CN216198987U

CN216198987U - Screw compressor with automatically adjustable internal volume ratio

Info

Publication number: CN216198987U
Application number: CN202122779705.6U
Authority: CN
Inventors: 钟伟华; 黄韶云; 季小军
Original assignee: Lisen Air Conditioning & Refrigeration Suzhou Co ltd
Current assignee: Lisen Air Conditioning & Refrigeration Suzhou Co ltd
Priority date: 2021-11-14
Filing date: 2021-11-14
Publication date: 2022-04-05
Anticipated expiration: 2031-11-14

Abstract

A screw compressor with automatically adjustable internal volume ratio comprises a compressor body, a slide valve is arranged on the inner wall of a shell of the compressor body, a first pressure channel is arranged in the slide valve, a second pressure channel is arranged on the shell, pressure buffer cavities are arranged on the slide valve and the inner wall of the shell, the first pressure channel and the second pressure channel are both communicated with the pressure buffer cavities, a main bearing seat is arranged in the shell, a screw rotor in the compressor body rotates through the main bearing seat, and the main bearing seat is arranged on a piston seat. Has very important significance.

Description

Screw compressor with automatically adjustable internal volume ratio

Technical Field

The utility model relates to the field of air conditioning equipment, in particular to a screw compressor with an automatically adjustable internal volume ratio.

Background

With the acceleration of the urbanization process and the improvement of the living standard of residents, the proportion of the energy consumption of the refrigeration air-conditioning unit to the total energy consumption of China is increased day by day, and the improvement of the energy efficiency level of the refrigeration air-conditioning unit has important significance for national energy conservation and emission reduction and the realization of the sustainable development of society.

The internal volume ratio of conventional screw compressors is generally not adjustable:

1. if the compression end pressure Pn of the gas in the compression cavity which is about to enter the exhaust stage at the end of the compression stage is greater than the back pressure Pw of the high-pressure cavity, the phenomenon of over-compression is generated due to the fact that the actual compression stroke is too long, the gas in the compression cavity suddenly expands after entering the exhaust stage, the pressure Pn of the gas in the compression cavity is reduced to the back pressure Pw of the high-pressure cavity after expanding, and redundant compression work is wasted.

2. If the compression end pressure Pn of the gas in the compression cavity at the end of the compression stage and about to enter the exhaust stage is less than the back pressure Pw of the high-pressure cavity, the actual compression stroke is too short, an under-compression phenomenon is generated, the gas in the compression cavity is forced to be compressed to Pw instantly in an equal volume mode after entering the exhaust stage and then is exhausted to the exhaust port, and redundant compression work is wasted.

From the above analysis, if the compression final pressure Pn of the gas in the compression chamber at the end of the compression stage, which is about to enter the exhaust stage, is equal to the back pressure Pw of the high-pressure chamber, the over-compression phenomenon or the under-compression phenomenon will not occur, which is the most ideal compression process, and the compression efficiency of the compressor is the highest at this time.

The screw cold and hot water unit is affected by the outdoor air temperature or cooling water temperature at the condensation side, the freezing water temperature at the evaporation side, the operation mode, the air conditioner load or the compressor capacity and other operation conditions, the suction pressure (Ps) and the exhaust pressure (Pw) of the screw cold and hot water unit are greatly changed, and the compression ratio (Pw/Ps) of the compressor is actually changed in a large range, so that the required optimal operation compression ratio and the corresponding internal volume ratio are synchronously adjusted, the final compression pressure Pn and the back pressure Pw of the high-pressure cavity can be ensured to be equal, and the compression efficiency of the compressor is improved to the maximum extent. However, the internal volume ratio of the conventional compressor is fixed, so the compressor is in an over-compression or under-compression state in most of time, which results in large energy consumption of the compressor in actual operation and low refrigeration energy efficiency.

SUMMERY OF THE UTILITY MODEL

In view of the above, the present invention is directed to a screw compressor with an automatically adjustable internal volume ratio to solve the above problems.

Based on the above purpose, the present invention provides a screw compressor with an automatically adjustable internal volume ratio, which comprises a compressor body, wherein a slide valve is arranged on an inner wall of a casing of the compressor body, a first pressure channel is arranged inside the slide valve, a second pressure channel is arranged on the casing, a pressure buffer cavity is arranged on the slide valve and the inner wall of the casing, the first pressure channel and the second pressure channel are both communicated with the pressure buffer cavity, a main bearing seat is arranged inside the casing, a screw rotor inside the compressor body rotates through the main bearing seat, the main bearing seat is arranged on a piston seat, a piston is arranged on the piston seat, the piston is composed of two piston cylinders which are fixedly communicated with each other, a first piston ring is slidably connected inside one of the piston cylinders, a second piston ring is slidably connected inside the other piston cylinder, and the first piston ring and the second piston ring are both fixedly connected with a piston rod of the piston, the first piston ring and the second piston ring divide the two piston cylinders into a first pressure cavity, a second pressure cavity and a third pressure cavity in sequence, the second pressure channel is communicated with the third pressure cavity through a first pipeline, a piston rod of the piston is fixedly connected with a connecting plate, the connecting plate is fixedly connected with a guide rod, and the guide rod is connected to a piston seat in a sliding mode.

Preferably, a throttling plug is arranged on the first pressure channel.

Preferably, the guide rod abuts against the slide valve.

Preferably, the shell is provided with a high-pressure tapping point, and the first pressure cavity is always communicated with the exhaust pressure Pd through a second pipeline.

Preferably, the second compression chamber is always in communication with the suction pressure Ps of the compressor through a third line.

From the above, it can be seen that the beneficial effects of the present invention are: according to the utility model, the first piston cavity, the second piston cavity and the third piston cavity are arranged in the piston, so that the internal volume ratio is continuously adjustable; the utility model connects the slide valve, the guide rod, the connecting plate and the piston together to form an adjusting component which can move along the axial direction of the rotor, the component is self-adaptive along with the stress of the piston in the piston cavity, and the compression state of the compressor is adjusted, thereby achieving the purpose of self-adaptive adjustment of the internal volume ratio; the screw refrigerating compressor with the internal volume ratio continuous control device and the control technology are adopted, so that the defects of over-compression or under-compression of the compressor in the large compression ratio range and variable working condition operation under different operating modes, outdoor air temperature, cooling water temperature and freezing water temperature working conditions are effectively overcome, the compression efficiency of the compressor and the refrigerating energy efficiency of a unit are improved, and the screw refrigerating compressor has very important significance.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of the present invention.

In the reference symbols: 1. a compressor body; 2. a spool valve; 3. a housing; 4. a throttling plug; 5. a first pressure channel; 6. a pressure buffer chamber; 7. a second pressure channel; 8. a first pipeline; 9. a high pressure point; 10. a second pipeline; 11. a first pressure chamber; 12. a third pipeline; 13. a second pressure chamber; 14. a third pressure chamber; 15. a piston; 16. a first piston ring; 17. a connecting plate; 18. a second piston ring; 19. a guide bar; 20. a piston seat; 21. a main bearing housing; 22. a screw rotor.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and the accompanying drawings.

It is to be noted that technical terms or scientific terms used in the embodiments of the present invention should have the ordinary meanings as understood by those having ordinary skill in the art to which the present disclosure belongs, unless otherwise defined. The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather is used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

Examples

Referring to fig. 1, a screw compressor with an automatically adjustable internal volume ratio includes a compressor body 1, a slide valve 2 is disposed on an inner wall of a casing 3 of the compressor body 1, a first pressure channel 5 is disposed inside the slide valve 2, a second pressure channel 7 is disposed on the casing 3, a pressure buffer chamber 6 is disposed on inner walls of the slide valve 2 and the casing 3, the first pressure channel 5 and the second pressure channel 7 are both communicated with the pressure buffer chamber 6, a main bearing seat 21 is disposed inside the casing 3, a screw rotor 22 inside the compressor body 1 rotates through the main bearing seat 21, the main bearing seat 21 is disposed on a piston seat 20, a piston 15 is disposed on the piston seat 20, the piston 15 is composed of two mutually fixed and communicated piston 15 cylinders, wherein a first piston ring 16 is slidably connected inside one piston 15 cylinder, and a second piston ring 18 is slidably connected inside the other piston 15 cylinder, the first piston ring 16 and the second piston ring 18 are fixedly connected with a piston 15 rod of a piston 15, the first piston ring 16 and the second piston ring 18 divide two piston 15 cylinders into a first pressure chamber 11, a second pressure chamber 13 and a third pressure chamber 14 in sequence, the second pressure channel 7 is communicated with the third pressure chamber 14 through a first pipeline 8, the piston 15 rod of the piston 15 is fixedly connected with a connecting plate 17, the connecting plate 17 is fixedly connected with a guide rod 19, and the guide rod 19 is connected to a piston seat 20 in a sliding mode.

As a modified scheme of the scheme, the first pressure channel 5 is provided with a throttling plug 4.

As a modification of the above, the guide rod 19 abuts against the slide valve 2.

As a modification of the above scheme, a high-pressure tapping point 9 is arranged on the shell 3, and the first pressure cavity 11 is always communicated with the exhaust pressure Pd through a second pipeline 10.

As a modification of the above, the second compression chamber is always in communication with the suction pressure Ps of the compressor through the third line 12.

The working principle is as follows: the slide valve 2 is provided with a first pressure channel 5, a throttling plug 4 is arranged in the first pressure channel 5, the position of the first pressure channel 5 can be always communicated with a first pressure cavity 11 and cannot be communicated with a compression cavity during air exhaust, so that misoperation or failure action is caused, and a second pressure channel 7 is arranged on a machine body and is always communicated with a pressure buffer cavity 6 on the slide valve 2 in the stroke range of the action of the slide valve 2.

The actual applied rotating speed of the compressor is 1400-6000rpm, the single screw compressor generates 12 times of compression per revolution, the slide valve 2 corresponds to 6 times of compression, therefore, the completion time of the pressure buffer cavity 6 corresponding to the first pressure channel 5 is 1/2-1/3 of each compression time, namely, the pressure fluctuation cycle of the first pressure channel 5 is 0.0007s-0.004s, the throttling plug 4 is arranged in the pressure channel, so that the pressure in the pressure buffer cavity 6 is maintained at the compression final pressure, and the self-adaptive adjustment of the whole compressor is smooth.

The cross-sectional area of the first piston ring 16 is S1, the cross-sectional area of the second piston ring 18 is S2S2 > S1, the cross-sectional area of the part of the piston 15 connecting the piston 15 with the connecting plate 17 is S3, 3 pressure chambers are arranged in the piston 15, the third pressure is always communicated with the second pressure channel 7 through the first pipeline 8, namely, the final pressure Pn is not compressed all the time, the second pressure chamber 13 is always communicated with the suction pressure Ps of the compressor through the second pipeline 10, the first pressure chamber 11 is always communicated with the exhaust pressure Pd, the cross-sectional area of the slide valve 2 is S4, then 2 slide valves 2 are subjected to the pressure Pd-Ps S4 directing from high pressure to low pressure, the second piston ring 18 is subjected to the pressure (Pd-Ps) S2-PS 3 directing from low pressure to high pressure,

the first piston ring (16) is subjected to a force (Pn-Ps) directed from high pressure to low pressure (S1-S3), and the whole system of connecting plates (17) is subjected to a force (Pd S3) directed from high pressure to low pressure, so that the whole internal volume ratio adjusts the self-adaptation of the movable assembly, and when the forces are balanced, the movable assembly is subjected to

(Pn-Ps)*(S1-S3)+Pd*s3+2*(Pd-Ps)*S4＝(Pd-Ps)*S2+PS*S3；

When the compressor is in the under-compression state, the compression end pressure Pn < Pd, at this time

(Pn-Ps) (S1-S3) + Pd S3+2 (Pd-Ps) × S4 < (Pd-Ps) × S2+ Ps S3, the slide valve (2) moves to the high pressure side, the opening of the slide valve (2) is reduced, the internal volume ratio of the compressor is increased, and the Pn value is increased until Pn is equal to Pd;

pn > Pd when the compressor is in an over-compression state, at which time

(Pn-Ps) (S1-S3) + Pd S3+2 (Pd-Ps) — S4 > (Pd-Ps) × S2+ Ps S3, the slide valve (2) moves to the low pressure side, the opening of the slide valve (2) increases, the internal volume of the compressor decreases, and the Pn value decreases until Pn becomes Pd; the mechanism of the utility model is always in the adjustable range of the internal volume ratio, can be self-adaptive, accurate and reliable, and effectively avoids the additional power consumption caused by over-compression or under-compression.

In the previous description, numerous specific details were set forth in order to provide a thorough understanding of the present invention. The foregoing description is only a preferred embodiment of the utility model, which can be embodied in many different forms than described herein, and therefore the utility model is not limited to the specific embodiments disclosed above. And that those skilled in the art may, using the methods and techniques disclosed above, make numerous possible variations and modifications to the disclosed embodiments, or modify equivalents thereof, without departing from the scope of the claimed embodiments. Any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. The screw compressor with the automatically adjustable internal volume ratio is characterized by comprising a compressor body (1), a slide valve (2) is arranged on the inner wall of a shell (3) of the compressor body (1), a first pressure channel (5) is formed inside the slide valve (2), a second pressure channel (7) is formed on the shell (3), a pressure buffer cavity (6) is formed in the inner walls of the slide valve (2) and the shell (3), the first pressure channel (5) and the second pressure channel (7) are communicated with the pressure buffer cavity (6), a main bearing seat (21) is arranged inside the shell (3), a screw rotor (22) inside the compressor body (1) rotates through the main bearing seat (21), the main bearing seat (21) is arranged on a piston seat (20), a piston (15) is arranged on the piston seat (20), the piston (15) consists of two piston (15) cylinders which are fixedly communicated with each other, wherein a first piston ring (16) is connected in the cylinder of one piston (15) in a sliding way, a second piston ring (18) is connected in the cylinder of the other piston (15) in a sliding way, the first piston ring (16) and the second piston ring (18) are both fixedly connected with a piston (15) rod of the piston (15), the first piston ring (16) and the second piston ring (18) divide the two piston (15) cylinders into a first pressure chamber (11), a second pressure chamber (13) and a third pressure chamber (14) in turn, the second pressure channel (7) communicates with a third pressure chamber (14) via a first line (8), a piston (15) rod of the piston (15) is fixedly connected with the connecting plate (17), the connecting plate (17) is fixedly connected with a guide rod (19), and the guide rod (19) is connected to the piston seat (20) in a sliding mode.

2. Screw compressor with automatically adjustable internal volume ratio according to claim 1, characterised in that the first pressure channel (5) is provided with a choke plug (4).

3. -screw compressor with an automatically adjustable internal volume ratio according to claim 1, characterised in that the guide rod (19) abuts against the slide valve (2).

4. Screw compressor with automatically adjustable internal volume ratio according to claim 1, characterized in that the housing (3) is provided with a high pressure tapping point (9), the first pressure chamber (11) being always in communication with the discharge pressure Pd via a second line (10).

5. -screw compressor with automatic adjustment of the internal volume ratio according to claim 1, characterised in that the second compression chamber is always in communication with the suction pressure Ps of the compressor through a third conduit (12).