A single-screw fixed-frequency compressor structure with high partial load performance

Abstract

This utility model discloses a single-screw fixed-frequency compressor structure with high partial load performance. The compressor has an exhaust side and an intake side, and includes a body and a slide valve. The body is provided with a screw engagement pair and a moving channel. The body has a compression area for accommodating the screw engagement pair to compress gas. The compression area is configured with a full-load section and a de-load section according to the position of the slide valve, and is connected to the moving channel. This utility model can quickly solve the problem of partial load over-compression through the cooperation of the slide valve, bypass port and compression ratio profile. At the same time, when solving the problem, it can also realize stepless adjustment of compression ratio volume to meet different operating conditions.

Description

Technical Field

[0001] This utility model relates to the field of compressor technology, specifically to a single-screw fixed-frequency compressor structure with high partial load performance. Background Technology

[0002] With the continuous advancement of single-screw compressor technology, single-screw compressors have been widely used in heating, refrigeration, and chemical industries. Different applications place varying requirements on the operating range of single-screw compressors.

[0003] A single-screw compressor includes a motor located on the intake side and a meshing pair located on the exhaust side. The meshing pair consists of a cylindrical screw and two symmetrically arranged planar star wheels. The power of the motor shaft is transmitted to the screw, which drives the star wheels to rotate. Gas enters the screw groove from the intake chamber, is compressed, and is discharged through the exhaust port and exhaust chamber.

[0004] Single-screw compressors are affected by various factors during refrigeration and heating operations, causing their operating compression ratio to fluctuate within a relatively large range. This can lead to undercompression or overcompression, reducing the compressor's operating efficiency. The internal volume ratio Vi (Vi = Vs / Vd) is a crucial operating parameter for screw compressors, where Vs is the rotor intake chamber volume and Vd is the rotor exhaust chamber volume. Therefore, to obtain the optimal compression ratio and adapt to changing external conditions, a slide valve mechanism is needed to adjust the internal volume ratio Vi. For current single-screw variable frequency compressors, the main purpose of the sliding valve, piston, and cylinder moving components is to adjust the volume ratio before and after compression to reduce performance losses caused by overcompression or undercompression.

[0005] A representative example is patent document CN221423438U, which discloses a high-performance volume ratio adjustment structure and a single-screw compressor using it. This design innovatively adjusts the volume ratio of the single-screw compressor by machining an exhaust port on the compressor body for partial load operation, simplifying the volume ratio adjustment structure. The structure is designed so that when the piston on the cylinder drives the slide valve body to slide to a first position within the compressor body, the first exhaust profile on the slide valve body forms the exhaust port profile; when the piston on the cylinder... When the piston drives the slide valve body to slide to the second position within the machine body, the exhaust port profile is formed by the second exhaust profile on the machine body. This allows the single screw compressor to have a profile that fits the required operating conditions (Vi that matches the rated operating conditions) during operation. This structure adopts a simple and reliable motion structure, reducing the risk of the slide valve body jamming. At the same time, the installation and sliding positions of the slide valve body, the slide valve guide rod, and the second exhaust profile on the machine body are all machined on the machine body, thereby reducing the number of parts, lowering assembly difficulty and production costs, and facilitating subsequent maintenance.

[0006] The aforementioned patent documents disclose a technical solution to reduce performance loss caused by overcompression or undercompression by adjusting the volume ratio before and after compression of the compressor. However, this technical solution still has limitations in practical application, as follows:

[0007] It cannot achieve stepless adjustment when adjusting the volume ratio. Specifically, the slide valve body can only switch between a preset first position and a second position. This design is essentially a two-stage adjustment. The switching of the exhaust profile depends on the discrete displacement of the slide valve, and it cannot form a continuous exhaust profile transition during the movement. This results in the compressor volume ratio being able to match only a limited number of preset operating conditions (such as rated operating conditions and partial load operating conditions), and it cannot dynamically adjust the profile parameters according to actual needs.

[0008] Therefore, how to overcome the shortcomings of the existing technology mentioned above has become the subject of this utility model. Utility Model Content

[0009] This invention provides a single-screw fixed-frequency compressor structure with high partial load performance, aiming to solve the technical problems mentioned in the background art.

[0010] To achieve the above objectives, the technical solution adopted by this utility model is: a single-screw fixed-frequency compressor structure with high partial load performance. The compressor has an exhaust side and an intake side. The compressor includes a body located on the exhaust side. The body is provided with a screw engagement pair, a slide valve, and a moving channel. The body has a compression region for accommodating the screw engagement pair to compress gas. This compression region is configured with a full-load section and a deload section according to the position of the slide valve and is connected to the moving channel. The body has a fixed compression ratio profile for controlling the volume ratio of the compression region and a bypass port. The bypass port is located near the intake side and is connected to the compression zone and the intake side. The bypass port is located on the side of the moving channel. The slide valve is located in the moving channel and is configured to reciprocate within the moving channel. When in the full-load section, the slide valve is driven to block the bypass port, and the gas flows completely through the compression zone constrained by the compression ratio profile line to output gas with a fixed compressor volume ratio. When in the unload section, the slide valve is driven to partially or completely open the bypass port, and some gas flows through the compression zone constrained by the compression ratio profile line and then enters the bypass port to achieve stepless adjustment of the compressor volume ratio.

[0011] The relevant content in the above plan is explained as follows:

[0012] In the above scheme, the full-load section and the unload section represent the area where the screw meshing pair compresses gas after the bypass port is completely blocked and the area where gas flows through the screw meshing pair after the bypass port is completely open, respectively.

[0013] In the above solution, the problem of partial load overcompression can be quickly solved by the cooperation of slide valve, bypass port and compression ratio profile. At the same time, when solving the problem, the compression ratio volume can be steplessly adjusted to meet different operating conditions.

[0014] Further technical solutions also include a control system;

[0015] The adjustment system is located on the exhaust side, and the actuator of the adjustment system is positioned and connected to the slide valve. The adjustment system is configured to drive the slide valve to reciprocate within the moving channel.

[0016] In the above scheme, the adjustment system only acts on the exposed end of the hollow cylinder. Unlike the existing technology that drives from both ends of the slide valve, this application drives from the outside of the machine body and from the side of the exposed end of the hollow cylinder, eliminating the need for internal drive, reducing machine body processing, and broadening its application range.

[0017] A further technical solution includes a hollow cylinder inserted into a moving channel and a sealing cylinder disposed at the exposed end of the hollow cylinder. A piston, which is slidably connected to a slide valve, is disposed inside the sealing cylinder, and the three are coaxially arranged. With the piston as a reference, the sealing cylinder is divided into a first chamber and a second chamber. The adjustment system also includes a drive system that communicates with the oil supply side and the air intake side, and the drive system communicates with the first chamber and the second chamber.

[0018] The above design enables the actuation of the slide valve.

[0019] Specifically, the pressure in the first and second chambers is controlled simultaneously by the drive system, which drives the piston to pull the slide valve along the moving channel via the connecting rod, thereby blocking or opening the bypass port.

[0020] It is important to note that the medium can be either gas or liquid. The drive system can even be an electric drive mechanism, meaning that the electric drive mechanism directly drives the connecting rod to move.

[0021] A further technical solution includes a drive system comprising a first valve, a second valve, a third valve, and a fourth valve; the end pipes of the first valve and the second valve are both connected to the intake side, the other end pipe of the first valve is connected to the second chamber, and the other end pipe of the second valve is connected to the first chamber; the end pipes of the third valve and the fourth valve are both connected to the oil supply side, the other end pipe of the third valve is connected to the second chamber, and the other end pipe of the fourth valve is connected to the first chamber; when the bypass port is blocked, only the first valve and the fourth valve are opened, the intake side extracts the medium from the second chamber, the oil supply side injects the medium into the first chamber and causes the piston and slide valve to move to the right; when the bypass port is opened, only the second valve and the third valve are opened, the oil supply side injects the medium into the second chamber and causes the piston and slide valve to move to the left, and the intake side extracts the medium from the first chamber.

[0022] In a further technical solution, a connecting rod is provided inside the hollow cylinder, and the two ends of the connecting rod are respectively positioned and connected to the slide valve and the piston, and the connecting rod is the actuator.

[0023] The above design enables the blocking and opening of the bypass port without requiring separate machining of the drive system on the machine body.

[0024] Specifically, before operation, the slide valve is in a blocked bypass port state and all valves are closed. Then, once it is necessary to open the bypass port, the second valve and the third valve are opened. Then, the oil supply side injects the medium into the second chamber, and the suction side extracts the medium from the first chamber in an amount equal to the amount injected into the second chamber. As the medium is gradually injected into the second chamber, the piston gradually moves towards the left end of the sealing cylinder, and the slide valve gradually moves to the left end of the contact movement channel, so that the bypass port is opened.

[0025] When it is necessary to block the bypass port, the second valve and the third valve are closed, and the first valve and the fourth valve are opened. The suction side extracts the medium from the second chamber, and the oil supply side injects the same amount of medium into the first chamber as the extracted medium. As the medium is gradually injected into the first chamber, the piston gradually moves to the right end of the sealing cylinder, and the slide valve gradually moves to the left end of the contact hollow cylinder, so that the bypass port is closed.

[0026] A further technical solution involves specifying that the height of the hollow cylinder is equal to the height of the moving channel. This design ensures that there is no large gap between the hollow cylinder and the screw meshing pair, preventing low efficiency when the gas pressure reaches the target value.

[0027] In a further technical solution, the slide valve and the piston are coaxially arranged. When the slide valve slides in the moving channel to completely block the bypass port, the piston is at the right end of the sealing cylinder, and the slide valve abuts against the insertion end of the hollow cylinder. When the slide valve slides in the moving channel to completely open the bypass port, the left end of the slide valve abuts against the left end of the moving channel, and the piston is at the left end of the sealing cylinder.

[0028] With the above design, when the piston is at the left or right end inside the sealing cylinder, the slide valve can open or close the bypass port. If the slide valve has already opened or closed the bypass port, but the piston can still move inside the sealing cylinder, it is easy for the slide valve to slide from the left end of the movement channel to close the bypass port, then continue to slide to the right and open the bypass port again.

[0029] The terms "first," "second," etc., used in this article do not specifically refer to order or sequence, nor are they intended to limit this case; they are merely used to distinguish components or operations described using the same technical terms.

[0030] The terms "connection" or "positioning" as used in this article can refer to two or more components or devices making direct physical contact with each other, or making indirect physical contact with each other, or to two or more components or devices operating or moving with each other.

[0031] The terms “include,” “including,” and “have” used in this article are all open-ended, meaning they include but are not limited to.

[0032] Unless otherwise specified, the terms used herein generally have their ordinary meaning in the context of the art, the subject matter, and the specific context. Certain terms used to describe this case will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the case.

[0033] The terms “front,” “back,” “up,” “down,” “left,” and “right” used in this article are directional terms. In this case, they are only used to describe the positional relationship between the structures and are not intended to limit the specific direction of the protection scheme or its actual implementation.

[0034] The working principle and advantages of this utility model are as follows:

[0035] This invention can quickly solve the problem of partial load overcompression by cooperating with the slide valve, bypass port and compression ratio profile. At the same time, while solving the problem, it can also realize stepless adjustment of compression ratio volume to meet different operating conditions.

[0036] Specifically, in the full-load section, the slide valve is driven to block the bypass port, and the gas flows completely through the compression region constrained by the compression ratio profile to output gas with a fixed compressor volume ratio. In the unload section, the slide valve is driven to partially or completely open the bypass port, and some gas flows through the compression region constrained by the compression ratio profile before entering the bypass port to achieve stepless adjustment of the compressor volume ratio. Attached Figure Description

[0037] Appendix Figure 1 This is a schematic diagram of the slide valve structure in an embodiment of the present utility model;

[0038] Appendix Figure 2 This is a schematic diagram of the moving channel structure in an embodiment of the present utility model;

[0039] Appendix Figure 3 This is a schematic diagram of the bypass port structure in an embodiment of the present utility model;

[0040] Appendix Figure 4 This is a schematic diagram of the adjustment system structure in an embodiment of the present invention.

[0041] In the attached diagrams: 1. Body; 2. Slide valve; 3. Hollow cylinder; 4. Drive system; 5. Compression zone; 6. Compression ratio profile; 7. Moving channel; 8. Bypass port; 9. Adjustment system; 10. Sealing cylinder; 11. Piston; 12. First chamber; 13. Second chamber; 14. Connecting rod; 15. First valve; 16. Second valve; 17. Third valve; 18. Fourth valve; 19. Screw engagement pair;

[0042] L1, Fully Loaded Section;

[0043] L2, unloading section;

[0044] A. Intake side; B. Fuel supply side; C. Exhaust side. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0046] Example: The present invention will be clearly described below with illustrations and detailed description. Any person skilled in the art who understands the examples of the present invention can make changes and modifications based on the technology taught in the present invention without departing from the spirit and scope of the present invention.

[0047] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of this work. Singular forms such as “a,” “this,” “this,” “the,” and “the” as used herein also include plural forms.

[0048] See appendix Figures 1-4As shown, a single-screw fixed-frequency compressor with high partial load performance is disclosed. The compressor has a discharge side C and a suction side A. The compressor includes a body 1 located on the discharge side C. The body 1 contains a screw engagement pair 19, a slide valve 2, and a moving channel 7. The body 1 has a compression zone 5 for accommodating the screw engagement pair 19 to compress gas. The compression zone 5 is configured with a full-load section L1 and a deload section L2 according to the position of the slide valve 2, and is connected to the moving channel 7. The body 1 has a fixed compression ratio profile 6 for controlling the volume ratio of the compression zone 5 and a bypass port 8. The compression ratio profile 6 is located near the bypass port 8. On the intake side, the bypass port 8 is connected to the compression zone 5 and the intake side; the bypass port 8 is located on the side of the moving channel 7; the slide valve 2 is located in the moving channel 7 and is configured to reciprocate within the moving channel 7; when in the full load section L1, the slide valve 2 is driven to block the bypass port 8, and the gas flows completely through the compression zone 5 constrained by the compression ratio profile 6 to output gas with a fixed compressor volume ratio; when in the unload section L2, the slide valve 2 is driven to partially or completely open the bypass port 8, and some gas flows through the compression zone 5 constrained by the compression ratio profile 6 and then enters the bypass port 8 to achieve stepless adjustment of the compressor volume ratio.

[0049] In this embodiment, the full-load section L1 and the unload section L2 represent the area where the gas is compressed in the screw meshing pair 19 after the bypass port 8 is completely blocked and the area where the gas flows through the screw meshing pair 19 after the bypass port 8 is completely open, respectively.

[0050] In this embodiment, the problem of partial overcompression can be quickly solved by the cooperation of slide valve 2, bypass port 8 and compression ratio profile 6. At the same time, while solving the problem, the compression ratio volume can also be steplessly adjusted to meet different operating conditions.

[0051] Preferably, it also includes a regulating system 9;

[0052] The adjustment system 9 is located on the intake side A. The actuator of the adjustment system 9 is positioned and connected to the slide valve 2. The adjustment system 9 is configured to drive the slide valve 2 to reciprocate within the moving channel 7.

[0053] In this embodiment, the adjustment system 9 operates only on the exposed end of the hollow cylinder 3. Unlike the prior art where the adjustment is sometimes driven from both ends of the slide valve 2, this application drives the adjustment from the outside of the body 1 and from the side of the exposed end of the hollow cylinder 3, requiring less processing of the body 1 and having a wider range of applications.

[0054] Preferably, the adjustment system 9 includes a hollow cylinder 3 inserted into the moving channel 7 and a sealing cylinder 10 disposed at the exposed end of the hollow cylinder 3. A piston 11, which is positioned and connected to the slide valve 2, is slidably disposed inside the sealing cylinder 10, and the three are coaxially arranged. With the piston 11 as a reference, the sealing cylinder 10 is divided into a first chamber 12 and a second chamber 13. The adjustment system 9 also includes a drive system 4 communicating with the oil supply side B and the air intake side A. The drive system 4 is connected to the first chamber 12 and the second chamber 13.

[0055] The above design enables the actuation of slide valve 2.

[0056] Specifically, the pressure of the first chamber 12 and the second chamber 13 is controlled simultaneously by the drive system 4, so as to drive the piston 11 to pull the slide valve 2 along the moving channel 7 through the connecting rod 14, thereby performing the operation of blocking or opening the bypass port 8.

[0057] It should be noted that the medium can be either gas or liquid. The drive system 4 can even be an electric drive mechanism, meaning the electric drive mechanism directly drives the connecting rod 14.

[0058] Preferably, the drive system 4 includes a first valve 15, a second valve 16, a third valve 17, and a fourth valve 18; the end pipes of the first valve 15 and the second valve 16 are both connected to the intake side, the other end pipe of the first valve 15 is connected to the second chamber 13, and the other end pipe of the second valve 16 is connected to the first chamber 12; the end pipes of the third valve 17 and the fourth valve 18 are both connected to the oil supply side, the other end pipe of the third valve 17 is connected to the second chamber 13, and the other end pipe of the fourth valve 18 is connected to the first chamber 12; when the bypass port 8 is blocked, only the first valve 15 and the fourth valve 18 are opened, the intake side draws out the medium in the second chamber 13, the oil supply side injects the medium into the first chamber 12 and causes the piston and slide valve to move to the right; when the bypass port 8 is opened, only the second valve 16 and the third valve 17 are opened, the oil supply side injects the medium into the second chamber 13 and causes the piston and slide valve to move to the left, and the intake side draws out the medium in the first chamber 12.

[0059] Preferably, a connecting rod 14 is provided inside the hollow cylinder 3, and the two ends of the connecting rod 14 are respectively positioned and connected to the slide valve 2 and the piston 11. The connecting rod 14 is the actuator.

[0060] With the above design, the blocking and opening operations of the bypass port 8 can be realized without the need for separate processing of the drive system 4 on the body 1.

[0061] Specifically, before operation, the slide valve 2 is in the state of blocking the bypass port 8 and all valves are closed. Then, once it is necessary to open the bypass port 8, the second valve 16 and the third valve 17 are opened. Then, the oil supply side B injects the medium into the second chamber 13, and the air intake side A extracts the medium from the first chamber 12 in an amount equal to the amount injected into the second chamber 13. As the medium is gradually injected into the second chamber 13, the piston 11 gradually moves towards the left end of the sealing cylinder 10, and the slide valve 2 gradually moves to the left end of the contact moving channel 7, so that the bypass port 8 is opened.

[0062] When it is necessary to block the bypass port 8, the second valve 16 and the third valve 17 are closed, and the first valve 15 and the fourth valve 18 are opened. The suction side A draws out the medium in the second chamber 13, and the oil supply side B injects the same amount of medium as the medium drawn out of the first chamber 12 into the first chamber 12. As the medium is gradually injected into the first chamber 12, the piston 11 gradually moves to the right end of the sealing cylinder 10, and the slide valve 2 gradually moves to the left end of the contact hollow cylinder 3, so that the bypass port 8 is closed.

[0063] Preferably, the height of the hollow cylinder 3 is equal to the height of the moving channel 7. This design ensures that there is no large gap between the hollow cylinder 3 and the screw engagement pair 19, preventing low efficiency when the gas pressure reaches the target value.

[0064] Preferably, the slide valve 2 and the piston 11 are coaxially arranged. When the slide valve 2 slides in the moving channel 7 to completely block the bypass port 8, the piston 11 is located at the right end of the sealing cylinder 10, and the slide valve 2 abuts against the insertion end of the hollow cylinder 3. When the slide valve 2 slides in the moving channel 7 to completely open the bypass port 8, the left end of the slide valve 2 abuts against the left end of the moving channel 7, and the piston 11 is located at the left end of the sealing cylinder 10.

[0065] With the above design, when the piston 11 is at the left or right end within the sealing cylinder 10, the slide valve 2 can open or block the bypass port 8. If the slide valve 2 has already achieved the purpose of opening or blocking the bypass port 8, but the piston 11 can still move within the sealing cylinder 10, it is easy for the slide valve 2 to slide from the left end of the moving channel 7 to block the bypass port 8, and then continue to slide to the right and open the bypass port 8 again.

[0066] Working principle:

[0067] Before operation, the slide valve 2 is in the state of blocking the bypass port 8 and all valves are in the closed state. Then, once it is necessary to open the bypass port 8, the second valve 16 and the third valve 17 are opened. Then, the oil supply side B injects oil into the second chamber 13, and the suction side A extracts the same amount of medium from the first chamber 12 as it is injected into the second chamber 13 (this is to ensure that the pressure in the first chamber 12 and the second chamber 13 is equal, and to prevent the suction side A from extracting too much, which would cause the piston 11 to not reach the desired position). As the medium is gradually injected into the second chamber 13, the piston 11 gradually moves towards the left end of the sealing cylinder 10, and the slide valve 2 gradually moves to the left end of the contact moving channel 7, so that the bypass port 8 is opened.

[0068] As bypass opening 8 is opened, the fully loaded section L1 gradually transforms into the unloaded section L2. For details after bypass opening 8 is fully opened, please refer to [link / reference needed]. Figure 2 and Figure 3 At this point, what exists is the area where the bypass port 8 is fully open and the screw meshing pair 19 compresses the gas, namely the unloading section L2.

[0069] When it is necessary to block the bypass port 8, the second valve 16 and the third valve 17 are closed, and the first valve 15 and the fourth valve 18 are opened. The suction side A draws out the medium from the second chamber 13, and the oil supply side B injects the same amount of medium as the medium drawn out of the first chamber 12 into the first chamber 12. As the medium is gradually injected into the first chamber 12, the piston 11 gradually moves to the right end of the sealing cylinder 10, and the slide valve 2 gradually moves to the left end of the contact hollow cylinder 3, thus sealing the bypass port 8. At this time, the screw operates at full power.

[0070] During the movement of the slide valve 2, the drive system 4 can stop the slide valve 2 at any position between the left end of the moving channel 7 and the insertion end of the hollow cylinder 3, thereby realizing stepless adjustment of the compressor volume ratio.

[0071] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. A single-screw fixed-frequency compressor structure with high partial load performance, the compressor having an exhaust side and an intake side, the compressor including a body (1) disposed on the exhaust side, the body (1) being provided with a screw engagement pair (19), a slide valve (2), and a moving channel (7), characterized in that: The body (1) has a compression area (5) for accommodating the screw meshing pair (19) to compress gas. The compression area (5) is provided with a full load section (L1) and a load reduction section (L2) according to the position of the slide valve (2), and is connected to the moving channel (7). The body (1) is provided with a fixed compression ratio profile (6) and a bypass port (8) for controlling the volume ratio of the compression area (5). The compression ratio profile (6) is located on the side of the bypass port (8) near the intake side. The bypass port (8) is connected to the compression area (5) and the intake side. The bypass port (8) is located on the side of the moving channel (7). The slide valve (2) is disposed within the moving channel (7) and configured to reciprocate within the moving channel (7); When in the full load section (L1), the slide valve (2) is driven to block the bypass port (8), and the gas flows completely through the compression region (5) constrained by the compression ratio profile (6) to output gas with a fixed compressor volume ratio. When in the unload section (L2), the slide valve (2) is driven to partially or completely open the bypass port (8), and some gas flows through the compression region (5) constrained by the compression ratio profile (6) and enters the bypass port (8) to achieve stepless adjustment of the compressor volume ratio.

2. The structure of the single-screw fixed-frequency compressor with high partial load performance according to claim 1, characterized in that: It also includes a control system (9); The regulating system (9) is located on the exhaust side, and the actuator of the regulating system (9) is positioned and connected to the slide valve (2). The regulating system (9) is configured to drive the slide valve (2) to reciprocate within the moving channel (7).

3. The high partial load performance single-screw fixed-frequency compressor structure according to claim 2, characterized in that: The adjustment system (9) includes a hollow cylinder (3) inserted into the moving channel (7) and a sealing cylinder (10) disposed at the exposed end of the hollow cylinder (3). A piston (11) that is positioned and connected to the slide valve (2) is slidably disposed inside the sealing cylinder (10), and the three are coaxially arranged. With the piston (11) as the reference, the sealing cylinder (10) is divided into a first chamber (12) and a second chamber (13). The regulating system (9) further includes a drive system (4) connected to the oil supply side and the air intake side, the drive system (4) being connected to the first chamber (12) and the second chamber (13).

4. The high partial load performance single-screw fixed-frequency compressor structure according to claim 3, characterized in that: The drive system (4) includes a first valve (15), a second valve (16), a third valve (17) and a fourth valve (18). The end pipes of the first valve (15) and the second valve (16) are both connected to the suction side. The other end pipe of the first valve (15) is connected to the second chamber (13), and the other end pipe of the second valve (16) is connected to the first chamber (12). The end pipes of the third valve (17) and the fourth valve (18) are both connected to the oil supply side. The other end pipe of the third valve (17) is connected to the second chamber (13), and the other end pipe of the fourth valve (18) is connected to the first chamber (12). When blocking the bypass port (8), only the first valve (15) and the fourth valve (18) are opened. The suction side draws out the medium in the second chamber (13), and the oil supply side injects the medium into the first chamber (12) and moves the piston and slide valve to the right. When the bypass port (8) is open, only the second valve (16) and the third valve (17) are opened. The oil supply side injects the medium into the second chamber (13) and moves the piston and slide valve to the left. The suction side extracts the medium from the first chamber (12).

5. The high partial load performance single-screw fixed-frequency compressor structure according to claim 3, characterized in that: The hollow cylinder (3) is provided with a connecting rod (14), and the two ends of the connecting rod (14) are respectively positioned and connected to the slide valve (2) and the piston (11). The connecting rod (14) is the actuator.

6. The high partial load performance single-screw fixed-frequency compressor structure according to claim 3, characterized in that: The height of the hollow cylinder (3) is equal to the height of the moving channel (7).

7. The high partial load performance single-screw fixed-frequency compressor structure according to claim 3, characterized in that: The slide valve (2) is coaxially arranged with the piston (11). When the slide valve (2) slides in the moving channel (7) to completely block the bypass port (8), the piston (11) is located at the right end of the sealing cylinder (10), and the slide valve (2) abuts against the insertion end of the hollow cylinder (3). When the slide valve (2) slides in the moving channel (7) to completely open the bypass port (8), the left end of the slide valve (2) abuts against the left end of the moving channel (7), and the piston (11) is located at the left end of the sealing cylinder (10).

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