Slide valve for twin-screw compressor

Abstract

To provide a slide valve configured to regulate the load of a twin-screw compressor.SOLUTION: The slide valve is configured to regulate the load of the twin-screw compressor. The slide valve includes a slide valve body having a connecting end and a free end. The connecting end is configured to be connected 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 at the free end of the slide valve body. The slide valve has a passage configured to fluidly couple the cavity to an external fluid so as to reduce suction-side airflow pulsation of the twin-screw compressor, thereby reducing overall airflow pulsation within the twin-screw compressor.SELECTED DRAWING: Figure 2B

Description

[Technical Field]

[0001] The present application relates to the field of compressors, and in particular to a slide valve for a twin-screw compressor. [Background technology]

[0002] The slide valve is a key component that allows the load adjustment of the twin screw compressor. By moving the position of the slide valve in the axial direction of the screw rotor of the twin screw compressor, the effective working length of the screw rotor can be changed to adjust the amount of air delivered by the twin screw compressor.

[0003] The engagement of the screw rotors of a twin-screw compressor can create discontinuous inter-tooth volumes, which can periodically connect the intake and exhaust cavities of the twin-screw compressor to the working cavity of the twin-screw compressor. As a result, the coolant fluid can flow unevenly through the twin-screw compressor, which can cause airflow pulsation during intake and exhaust. The airflow pulsation on the intake and exhaust sides of the twin-screw compressor can cause vibration and noise during operation of the twin-screw compressor. Therefore, it is desirable to reduce the airflow pulsation of the twin-screw compressor.

[0004] Due to the characteristics of twin-screw compressors, fluid pressure pulsations exist on both the suction side and the exhaust side of the twin-screw compressor, and the energy of the pulsations can be correlated to the acoustic load of the fluid inside the compressor. Currently, many technologies for suppressing exhaust pulsations are reflected in the construction of slide valve structures, but the slide valve structure has not been effectively utilized to construct a pulsation damping design on the suction side of the compressor to attenuate the energy of airflow pulsations, reduce the overall pressure pulsation level inside the compressor, or reduce compressor vibration and noise. Summary of the Invention [Problem to be solved by the invention]

[0005] To solve the above-mentioned problems, an object of the present disclosure is to provide a slide valve for a twin-screw compressor, which attenuates the energy of the airflow on the suction side of the twin-screw compressor to reduce the airflow pulsation on the suction side, thereby reducing the overall airflow pulsation level and alleviating vibration and noise of the twin-screw compressor. [Means for solving the problem]

[0006] To achieve the above-mentioned objectives, in a first aspect, the present disclosure provides a slide valve configured to adjust the load of a twin-screw compressor.

[0007] The slide valve includes a slide valve body having a connection end and a free end, the connection end configured to connect to a slide valve connecting rod, and the slide valve being driven to slide within the twin-screw compressor by the slide valve connecting rod, a cavity formed in the free end of the slide valve body, and the slide valve having at least one passage configured to fluidly connect the cavity to an external fluid to reduce airflow pulsation on the suction side of the twin-screw compressor.

[0008] According to this embodiment, one cavity is formed at the free end, and the slide valve has a cover on the end face of the free end, and the cover has a plurality of holes, which are connected to the cavity to form a plurality of passages.

[0009] According to this embodiment, each hole of the plurality of holes is circular and each hole is the same size.

[0010] According to this embodiment, a plurality of cavities are formed in the free end, each cavity of the plurality of cavities having its own passageway.

[0011] According to this embodiment, a plurality of cavities are formed in the free end, a first set of the plurality of cavities each having one passageway, and at least one cavity of the plurality of cavities having multiple passageways.

[0012] In a second aspect, the present disclosure provides a slide valve configured to adjust the load of a twin-screw compressor. The slide valve includes a slide valve body having a connection end and a free end. The connection end is configured to couple to a slide valve connecting rod to drive the slide valve for sliding within the twin-screw compressor. The free end of the slide valve body has a free end extension extending away from the free end. The free end extension has a cavity formed therein, and the slide valve has a passage configured to fluidly connect the cavity with an external fluid to reduce airflow pulsation on the suction side of the twin-screw compressor.

[0013] According to this embodiment, the free end extension is configured to provide additional support at part loads of the twin screw compressor.

[0014] According to this embodiment, the free end extension has a hole in a surface of the free end extension, which hole is connected to the cavity to form a passageway.

[0015] According to this embodiment, holes are provided in the outer surface of the free end extension.

[0016] According to this embodiment, the upper end of the free end extension is offset from the upper end of the free end so that a stepped surface is formed, and a hole is formed in the stepped surface.

[0017] In a third aspect, the present disclosure provides a twin-screw compressor, the twin-screw compressor configured to use a slide valve as described in any of the previous aspects.

[0018] Based on the aforementioned slide valve structure, the slide valve's function of adjusting the load of the twin-screw compressor is ensured in the slide valve of the present disclosure. Furthermore, a fluid pulsation damping structure is formed by providing a cavity in the slide valve body configured to connect to an external fluid, thereby reducing the energy of airflow pulsation on the suction side of the twin-screw compressor, reducing the overall airflow pulsation in the twin-screw compressor, alleviating the vibration and noise of the twin-screw compressor, and improving the operating reliability of the twin-screw compressor under various loads. Furthermore, the structure of the present disclosure is simple, does not use an additional damping device, and does not cause extra pressure loss.

[0019] These and other features and advantages of the present disclosure may be better understood by reading the following description in conjunction with the drawings, in which like reference numerals represent like elements throughout. [Brief explanation of the drawings]

[0020] [Figure 1A] FIG. 1 is a longitudinal cross-sectional view of a screw rotor of a twin screw compressor in which a slide valve is provided below the screw rotor. [Figure 1B] FIG. 1 is a partial cross-sectional view of a twin-screw compressor in the longitudinal direction of the screw rotor, showing the position of the slide valve (above the screw rotor) at maximum load. [Figure 1C] FIG. 1 is a partial cross-sectional view of a twin-screw compressor in the longitudinal direction of the screw rotor, showing the position of the slide valve (above the screw rotor) at part load. [Figure 1D] FIG. 1C is a cross-sectional view of the embodiment shown in FIG. 1B taken along line DD in FIG. 1B, illustrating the positional relationship between the slide valve and the screw rotor of the twin screw compressor. [Figure 2A] FIG. 1 is a perspective view of a slide valve body in one embodiment of the present disclosure. [Figure 2B] 2B is a cross-sectional view of the embodiment of the slide valve body shown in FIG. 2A taken along line AA in FIG. 2A. [Figure 3A] FIG. 10 is a perspective view of a slide valve body according to another embodiment of the present disclosure. [Figure 3B] 3B is a cross-sectional view of the embodiment of the slide valve body shown in FIG. 3A taken along line BB in FIG. 3A. [Figure 3C] 3B is a cross-sectional view of the embodiment of the slide valve body shown in FIG. 3A taken along line BB in FIG. 3A. [Figure 4A] FIG. 10 is a perspective view of a slide valve body according to a third embodiment of the present disclosure. [Figure 4B] 4B is a cross-sectional view of the embodiment of the slide valve body shown in FIG. 4A taken along line CC in FIG. 4A. DETAILED DESCRIPTION OF THE INVENTION

[0021] Various specific implementation modes of the present disclosure will be described below with reference to the drawings that form a part of this disclosure. Although directional terms such as "front," "rear," "up," "down," "left," and "right" are used in this disclosure to describe various exemplary structural parts and components of the present disclosure, it should be understood that these terms are used merely for convenience of illustration and are determined based on the exemplary orientation in the drawings. Because the embodiments disclosed in this disclosure may be configured in different orientations, these directional terms are used for illustration only and not for limitation. In the following drawings, identical components use the same reference numerals, and similar components use similar reference numerals to avoid repetition of description.

[0022] 1A is a cross-sectional view of a twin screw compressor 90 in the longitudinal direction of the screw rotor 92, with the slide valve 100 provided below the screw rotor 92. However, the slide valve 100 may also be provided above the screw rotor 92, as shown in FIGS. 1B and 1C.

[0023] 1B is a partial cross-sectional view of the twin-screw compressor (90) in the longitudinal direction of the screw rotor (92), showing the position of the slide valve (100) at full load. FIG. 1C is a partial cross-sectional view of the twin-screw compressor (90) in the longitudinal direction of the screw rotor (92), showing the position of the slide valve (100) at partial load. As shown in FIGS. 1B and 1C, the slide valve (100) of the present disclosure is used in the twin-screw compressor (90) and includes a slide valve body (101), a slide valve connecting rod (102) connected to the connecting end of the slide valve body (101), a spring (106) disposed on the slide valve body (101), and a piston (103) connected to the end of the slide valve connecting rod (102). The slide valve connecting rod (102) can drive the slide valve body (101) to slide within the slide valve slot (190) so that a return air passage (109) can be formed between the slide valve body (101) and the cylinder of the compressor (90). Thus, the effective working length of the screw rotor (92) of the twin screw compressor (90) can be adjusted to regulate the load of the twin screw compressor (90) by adjusting the position of the slide valve body (101) within the slide valve slot (190). Figure 1B shows the position of the slide valve (100) in the twin screw compressor (90) at maximum load, with the slide valve body (101) sliding within the slide valve slot. The slide valve (100) is fully positioned within the slide valve slot (190), and the slide valve body (101) is fully filled, thereby completely compressing and discharging the refrigerant vapor drawn from the suction side (107) of the twin-screw compressor (90). FIG. 1C shows the position of the slide valve (100) in a partially loaded twin-screw compressor (92), with a portion of the slide valve body (101) positioned within the slide valve slot (190), thereby forming a return air passage (109), such that a portion of the refrigerant vapor drawn from the suction side (107) is not compressed but instead returns to the suction side (107) via the return air passage (109). Therefore, the effective working length of the screw rotor (92) is shortened in the configuration shown in FIG. 1C.

[0024] To more clearly illustrate the relationship between the slide valve (100) and the screw rotors (92) of the twin screw compressor (90), Figure 1D is a cross-sectional view of the twin screw compressor (90) shown in Figure 1B taken along line DD in Figure 1B, in which the slide valve body (101) has at least two screw rotor contact surfaces (131 and 132). The two rotor contact surfaces (131 and 132) contact the pair of screw rotors (92), respectively, and a sealing interface is formed between the rotor contact surfaces (131 and 132) and the screw rotors (92).

[0025] 2A shows the structure of an embodiment of a slide valve body (201) according to the present disclosure. The slide valve body (201) has two screw rotor contact surfaces (131 and 132) and a slide valve slot contact surface (232), which 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) disposed opposite each other. The connecting end (204) and the free end (205) are located at two ends of the slide valve body (201), respectively. The connecting end (204) is configured to connect to the slide valve connecting rod (102), thereby driving the slide valve body (201) to slide within the slide valve slot (190) when the slide valve connecting rod (102) moves. When the slide valve body (201) slides within the slide valve slot (190), the free end (205) may form a return air passage (109) with the screw rotor (92) and the compressor housing.

[0026] As shown in Figure 2A, a cover 223 is coupled to the end surface 224 of the free end 205, and the cover 223 has a plurality of holes 229. The holes 229 may be of any shape. In the embodiment shown in Figure 2A, the holes 229 are circular or approximately circular holes, and each hole 229 has the same or similar size.

[0027] To illustrate the internal structure of the slide valve body 201, FIG. 2B is a cross-sectional view of the embodiment of the slide valve body 201 shown in FIG. 2A taken along line AA in FIG. 2A. As shown in FIG. 2B, holes 229 pass through the cover 223 to form a plurality of passages 221. Cavities 220 are formed inside the slide valve body 201. Specifically, the cavities 220 extend from the end face 224 of the free end 205 into the slide valve body 201. 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 cavities 220 are configured to be fluidly connected to the external fluid via the passages 221.

[0028] When the airflow of the twin screw compressor (90) pulsates, the cavity (220) accommodates the pulsating airflow by absorbing the energy of the airflow pulsations and by cushioning the airflow. This reduces the airflow pulsations and improves the efficiency of the twin screw compressor (90). 0) vibration and noise are reduced.

[0029] In an exemplary embodiment, cavity 220 may be a unitary cavity 220, as shown in Figure 2B. In other exemplary embodiments, cavity 220 may also be or include multiple cavities 320, as shown in Figures 3B and 3C.

[0030] In another implementation of the present disclosure, the cover 223 may not be provided on the end face 224 of the free end 205 of the slide valve body 201. As shown in FIG. 3A , holes 329 may be formed directly in and on the end face 224 of the free end 205 such that one end of each passage 321 is connected to a respective one of the cavities 320 and the other end of each passage 321 is connected to the external air flow by direct passage of the holes 329 through the end face 224 of the free end 205. Thus, the cavities 320 in the slide valve body 201 may be connected to the external air flow via the passages 321. In an exemplary embodiment, the holes 329 may have different sizes and / or shapes, and therefore the passages 321 may also have different inner diameters.

[0031] 3B and 3C are cross-sectional views of the slide valve body (201) shown in FIG. 3A taken along line BB in FIG. 3A, illustrating two exemplary embodiments in which multiple cavities (320) are provided within the slide valve body (201). By providing multiple cavities (320) within the slide valve body (201), the weight of the slide valve body (201) can be reduced and the structural reliability of the slide valve body (201) can be improved. In the exemplary embodiment shown in FIG. 3B, each cavity (320) of the multiple cavities (320) has its own passageway (321) such that each cavity (320) of the multiple cavities (320) is connected to the external air flow via its own passageway (321). In the exemplary embodiment shown in FIG. 3C, a portion or subset of the multiple cavities (320) has its own passageway (321). Other cavities, such as cavity 3201, are connected to the external fluid via multiple passages 3211.1 and 3211.2. In an exemplary embodiment, when one of cavities 320 is connected to the external fluid via multiple passages 3211.1 and 3211.2, the cavity 320 may be larger than a cavity 320 having its own single passage 321. This improves the ability of cavity 320 to absorb airflow pulsations and improves the structural reliability of slide valve body 201.

[0032] The slide valve body (201) may have different shapes depending on the type of twin-screw compressor (90) that includes the slide valve body (201). As an example 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 (408) extending away from the free end (405). The upper portion (409) of the free end extension (408) is lower than the screw rotor contact surfaces (431 and 432) of the free end (405) so that a stepped connecting surface, such as a stepped surface (410), is formed. If there is room within the twin-screw compressor (90), the free end extension (408) may extend between the wall of the cylinder of the twin-screw compressor (90) and the housing of the screw rotor (92) when the slide valve (100) moves therein. This improves the stability of the slide valve (100) during sliding, further improving the reliability of the slide valve (100).

[0033] The free end extension (408) has holes (429) on the surface of the free end extension (408). Specifically, as shown in FIG. 4A, the holes (429) may be located on the stepped surface (410) of the free end extension (408), or on the outer surface (411) of the free end extension (408). 4B shows a cross-sectional view of the embodiment of the slide valve body (401) shown in FIG. 4A taken along line CC in FIG. 4A. As shown in FIG. 4B, the free end extension (408) has an integral cavity (420) formed therein, the cavity (420) having a plurality of passages (421). The passages (421) are connected to an external fluid via holes (429), thereby fluidly connecting the cavity (420) to the external fluid. The outer surface (411) may have holes (429) or may be a closed end surface.

[0034] 3B and 3C, the free end extension 408 may have a plurality of cavities 420 formed therein, which may be connected to an external fluid via one or more passages 421. Thus, airflow pulsations occurring during operation of the twin-screw compressor 90 may be damped via the cavities 420, forming an airflow pulsation damping structure.

[0035] The slide valve body (101) of the present disclosure may be integrally formed as a one-piece structure by use of a mold, or the slide valve body may be formed by machining a conventional slide valve body. The machining method is simple and easy to implement.

[0036] While certain features of the present disclosure have been shown and described in the present discussion, various improvements and modifications may be made by those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such improvements and modifications within the spirit and scope of the present disclosure.

Claims

1. A slide valve (100) configured to adjust the load of a twin screw compressor (90), comprising: a slide valve body (201) of the slide valve (100), the slide valve body (201) having a connection end (204) and a free end (205), the connection end (204) configured to connect to a slide valve connecting rod (102) of the twin-screw compressor (90), the slide valve (100) configured to be driven by the slide valve connecting rod (102), a cavity (220) formed in the free end (205) and extending into the slide valve body (201), the slide valve (100) having at least one passage (221) configured to fluidly couple the cavity (220) to an external fluid to reduce airflow pulsation on the intake side of the twin-screw compressor (90).

2. 2. The slide valve (100) of claim 1, wherein the cavity (220) comprises a single cavity (220), and the slide valve (100) has a cover (223) on an end face (224) of the free end (205), the cover (223) having a plurality of holes (229), the plurality of holes (229) fluidly connected to the single cavity (220) to form a plurality of passages (221) including the at least one passage (221).

3. 3. The slide valve (100) of claim 2, wherein each hole (229) of the plurality of holes (229) is circular, and each hole (229) of the plurality of holes (229) is the same size.

4. 2. The slide valve (100) of claim 1, wherein the cavity (220) is one of a plurality of cavities (320) formed in the free end (205), and each cavity (320) of the plurality of cavities (320) has its own single passage (321).

5. 2. The slide valve of claim 1, wherein the cavity is one of a plurality of cavities formed in the free end, the plurality of cavities comprising a first set of cavities, each cavity of the first set of cavities having a single passage, the plurality of cavities comprising a second cavity not within the first set of cavities, the second cavity having a plurality of passages.

6. A slide valve (100) configured to adjust the load of a twin screw compressor (90), comprising: a slide valve body (401) of the slide valve (100), the slide valve body (401) having a connection end (404) and a free end (405), the connection end (404) configured to connect to a slide valve connecting rod (102) of the twin screw compressor (90) to drive the slide valve (100) in sliding motion within the twin screw compressor (90), the free end (405) of the slide valve body (401) having a free end extension (408) extending away from the free end (405), the cavity (420) formed in the free end extension (408), the slide valve (100) having a passage (421) configured to fluidly couple the cavity (420) to an external fluid to reduce airflow pulsations on the intake side of the twin screw compressor (90). Boo.

7. The slide valve (100) of claim 6, wherein the free end extension (408) is configured to provide additional support at part loads of the twin screw compressor (90).

8. 7. The slide valve (100) of claim 6, wherein the free end extension (408) has a hole (429) formed in a surface (410) of the free end extension (408), the hole (429) being connected to the cavity (420) to form the passage (421) and an additional passage (421).

9. 9. The slide valve (100) of claim 8, wherein the hole (429) is formed in an outer surface (411) of the free end extension (408).

10. 9. The slide valve (100) of claim 8, wherein an upper end (409) of the free end extension (408) is offset from an upper end (431, 432) of the free end (405) so as to form a stepped surface (410), and the hole (429) is formed in the stepped surface (410).

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