressure. As an example, as shown in FIG. 9, the pressure limiting valve RV is an arc valve 50 which is fixed to the end plate 30a of the fixed scroll 30 by bolts 53, and has a first valve piece 50a and a second valve piece 50b which are elastic. The first valve piece 50a and the second valve piece 50b are respectively pressed against the third bypass port 31c and the fourth bypass port 31d, and are disposed in the corresponding first compression path CP1 and second compression path CP2 thereof. When the pressure is greater than the exhaust pressure in the third bypass line 32c, it opens unidirectionally toward the third bypass line 32c. The first valve piece 50a and the second valve piece 50b can be independently opened or closed.

When the corresponding first main solenoid valve MV1 is opened (or the first main solenoid valve MV1 is not provided, the working medium can always enter the first compression path CP1 and the first intake line 52 from the first suction line 52 During the operation of the second compression path CP2), when the third bypass solenoid valve BV3 is closed, the pressure limiting valve RV functions to adjust the pressure ratio. Specifically, when the pressure at the third bypass port 31c or the pressure at the fourth compression port CP2 and the fourth bypass port 31d in the first compression path CP1 is greater than the pressure of the first exhaust port Out1, When the compression occurs, the first valve piece 50a or the second valve piece 50b of the pressure limiting valve RV is opened, so that the compressed working medium in the corresponding compression path is discharged to the first exhaust port Out1 through the third bypass line 32c. In order to avoid the power loss caused by over-compression. When the pressures at the third bypass port 31c and the fourth bypass port 31d are both smaller than the pressure of the first exhaust port Out1, the pressure limiting valve RV is closed, and the first compression path CP1 and the second compression path CP2 are normally compressed. .

When the third bypass solenoid valve BV3 is opened, the compressed or partially compressed working fluid at the first exhaust port Out1 and the third bypass port 31c and the fourth bypass port 31d is discharged through the third bypass line 32c. The first suction line 52 is returned, thereby depressurizing the first compression path CP1 and the second compression path CP2. Therefore, by performing pulse width modulation on the third bypass solenoid valve BV3, it is possible to realize capacity adjustment without stopping the operation of the compression mechanism CM and keeping the movable and fixed scrolls engaged. Specifically, in the case where the first main solenoid valve MV1 is kept open or the first main solenoid valve MV1 is not provided, when the second main solenoid valve MV2 is closed, it can pass through the third bypass solenoid valve BV3 from 0% to The adjustment is made within a range of 50% capacity; and when the second main solenoid valve MV2 is opened, it can be adjusted from a range of 50% to 100% by the third bypass solenoid valve BV3.

Since the third bypass line can be adjusted within a 50% interval, a lower cooling output can be obtained at a lower bypass rate, thereby reducing the loss due to bypass and improving the cooling capacity adjustment. effectiveness. In addition, by providing the third bypass port 31c and the fourth bypass port 31d, it is possible to return the working medium to the intake line through these bypass ports before being completely compressed, instead of passing through the exhaust port after being fully compressed. Returning to the suction line, energy efficiency can be improved.

The above description is only made in detail with respect to the first suction line 52. It can be understood that since the second intake line 54 is similar to the first intake line 52, the same third bypass line can be disposed between the second intake line 54 and the second exhaust port Out2. This will not be repeated here.

Next, a fourth embodiment of the scroll compressor 1 will be described with reference to Figs. 11 to 15, which is an improvement on the basis of the first embodiment, and therefore, the description of the same portions as those in the first embodiment will be omitted.

The vortex teeth 30b of the fixed scroll 30 of the scroll compressor 1 are in a tooth top sealing manner. Optional The vortex teeth 40b of the orbiting scroll 40 are also in a tooth top sealing manner. A tip seal groove 34 is provided at the tip end of the volute tooth 30b of the fixed scroll 30, and a seal member 36 is provided in the addendum seal groove 34 to seal against the end plate 40a of the movable scroll 40. One vortex of the volute 30b in the fixed scroll 30 spaces the first compression path CP1 from the fourth compression path CP4, and the other vortex spaces the second compression path CP2 from the third compression path CP3. The case of the two scrolls is the same, and the seal 36 on the scroll 30b between the first compression path CP1 and the fourth compression path CP4 will be described below as an example. A back pressure line 38 is provided in the end plate 30a of the fixed scroll 30 and the vortex 30b. The back pressure line 38 includes an axial portion 38a located in the volute 30b and a lateral portion 38b located in the end plate 30a. . The end of the axial portion 38a of the back pressure line 38 communicates with the addendum seal groove 34, and the end of the lateral portion 38b is at the fourth joint point 52d with a corresponding suction line (here, the first suction line 52). ) Connected. In the back pressure line 38, for example, a back pressure solenoid valve BV4 is provided at the connection point 52d to control the on and off of the back pressure line 38.

The operation of the back pressure line 38 will now be described with reference to Figs. 14 and 15. 14 and 15 show enlarged views of the addendum seal portion A in an exaggerated manner, in which Fig. 14 shows a normal operation state, and Fig. 15 shows a state in which the back pressure line 38 is in communication.

As shown in Fig. 14, in the normal operation, that is, when the back pressure solenoid valve BV4 is closed and the back pressure line 38 is disconnected, the seal member 36 is oriented toward the pressure due to the pressure difference in the compression path on both sides of the seal member 36. The lower side is pressed against the side wall of the addendum sealing groove 34, and a higher pressure can act on the back surface of the sealing member 36 to press the sealing member 36 downward against the end plate of the movable scroll to realize the tooth. Top seal.

As shown in FIG. 15, when the back pressure solenoid valve BV4 is open and the back pressure line 38 is in communication, the pressure on the back side of the seal member 36 is the suction pressure introduced by the back pressure line 38, which is lower than the sides of the seal member 36. Compressing the pressure in the path, whereby the sealing member 36 is pressed against the bottom of the addendum sealing groove 34, so that the first compression path CP1 and the fourth compression path CP4 communicate with each other, and with the suction port and the suction path Connected to relieve pressure. However, the other two compression paths separated by the orbiting scroll vortex 40b and the other fixed scroll vortex 30b, that is, the second compression path CP2 (controlled by the first main solenoid valve MV1) and the third compression path The CP3 (controlled by the second main solenoid valve MV2) remains isolated from the pressure-reduced compression paths CP1 and CP4.

In this case, the pressure of the two compression paths respectively communicating with the two intake ports can be controlled by pulse width modulating the back pressure solenoid valve BV4, thereby finely adjusting the double scroll type scroll compressor capacity. In addition, this capacity is achieved by adjusting the position of the seal The amount adjustment method can further improve the energy efficiency as compared with the capacity adjustment method realized by adjusting the positions of the movable and fixed scrolls.

A scroll compressor 100 according to a fifth embodiment of the present invention will be described below with reference to Figs. 16 and 17 . Unlike the scroll compressor 1, in the present example, the scroll compressor 100 is a low pressure side scroll compressor, that is, the drive mechanism DM is located on the suction pressure side, and the external environment of the compression mechanism CM is also under suction pressure. . The solutions described above in the first to fourth embodiments can be applied to the low-pressure side scroll compressor 100, except for the following modifications.

Specifically, in the scroll compressor 100, an opening G is provided in a path between at least one of the first suction line 52 and the second suction line 54 and the corresponding intake port to A small amount of the working fluid leaks into the housing 110 of the scroll compressor 100 to cool the drive mechanism DM. The opening G may be provided on at least one suction line or at a connection point between the suction line and the suction port. In the figure, the opening portion G is shown at a connection point between the second intake line 54 and the second intake port In2. This opening G is located, for example, downstream of the corresponding main solenoid valve MV2.

The main bearing housing 18 is not shown in the drawings, but those skilled in the art understand that the space on either side of the movable scroll end plate 40 of Figure 17 will be closed by the main bearing housing 18.

It should be noted that this arrangement of the first suction line 52 and the second suction line 54 is different from that of the prior art. In the prior art, the suction line is only connected to the housing, all the working medium enters the housing, and the compression mechanism CM is free to inhale in the housing. In the present embodiment, the compression mechanism CM directly inhales through the first intake line 52 and the second intake line 54, and only part of the working fluid leaks into the casing. In this way, the amount of intake of each intake port of the compression mechanism CM can be controlled more accurately.

Another difference between the scroll compressor 100 and the scroll compressor 1 is that since the pressure in the housing 110 is the suction pressure, the respective bypass lines 32a-described in the second to fourth embodiments are The end of 32d connected to the corresponding suction line (i.e., the end where 52a-52d is located) can be implemented as a free opening without being connected to a specific suction line, so that the same pressure relief effect can be achieved. That is, it is sufficient that the bypass lines 32a-32d are in communication with the portion at the suction pressure.

In addition, since the internal space of the scroll compressor 100 is at the suction pressure, in order to convey the lubricant into the lubricant passage 40d in the movable scroll end plate 40b, it may be provided in the lubricant passage 16b in the drive shaft 16. Pumping device 502.

In addition to this, those skilled in the art can apply the first to fourth embodiments regarding the high pressure side compressor to the low pressure type compressor, and thus the description will not be repeated.

Although the various embodiments of the present invention have been described in detail herein, it is understood that the invention The skilled person implements other variations and variants. All such variations and modifications are intended to fall within the scope of the invention. Moreover, all of the components described herein can be replaced by other technically equivalent components.

Claims

A scroll compressor (1; 100) comprising:

a housing (10; 110), the housing (10; 110) defining an interior space;

a compression mechanism (CM) located in the housing (10; 110), the compression mechanism (CM) comprising a fixed scroll (30) and an orbiting scroll (40), the fixed scroll (30) And the movable scroll (40) respectively include an end plate (30a; 40a) and a vortex (30b; 40b) in the form of a double vortex, and the fixed scroll (30) and the movable scroll (40) intermeshing to form a first compression path (CP1) and a second compression path (CP2) between the first suction port (In1) and the first exhaust port (Out1), and at the second suction a third compression path (CP3) and a fourth compression path (CP4) between the port (In2) and the second exhaust port (Out2);

Wherein the scroll compressor (1; 100) further includes a first intake line (52) leading to the first intake port (In1) and a second intake port (In2) The second suction line (54) is provided on the first suction line (52) with a first main solenoid valve (MV1) for controlling the opening and closing of the suction line.
The scroll compressor (1; 100) according to claim 1, wherein a lubricant passage (40d) is provided in an end plate (40a) of the movable scroll (40) through which the lubricant passes A lubricant passage (40d) is supplied to each of the first to fourth compression paths (CP1; CP2; CP3; CP4).
The scroll compressor (1; 100) according to claim 1, wherein, in a state where the first main solenoid valve (MV1) is closed and the first intake line (52) is disconnected, The first main solenoid valve (MV1) is opened for a predetermined time when the temperature near the first exhaust port (Out1) exceeds a predetermined threshold.
The scroll compressor (1; 100) according to claim 1, wherein a main solenoid valve is not provided on the second intake line (54), in the fixed scroll (30) A bypass line is formed in the end plate (30a), the bypass line is to the third compression path (CP3) at a predetermined profile length of the vortex (30b) of the fixed scroll (30) a communication with a portion of the scroll compressor (1; 100) at an intake pressure, and a bypass solenoid valve is disposed on the bypass line Controlling the on and off of the bypass line.
The scroll compressor (1; 100) according to claim 1, wherein a bypass line (32a; 32b; 32c) is formed in an end plate (30a) of the fixed scroll (30), The bypass line (32a; 32b; 32c) rotates the first compression path (CP1) with the vortex at a predetermined profile length of the vortex (30b) of the fixed scroll (30) a portion of the compressor (1; 100) at the suction pressure is communicated, and a bypass solenoid valve (BV1; BV2; BV3) is disposed on the bypass line (32a; 32b; 32c) to control the side The through pipe (32a; 32b; 32c) is turned on and off.
The scroll compressor (1; 100) according to claim 5, wherein the portion at the suction pressure is the first suction line (52).
The scroll compressor (1; 100) according to claim 6, wherein a connection point (52a) between the bypass line (32a) and the first suction line (52) is located Downstream of the first main solenoid valve (MV1).
The scroll compressor (1; 100) according to claim 7, wherein the bypass solenoid valve (BV1) is disposed to be in an open state when the first main solenoid valve (MV1) is closed, so that a portion The working fluid circulates in the first compression path (CP1) via the bypass line (32a).
The scroll compressor (1; 100) according to claim 7, wherein the bypass solenoid valve (BV1) is provided to be in an open state and a closed state when the first main solenoid valve (MV1) is opened Switching between, and when in the open state, at least part of the working medium in the first compression path (CP1) is discharged to the first suction line (52) through the bypass line (32a).
The scroll compressor (1; 100) according to claim 5, wherein a connection point (52b) between the bypass line (32b) and the portion at the suction pressure is located at the first Upstream of the main solenoid valve (MV1).
A scroll compressor (1; 100) according to claim 10, wherein said bypass solenoid valve (BV2) is arranged to be in a closed state when said first main solenoid valve (MV1) is closed.
The scroll compressor (1; 100) according to claim 10, wherein the bypass solenoid valve (BV2) is provided to be in an open state and a closed state when the first main solenoid valve (MV1) is opened Switching between, and when the bypass solenoid valve (BV2) is opened, at least part of the working fluid in the first compression path (CP1) is discharged through the bypass line (32b) to the inhaling The part of the pressure.
A scroll compressor (1; 100) according to claim 5, wherein a bypass hole (31a) between the bypass line (32a; 32b; 32c) and the first compression path (CP1) ; 31b; 31c) disposed in close proximity to the vortex (30b) of the fixed scroll (30), and capable of being completely covered by the vortex (40b) of the orbiting scroll (40) such that the bypass hole (31a; 31b; 31c) leads only to the first compression path (CP1).
The scroll compressor (1; 100) according to claim 5, wherein the bypass line (32c) leads to the first exhaust port (Out1) and is in the bypass line ( A finite pressure valve (RV) is provided in 32c) to cover a bypass port (31c) between the bypass line (32c) and the first compression path (CP1), the pressure limiting valve (RV) The unidirectional opening is made toward the bypass line (32c) only when the pressure at the bypass port (31c) is greater than the exhaust pressure at the first exhaust port (Out1).
The scroll compressor (1; 100) according to claim 14, wherein in the first exhaust port (Out1), the bypass line (32c) and the first exhaust port ( A check valve is disposed downstream of the bypass port (31e) between Out1) to prevent gas outside the compression mechanism (CM) from entering the first exhaust port (Out1).
The scroll compressor (1; 100) according to claim 14, wherein the bypass line (32c) separates the first and second compression paths (CP1; CP2) from the suction pressure The parts are connected, and the pressure limiting valve (RV) has the ability to open and close independently of each other. Two valve plates (50a; 50b) respectively disposed at a bypass port between the bypass line (32c) and the first compression path (CP1) (31c) and a bypass port (31d) between the bypass line (32c) and the second compression path (CP2).
The scroll compressor (1; 100) according to claim 16, wherein the portion at the suction pressure is the first suction line (52).
A scroll compressor (1; 100) according to claim 17, wherein a connection point between said bypass line (32c) and said first intake line (52) is located at said first Downstream of the main solenoid valve (MV1).
A scroll compressor (1; 100) according to claim 18, wherein said bypass solenoid valve (BV3) is arranged to be in an open state when said first main solenoid valve (MV1) is closed, so that Part of the working fluid in the first and second compression paths (CP1; CP2) circulates in these first compression paths via the bypass line (32c).
A scroll compressor (1; 100) according to claim 18, wherein said bypass solenoid valve (BV3) is arranged to be in an open state and a closed state when said first main solenoid valve (MV1) is open Switching between, and when in an open state, the pressure limiting valve (RV) can be opened based on a pressure difference such that at least a portion of the working fluids of the first and second compression paths (CP1; CP2) pass the side The through line (32c) is discharged to the first suction line (52).
The scroll compressor (1; 100) according to claim 16, wherein a connection point (52c) between the bypass line (32c) and the portion at the suction pressure is located at the first Upstream of the main solenoid valve (MV1).
A scroll compressor (1; 100) according to claim 21, wherein said bypass solenoid valve (BV3) is arranged to be in a closed state when said first main solenoid valve (MV1) is closed.
A scroll compressor (1; 100) according to claim 21, wherein said bypass solenoid valve (BV3) is arranged to be in an open state and a closed state when said first main solenoid valve (MV1) is open Switching between, and when in an open state, the pressure limiting valve (RV) can be opened based on a pressure difference such that at least a portion of the working fluids of the first and second compression paths (CP1; CP2) pass the side The through line (32c) is discharged to the first suction line (52).
The scroll compressor (1; 100) according to claim 1, wherein the vortex (30b) of the fixed scroll (30) is provided with a tip seal groove (34) and is located at the tip seal a seal (36) in the groove (34), a back pressure line (38) is disposed in the vortex (30b) of the fixed scroll (30) and the end plate (30a) to One of the suction line (52) and the second suction line (54) is in communication with the addendum sealing groove (34), and in the back pressure line ( A back pressure solenoid valve (BV4) is provided in 38) to control the on and off of the back pressure line (38).
The scroll compressor (1; 100) according to any one of claims 1 to 23, wherein the scroll compressor is a high pressure side compressor (1), and the first suction line (52) And the first suction ports (In1) are sealingly connected to each other, and the second suction line (54) and the second suction port (Out1) are sealingly connected to each other.
The scroll compressor (1; 100) according to any one of claims 1 to 23, wherein the scroll compressor is a low pressure side compressor (100) through which the compression mechanism (CM) is The first suction line (52) and the second suction line (54) directly inhale rather than inhale from the housing (10; 110) of the scroll compressor (1; 100).
A scroll compressor (1; 100) according to claim 26, wherein said first intake line (52) is between said first intake port (In1) and/or said second There is an opening (G) between the suction line (54) and the second suction port (In2), and the opening (G) enables the working fluid from the corresponding suction line (52; 54) Partial access to the interior space of the housing (110).