Slide valve assembly and two-stage screw compressor

Abstract

The present invention provides a slide valve assembly and a two-stage screw compressor. The slide valve assembly includes a first slide valve; a second slide valve; and a piston, wherein both the first slide valve and the second slide valve are connected to the piston, and the piston can drive the first slide valve and the second slide valve to move simultaneously; the cross-sectional area of the piston is greater than or equal to the sum of the cross-sectional areas of the first slide valve and the second slide valve. The slide valve assembly and the two-stage screw compressor provided by the present invention use the same piston to drive the first slide valve and the second slide valve to move synchronously, and the capacity adjustment of the high and low pressure stages of the compressor is completely synchronous, ensuring that the single-stage two-stage compressor has the same capacity adjustment stability as a conventional single-stage compressor; and by using a piston with a relatively large cross-sectional area, it can be ensured that the driving force provided by the piston can ensure the reliable movement of the first slide valve and the second slide valve.

Description

Technical Field

[0001] The present invention relates to the technical field of compression equipment, in particular to a slide valve assembly and a two-stage screw compressor. Background Art

[0002] At present, the most common capacity regulation method for a refrigeration screw compressor driven by a fixed-frequency motor is slide valve regulation. During the movement of the slide valve, it becomes the short board of the closed tooth volume. The reciprocating movement of the slide valve realizes the capacity regulation (loading / unloading) of the compressor. For a single-stage two-stage compressor driven by a fixed-frequency motor, since there are two sets of series-connected rotor pairs, if fully matched capacity regulation is required, two complete slide valve actuators are needed for regulation, which will increase the size, number of parts, and failure rate of the compressor. Two sets of control solenoid valve groups will also increase the control complexity and control cost for the compressor user. At the same time, in actual engineering applications, due to differences in oil pressure, friction, and sealing performance, it is difficult to ensure that the capacity regulation between the high-pressure and low-pressure stage rotor groups is completely synchronous, resulting in unreliable operation of the compressor. Summary of the Invention

[0003] In order to solve the technical problem that the unreliable movement of the slide valve in the prior art causes unreliable operation of the compressor, a slide valve assembly and a two-stage screw compressor that simultaneously control the second slide valve and the first slide valve are provided.

[0004] A slide valve assembly includes:

[0005] A first slide valve disposed in the low-pressure stage of the compressor;

[0006] A second slide valve disposed in the high-pressure stage of the compressor;

[0007] A piston, both the first slide valve and the second slide valve are connected to the piston, and the piston can drive the first slide valve and the second slide valve to move simultaneously;

[0008] The cross-sectional area of the piston is greater than or equal to the sum of the cross-sectional areas of the first slide valve and the second slide valve.

[0009] The slide valve assembly further includes a slide valve connecting rod. One end of the slide valve connecting rod is connected to the first slide valve, and the other end of the slide valve connecting rod is connected to the second slide valve. The piston is connected to the first slide valve or the second slide valve or the slide valve connecting rod.

[0010] The axis of the piston is collinear with the axis of the slide valve connecting rod.

[0011] The slide valve assembly further includes a cylinder block. The piston is movably disposed in the cylinder block, and the cylinder block is communicated with a pressure supply mechanism.

[0012] The slide valve assembly further includes a control mechanism, and the cylinder block is communicated with the pressure supply mechanism through the control mechanism.

[0013] The piston includes a first piston and a second piston which are connected to each other, and the sum of the cross-sectional areas of the first piston and the second piston is greater than or equal to the sum of the cross-sectional areas of the first slide valve and the second slide valve.

[0014] The first piston is movably arranged in a first cylinder block, the second piston is movably arranged in a second cylinder block, and both the first cylinder block and the second cylinder block are communicated with the pressure supply mechanism.

[0015] The slide valve assembly includes a cylinder block and a partition plate. The partition plate is arranged in the cylinder block, and the partition plate divides the cylinder block into the first cylinder block and the second cylinder block.

[0016] The axis of the first piston and the axis of the second piston are collinear.

[0017] A two-stage screw compressor includes the above-mentioned slide valve assembly.

[0018] For the slide valve assembly and the two-stage screw compressor provided by the present invention, the same piston is used to drive the first slide valve and the second slide valve to move synchronously, and the capacity regulation of the high and low pressure stages of the compressor is completely synchronous, ensuring that the single-stage two-stage compressor has the same capacity regulation stability as the conventional single-stage compressor; and by using a piston with a larger cross-sectional area, it can be ensured that the driving force provided by the piston can ensure the reliable movement of the first slide valve and the second slide valve. Using the same piston can control a set of control mechanisms, avoiding the problem of complex control methods of the single-stage two-stage compressor due to the setting of two sets of control mechanisms in the prior art, and making the structure of the compressor simple and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of the slide valve assembly provided by an embodiment of the present invention;

[0020] Figure 2 It is another schematic structural diagram of the slide valve assembly provided by an embodiment of the present invention;

[0021] Figure 3 It is another schematic structural diagram of the slide valve assembly provided by an embodiment of the present invention;

[0022] Figure 4 It is another schematic structural diagram of the slide valve assembly provided by an embodiment of the present invention;

[0023] In the figure:

[0024] 1. First slide valve; 2. Second slide valve; 3. Piston; 4. Slide valve connecting rod; 5. Cylinder block; 31. First piston; 32. Second piston; 6. Partition plate; 53. First cylinder block; 54. Second cylinder block. Detailed implementation mode

[0025] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0026] As Figures 1 to 4 shown in the slide valve assembly, including: a first slide valve 1 arranged at the low-pressure stage of the compressor; a second slide valve 2 arranged at the high-pressure stage of the compressor; a piston 3, both the first slide valve 1 and the second slide valve 2 are connected to the piston 3, and the piston 3 can drive the first slide valve 1 and the second slide valve 2 to move simultaneously; the cross-sectional area of the piston 3 is greater than or equal to the sum of the cross-sectional areas of the first slide valve 1 and the second slide valve 2. Among them, the first slide valve 1 cooperates with the low-pressure stage rotor pair to realize the loading and unloading of the low-pressure stage of the compressor, and the second slide valve 2 cooperates with the high-pressure stage rotor pair to realize the loading and unloading of the high-pressure stage of the compressor. Using the same piston 3 to drive the first slide valve 1 and the second slide valve 2 to move synchronously, the capacity adjustment of the high and low pressure stages of the compressor is completely synchronous, ensuring that the single-stage two-stage compressor has the same capacity adjustment stability as the conventional single-stage compressor; and using the piston 3 with a larger cross-sectional area, it can ensure that the driving force provided by the piston 3 can ensure the reliable movement of the first slide valve 1 and the second slide valve 2. Using the same piston 3 can control a set of control mechanisms, avoiding the problem that the control method of the single-stage two-stage compressor is complicated due to the setting of two sets of control mechanisms in the prior art, making the structure of the compressor simple and reliable. In Figure 1 and Figure 3 the shape of the cross-hatching on the first slide valve 1 is the cross-sectional shape of the first slide valve 1, and the shape of the cross-hatching on the second slide valve 2 is the cross-sectional shape of the second slide valve 2.

[0027] Specifically, the slide valve assembly further includes a slide valve connecting rod 4, one end of the slide valve connecting rod 4 is connected to the first slide valve 1, the other end of the slide valve connecting rod 4 is connected to the second slide valve 2, and the piston 3 is connected to the first slide valve 1 or the second slide valve 2 or the slide valve connecting rod 4. Using the slide valve connecting rod 4 to connect the first slide valve 1 and the second slide valve 2 into a whole, the piston 3 can drive the movement simultaneously when connected to any component of this whole.

[0028] Preferably, the axis of the piston 3 is collinear with the axis of the slide valve connecting rod 4. This can prevent the driving force of the piston 3 from causing the first slide valve 1 or the second slide valve 2 to shift, ensuring the reliable movement of the first slide valve 1 and the second slide valve 2, and further ensuring the reliable loading and unloading of the compressor.

[0029] The slide valve assembly further includes a cylinder block 5. The piston 3 is movably disposed within the cylinder block 5, and the cylinder block 5 is in communication with a pressure supply mechanism. By feeding or discharging pressurized liquid into the cylinder block 5, the movement of the piston 3 is achieved, thereby driving the movement of the first slide valve 1 and the second slide valve 2.

[0030] The slide valve assembly further includes a control mechanism. The cylinder block 5 is in communication with the pressure supply mechanism through the control mechanism. By using the same control mechanism, the synchronous movement of the first slide valve 1 and the second slide valve 2 can be controlled simultaneously, avoiding problems such as complex control and inaccurate synchronization that may occur when using two sets of control mechanisms for separate control, effectively simplifying the structure of the compressor and improving the reliability of the compressor operation. As Figure 1 shown, the control mechanism includes an electromagnetic assembly. The electromagnetic assembly includes a first solenoid valve and a second solenoid valve. The first solenoid valve controls the injection of pressurized liquid into the cylinder block 5, and the second solenoid valve controls the discharge of the pressurized liquid from the cylinder block 5 to the outside.

[0031] As an implementation, when the cross-sectional area of the piston 3 is too large, it will result in a large diameter of the piston 3, making it difficult to arrange in space. Therefore, as Figure 3 and Figure 4 shown, the piston 3 includes a first piston 31 and a second piston 32 that are connected to each other, and the sum of the cross-sectional area of the first piston 31 and the cross-sectional area of the second piston 32 is greater than or equal to the sum of the cross-sectional area of the first slide valve 1 and the cross-sectional area of the second slide valve 2. The first piston 31 and the second piston 32 are used to reduce the required diameter of the piston 3, thereby facilitating the arrangement of the piston 3 and reducing the space occupied by the piston 3. Moreover, since the first piston 31 and the second piston 32 are connected, the first piston 31 and the second piston 32 can move synchronously, and can simultaneously generate a driving force on the first slide valve 1 and the second slide valve 2, achieving the same driving effect as a piston 3 with a larger diameter.

[0032] Wherein, the first piston 31 is movably arranged in the first cylinder block 53, the second piston 32 is movably arranged in the second cylinder block 54, and both the first cylinder block 53 and the second cylinder block 54 are communicated with a pressure supply mechanism. When the first slide valve 1 and the second slide valve 2 need to be loaded, the pressure supply mechanism simultaneously supplies pressurized liquid to the first cylinder block 53 and the second cylinder block 54. At this time, the pressurized liquid in the first cylinder block 53 presses the first piston 31 to move the first piston 31, and the movement of the first piston 31 generates a first driving force. At the same time, the pressurized liquid in the second cylinder block 54 presses the second piston 32 to move the second piston 32, and the movement of the second piston 32 generates a second driving force. The directions of the first driving force and the second driving force are the same. Therefore, the resultant force of the first driving force and the second driving force is greater than the first driving force or the second driving force, thus ensuring reliable driving of the first slide valve 1 and the second slide valve 2.

[0033] The slide valve assembly includes a cylinder block 5 and a partition plate 6. The partition plate 6 is arranged in the cylinder block 5, and the partition plate 6 divides the cylinder block 5 into the first cylinder block 53 and the second cylinder block 54.

[0034] A communication hole is provided on the partition plate 6. The slide valve assembly further includes a piston connecting rod. The piston connecting rod is connected to the first piston 31 and the second piston 32 through the communication hole, and a sealing structure is also provided at the communication hole to ensure relative sealing between the first back pressure chamber 56 and the second pressure chamber 57, thereby ensuring reliable movement of the first piston 31 and the second piston 32, and further ensuring reliable loading and unloading of the slide valve assembly.

[0035] The axes of the first piston 31 and the second piston 32 are collinear. This avoids the problem that the direction of the resultant force is inaccurate due to a deviation between the first driving force generated by the first piston 31 and the second driving force generated by the second piston 32, and ensures that the first slide valve 1 and the second slide valve 2 can move in the set direction.

[0036] A two-stage screw compressor includes the above-mentioned slide valve assembly.

[0037] The above embodiments only represent several implementation manners of the present invention, and the description thereof is relatively specific and detailed. However, it should not be construed as a limitation to the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. A spool valve assembly, characterized in that: Comprising: A first slide valve (1), arranged in the low-pressure stage of the compressor; A second slide valve (2), arranged in the high-pressure stage of the compressor; A piston (3), both the first slide valve (1) and the second slide valve (2) are connected to the piston (3), and the piston (3) can drive the first slide valve (1) and the second slide valve (2) to move simultaneously; The cross-sectional area of the piston (3) is greater than or equal to the sum of the cross-sectional areas of the first slide valve (1) and the second slide valve (2); The slide valve assembly further includes a slide valve connecting rod (4), one end of the slide valve connecting rod (4) is connected to the first slide valve (1), the other end of the slide valve connecting rod (4) is connected to the second slide valve (2), and the piston (3) is connected to the first slide valve (1) or the second slide valve (2); The axis of the piston (3) is collinear with the axis of the slide valve connecting rod (4).

2. The spool valve assembly according to claim 1, wherein: The slide valve assembly further includes a cylinder block (5), the piston (3) is movably arranged in the cylinder block (5), and the cylinder block (5) is communicated with a pressure supply mechanism.

3. The spool valve assembly according to claim 2, wherein: The slide valve assembly further includes a control mechanism, and the cylinder block (5) is communicated with the pressure supply mechanism through the control mechanism.

4. The spool valve assembly according to claim 1, characterized in that: The piston (3) includes a first piston (31) and a second piston (32) connected to each other, and the sum of the cross-sectional areas of the first piston (31) and the second piston (32) is greater than or equal to the sum of the cross-sectional areas of the first slide valve (1) and the second slide valve (2).

5. The spool valve assembly according to claim 4, wherein: The first piston (31) is movably arranged in a first cylinder block (53), the second piston (32) is movably arranged in a second cylinder block (54), and both the first cylinder block (53) and the second cylinder block (54) are communicated with the pressure supply mechanism.

6. The spool valve assembly according to claim 5, characterized in that: The slide valve assembly includes a cylinder block (5) and a partition plate (6), the partition plate (6) is arranged in the cylinder block (5), and the partition plate (6) divides the cylinder block (5) into the first cylinder block (53) and the second cylinder block (54).

7. The spool valve assembly according to claim 4, characterized in that: The axis of the first piston (31) is collinear with the axis of the second piston (32).

8. A two-stage screw compressor, characterized in that: Comprising the slide valve assembly according to any one of claims 1 to 7.

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