Screw compressor slide valve mechanism, screw compressor and refrigerating unit

Abstract

The utility model discloses screw compressor slide valve mechanism, screw compressor and refrigerating unit, screw compressor slide valve mechanism includes: slide valve, piston and at least one positioning guide rod, and piston promotes slide valve linear movement in the body of screw compressor, and slide valve is equipped with the guide structure between the body, and the guide structure includes: at least one positioning guide rod who sets along the slide valve movement direction and the movement cavity of the insertion joint cooperation with positioning guide rod, and slide valve removes when drive positioning guide rod and movement cavity happen relative movement, each pair of magnetic force module is by the coaxial setting of moving magnet and static magnet and is constituted, and moving magnet is installed on slide valve, and static magnet is installed on the body, and moving magnet follows slide valve synchronous movement to be close to or away from static magnet, the utility model discloses through positioning guide rod and magnetic force module realizes the axial positioning of slide valve, and effectively reduces the slide valve surface scratch phenomenon under the compression tooth groove fluctuation.

Description

Technical Field

[0001] This utility model relates to the field of compressor technology, and in particular to the slide valve mechanism of a screw compressor, a screw compressor and a refrigeration unit. Background Technology

[0002] Screw compressors, as core equipment in modern industry, are widely used due to their high efficiency, stability, smooth operation, and ease of maintenance. Their capacity regulation function is key to achieving efficient and energy-saving operation, and among various techniques, slide valve regulation is one of the most widely used. The slide valve, through its axial movement within the compressor body, changes the effective working length of the rotor, thereby achieving stepless regulation of the discharge volume. This allows the compressor's output power to precisely match the system load, effectively reducing energy consumption.

[0003] In existing technologies, the actuation of a slide valve is typically achieved by an oil piston assembly, while its circumferential and axial positioning generally relies on the mating structure of a keyway and a locating key. Specifically, a keyway is provided at the bottom of the slide valve, and a matching locating key is installed on the compressor body. When the oil piston pushes the slide valve to move, the main function of this locating key is to prevent the slide valve from rotating circumferentially or shifting radially under the action of airflow, while also providing axial positioning to a certain extent.

[0004] However, in practical applications, it has been found that this traditional locating key method has inherent defects. Due to significant airflow pulsations during compressor operation, the slide valve experiences continuous dynamic excitation. Under long-term alternating loads, the mating surfaces of the traditional locating key and keyway are prone to wear and gaps. This gap can cause slight axial movement or fluctuations in the slide valve during operation, affecting not only the accuracy of capacity regulation but, more seriously, potentially leading to abnormal contact and friction between the upper surface of the slide valve and the rotor, causing scratches or even more severe wear, directly impacting the reliability and service life of the compressor.

[0005] Therefore, how to design a screw compressor slide valve mechanism that can effectively suppress axial fluctuations of the slide valve under complex working conditions and improve its operational stability and positioning accuracy is a technical problem that the industry urgently needs to solve. Utility Model Content

[0006] To address the risk of fluctuation in existing slide valves, this invention proposes a slide valve mechanism for a screw compressor, a screw compressor, and a refrigeration unit. The axial positioning of the slide valve is achieved through a positioning guide rod, effectively reducing surface scratches on the slide valve caused by fluctuations in the compression tooth grooves.

[0007] The technical solution adopted in this utility model is to design a screw compressor slide valve mechanism, including: a slide valve, a piston, and at least one positioning guide rod. The piston pushes the slide valve to move linearly within the screw compressor body. A guide structure is provided between the slide valve and the body. The guide structure includes: at least one positioning guide rod arranged along the movement direction of the slide valve, and a motion cavity that is inserted and cooperates with the positioning guide rod. When the slide valve moves, it drives the positioning guide rod to move relative to the motion cavity.

[0008] Furthermore, the slide valve is equipped with two positioning guide rods, which are symmetrically distributed on both sides of the slide valve's axis.

[0009] Furthermore, the end of the positioning guide rod inserted into the motion cavity is the movable end, and the movable end is fitted with a square ring with holes, which is supported between the positioning guide rod and the motion cavity.

[0010] Furthermore, the end of the positioning guide rod away from the motion cavity is the fixed end, and the fixed end of the positioning guide rod is installed on the slide valve. The motion cavity is located on the machine body, and the opening of the motion cavity faces the slide valve.

[0011] Furthermore, the screw compressor slide valve mechanism also includes at least one pair of magnetic modules. Each pair of magnetic modules consists of a moving magnet and a stationary magnet arranged coaxially. The moving magnet is mounted on the slide valve, and the stationary magnet is mounted on the machine body. The moving magnet moves synchronously with the slide valve to move closer to or away from the stationary magnet.

[0012] Furthermore, the moving magnet is mounted on the end face of the slide valve and is located at the top center of the end face.

[0013] In some embodiments, three moving magnets are mounted on the end face of the slide valve, and the three moving magnets are arranged in a triangular pattern.

[0014] Furthermore, static magnets employ electromagnets capable of changing polarity to attract or repel moving magnets.

[0015] This utility model also proposes a screw compressor, including: a body, a pair of meshing rotors, and the aforementioned screw compressor slide valve mechanism.

[0016] This utility model also proposes a refrigeration unit, including the aforementioned screw compressor.

[0017] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0018] 1. The axial positioning of the spool valve is achieved by using a positioning guide rod, which effectively reduces the scratches on the spool valve surface caused by compression tooth groove fluctuations;

[0019] 2. The axial positioning of the slide valve is achieved with the assistance of a magnetic module, and loading and unloading are achieved by controlling the polarity of the electromagnet during startup. Attached Figure Description

[0020] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, wherein:

[0021] Figure 1 This is a schematic diagram of the internal structure of the screw compressor of this utility model;

[0022] Figure 2 This is a three-dimensional schematic diagram of the slide valve of this utility model;

[0023] Figure 3 This is an internal schematic diagram of the body of this utility model;

[0024] Figure 4 This is a side view of the positioning guide rod of this utility model;

[0025] Figure 5 yes Figure 1 Enlarged view of point A in the middle;

[0026] Figure 6 This is a schematic diagram of the loading of the slide valve mechanism of this utility model;

[0027] Figure 7 This is a schematic diagram of the unloading of the slide valve mechanism of this utility model;

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Screw compressor; 11. Body; 12. Moving chamber; 13. Static magnet; 14. Cylinder; 2. Slide valve; 21. Keyway; 22. Threaded hole; 23. Moving magnet; 24. Positioning guide rod; 241. Groove; 25. Square ring for hole; 3. Piston; 4. Rotor. Detailed Implementation

[0030] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0031] like Figure 1 , 2 As shown, a common slide valve mechanism is usually a piston that pushes the slide valve to move linearly within the body 11 of the screw compressor 1. The bottom of the slide valve 2 is provided with a keyway 21 arranged along the axial direction of the slide valve 2. The body 11 of the screw compressor is provided with a positioning key corresponding to the keyway 21. When the piston 3 pushes the slide valve 2 to move, the keyway 21 slides along the positioning key, thereby realizing the free axial movement of the slide valve 2.

[0032] During the operation of the slide valve mechanism, especially under full load, the rotor compresses the refrigerant to its maximum volume. At this time, due to the pressure difference within the tooth grooves, the slide valve 2 will shift and come into contact with the moving rotor 4, resulting in varying degrees of abrasion. This is because the piston 3 at the far end only acts as a power source, and the positioning key can only achieve axial positioning. The slide valve 2 will "warp" under the action of a large pressure difference.

[0033] like Figures 2 to 4 As shown, the present invention proposes an improvement on the existing positioning key for the screw compressor slide valve mechanism. Specifically, a guide structure is designed between the slide valve 2 and the machine body 11. The guide structure includes at least one positioning guide rod 24 arranged along the moving direction of the slide valve 2, and a motion cavity 12 that is inserted and engaged with the positioning guide rod 24. When the slide valve 2 moves, it drives the positioning guide rod 24 to move relative to the motion cavity 12. The positioning guide rod 24 can be selectively installed on the slide valve 2 or the machine body 11. If the positioning guide rod 24 is installed on the slide valve 2, the motion cavity 12 is located on the machine body 11; if the positioning guide rod 24 is installed on the machine body 11, the motion cavity 12 is located on the slide valve 2.

[0034] This article mainly uses the example of the positioning guide rod 24 being installed on the slide valve 2 for detailed explanation. The body 11 is provided with a motion cavity 12 that is inserted and matched with the positioning guide rod 24. One end of the positioning guide rod 24 is installed on the slide valve 2, and the other end of the positioning guide rod 24 is movably inserted into the motion cavity 12. The positioning guide rod 24 moves synchronously with the slide valve 2, and the insertion distance of the positioning guide rod 24 into the motion cavity 12 changes accordingly.

[0035] This design uses the insertion and engagement of the positioning guide rod 24 with the moving cavity 12 to form a sliding pair with a long guiding distance, which forcibly constrains the slide valve 2 to move linearly in the axial direction, thereby effectively resisting airflow pulsation during compressor operation and fundamentally eliminating the fluctuation phenomenon of the slide valve 2. In addition, compared with the line contact of the traditional keyway, the surface contact characteristics of the guide rod pair have lower contact stress and better wear resistance, enhancing structural rigidity and extending the service life of the mechanism.

[0036] In a preferred embodiment of this invention, the slide valve 2 is equipped with two positioning guide rods 24. The pairing of the positioning guide rods 24 enables anti-torsion function. Specifically, although a single positioning guide rod 24 can restrict the movement of the slide valve 2 in the radial direction, the slide valve 2 may have a slight degree of freedom of rotation around the axis of the single guide rod. The two symmetrically distributed guide rods can completely restrict all unnecessary degrees of freedom of the slide valve 2 (including rotation around its own axis), retaining only the single, required axial movement degree of freedom. This fundamentally eliminates any form of jamming or torsional deformation, ensuring that the slide valve 2 is strictly restricted to the axial straight line, effectively preventing end deflection caused by gaps or external forces, thereby ensuring the uniformity of the gap between the slide valve end face and the rotor 4, and improving the efficiency and reliability of the compressor.

[0037] like Figure 1 , 5 As shown, for the entire spool valve mechanism, on the exhaust side of spool valve 2, its axial positioning is achieved as follows: a clearance fit is formed between the outer circumferential surface of piston 3 and the inner wall of cylinder 14, which together constitute the first axial positioning part of the spool valve mechanism. Its main function is to constrain the radial position of spool valve 2 on this side and provide guidance for axial movement. On the intake side of spool valve 2, its axial positioning is achieved through two positioning guide rods 24. The positioning guide rods 24 are symmetrically distributed on both sides of the axis of spool valve 2 and are respectively inserted into the corresponding motion chambers 12 on the body 11. The insertion fit between the positioning guide rods 24 and the motion chambers 12 together constitutes the second axial positioning part of the spool valve mechanism. Through the two support points of the first axial positioning part (exhaust side) and the second axial positioning part (intake side), three non-collinear constraint points are formed in space. These three constraint points together determine a stable guide plane, making the entire spool valve mechanism a statically determinate and stable triangular support structure in kinematics. This structure can effectively restrict the five degrees of freedom of the slide valve 2 other than axial movement. In particular, it can resist the overturning moment caused by gas force fluctuations, thereby ensuring the straightness and stability of the slide valve 2 in long-stroke reciprocating motion and fundamentally avoiding skewness and abnormal wear.

[0038] like Figures 2 to 5 As shown, in some feasible embodiments of this utility model, one end of the positioning guide rod 24 inserted into the motion cavity 12 is a movable end. The movable end is provided with a groove 241 for mounting a square ring 25. The square ring 25 is nested in the groove 241 and supported between the positioning guide rod 24 and the motion cavity 12. The rectangular cross-section of the square ring allows it to form a large surface contact with the inner wall of the motion cavity 12 and the surface of the positioning guide rod 24, which is completely different from the line contact of a traditional O-ring. The square ring 25 can provide a large radial support force, which can effectively suppress the shaking and swaying of the positioning guide rod 24 during movement, and ensure the linear accuracy and stability of the movement of the slide valve 2.

[0039] The positioning guide rod 24 is fixed at one end of the slide valve 2. The fixed end of the positioning guide rod is installed on the slide valve, and the moving chamber is located on the machine body with the opening of the moving chamber facing the slide valve. This structure integrates the moving parts (slide valve and guide rod), provides a direct power transmission path, improves the reliability of movement, and allows the slide valve assembly to be easily assembled and maintained by insertion.

[0040] In some feasible embodiments, the fixed end is provided with a threaded section, and the slide valve 2 is provided with a threaded hole 22 that mates with the threaded section. The threaded connection method does not require additional fasteners such as pins and retaining rings, making the structure very compact. Moreover, once the positioning guide rod or square ring wears out due to long-term use, it can be easily unscrewed from the slide valve 2 for replacement, greatly simplifying the maintenance process.

[0041] It should be noted that the installation structure described above is only an example. In actual applications, it can be designed according to usage requirements. This utility model does not impose any special restrictions on it.

[0042] like Figure 5 As shown, in a preferred embodiment of this utility model, the screw compressor slide valve mechanism further includes at least one pair of magnetic modules, each pair of magnetic modules consisting of a moving magnet 23 and a stationary magnet 13 coaxially arranged. The moving magnet 23 is mounted on the end face of the slide valve 2 and moves axially together with the slide valve 2. The stationary magnet 13 is mounted on the machine body 11 at a position corresponding to the moving magnet 23. When the slide valve 2 moves, the moving magnet 23 moves synchronously with it, thereby changing the axial distance between it and the stationary magnet 13.

[0043] The magnetic force generated by the magnetic module provides an additional axial positioning force for the slide valve 2. When the slide valve 2 tends to sway slightly due to airflow pulsation, the magnetic force can quickly "pull back" or "push back" it to the equilibrium position, like an invisible magnetic lock, which significantly suppresses the axial fluctuation of the slide valve 2 and enhances its stability in any position.

[0044] In addition, the magnetic force can be used as a supplement to the driving force. When loading is required, if it is set to attractive force, it can assist piston 3 in pushing slide valve 2 to move, reducing the required oil pressure; when unloading is required, if it is set to repulsive force, it can assist slide valve 2 to return quickly, improving the response speed of capacity regulation and enabling the compressor to match load changes more quickly.

[0045] Based on the magnetic module, the preferred embodiment is to install the moving magnet 23 at the top center of the end face of the slide valve 2. Setting the point of application of the magnetic force at the top center of the end face of the slide valve 2 is equivalent to applying a force at the highest point of the slide valve 2. When the magnetic force is applied at this time, the torque generated can most effectively counteract the tendency of the slide valve 2 to "rise" or "fall" due to uneven gravity or gas force, thereby enhancing the linearity and stability of the slide valve 2's movement.

[0046] like Figure 2 As shown, in another further optimized embodiment, three moving magnets 23 are mounted on the end face of the slide valve 2, and the three moving magnets 23 are arranged in a triangular pattern. The three triangularly distributed magnetic modules form a magnetic force plane. This design ensures that the magnetic force applied to the slide valve 2 is evenly distributed on the end face, avoiding the additional torque that may be caused by single-point or asymmetrical force, and making the force on the slide valve more balanced.

[0047] To achieve automatic control of auxiliary loading and unloading, the stationary magnet 13 preferably uses an electromagnet capable of changing polarity. By controlling the direction and magnitude of the current in the electromagnet, its force on the moving magnet 23 can be changed in real time and precisely, generating both attractive and repulsive forces, and the strength of the magnetic force can be steplessly adjusted. This upgrades the magnetic module from a passive component to an active component. The controller can intelligently control the magnitude and direction of the magnetic force according to real-time operating conditions (such as exhaust pressure and load demand), achieving precise closed-loop control of the slide valve position. For example, during stable operation, only a small amount of magnetic force can be used for "fine-tuning" positioning, thereby reducing the energy consumption of the hydraulic cylinder and achieving energy-saving effects.

[0048] Figure 6 The diagram shows the loading process of the slide valve mechanism. The slide valve 2 moves towards the suction side, at which time the rotor increases the compression volume and the compressor's volumetric flow rate increases. Theoretically, the slide valve 2 fluctuates more at this time. At this time, the electromagnet is controlled by the circuit to make the stationary magnet 13 on the body 11 and the moving magnet 23 on the slide valve 2 attract each other, thus achieving the centering function and assisting the piston to complete the loading movement.

[0049] Figure 7 The diagram shows the unloading process of the slide valve mechanism. The slide valve 2 moves towards the exhaust side. At this time, the rotor reduces the compression volume and the compressor's volumetric flow rate decreases. Theoretically, the fluctuation of the slide valve 2 is relatively small at this time. At this time, the electromagnet is controlled by the circuit so that the stationary magnet 13 on the body 11 and the moving magnet 23 on the slide valve 2 are in a state of mutual repulsion. When the unloading reaches a certain level, the electromagnet circuit can be turned off to save energy.

[0050] like Figure 1 As shown, this utility model also proposes a screw compressor 1, including: a body 11, a pair of meshing rotors 4, and the aforementioned screw compressor slide valve mechanism.

[0051] Low-temperature, low-pressure refrigerant gas enters the compressor through the suction port, filling the inter-tooth volume of rotor 4. As rotor 4 rotates, the inter-tooth volume continuously increases, drawing in more gas. Once the inter-tooth volume passes the suction port, the compression process begins. Rotor 4 continues to rotate, causing the inter-tooth volume to continuously decrease, compressing the gas. The high-temperature, high-pressure oil-gas mixture, compressed to condensing pressure, is discharged from the compressor through the discharge port and enters subsequent components such as the oil separator.

[0052] In this process, the guiding structure of this invention plays a crucial role. When the slide valve 2 moves under the drive of the piston 3 and with magnetic assistance, the double guide rod structure ensures that the slide valve 2 moves strictly and smoothly along the axial direction without any shaking or deviation. This ensures that the end face of the slide valve 2 and the rotor 4 always maintain the optimal clearance, completely avoiding scratches caused by fluctuations. At the same time, the additional force provided by the magnetic module can quickly suppress any slight axial movement, making the slide valve positioning more precise and the capacity adjustment more linear and stable.

[0053] This utility model also proposes a refrigeration unit, including the aforementioned screw compressor 1. This unit, through the positioning guide rod 24 of the slide valve 2 and the magnetic module, fundamentally eliminates the axial fluctuation of traditional slide valves, preventing the risk of rotor abrasion caused by this, and greatly improving operational reliability and service life. Furthermore, the stable operating state also results in lower maintenance requirements and lower noise and vibration levels, making the unit more widely applicable and providing a better user experience.

[0054] It should be noted that the terminology used above is for describing specific embodiments only and is not intended to limit the exemplary embodiments according to this utility model. When the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. The order of execution of actions, steps, etc., in the apparatus and methods shown in the specification and drawings can be implemented in any order unless a specific express order is specified, and as long as the output of the preceding process is not used in the subsequent process. Similar sequential terms used for ease of description do not imply that such an order must be followed.

[0055] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as exemplary only and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0056] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A screw compressor slide valve mechanism, comprising: A slide valve and a piston, wherein the piston pushes the slide valve to move linearly within the body of a screw compressor; characterized in that a guide structure is provided between the slide valve and the body, the guide structure comprising: at least one positioning guide rod arranged along the moving direction of the slide valve, and a motion cavity that is inserted and engaged with the positioning guide rod, wherein the slide valve drives the positioning guide rod to move relative to the motion cavity when the slide valve moves.

2. The screw compressor slide valve mechanism according to claim 1, characterized in that, The guide structure includes two positioning guide rods, which are symmetrically distributed on both sides of the axis of the slide valve.

3. The screw compressor slide valve mechanism according to claim 1, characterized in that, The end of the positioning guide rod that is inserted into the motion cavity is a movable end, and the movable end is fitted with a square ring with a hole, which is supported between the positioning guide rod and the motion cavity.

4. The screw compressor slide valve mechanism according to claim 1, characterized in that, The end of the positioning guide rod away from the motion cavity is a fixed end, and the fixed end of the positioning guide rod is installed on the slide valve. The motion cavity is located on the machine body, and the opening of the motion cavity faces the slide valve.

5. The screw compressor slide valve mechanism according to any one of claims 1 to 4, characterized in that, Also includes: At least one pair of magnetic modules, each pair of magnetic modules consisting of a moving magnet and a stationary magnet arranged coaxially, the moving magnet being mounted on the slide valve, the stationary magnet being mounted on the machine body, the moving magnet moving synchronously with the slide valve to move closer to or further away from the stationary magnet.

6. The screw compressor slide valve mechanism according to claim 5, characterized in that, The moving magnet is mounted on the end face of the slide valve and is located at the top center of the end face.

7. The screw compressor slide valve mechanism according to claim 6, characterized in that, The end face of the slide valve is equipped with three moving magnets, which are arranged in a triangular pattern.

8. The screw compressor slide valve mechanism according to claim 5, characterized in that, The static magnet is an electromagnet capable of changing its polarity to attract or repel the moving magnet.

9. A screw compressor, characterized in that, include: The machine body, a pair of meshing rotors, and the screw compressor slide valve mechanism as described in any one of claims 1 to 8.

10. A refrigeration unit, characterized in that, include: The screw compressor according to claim 9.

Images