Slide Valve for a Twin-Screw Compressor

Abstract

The present application provides a slide valve, wherein the slide valve is configured to regulate a load of a twin-screw compressor. The slide valve comprises a slide valve body, wherein the slide valve body has a connecting end and a free end, the connecting end is configured to connect to a slide valve connecting rod of the twin-screw compressor, and the slide valve is driven to slide by the slide valve connecting rod. A cavity is formed in the free end of the slide valve body, and the slide valve has a passage configured to fluidly couple the cavity with an external fluid to reduce air flow pulsations on a suction side of the twin-screw compressor and thereby reduce overall air flow pulsations in the twin-screw compressor.

Claims

1. A slide valve configured to regulate a load of a twin-screw compressor, comprising: a slide valve body of the slide valve, wherein the slide valve body comprises a connecting end and a free end, the connecting end is configured to connect to a slide valve connecting rod of the twin-screw compressor, the slide valve is configured to be driven by the slide valve connecting rod, the free end of the slide valve body is configured to at least partially define an air return passage of the twin-screw compressor, a cavity is formed in the free end and extends into the slide valve body, and the slide valve comprises at least one passage configured to fluidly couple the cavity to the air return passage.

2. The slide valve of claim 1, wherein the cavity is a single cavity, the slide valve comprises a cover coupled to an end face of the free end, the cover comprises a plurality of holes, and the plurality of holes is fluidly connected to the single cavity to form a plurality of passages comprising the at least one passage.

3. The slide valve of claim 2, wherein each hole of the plurality of holes is circular, and each hole of the plurality of holes comprises a common size.

4. The slide valve of claim 2, the single cavity extends into the slide valve body from the end face of the free end.

5. The slide valve of claim 4, wherein the single cavity is formed completely internal to the slide valve body.

6. The slide valve of claim 2, wherein the plurality of passages is configured to fluidly couple the single cavity to the air return passage to enable flow of an external fluid from the air return passage into the single cavity.

7. The slide valve of claim 1, wherein the slide valve body is an integrally formed, one-piece structure.

8. The slide valve of claim 1, wherein the slide valve body comprises a first rotor contact surface and a second rotor contact surface, wherein the first rotor contact surface is configured to contact a first screw rotor of the twin-screw compressor, and the second rotor contact surface is configured to contact a second screw rotor of the twin-screw compressor.

9. The slide valve of claim 1, wherein the free end of the slide valve body comprises an end face, and the cavity extends into the slide valve body from the end face of the free end.

10. The slide valve of claim 9, comprising a cover coupled to the end face, wherein the cover comprises the at least one passage formed therein, and the at least one passage is configured to enable flow of an external fluid from the air return passage into the cavity.

11. A slide valve configured to regulate a load of a twin-screw compressor, comprising: a slide valve body of the slide valve, wherein the slide valve body comprises a connecting end and a free end, the connecting end is configured to connect to a slide valve connecting rod of the twin-screw compressor, the slide valve is configured to be driven by the slide valve connecting rod, a cavity is formed in an end face of the free end, and the cavity extends into the slide valve body; and a cover coupled to the end face of the free end, wherein the cover comprises at least one passage configured to fluidly couple the cavity to an external fluid to reduce air flow pulsations on a suction side of the twin-screw compressor.

12. The slide valve of claim 11, wherein the slide valve body is an integrally formed, one-piece structure.

13. The slide valve of claim 11, wherein the cavity comprises a plurality of passages formed therein, the plurality of passages comprises the at least one passage, and each passage of the plurality of passages is configured to fluidly couple the cavity to an air return passage of the twin-screw compressor.

14. The slide valve of claim 11, wherein the slide valve body comprises a first rotor contact surface and a second rotor contact surface, wherein the first rotor contact surface is configured to contact a first screw rotor of the twin-screw compressor, and the second rotor contact surface is configured to contact a second screw rotor of the twin-screw compressor.

15. The slide valve of claim 11, wherein the connecting end and the free end are arranged at opposite ends of the slide valve body.

16. A slide valve configured to regulate a load of a twin-screw compressor, comprising: a slide valve body comprising a connecting end and a free end, wherein the connecting end is configured to connect to a slide valve connecting rod of the twin-screw compressor, the slide valve is configured to be driven by the slide valve connecting rod, the free end is configured to at least partially define an air return passage of the twin-screw compressor, and a cavity is formed in the free end and extends into the slide valve body; and a cover coupled to an end face of the free end, wherein the cover comprises a plurality of passages extending through the cover, and the plurality of passages is configured to fluidly couple the cavity to the air return passage and configured to enable flow of an external fluid from the air return passage into the cavity to reduce air flow pulsations on a suction side of the twin-screw compressor.

17. The slide valve of claim 16, wherein the plurality of passages is formed via a plurality of holes formed in the cover, wherein each hole of the plurality of holes comprises a circular geometry.

18. The slide valve of claim 16, wherein the cavity is formed completely internal to the slide valve body.

19. The slide valve of claim 16, wherein the slide valve body is an integrally formed, one-piece structure.

20. The slide valve of claim 16, wherein the slide valve body comprises: a first rotor contact surface and a second rotor contact surface, wherein the first rotor contact surface is configured to contact a first screw rotor of the twin-screw compressor, and the second rotor contact surface is configured to contact a second screw rotor of the twin-screw compressor; and a slide valve slot contact surface configured to contact a slide valve slot of the twin-screw compressor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] These and other characteristics and advantages of the present disclosure can be better understood by reading the following description with reference to the drawings. In all the drawings, the same reference number represents the same component, wherein

[0021] FIG. 1A is a cutaway view of a twin-screw compressor in the longitudinal direction of a screw rotor, where the slide valve is provided below the screw rotor.

[0022] FIG. 1B is a partial cutaway view of a twin-screw compressor in the longitudinal direction of a screw rotor and shows a position (above the screw rotor) of the slide valve at full load.

[0023] FIG. 1C is a partial cutaway view of a twin-screw compressor in the longitudinal direction of a screw rotor and shows a position (above the screw rotor) of the slide valve at partial load.

[0024] FIG. 1D is a cutaway view of the embodiment shown in FIG. 1B, taken along line D-D of FIG. 1B, and shows a position relationship between the slide valve and the screw rotors of the twin-screw compressor.

[0025] FIG. 2A is a perspective view of a slide valve body in one embodiment of the present disclosure.

[0026] FIG. 2B is a cutaway view of the embodiment of the slide valve body shown in FIG. 2A, taken along line A-A of FIG. 2A.

[0027] FIG. 3A is a perspective view of a slide valve body of another embodiment of the present disclosure.

[0028] FIG. 3B is a cutaway view of the embodiment of the slide valve body shown in FIG. 3A, taken along line B-B of FIG. 3A.

[0029] FIG. 3C is a cutaway view of the embodiment of the slide valve body shown in FIG. 3A, taken along line B-B of FIG. 3A.

[0030] FIG. 4A is a perspective view of a slide valve body of a third embodiment of the present disclosure.

[0031] FIG. 4B is a cutaway view of the embodiment of the slide valve body shown in FIG. 4A, taken along line C-C of FIG. 4A.

DETAILED DESCRIPTION

[0032] The following will describe various specific implementation modes of the present disclosure by reference to the drawings which constitute a part of the present description. It should be understood that although the terms indicating directions, such as before, behind, above, below, left, and right are used in the present disclosure to describe various exemplified structural parts and components of the present disclosure, these terms are just used for the convenience of illustrations and are determined based on the exemplified directions in the drawings. Since the embodiments disclosed in the present disclosure can be set in different directions, these terms indicating directions are only used for illustrations, instead of restrictions. In the following drawings, the same components use the same reference numbers, and similar components use similar reference numbers so as to avoid repeated descriptions.

[0033] FIG. 1A is a cutaway view of a twin-screw compressor (90) in the longitudinal direction of a screw rotor (92), where a slide valve (100) is provided below the screw rotor (92). However, the slide valve (100) can be provided above the screw rotor (92), as shown in FIG. 1B and FIG. 1C.

[0034] FIG. 1B is a partial cutaway view of the twin-screw compressor (90) in the longitudinal direction of the screw rotor (92) and shows a position of the slide valve (100) at full load, and FIG. 1C is a partial cutaway view of the twin-screw compressor (90) in the longitudinal direction of the screw rotor (92) and shows a position of the slide valve (100) at partial load. As shown in FIG. 1B and FIG. 1C, the slide valve (100) of the present disclosure is used in the twin-screw compressor (90) and comprises a slide valve body (101), a slide valve connecting rod (102) connected to a connecting end of the slide valve body (101), a spring (106) placed on the slide valve body (101), and a piston (103) connected to an end of the slide valve connecting rod (102). The slide valve connecting rod (102) can drive the slide valve body (101) to slide in a slide valve slot (190) so that an air return passage (109) can be formed between the slide valve body (101) and a cylinder of the compressor (90). Therefore, the effective working length of screw rotors (92) of the twin-screw compressor (90) can be adjusted to regulate a load of the twin-screw compressor (90) by adjusting a position of the slide valve body (101) in the slide valve slot (190). FIG. 1B shows the position of the slide valve (100) in the twin-screw compressor (90) at full load, where the slide valve body (101) is completely located in the slide valve slot (190), and the slide valve slot (190) is fully filled by the slide valve body (101) so that cooling medium vapors drawn in from a suction side (107) of the twin-screw compressor (90) are completely compressed and discharged. FIG. 1C shows the position of the slide valve (100) in the twin-screw compressor (92) at partial load, where a portion of the slide valve body (101) is located in the slide valve slot (190) so that the slide valve slot (190) forms the air return passage (109) and a part of the cooling medium vapors drawn in from the suction side (107) are not compressed and instead return to the suction side (107) via the air return passage (109). Therefore, the effective working length of the screw rotors (92) is shortened in the configuration shown in FIG. 1C.

[0035] To more clearly show the relationship between the slide valve (100) and the screw rotors (92) of the twin-screw compressor (90), FIG. 1D is a cutaway view of the twin-screw compressor (90) shown in Figure IB, taken along line D-D of FIG. 1B, where the slide valve body (101) has at least two screw rotor contact surfaces (131 and 132). The two rotor contact surfaces (131 and 132) respectively contact a pair of screw rotors (92), and a sealing interface is formed between the rotor contact surfaces (131 and 132) and the screw rotors (92).

[0036] FIG. 2A shows the structure of an embodiment of a slide valve body (201), in accordance with the present disclosure. The slide valve body (20 I) has two screw rotor contact surfaces (131 and 132) and a slide valve slot contact surface (232), where the slide valve slot contact surface (232) is configured to contact the slide valve slot (190). The slide valve body (201) further has a connecting end (204) and a free end (205) which are arranged opposite one another, and the connecting end (204) and the free end (205) are respectively located at the two ends of the slide valve body (201). The connecting end (204) is configured to connect to the slide valve connecting rod (102) so that the slide valve connecting rod (102) can drive the slide valve body (201) to slide within the slide valve slot (190) when the slide valve connecting rod (102) moves. The free end (205) can form the air return passage (109) together with the screw rotors (92) and a housing of the compressor when the slide valve body (201) slides within the slide valve slot (190).

[0037] As shown in FIG. 2A, a cover (223) is connected to an end face (224) of the free end (205), and the cover (223) has a plurality of holes (229). The holes (229) can be in any shape. In the embodiment shown in FIG. 2A, the holes (229) are circular holes or approximately circular holes, and each hole (229) has the same size or a similar size.

[0038] To show the internal structure of the slide valve body (201), FIG. 2B is a cutaway view of an embodiment of the slide valve body (201) shown in FIG. 2A, taken along line A-A of FIG. 2A. As shown in FIG. 2B, the holes (229) pass through the cover (223) to form a plurality of passages (221). A cavity (220) is formed inside of the slide valve body (201). Specifically, the cavity (220) extends into the slide valve body (201) from the end face (224) of the free end (205). One end of each passage (221) is connected to the cavity (220), and the other end of each passage (221) is connected to an external fluid via the holes (229). Thus, the cavity (220) is configured to be fluidly connected to the external fluid via the passages (221).

[0039] When air flow of the twin-screw compressor (90) pulsates, the cavity (220) accommodates the pulsating air flow by absorbing energy of the air flow pulsations and buffering the air flow. Thus, air flow pulsations are reduced, and vibrations and noise of the twin-screw compressor (90) are alleviated.

[0040] As an exemplified embodiment, the cavity (220) can be an integral cavity (220), as shown in FIG. 2B. In other exemplified embodiments, the cavity (220) can also be or include a plurality of cavities (320), as shown in FIG. 3B and FIG. 3C.

[0041] As another implementation of the present disclosure, no cover (223) may be provided on the end face (224) of the free end (205) of the slide valve body (201). As shown in FIG. 3A, the holes (329) can be directly formed in and on the end face (224) of the free end (205) so that one end of each of the passages (321) is connected to a respective one of the cavities (320), and the other end of each of the passages (321) is connected to external air flow via the direct passing of holes (329) though the end face (224) of the free end (205). Thus, the cavities (320) in the slide valve body (201) can be connected to the external air flow via the passages (321). As an exemplified embodiment, holes (329) can have different sizes and/or shapes so that the passages (321) can also have different inside diameters.

[0042] FIG. 3B and FIG. 3C are cutaway views of the slide valve body (201) shown in FIG. 3A, taken along line B-B of FIG. 3A, and show two exemplified embodiments in which a plurality of cavities (320) is provided in the slide valve body (201). By providing the plurality of cavities (320) in the slide valve body (201), the weight of the slide valve body (201) can be reduced and the reliability of the structure of the slide valve body (201) can be improved. In the exemplified embodiment shown in FIG. 3B, each cavity (320) of said plurality of cavities (320) has its own passage (321) so that each cavity (320) of the plurality of cavities (320) is connected to external air flow via its own passage (321). In the exemplified embodiment shown in FIG. 3C, a portion or subset of the plurality of cavities (320) has their own passage (321). Other cavities, such as cavity (3201), are connected to the external fluid via a plurality of passages (3211.1 and 3211.2). As an exemplified embodiment, when one of the cavities (320) is connected to the external fluid via the plurality of passages (3211.1 and 3211.2), the cavity (320) may be larger than the cavities (320) having their own, single passage (321). Therefore, the ability of the cavities (320) to absorb air flow pulsations is improved, and the reliability of the structure of the slide valve body (201) is improved.

[0043] The slide valve body (201) can have different shapes, depending on the type of the twin-screw compressor (90) having the slide valve body (201). As an exemplified embodiment, FIG. 4A shows the shape of a slide valve body (401). The slide valve body (401) has a connecting end (404) and a free end (405). The free end (405) has a free end extension portion (408) extending away from the free end (405). A top (409) of the free end extension portion (408) is lower than screw rotor contact surfaces (431 and 432) of the free end (405) so that a stepped connecting surface, such as stepped surface (410), is formed. If space in the twin-screw compressor (90) permits, the free end extension portion (408) can extend between a wall of the twin-screw compressor (90) cylinder and a housing of the screw rotors (92) when the slide valve (100) moves therein. Thus, the stability of the slide valve (100) during sliding is improved, and the reliability of the slide valve (100) is further improved.

[0044] The free end extension portion (408) has holes (429) on a surface of the free end extension portion (408). Specifically, as shown in FIG. 4A, the holes (429) can be located on the stepped surface (410) of the free end extension portion (408) or can be located on an outside surface (411) of the free end extension portion (408). FIG. 4B shows a cutaway view of an embodiment of the slide valve body (401) shown in FIG. 4A, taken along line C-C of FIG. 4A. As shown in FIG. 4B, the free end extension portion (408) has an integral cavity (420) formed inside the free end extension portion (408), and the cavity (420) has a plurality of passages (421). The passages (421) are connected to an external fluid via holes (429), thereby fluidly connecting the cavity (420) with the external fluid. The outside surface (411) can have holes (429) or can be a closed end face.

[0045] Similar to FIG. 3B and FIG. 3C, the free end extension portion (408) can have a plurality of cavities (420) formed therein, and the plurality of cavities (420) can be connected to the external fluid via one or more passages (421). Thus, air flow pulsations produced during operation of the twin-screw compressor (90) can be buffered via the cavities (420), and an air flow pulsation attenuating structure is formed.

[0046] The slide valve body (101) of the present disclosure can be integrally formed as a one piece structure, via the use of molds, or the slide valve body can be formed by machining a conventional slide valve body. The machining method is simple and easy to realize.

[0047] Although some characteristics of the present disclosure are shown and described in the present discussion, those skilled in the art can make various improvements and modifications. Therefore, it should be understood that the attached claims are intended to cover the above-mentioned improvements and modifications within the spirit and scope of the present disclosure.