Screw compressor, control method and air conditioning apparatus

Abstract

This application discloses a screw compressor, a control method, and an air conditioning device. The screw compressor includes: a housing having a screw cavity and a slide valve cavity extending in a first direction parallel to the screw cavity; the screw cavity having a communication port communicating with the slide valve cavity on a cross section perpendicular to the first direction; a screw assembly including a male rotor disposed in the screw cavity and a female rotor disposed in the screw cavity and meshing with the male rotor; a first slide valve movably disposed in the slide valve cavity in the first direction to close a section of the communication port in the first direction, the first slide valve having an exhaust portion for discharging compressed gas at one end near the exhaust end of the screw assembly; a second slide valve disposed in the slide valve cavity and configured to move in the first direction and close a section of the communication port in the first direction; and a third slide valve disposed in the slide valve cavity and configured to move in the first direction and close a section of the communication port in the first direction.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and more specifically, to a screw compressor, a control method, and an air conditioning device. Background Technology

[0002] There are two main types of air volume regulation in screw compressors. One type regulates air volume by changing the screw speed; this method is commonly used in air conditioning units that employ variable frequency motors. The other type uses mechanisms such as slide valves. Figure 1 As shown, by changing the effective wrapping area of ​​the screw cavity on the screw (the length along the axial direction of the screw forms the effective working section length), the actual effective working section length of the screw is changed in the form of a "short plank in a barrel", thereby realizing the regulation of air volume (capacity).

[0003] The most common capacity adjustment method for screw compressors driven by fixed-frequency motors is slide valve regulation. During its movement, the slide valve acts as a short-circuit seal between the gear teeth, and its reciprocating motion achieves capacity adjustment (loading / unloading) of the compressor. These two methods can also be combined to achieve a wider range of gas volume adjustment. Adjusting the gas volume according to changes in the user's cooling (or heating) capacity needs ensures long-term stable compressor operation and avoids frequent start-stop cycles.

[0004] See Figure 1 and Figure 2 The screw compressor includes a housing 1', a screw assembly 2', and a slide valve 3'. The housing 1' has a screw cavity for accommodating the screw assembly 2' and a slide valve cavity connected to the screw cavity. The screw assembly 2' includes a male rotor disposed in the screw cavity and a female rotor disposed in the screw cavity and meshing with the male rotor. The screw cavity includes a first cavity for accommodating the male rotor and a second cavity for accommodating the female rotor, wherein the first and second cavities are connected, and the cross-sections of the first and second cavities are two intersecting circles. The slide valve cavity is disposed at the intersection of the first and second cavities and extends in a direction F parallel to the axial direction of the screw assembly; the slide valve cavity is connected to both the first and second cavities.

[0005] The slide valve 3' is movable in the slide valve cavity along direction F so that the first and second chambers are circumferentially closed, that is, the slide valve and the housing 1' form an enclosing area (the area for effectively compressing gas) adapted to the screw assembly 2'. The slide valve 3' can be movable in the slide valve cavity along direction F to change the length of the enclosing area, thereby changing the load on the screw compressor.

[0006] The screw compressor also includes a hydraulic cylinder that drives the slide valve 3' to move within the slide valve chamber. The hydraulic cylinder includes a cylinder body 5', a piston 6' that moves within the cylinder body 5', and a connecting rod 7' that connects the piston 6' and the slide valve 3'. The screw compressor also includes a control valve assembly that controls the movement of the hydraulic cylinder.

[0007] See Figure 1 One axial end of the screw assembly 2' is the intake end 2a' for introducing the gas to be compressed, and the other end is the exhaust end 2b' for discharging the compressed gas. The gas to be compressed introduced at the intake end enters the gap between the male rotor and the female rotor. As the screw assembly 2 rotates, the gas is continuously compressed, and the compressed gas is discharged from the exhaust end 2b'.

[0008] A thrust surface 4' is provided on the side of the slide valve cavity near the aforementioned suction end 2a' to restrict the movement of the slide valve. When the slide valve 3' moves to the thrust surface 4', the slide valve 3' closes the entire circumferential area of ​​the screw assembly 2' in the length direction. At this time, the effective working length of the screw assembly 1' is L1, and the screw compressor is in full-load operation.

[0009] Furthermore, an exhaust port 10' is provided at the end of the slide valve near the exhaust end 2b'. As the slide valve moves toward the intake end 2a', the exhaust port 10' moves toward the intake end 2a', and the gas compression stroke is shortened accordingly, and the gas compression ratio decreases.

[0010] See Figure 2 After the slide valve 3' moves a certain distance away from the thrust surface 4' along direction F, a bypass port 9' is formed between the thrust surface 4' and the slide valve 3'. The bypass port 9' returns part of the refrigerant drawn in at the suction end 2a' to the suction end 2a', thereby reducing the gas volume (capacity, the gas volume of the compression chamber formed by the tooth grooves of the male and female rotors, the housing, and the slide valve) of the screw compressor. At this time, the effective working length of the screw assembly 1' is L2.

[0011] Besides regulating gas volume, the slide valve 3' can also be used to adjust the compression ratio. By linearly shifting the slide valve 3', the position of the exhaust port 10' located on the slide valve 3' is changed. Generally speaking, delayed exhaust means an increase in the compression ratio, while advanced exhaust means a decrease in the compression ratio, thus achieving compression ratio adjustment. According to the operating conditions, matching an appropriate compression ratio based on different ambient temperatures and user-required temperatures can enable the compressor and unit to achieve higher energy efficiency. Summary of the Invention

[0012] The present invention aims to provide a screw compressor, a control method, and an air conditioning device that simultaneously have compression ratio regulation and gas volume regulation.

[0013] According to one aspect of the present invention, a screw compressor is provided, the screw compressor comprising: The housing has a screw cavity and a slide valve cavity extending in a first direction parallel to the screw cavity, and the screw cavity has a communication port communicating with the slide valve cavity on a cross section perpendicular to the first direction; The screw assembly includes a male rotor disposed within a screw cavity and a female rotor disposed within the screw cavity and meshing with the male rotor; The first slide valve is movably disposed in the slide valve cavity in the first direction to close a section of the communication port in the first direction. The end of the first slide valve near the exhaust end of the screw assembly is provided with an exhaust section for discharging compressed gas. The second slide valve is disposed in the slide valve cavity and located on the side of the first slide valve away from the exhaust end. The second slide valve is configured to move along the first direction and close a section of the communication port along the first direction. The third slide valve is disposed in the slide valve cavity and located on the side of the second slide valve away from the exhaust end. The third slide valve is configured to move in the first direction and close a section of the communication port in the first direction. Wherein, the length of the first slide valve along the first direction is greater than the pitch of the male rotor, and the sum of the lengths of the second slide valve and the third slide valve along the first direction is greater than the pitch of the male rotor.

[0014] In some embodiments, the screw compressor further includes a fourth slide valve disposed in a slide valve chamber and located on the side of the third slide valve away from the exhaust end. The fourth slide valve is configured to move along a first direction and close a segment of the communication port along the first direction, and the sum of the lengths of the fourth slide valve and the third slide valve along the first direction is greater than the pitch of the male rotor.

[0015] In some embodiments, the length of the fourth slide valve along the first direction is less than the pitch of the male rotor.

[0016] In some embodiments, the first slide valve, the second slide valve, the third slide valve, and the fourth slide valve move independently along a first direction.

[0017] In some embodiments, the screw compressor further includes: The first hydraulic cylinder body has its axial direction aligned with the first direction, and the first hydraulic cylinder body is located at the exhaust end of the screw assembly; The first piston is movable in the first hydraulic cylinder body in the first direction; The first piston rod is connected at one end to the first piston and at the other end to the first slide valve; The second piston is movably disposed in the first hydraulic cylinder body in the first direction and is located on the side of the first piston away from the first piston rod; The second piston rod is connected at one end to the second piston and at the other end to the second slide valve. The second piston rod passes through the first piston and the first piston rod and can move relative to the first piston and the first piston rod in a first direction.

[0018] In some embodiments, the first hydraulic cylinder body is further provided with a first hydraulic oil inlet and a second hydraulic oil inlet and a third hydraulic oil inlet and a fourth hydraulic oil inlet and a fifth hydraulic oil inlet and a sixth hydraulic oil inlet and a seventh ...

[0019] In some embodiments, the screw compressor further includes: The second hydraulic cylinder body has its axial direction aligned with the first direction, and the second hydraulic cylinder body is located at the intake end of the screw assembly; The third piston is movable in the second hydraulic cylinder. The third piston rod is connected to the third piston at one end and to the third slide valve at the other end. The fourth piston is movably disposed in the second hydraulic cylinder and located on the side of the third piston near the third piston rod. The fourth piston rod is connected to the fourth piston at one end and to the fourth slide valve at the other end. The third piston rod passes through the fourth piston and the fourth piston rod and can move relative to the fourth piston and the fourth piston rod in the first direction.

[0020] In some embodiments, the second hydraulic cylinder body is further provided with a third hydraulic oil inlet and a fourth hydraulic oil inlet and a fourth hydraulic oil inlet and a fifth hydraulic oil inlet and a sixth hydraulic oil inlet and a seventh hydraulic oil inlet and a eighth hydraulic oil inlet and a ninth hydraulic oil inlet and a eleventh ...

[0021] In some embodiments, The length of the second slide valve along the first direction is less than the pitch of the male rotor; and / or The length of the third slide valve along the first direction is less than the pitch of the male rotor.

[0022] According to another aspect of this application, a control method for the above-described screw compressor is also provided, which in some embodiments includes: Controlling the first, second, and third slide valves to sequentially engage along a first direction, and synchronously adjusting the positions of the first, second, and third slide valves along the first direction; and / or Controlling the third slide valve and the second slide valve to be spaced apart in a first direction, and controlling the first slide valve and the second slide valve to be in contact, synchronously adjusting the positions of the first slide valve and the second slide valve along the first direction; and / or The first slide valve and the second slide valve are spaced apart in the first direction, and the second slide valve and the third slide valve are engaged.

[0023] According to another aspect of this application, an air conditioning device is also provided, which includes the aforementioned screw compressor.

[0024] By applying the technical solution of this application, one or more closed communication ports of the first, second, and third slide valves, or sequentially fitted together, form a circumferentially closed compression chamber, thereby forming an effective working section. The capacity of the screw compressor can be changed by altering the length of the closed communication port.

[0025] Furthermore, by changing the distance between the first slide valve with the exhaust section and the exhaust end, the effective compression stroke of the screw assembly can be changed, thereby changing the compression ratio of the gas.

[0026] Furthermore, since the sum of the lengths of the second and third slide valves along the first direction is greater than the pitch of the male rotor, the second and third slide valves can form a circumferentially closed compression chamber when they are fitted together. Therefore, the second and third slide valves form an integral slide valve assembly when fitted together, and when the second slide valve is separated from the first slide valve, the second and third slide valves close the communication port and form an effective working section, thus forming a first-stage compression. The first slide valve forms another effective working section that performs secondary compression on the gas compressed in the effective working section formed by the second and third slide valves.

[0027] Therefore, it can be seen that the screw compressor in this embodiment can not only adjust the capacity and compression ratio, but also achieve two-stage compression of gas.

[0028] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A schematic diagram of the structure of a prior art screw compressor under the first operating condition is shown.

[0031] Figure 2 A schematic diagram of the structure of a prior art screw compressor under the second operating condition is shown.

[0032] Figure 3 A schematic diagram of the structure of a screw compressor according to an embodiment of the invention is shown.

[0033] Figure 4 A schematic diagram of the screw compressor in the first operating condition of an embodiment of the invention is shown.

[0034] Figure 5 A schematic diagram of the screw compressor in the second operating condition of an embodiment of the invention is shown.

[0035] Figure 6 A schematic diagram of the screw compressor in the third operating condition according to an embodiment of the invention is shown.

[0036] Figure 7 A schematic diagram of the screw compressor in the fourth operating condition according to an embodiment of the invention is shown.

[0037] Figure 8 A schematic diagram of the screw compressor in the fifth operating condition according to an embodiment of the invention is shown.

[0038] Figure 9 A schematic diagram of the screw compressor in the sixth operating condition according to an embodiment of the invention is shown.

[0039] Figure 10 A schematic diagram of the screw compressor in the seventh operating condition according to an embodiment of the invention is shown.

[0040] Figure 11 A schematic diagram of the screw compressor in the eighth operating condition according to an embodiment of the invention is shown.

[0041] Figure 12 A schematic diagram of the screw compressor in the ninth operating condition according to an embodiment of the invention is shown.

[0042] Figure 13 A schematic diagram of the tenth operating condition of a screw compressor according to an embodiment of the invention is shown.

[0043] In the diagram: 1. First control valve assembly; 2. First hydraulic cylinder; 3. First piston; 4. Second piston; 5. Second control valve assembly; 6. ; 7. Housing; 8. Screw assembly; 9. First slide valve; 10. Second slide valve; 11. Third slide valve; 12. Fourth slide valve; 13. Fourth control valve assembly; 14. Second hydraulic cylinder; 15. Third piston; 16. Fourth piston; 17. Third control valve assembly; 18. First piston rod; 19. Second piston rod; 20. Third piston rod; 21. Fourth piston rod. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0046] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0047] In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the allowable tolerance range. "Parallel" is not parallel in the strict sense, but within the allowable tolerance range.

[0048] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0049] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0050] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true or exist.

[0051] See Figure 3 The screw compressor in this embodiment includes a housing 7, a screw assembly 8, a first slide valve 9, a second slide valve 10, and a third slide valve 11.

[0052] The housing 7 is provided with a screw cavity and a slide valve cavity extending along a first direction F1 parallel to the screw cavity. The screw cavity has a communication port on a cross section perpendicular to the first direction F1 that connects to the slide valve cavity. The communication port extends along the first direction F1.

[0053] The screw assembly 8 includes a male rotor disposed within the screw cavity and a female rotor disposed within the screw cavity and meshing with the male rotor. The axial direction of the male rotor is parallel to the first direction F1. One end of the screw assembly 8 is an intake end for drawing in gas to be compressed, and the other end is an exhaust end for discharging compressed gas.

[0054] The first slide valve 9 is movably disposed in the slide valve cavity along the first direction F1 to close a section of the communication port along the first direction F1. An exhaust section 6 for discharging compressed gas is provided at one end of the first slide valve 9 near the exhaust end of the screw assembly 8.

[0055] The second slide valve 10 is disposed in the slide valve cavity and located on the side of the first slide valve 9 away from the exhaust end. The second slide valve 10 is configured to move along the first direction F1 and close a section of the communication port along the first direction F1.

[0056] The third slide valve 11 is disposed in the slide valve cavity and located on the side of the second slide valve 10 away from the exhaust end. The third slide valve 11 is configured to move along the first direction F1 and close the section of the communication port along the first direction F1. Among them, the length of the first slide valve 9 along the first direction F1 is greater than the pitch of the male rotor, and the sum of the lengths of the second slide valve 10 and the third slide valve 11 along the first direction F1 is greater than the pitch of the male rotor.

[0057] The screw cavity includes a first cavity and a second cavity arranged side-by-side and connected. The male rotor is rotatably disposed in the first cavity, and the female rotor is rotatably disposed in the second cavity. A compression chamber for compressed gas is formed between the tooth grooves of the male rotor and the housing 7. A compression chamber for compressed gas is formed between the tooth grooves of the female rotor and the housing 7.

[0058] The intersection of the first cavity and the second cavity forms the aforementioned communication port, and the first slide valve 9, the second slide valve 10 and the third slide valve 11 are sequentially arranged in the slide valve cavity.

[0059] One or more of the first slide valve 9, the second slide valve 10, and the third slide valve 11, in sequence, form a closed communication port to create a circumferentially closed compression chamber, thereby forming an effective working section. The capacity of the screw compressor can be changed by altering the length of the closed communication port (the length of the effective working section). Two or three adjacent slide valves of the first slide valve 9, the second slide valve 10, and the third slide valve 11 are sequentially fitted together to form an integral slide valve group.

[0060] Furthermore, by changing the distance between the first slide valve 9 with the exhaust section 6 and the exhaust end, the stroke of the screw assembly 8 that effectively compresses the gas can be changed, thereby changing the compression ratio of the gas.

[0061] Furthermore, since the sum of the lengths of the second slide valve 10 and the third slide valve 11 along the first direction F1 is greater than the pitch of the male rotor, the second slide valve 10 and the third slide valve 11 can form a circumferentially closed compression chamber when they are fitted together. Therefore, the second slide valve 10 and the third slide valve 11 are fitted together to form an integral slide valve assembly, and when the second slide valve 10 is separated from the first slide valve 9, the second slide valve 10 and the third slide valve 11 close the communication port and form an effective working section, thereby forming a first-stage compression. The first slide valve 9 forms another effective working section for secondary compression of the gas compressed in the effective working section formed by the second slide valve 10 and the third slide valve 11.

[0062] Therefore, it can be seen that the screw compressor in this embodiment can not only adjust the capacity and compression ratio, but also achieve two-stage compression of gas.

[0063] See Figure 3 The valve chamber protrudes from the screw chamber near the intake end along the first direction F1. A portion of the integral valve assembly can be moved to the protruding part of the valve chamber to increase the adjustment range of the compression ratio.

[0064] See Figure 3 The screw compressor also includes a fourth slide valve 12, which is disposed in the slide valve cavity and located on the side of the third slide valve 11 away from the exhaust end. The fourth slide valve 12 is configured to move along the first direction F1 and close a section of the communication port along the first direction F1, and the sum of the lengths of the fourth slide valve 12 and the third slide valve 11 along the first direction F1 is greater than the pitch of the male rotor.

[0065] By increasing the number of slide valves, two, three, or four adjacent slide valves can form the aforementioned integral slide valve group, thereby obtaining effective working sections of different lengths and expanding the capacity adjustment range of the screw compressor.

[0066] In some embodiments, the length of the second slide valve 10 along the first direction F1 is less than the pitch of the male rotor; and / or, the length of the third slide valve 11 along the first direction F1 is less than the pitch of the male rotor; and / or, the length of the fourth slide valve 12 along the first direction F1 is less than the pitch of the male rotor.

[0067] Because the lengths of the fourth slide valve 12, the third slide valve 11, and the second slide valve 10 are all less than the pitch of the male rotor, none of these valves can independently form an effective working section. If any one of these valves could independently form an effective working section, a certain air capacity would be provided between the valve, the housing, and the screw assembly 8, thus reducing the number of valve combinations. This facilitates obtaining more effective working sections of varying lengths. The pitch of the male rotor is equal to the pitch of the female rotor.

[0068] The first slide valve 9, the second slide valve 10, the third slide valve 11, and the fourth slide valve 12 move independently along the first direction F1. These four slide valves move independently and can be arbitrarily combined into slide valve groups of different lengths as needed, enabling more levels of capacity and compression ratio adjustment. Simultaneously, they can flexibly achieve single-stage compression, two-stage compression, and even three-stage compression modes, greatly improving the adaptability of the screw compressor to various operating conditions.

[0069] The screw compressor also includes a first hydraulic cylinder 2, a first piston 3, a second piston 4, a first piston rod 18, and a second piston rod 19.

[0070] The axial direction of the first hydraulic cylinder 2 is aligned with the first direction F1, and the first hydraulic cylinder 2 is located at the exhaust end of the screw assembly 8. The first piston 3 is movably disposed in the first hydraulic cylinder 2 along the first direction F1. One end of the first piston rod 18 is connected to the first piston 3, and the other end is connected to the first slide valve 9.

[0071] The second piston 4 is movably disposed in the first hydraulic cylinder 2 along the first direction F1 and is located on the side of the first piston 3 away from the first piston rod 18. One end of the second piston rod 19 is connected to the second piston 4, and the other end is connected to the second slide valve 10. The second piston rod 19 passes through the first piston 3 and the first piston rod 18 and is movable relative to the first piston 3 and the first piston rod 18 along the first direction F1.

[0072] By setting the first hydraulic cylinder 2 at the exhaust end and adopting a through-type piston rod structure, the first piston 3 and the second piston 4 can independently drive the first slide valve 9 and the second slide valve 10 to move within the same hydraulic cylinder. The structure is compact, saves axial space, and ensures that the stroke control of the two slide valves does not interfere with each other, resulting in precise and reliable control.

[0073] In some embodiments, the first hydraulic cylinder body 2 is further provided with a first hydraulic oil inlet and a second hydraulic oil inlet and a third hydraulic oil inlet and a fourth hydraulic oil inlet and a fifth hydraulic oil inlet and a sixth hydraulic oil inlet and a seventh hydraulic oil inlet and a stern side of the second piston 4 away from the first piston 3, and the second hydraulic oil inlet and a stern hydraulic oil inlet and a stern side of the first piston 3 and the second piston 4.

[0074] By setting first and second hydraulic oil inlets and outlets on the first hydraulic cylinder body 2 respectively, the oil pressure on both sides of the first piston 3 and the second piston 4 can be controlled independently, thereby achieving precise hydraulic adjustment of the positions of the first slide valve 9 and the second slide valve 10, with fast response speed and high control stability.

[0075] The screw compressor also includes a second hydraulic cylinder 14, a third piston 15, a third piston rod 20, a fourth piston 16, and a fourth piston rod 21.

[0076] The axial direction of the second hydraulic cylinder body 14 is consistent with the first direction F1, and the second hydraulic cylinder body 14 is located at the intake end of the screw assembly 8.

[0077] The third piston 15 is movably disposed in the second hydraulic cylinder 14 along the first direction F1. One end of the third piston rod 20 is connected to the third piston 15, and the other end is connected to the third slide valve 11.

[0078] The fourth piston 16 is movably disposed in the second hydraulic cylinder 14 along the first direction F1 and is located on the side of the third piston 15 near the third piston rod 20. One end of the fourth piston rod 21 is connected to the fourth piston 16, and the other end is connected to the fourth slide valve 12. The third piston rod 20 passes through the fourth piston 16 and the fourth piston rod 21 and is movable relative to the fourth piston 16 and the fourth piston rod 21 along the first direction F1.

[0079] By setting a second hydraulic cylinder 14 at the intake end and using a through-type piston rod structure to drive the third slide valve 11 and the fourth slide valve 12, different slide valves can be controlled from the intake end and the exhaust end respectively, which increases the flexibility and reliability of control.

[0080] In some embodiments, the second hydraulic cylinder body 14 is further provided with a third hydraulic oil inlet and a fourth hydraulic oil inlet and a fourth hydraulic oil inlet and a fifth hydraulic oil inlet and a sixth hydraulic oil inlet and a seventh hydraulic oil inlet and a stern. The third hydraulic oil inlet and a stern are located on the side of the third piston 15 away from the fourth piston 16, and the fourth hydraulic oil inlet and a stern ...

[0081] By setting two independent hydraulic oil inlets and outlets on the second hydraulic cylinder, the pressure of the third piston 15 and the fourth piston 16 can be controlled independently, thereby precisely adjusting the position of the third slide valve 11 and the fourth slide valve 12, further improving the performance of multi-stage compression and capacity regulation.

[0082] Specifically, this embodiment provides a screw compressor with combined compression ratio and capacity adjustment function. Its core structure is a slide valve group, which includes multiple slide valves and is driven by their respective pistons.

[0083] As attached Figure 3 As shown, in this embodiment, the first control valve group 1, the second control valve group 5, the third control valve group 17, and the fourth control valve group 13 of the screw compressor control the entry and exit of hydraulic oil in four locations within the hydraulic cylinder, thereby driving the first piston 3, the second piston 4, the third piston 15, and the fourth piston 16 to reciprocate. Finally, the four pistons drive the first slide valve 9, the second slide valve 10, the third slide valve 11, and the fourth slide valve 12 to move as needed, thus forming a complete slide valve group. Taking the movement of the third slide valve 11 and the fourth slide valve 12 as an example: the third control valve group 17 controls the hydraulic oil to enter the hydraulic cylinder area to the left of the third slide valve 11, while the fourth control valve group 13 controls the hydraulic oil to be discharged from the hydraulic cylinder area to the right of the third slide valve 11. At this time, the third slide valve 11 moves to the exhaust end (to the right). The movement of the fourth slide valve 12 is relatively simple; the fourth control valve group 13 only needs to control the hydraulic oil to enter and exit the hydraulic cylinder area to the right of the third slide valve 11 to achieve the left and right translation of the fourth slide valve 12 (moving along the first direction F1).

[0084] The compressor screw assembly 8 periodically completes the intake, compression, and exhaust processes during rotation. The screw assembly 8 is surrounded by the housing 7 and the slide valve assembly. With the assistance of the housing 7 and the slide valves, the gas is confined within the rotor tooth grooves to complete the compression process. (See attached...) Figure 1 and appendix Figure 2 Under full load, the suction end of the screw assembly 8 is completely surrounded, so that the suction volume of the screw assembly 8 is at its maximum when the suction ends and compression begins. At this time, the compressor is in full load state, that is, the capacity is 100%.

[0085] As attached Figure 4 As shown, the four slide valves are tightly fitted, indicating that the compressor is at full load.

[0086] See Figure 5 The fourth control valve group 13 opens the unloading solenoid valve, while the other three control valve groups remain closed. At this time, in the four hydraulic cylinder areas on both sides of the third piston 15 and the second piston 4, only the hydraulic oil in the hydraulic cylinder area on the left side of the fourth piston 16 is released. Ultimately, only the fourth piston 16 and the fourth slide valve 12 move towards the intake end (to the left). At this point, the intake end of the screw assembly 8 is no longer completely surrounded. When the intake volume of the screw assembly 8 is at its maximum, the intake has not yet ended. Instead, the intake ends and compression begins after the intake volume of the screw assembly 8 decreases from its maximum for a period of time. This creates a state with a relatively smaller load compared to the full load state, i.e., a first load state less than full load.

[0087] See Figure 6 The third control valve group 17 opens the unloading solenoid valve to release the hydraulic oil in the hydraulic cylinder area to the left of the third piston 15. At the same time, the fourth control valve group 13 opens the supply solenoid valve to replenish an equal amount of hydraulic oil to the hydraulic cylinder area to the right of the third piston 15, ultimately causing the third piston 15 and the third slide valve 11 to move towards the intake end. At this time, the intake volume of the screw assembly 8 reaches its maximum, and the time for the intake to end is longer. The amount of intake gas is reduced more before the compression begins, thus obtaining a second load state with a lower load than the first load state.

[0088] See Figure 7 The first control valve group 1 opens the oil supply solenoid valve to supply oil to the hydraulic cylinder area on the right side of the second piston 4. At the same time, the second control valve group 5 opens the oil discharge solenoid valve to release the hydraulic oil in the hydraulic cylinder area on the left side of the second piston 4, ultimately causing the second piston 4 and the second slide valve 10 to move towards the suction end. At this time, the suction volume of the screw assembly 8 reaches its maximum, and the time for delaying the end of suction reaches its longest, thus obtaining the third load with the minimum load.

[0089] It should be noted that when adjusting the third load state, the second slide valve 10 moves towards the intake end and disengages from the first slide valve 9. At the same time, the second slide valve 10 should not be in contact with the third slide valve 11. Otherwise, if the second slide valve 10, the third slide valve 11, and the fourth slide valve 12 are in contact, the length will be too long, forming a closed section, i.e., the compression stage, and ultimately forming a two-stage compression process, i.e., two-stage compression.

[0090] As can be seen above, the control valve assembly can coordinate and control the piston and spool valve movement in any desired manner. Therefore, the on / off states of the control valve assembly will not be described in detail hereafter, but only the results of the spool valve action will be described.

[0091] As attached Figure 8 As shown, all the slide valves are fitted together to form an integral slide valve group. When the compressor is running at full load, it stops at a certain position to obtain the first compression ratio state under full load conditions. In the figure, under the first compression ratio state under full load conditions, the position of all slide valves is close to the rightmost limit, which can be regarded as close to the highest compression ratio state.

[0092] See Figure 9 The four slide valves remain in contact and move as a whole towards the intake end to obtain the second compression ratio under full load conditions. The second compression ratio is lower than the first compression ratio under full load conditions, and the compression ratio decreases as it moves to the left.

[0093] See Figure 10 When the fourth slide valve 12 disengages from the other slide valves, the compressor enters a partial load state. At this time, the left end face of the third slide valve 11 serves as the actual starting point for the compressor to start compression after the intake ends, and the current state is the first compression ratio under partial load conditions.

[0094] See Figure 11 The third slide valve 11 moves towards the intake end, disengaging from the first slide valve 9 and the second slide valve 10. Simultaneously, the first slide valve 9 and the second slide valve 10 remain in contact and move together towards the intake end until the left end face of the second slide valve 10 reaches the original position of the left end face of the third slide valve 11, thus achieving the same partial load condition. At this point, the exhaust section 6 on the first slide valve 9 is positioned to the left compared to the exhaust section 6 under the first compression ratio condition of partial load. This indicates a shorter compressor compression process and earlier exhaust, i.e., a second compression ratio condition under partial load with a lower compression ratio. This achieves compression ratio adjustment under partial load.

[0095] As attached Figure 12 As shown, the second slide valve 10, the third slide valve 11, and the fourth slide valve 12 are fitted together to form a closed section, i.e., the compression stage. The first slide valve 9, which is relatively long, is detached and located independently in a certain place, forming another closed compression section. Thus, a two-stage compression state is formed.

[0096] See Figure 13 The second slide valve 10, the third slide valve 11, and the fourth slide valve 12 remain in contact and move towards the intake end to obtain a smaller exhaust volume (partial load). At the same time, the first slide valve 9 moves towards the exhaust end, also forming a smaller exhaust volume (partial load), thus achieving a two-stage compression state. The movement of the second slide valve 10, the third slide valve 11, and the fourth slide valve 12 towards the intake end and the movement of the first slide valve 9 towards the exhaust end are relatively independent. If the movement results in a proportional reduction in load, it can be regarded as a simple two-stage compression capacity adjustment (partial load adjustment). If the two load reductions are not proportional, the intermediate pressure ratio and the final compression ratio of the entire compressor are also changed accordingly, thus achieving part-load compression ratio adjustment of the two-stage compression.

[0097] The length of the slide valve assembly determines the formation of the above states. In practical applications, specific values ​​are selected in conjunction with the parameters of the screw assembly 8. The core lies in the relationship between the individual length of the slide valve, the total length of the slide valves after various combinations, and the length of the closed compression section of the complete screw assembly 8.

[0098] The above describes the technical solution of this application using four slide valves as an example. Of course, the number of slide valves can be increased (more slide valves in addition to the fourth slide valve 12 as described in claim 2) to obtain a richer variety of states and a wider adjustment range. However, in practical applications, four slide valves are the solution with the lowest implementation difficulty and the highest reliability.

[0099] According to another aspect of the present invention, a control method for the above-described screw compressor is also provided.

[0100] The control method includes: controlling the first slide valve 9, the second slide valve 10, and the third slide valve 11 to sequentially engage along the first direction F1, and synchronously adjusting the positions of the first slide valve 9, the second slide valve 10, and the third slide valve 11 along the first direction F1 to adjust the compression ratio. (See [reference]). Figure 10 .

[0101] The control method also includes controlling the third slide valve 11 and the second slide valve 10 to be spaced apart in the first direction F1, thereby changing the length of the effective working section. Controlling the first slide valve 9 and the second slide valve 10 to be in contact, and synchronously adjusting the positions of the first slide valve 9 and the second slide valve 10 along the first direction F1, thereby adjusting the compression ratio, see [link to relevant documentation]. Figure 11 .

[0102] The control method also includes controlling the first slide valve 9 and the second slide valve 10 to be spaced apart in the first direction F1, and the second slide valve 10 and the third slide valve 11 to be in contact with each other, thereby forming a two-stage compression, see [link to relevant documentation]. Figure 13 .

[0103] According to another aspect of the present invention, an air conditioning device is also provided, which includes the screw compressor described above.

[0104] The above are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A screw compressor, characterized in that include: The housing (7) is provided with a screw cavity and a slide valve cavity extending in a first direction (F1) parallel to the screw cavity, and the screw cavity has a communication port communicating with the slide valve cavity on a cross section perpendicular to the first direction (F1); The screw assembly (8) includes a male rotor disposed in the screw cavity and a female rotor disposed in the screw cavity and meshing with the male rotor; The first slide valve (9) is movably disposed in the slide valve cavity along the first direction (F1) to close a section of the communication port along the first direction (F1). The first slide valve (9) is provided with an exhaust section (6) for discharging compressed gas at one end near the exhaust end of the screw assembly (8). The second slide valve (10) is disposed in the slide valve cavity and located on the side of the first slide valve (9) away from the exhaust end. The second slide valve (10) is configured to move along the first direction (F1) and close a section of the communication port along the first direction (F1). A third slide valve (11) is disposed in the slide valve cavity and located on the side of the second slide valve (10) away from the exhaust end. The third slide valve (11) is configured to move along the first direction (F1) and close a section of the communication port along the first direction (F1). Wherein, the length of the first slide valve (9) along the first direction (F1) is greater than the pitch of the male rotor, and the sum of the lengths of the second slide valve (10) and the third slide valve (11) along the first direction (F1) is greater than the pitch of the male rotor.

2. Screw compressor according to claim 1, characterized in that It also includes a fourth slide valve (12), which is disposed in the slide valve cavity and located on the side of the third slide valve (11) away from the exhaust end. The fourth slide valve (12) is configured to move along the first direction (F1) and close a section of the communication port along the first direction (F1). The sum of the lengths of the fourth slide valve (12) and the third slide valve (11) along the first direction (F1) is greater than the pitch of the male rotor.

3. Screw compressor according to claim 2, characterized in that The length of the fourth slide valve (12) along the first direction (F1) is less than the pitch of the male rotor.

4. Screw compressor according to claim 2, characterized in that The first slide valve (9), the second slide valve (10), the third slide valve (11) and the fourth slide valve (12) move independently along the first direction (F1).

5. Screw compressor according to claim 1, characterized in that Also includes: The first hydraulic cylinder (2) has its axial direction aligned with the first direction (F1), and the first hydraulic cylinder (2) is disposed at the exhaust end of the screw assembly (8); The first piston (3) is movably disposed in the first hydraulic cylinder (2) along the first direction (F1); The first piston rod (18) is connected at one end to the first piston (3) and at the other end to the first slide valve (9); The second piston (4) is movably disposed in the first hydraulic cylinder (2) along the first direction (F1) and located on the side of the first piston (3) away from the first piston rod (18); The second piston rod (19) is connected at one end to the second piston (4) and at the other end to the second slide valve (10). The second piston rod (19) passes through the first piston (3) and the first piston rod (18) and can move relative to the first piston (3) and the first piston rod (18) in the first direction (F1).

6. Screw compressor according to claim 5, characterized in that The first hydraulic cylinder body (2) is also provided with a first hydraulic oil inlet and a second hydraulic oil inlet and a third hydraulic oil inlet and a fourth hydraulic oil inlet and a fifth hydraulic oil inlet and a sixth hydraulic oil inlet and a seventh ...

7. The screw compressor according to claim 2, characterized in that, Also includes: The second hydraulic cylinder (14) has its axial direction aligned with the first direction (F1), and the second hydraulic cylinder (14) is located at the intake end of the screw assembly (8); The third piston (15) is movably disposed in the second hydraulic cylinder (14) along the first direction (F1); The third piston rod (20) is connected at one end to the third piston (15) and at the other end to the third slide valve (11); The fourth piston (16) is movably disposed in the second hydraulic cylinder (14) along the first direction (F1) and is located on the side of the third piston (15) near the third piston rod (20); The fourth piston rod (21) is connected at one end to the fourth piston (16) and at the other end to the fourth slide valve (12). The third piston rod (20) passes through the fourth piston (16) and the fourth piston rod (21) and can move relative to the fourth piston (16) and the fourth piston rod (21) in the first direction (F1).

8. The screw compressor according to claim 7, characterized in that, The second hydraulic cylinder body (14) is also provided with a third hydraulic oil inlet and a fourth hydraulic oil inlet and a fourth hydraulic oil inlet and a fifth hydraulic oil inlet and a sixth hydraulic oil inlet and a seventh hydraulic oil inlet and a eighth hydraulic oil inlet and a ninth hydraulic oil inlet and a eleventh ...

9. The screw compressor according to claim 1, characterized in that, The length of the second slide valve (10) along the first direction (F1) is less than the pitch of the male rotor; and / or The length of the third slide valve (11) along the first direction (F1) is less than the pitch of the male rotor.

10. A control method for a screw compressor according to any one of claims 1 to 9, characterized in that, include: Control the first slide valve (9), the second slide valve (10), and the third slide valve (11) to sequentially engage along the first direction (F1), and synchronously adjust the positions of the first slide valve (9), the second slide valve (10), and the third slide valve (11) along the first direction (F1); and / or Controlling the third slide valve (11) and the second slide valve (10) to be spaced apart in the first direction (F1), and controlling the first slide valve (9) and the second slide valve (10) to be in contact, synchronously adjusting the positions of the first slide valve (9) and the second slide valve (10) along the first direction (F1); and / or The first slide valve (9) and the second slide valve (10) are positioned at intervals in the first direction (F1), and the second slide valve (10) and the third slide valve (11) are positioned in contact.

11. An air conditioning device, characterized in that, The screw compressor includes any one of claims 1 to 8.

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