EP3018350A1

EP3018350A1 - Low backpressure rotary compressor

Info

Publication number: EP3018350A1
Application number: EP13888730.2A
Authority: EP
Inventors: Bin Gao; Zhenhua Chen
Original assignee: Guangdong Meizhi Compressor Co Ltd
Current assignee: Guangdong Meizhi Compressor Co Ltd
Priority date: 2013-07-04
Filing date: 2013-07-04
Publication date: 2016-05-11
Anticipated expiration: 2033-07-04
Also published as: AU2013393765B2; EP3018350B1; EP3018350A4; AU2013393765A1; WO2015000162A1

Abstract

A low backpressure rotary compressor comprises a housing, a motor and a compressing mechanism. A chamber is provided inside the housing. An air suction pipe is provided on the top of the housing. The motor is arranged in the chamber, and the chamber is divided into an upper chamber and a lower chamber by the motor. Channels are formed between an outer surface of the motor and an inner surface of the housing, and/or in the motor. One end of each channel is communicated with the upper chamber, and the other end of each channel is communicated with the lower chamber. The exhaust volume of the compressor is V, the flow area of the channels is S, the rotating speed of the motor is F, and the flow rate of air passing through the channels is v, so that v=(V*F)/S. Wherein, when F≤60 rad/s, 2 (m/s)≤v≤25 (m/s); when F>60 rad/s, 8 (m/s)≤v≤40 (m/s).

Description

FIELD

The present disclosure relates to a compressor, and more particularly to a low backpressure rotary compressor.

BACKGROUND

A rotary compressor widely used in related art has a structure with high pressure in the housing, i.e. high backpressure structure, a gaseous refrigerant formed after a refrigerant returning to the compressor from a system passes through an air-liquid separator is directly inhaled into a cylinder to complete compression, the high-temperature and high-pressure refrigerant after being compressed is discharged into an interior space of the housing of the compressor, then discharged out of the compressor after cooling the motor, afterward enters the system for circulation.
Compared to the rotary compressor with a high backpressure structure, there is a low backpressure rotary compressor with low pressure in the housing, i.e. the interior space of the housing is communicated with the suction pressure. Compared to the high backpressure compressor, a compressor with such a structure has a special advantage in some areas, especially in the future application of the rotary compressor, because the motor of the low backpressure compressor in a low-temperature and low-pressure suction environment will not result in an over high temperature or insufficient cooling of the motor caused by high exhaust temperature of the high pressure compressor. In addition, the content of the refrigerant in the compressor will be significantly reduced and the refrigerant charge of the refrigeration system can be greatly reduced in the low pressure environment. Therefore, the low backpressure compressor will be widely used in these fields.
However, the motor of the low backpressure compressor dissipates heat mainly through low temperature and low pressure suction in the low pressure environment. However, as a gas inhaled is heated and expanded by the motor, the intake of the compressor will decline, and the compression power consumption of unit mass air will increase, thereby resulting in a significant decrease in the performance of the low backpressure compressor compared to that of the high backpressure compressor.

SUMMARY

The present disclosure seeks to solve at least one of the problems existing in the related art to at least some extent.
For this, an object of the present disclosure is to provide a low backpressure rotary compressor. Through a rational design of the low backpressure rotary compressor, it is possible to enable the motor to obtain a better cooling effect, and the air flow resistance within a channel is reduced, thereby improving the overall energy efficiency of the low backpressure rotary compressor.
According to one aspect of the present disclosure, a low backpressure rotary compressor is provided. The low backpressure rotary compressor includes: a housing defining a chamber therein; an air suction pipe disposed on the housing; a motor disposed within the chamber, and dividing the chamber into an upper chamber communicated with the air suction pipe and a lower chamber, a channel being formed within the motor and/or between an outer circumferential surface of the motor and an inner circumferential surface of the housing, and the channel defining a first end communicated with the upper chamber and a second end communicated with the lower chamber; a compression mechanism disposed below the motor and defining an air suction port; in which an exhaust volume of the compressor is V, a total flow area of the channel is S, a rotating speed of the motor is F, and a flow rate of a gas passing through the channel is v, so that v=(V×F)/S, in which when F≤60 rev/s, 2 (m/s) ≤v≤ 25 (m/s); when F>60 rev/s, 8 (m/s) ≤v≤ 40 (m/s).
With the low backpressure rotary compressor according to embodiments of the present disclosure, it is possible to realize a good balance between the circulation loss of the gas and the heat dissipation requirements of the motor by making the flow rate v of the gas in the channel in an appropriate range when the motor operates at different rotating speeds, for example, when F≤60 rev/s, 2 (m/s)≤v≤25 (m/s), as another example, when F>60 rev/s, 8 (m/s)≤v≤40 (m/s), thus ensuring that the motor works at a suitable temperature to avoid the occurrence of high temperature to damage the motor or affect the work efficiency of the motor. Meanwhile, the circulation loss of the gas is minimized, thereby improving the overall efficiency of the compressor.
In addition, the low backpressure rotary compressor according to embodiments of the present disclosure may further have the following additional technical features:

In some embodiments, the housing includes an upper housing, a lower housing and a middle housing connected between the upper housing and the lower housing, and the air suction pipe is disposed on the upper housing.

In some embodiments, the motor is a constant speed motor.
In some embodiments, the motor has a rated rotating speed of 50 rev/s or 60 rev/s.
In some embodiments, the motor is a variable speed motor.
In some embodiments, the motor has an adjustable exhaust volume V
In some embodiments, the channel includes a first channel, and the motor includes a stator and a rotor, in which at least a part of an outer circumferential surface of the stator is spaced apart from the inner circumferential surface of the housing to form the first channel.
In other embodiments, the channel further includes a second channel, and the motor includes a stator and a rotor, the stator defining at least one through hole penetrating the stator in an up-down direction to form the second channel.
In other embodiments, the channel further includes a third channel, and the motor includes a stator and a rotor, the rotor defining at least one through hole penetrating the rotor in an up-down direction to form the third channel.
In some embodiments, the air suction port is formed in a main bearing or a cylinder.
Additional aspects and advantages of embodiments of present disclosure will be given in part in the following descriptions, become apparent in part from the following descriptions, or be learned from the practice of the embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and advantages of embodiments of the present disclosure will become apparent and more readily appreciated from the following descriptions made with reference to the drawings, in which:

Fig.1 is a schematic view of a low backpressure rotary compressor according to an embodiment of the present disclosure;
Fig. 2 is a schematic cross-sectional view of a low backpressure rotary compressor according to an embodiment of the present disclosure.

Reference Numerals:

compressor 100;
- upper housing 11, middle housing 12, lower housing 13, air suction pipe 14, upper chamber 15, lower chamber 16;
- motor 2, stator 21, rotor 22, first channel 231, second channel 232, third channel 233;
- main bearing 31, cylinder 32, supplementary bearing 33, piston 34, crankshaft 35, air suction port 36.

DETAILED DESCRIPTION

Reference will be made in detail to embodiments of the present disclosure. The embodiments described herein with reference to drawings are explanatory, illustrative, and used to generally understand the present disclosure. The embodiments shall not be construed to limit the present disclosure. The same or similar elements and the elements having same or similar functions are denoted by like reference numerals throughout the descriptions.
In the specification, it is to be understood thatterms such as "central," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom,""inner," and "outer," should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the present disclosurebe constructed or operated in a particular orientation.
In addition, terms such as "first" and "second" are used herein for purposes of description and are not intended to indicate or imply relative importance or significance or to imply the number of indicated technical features.Thus, the feature defined with "first" and "second" may include one or more of this feature. In the description of the present disclosure, "a plurality of" means two or more than two, unless specified otherwise.
In the following, the low backpressure rotary compressor 100 according to embodiments of the present disclosure will be described in detail referring to Fig. 1 and Fig. 2.
A low backpressure rotary compressor 100 according to embodiments of the present disclosure includes a housing, a motor 2 and a compression mechanism.
As shown in Fig. 1, the housing defines a chamber therein, and includes an upper housing 11, a middle housing 12 and a lower housing 13 mentioned below, and an air suction pipe 14 is disposed on the housing. A first end of the air suction pipe 14 is communicated with the chamber, specifically, the first end of the air suction pipe 14 is communicated with an upper chamber 15 mentioned below, a second end of the air suction pipe 14 is adapted to be communicated with a low pressure side heat exchanger of a refrigeration system having the compressor according to embodiments of the present disclosure. Thus, the refrigeration medium flowing back from the low pressure side heat exchanger may enter the housing via the air suction pipe 14.
As shown in Fig. 1, the motor 2 is disposed within the chamber and divides the chamber into an upper chamber 15 and a lower chamber 16, and the upper chamber 15 may be communicated with the lower chamber 16 via a channel. Specifically, a channel, for example, including a first channel 231, a second channel 232 and a third channel 233, is formed between an outer circumferential surface of the motor 2 and an inner circumferential surface of the housing and/or within the motor 2, in other words, for example, the channel may be defined between the outer circumferential surface of the motor 2 and the inner circumferential surface of the housing. As another example, the channel may be formed only inside the motor 2, for example, the channel may be formed in at least one of a stator 21 and a rotor 22. As still another example, a part of the channel is defined between the outer circumferential surface of the motor 2 and the inner circumferential surface of the housing, while another part of the channel is formed inside the motor 2.
A first end (such as an upper end) of each channel is communicated with the upper chamber 15 and a second end (such as a lower end) of each channel is communicated with the lower chamber 16.
As shown in Fig. 1, the motor 2 may include the stator 21 and the rotor 22. The stator 21 may have a roughly circular shape and may be adapted to be fixed on the housing, for example, the stator 21 may be welded onto an inner wall surface of the middle housing 12. The rotor 22 is rotatably disposed within the stator 21 and adapted to be fixed with a crankshaft 35.
The compression mechanism is disposed below the motor 2 and defines an air suction port 36. According to some embodiments of the present disclosure, the compression mechanism may include a main bearing 31, a cylinder 32 and a supplementary bearing 33. The main bearing 31 is disposed above the cylinder 32, for example, the main bearing 31 can be detachably fixed above the cylinder 32 via a plurality of bolts. The supplementary bearing 33 is disposed below the cylinder 32, for example, the supplementary bearing 33 can be detachably fixed below the cylinder 32 via a plurality of bolts.
A compression chamber is defined between the main bearing 31, the cylinder 32 and the supplementary bearing 33, and used to compress the refrigeration medium, such as a gaseous refrigerant. An upper part of the crankshaft 35 can be fixed with the rotor 22 of the motor 2, a lower end of the crankshaft 35 can extend downward though the main bearing 31, the cylinder 32 and the supplementary bearing 33. A piston 34 is fitted over the crankshaft 35 and positioned within the compression chamber, and an outer circumferential surface of the piston 34 is circular or elliptic.
The air suction port 36 can be formed in the main bearing 31, and certainly can also be formed in the cylinder 32. Two ends of the air suction port 36 are communicated with the lower chamber 16 and the compression chamber, respectively.
The exhaust volume of the low backpressure rotary compressor is V (cm³/rev), in which cm³/rev represents cubic centimeters per revolution, the flow area of the channel is S (mm²), in which mm² represents square millimeter, the rotating speed of the motor 2 is F and the flow rate of a gas passing through the channel is v (m/s) which should be understood as an average rate of the gas passing through the channel, so that v=(V×F)/S, in which

when F≤60 rev/s, 2 (m/s)≤v≤25 (m/s);
when F>60 rev/s, 8 (m/s)≤v≤40 (m/s),

Thus, a good balance can be established between the circulation loss of the gas and the heat dissipation requirements of the motor 2 when the numerical ranges are satisfied.
It should be noted that, the exhaust volume of the low backpressure rotary compressor described above, i.e. working capacity of the compressor, refers to the volume of the gas discharged and converted to a suction state at an air inlet when the eccentric crankshaft rotates a cycle and the compressor works according to the circulation theory. The flow area refers to an area of through holes which enable the upper and lower sides of the motor 2 to be communicated with each other and enable the gas to pass through the through holes smoothly after the assembly of the compressor is completed. Specifically, the through holes generally can include through holes or slots for connecting two sides of the motor, such as the first channel 231, the second channel 232 and the third channel 233 as described in Fig. 1. Then, according to embodiments of the present disclosure, the total flow area S of the channels include a sum of flow areas of those channels (the first channel 231, the second channel 232 and the third channel 233). However, it should be understood that, those channels do not include holes or slots (such as slots used for installing windings, cast aluminum holes, rivet holes, and positioning holes of cores) which only have an assembly function.
With the low backpressure rotary compressor 100 according to embodiments of the present disclosure, it is possible to realize a good balance between the circulation loss of the gas and the heat dissipation requirements of the motor 2 by making the flow rate v of the gas in the channel in an appropriate range when the motor 2 operates at different rotating speeds, for example, when F≤60 rev/s, 2 (m/s)≤v≤25 (m/s), as another example, when F>60 rev/s, 8 (m/s)≤v≤40 (m/s), thus ensuring that the motor 2 works at a suitable temperature to avoid the occurrence of high temperature to damage the motor 2 or affect the work efficiency of the motor 2. Meanwhile, the circulation loss of the gas is minimized, thereby improving the overall efficiency of the compressor.
According to some embodiments of the present disclosure, as shown in Fig. 1, the housing may include the upper housing 11, the middle housing 12 and the lower housing 13. The middle housing 12 is connected between the upper housing 11 and the lower housing 13. Specifically, a lower end of the upper housing 11 can be fixed with an upper end of the middle housing 12 by e.g., welding, and a lower end of the middle housing 12 can be fixed to an upper end of the lower housing 13 by e.g., welding. As the molding and processing of individual small parts are relatively easy, dividing the housing into the upper housing 11, the middle housing 12 and the lower housing 13 can greatly facilitate the production and processing of the housing, and reduce the overall cost. The air suction pipe 14 is disposed on the upper housing 11, for example, the air suction pipe 14 can be fixed at a center of a top of the upper housing 11 by welding.
According to embodiments of the present disclosure, the motor 2 can be a constant speed motor, in other words, the output rotating speed of the motor 2 is constant, i.e. non-adjustable. For example, the rated rotating speed of the motor 2 can be 50 rev/s or 60 rev/s, that is, in some embodiments, the motor 2 only have a unique output rotating speed of 50 rev/s or 60 rev/s.
Certainly, the present disclosure is not limited to this. In other embodiments, the motor 2 can be a variable speed motor, in other words, the output rotating speed of the motor 2 is adjustable. For example, the motor 2 may have several different preset rotating speeds. When the power of the compressor needs to be increased, the rotating speed of the motor 2 can be increased. When the power of the compressor needs to be decreased, the rotating speed of the motor 2 can be reduced. Of course, the rotating speed of the motor 2 can be continuously adjustable.
According to embodiments of the present disclosure, the exhaust volume V of the compressor is adjustable, in other words, the compressor is a variable exhaust volume compressor. It should be understood that, the variable exhaust volume compressor is known in the related art and known to those skilled in art, will not be elaborated here.
According to embodiments of the present disclosure, the compressor has a double-cylinder structure, i.e. the compressor has two compression chambers (i.e. the pump body of the compressor includes two cylinders). It should be understood that, the rotary compressor with the double-cylinder structure is well known to those skilled in art, which will not be elaborated here.
As shown in Fig. 1 and Fig. 2, the channel includes the first channel 231, the second channel 232 and the third channel 233, and these three channels will be described below in detail, respectively.
As shown in Fig. 1 and Fig. 2, at least a part of an outer circumferential surface of the stator 21 is spaced apart from the inner circumferential surface of the housing to form the first channel 231. In other words, the outer circumferential surface of the stator 21 can be a standard circumferential surface, a part (i.e. the first channel 231 mentioned above) of the outer circumferential surface of the stator 21 is removed, while the remaining part of the outer circumferential surface of the stator 21 which is not removed can closely adhere to the inner wall surface of the housing.
The second channel 232 can be formed in the stator 21. Specifically, the stator 21 is formed with at least one through hole (i.e. the second channel 232) penetrating the stator 21 in an up-down direction. Similarly, the third channel 233 can be configured as a through hole penetrating the rotor 22 in the up-down direction. Specifically, the rotor 22 is formed with at least one through hole (i.e. the third channel 233) penetrating the rotor 22 in the up-down direction.
The flow area of the first channel 231 is S1, the flow area of the second channel 232 is S2, the flow area of the third channel 233 is S3, so that the total flow area S = S1 + S2 + S3.
Certainly, it should be understood that, according to other embodiments of the present disclosure, the channel may include any one of the first channel 231, the second channel 232 and the third channel 233, so the corresponding total flow area S is any corresponding one of S1, S2 and S3. Alternatively, the channel may include the first channel 231 and the second channel 232, or include the second channel 232 and the third channel 233, or include the first channel 231 and the third channel 233, i.e. the channel may include any two of the first channel 231, the second channel 232 and the third channel 233, so the corresponding total flow area S is S1 + S2, S1 + S3 or S2 + S3.
Preferably, there are a plurality of the first channels 231 which are evenly distributed in a circumferential direction. For example, there are four first channels 231, and the angle between two adjacent first channels 231 can be 90°. Then, the flow area S1 of the first channels 231 should be understood as the total flow area of the plurality of first channels 231.
There are a plurality of the second channels 232 which are evenly distributed in a circumferential direction. For example, there are four second channels 232, and the angle between two adjacent second channels 232 can be 90°. Then, the flow area S2 of the second channels 232 should be understood as the total flow area of the plurality of second channels 232.
Similarly, there are a plurality of the third channels 233 which are evenly distributed in a circumferential direction. For example, there are three third channels 233, and the angle between two adjacent third channels 233 can be 120°. Then, the flow area S3 of the third channels 233 should be understood as the total flow area of the plurality of third channels 233.
Certainly, the present disclosure is not limited to this. In other embodiments of the present disclosure, the first channels 231, the second channels 232 and the third channels 233 also can be unevenly distributed in the circumferential direction.
Briefly, with the low backpressure rotary compressor 100 according to embodiments of the present disclosure, it is possible to enable the motor 2 to achieve a higher efficiency with a lower air flow resistance within the channel, thus achieving a better performance of the compressor. Meanwhile, the compressor according to embodiments of the present disclosure has a simple structure, a rational design and an excellent performance.
Reference throughout this specification to "an embodiment," "some embodiments," "one embodiment", "another example," "an example," "a specific example," or "some examples," means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. Thus, the appearances of the phrases such as "in some embodiments," "in one embodiment", "in an embodiment", "in another example," "in an example," "in a specific example," or "in some examples," in various places throughout this specification are not necessarily referring to the same embodiment or example of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.
Although explanatory embodiments have been shown and described, it would be appreciated by those skilled in the art that the above embodiments cannot be construed to limit the present disclosure, and changes, alternatives, and modifications can be made in the embodiments without departing from spirit, principles and scope of the present disclosure.

Claims

A low backpressure rotary compressor, comprising:
a housing defining a chamber therein;

an air suction pipe disposed on the housing;

a motor disposed within the chamber, and dividing the chamber into an upper chamber communicated with the air suction pipe and a lower chamber, a channel being formed within the motor and/or between an outer circumferential surface of the motor and an inner circumferential surface of the housing, and the channel defining a first end communicated with the upper chamber and a second end communicated with the lower chamber;

a compression mechanism disposed below the motor and defining an air suction port;

wherein an exhaust volume of the compressor is V, a total flow area of the channel is S, a rotating speed of the motor is F, and a flow rate of a gas passing through the channel is v, so that v=(V×F)/S, wherein $when F \leq 60 rev / s, 2 (m / s) \leq v \leq 25 (m / s);$
$when F > 60 rev / s, 8 (m / s) \leq v \leq 40 (m / s) .$
The low backpressure rotary compressor according to claim 1, wherein the housing comprises an upper housing, a lower housing and a middle housing connected between the upper housing and the lower housing, and the air suction pipe is disposed on the upper housing.
The low backpressure rotary compressor according to claim 1, wherein the motor is a constant speed motor.
The low backpressure rotary compressor according to claim 3, wherein the motor has a rated rotating speed of 50 rev/s or 60 rev/s.
The low backpressure rotary compressor according to claim 1, wherein the motor is a variable speed motor.
The low backpressure rotary compressor according to claim 1, wherein the motor has an adjustable exhaust volume V
The low backpressure rotary compressor according to claim 1, wherein the channel comprises a first channel, and the motor comprises a stator and a rotor,
wherein at least a part of an outer circumferential surface of the stator is spaced apart from the inner circumferential surface of the housing to form the first channel.
The low backpressure rotary compressor according to claim 1, wherein the channel further comprises a second channel, and the motor comprises a stator and a rotor, the stator defining at least one through hole penetrating the stator in an up-down direction to form the second channel.
The low backpressure rotary compressor according to claim 1, wherein the channel further comprises a third channel, and the motor comprises a stator and a rotor, the rotor defining at least one through hole penetrating the rotor in an up-down direction to form the third channel.
The low backpressure rotary compressor according to claim 9, wherein the air suction port is formed in a main bearing or a cylinder.