Compressor and Control Method

Abstract

This invention provides a compressor and its control method. The compressor includes a compressor body, a drive unit, a magnetic fluid sealing device, and a control unit. The compressor body has a first housing and an input shaft, with the input end of the input shaft located outside the first housing. The drive end of the drive unit is connected to the input end of the input shaft, and the drive unit is used to drive the input shaft to rotate. The magnetic fluid sealing device is sleeved on the input shaft, and at least a portion of the magnetic fluid sealing device is located inside the first housing, and the magnetic fluid sealing device is fixedly connected to the first housing. The drive unit is located on the side of the magnetic fluid sealing device away from the first housing. The magnetic fluid sealing device is filled with magnetic fluid, which is located on the outer wall of the input shaft to seal the input shaft through the magnetic fluid. The compressor of this invention effectively solves the technical problem of poor sealing performance of the input shaft in existing open-type screw compressors, which may lead to refrigerant leakage.

Description

Technical Field

[0001] This invention relates to the field of compressor technology, and more specifically to a compressor and its control method. Background Technology

[0002] In existing technologies, commonly used refrigeration screw compressors generally employ a fully enclosed structure. In this structure, the motor and compressor are coaxial and completely enclosed within a metal casing, with the motor's stator and rotor surrounded by refrigerant. The advantage of this design is its small overall size and prevention of refrigerant leakage. However, the disadvantages are also obvious: during compressor operation, the heat dissipated by the motor needs to be carried away through the refrigeration cycle system. In high-temperature environments, this heat load is significant, leading to poor motor heat dissipation and a high risk of overheating and burnout. Furthermore, motor heat dissipation consumes a portion of the refrigeration capacity. Simultaneously, the fully enclosed structure increases the difficulty of maintenance and repair. Additionally, the stator and rotor windings of the motor are immersed in gaseous or liquid refrigerant, requiring high insulation and chemical corrosion resistance, thus necessitating the use of specialized motors.

[0003] To address the aforementioned issues, open-type screw compressors have emerged. Compared to hermetic compressors, the power unit (such as the motor) and compressor unit of an open-type screw compressor are two independent components. The power unit drives the compressor via a drive shaft, pulley, coupling, or gears. The advantages of this structure are that the heat generated by the motor is cooled by a fan and is independent of the refrigeration cycle. Regardless of the heat load of the refrigeration system, it will not affect the motor's heat dissipation and normal operation, and the motor's heat dissipation does not consume energy from the refrigeration system. Furthermore, a mature, standard motor can be used. The separate structure of the open-type compressor also facilitates maintenance and upkeep.

[0004] However, open-type screw compressors also have significant drawbacks: increased overall size, and potential refrigerant leakage if the compressor input shaft seal is inadequate. Furthermore, the sealing rings require regular replacement, and their sealing performance may be unstable. Therefore, excessive refrigerant leakage can severely impact the operation and maintenance of the entire system and the compressor.

[0005] Therefore, the existing technology still needs further development. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a compressor and control method to solve the technical problem that the poor sealing performance of the input shaft of the open screw compressor in the prior art may lead to refrigerant leakage.

[0007] To achieve the above-mentioned technical objectives, according to one aspect of the present invention: a compressor is provided, comprising: a compressor body and a drive device, the compressor body having a first housing and an input shaft, the input end of the input shaft being located outside the first housing; a drive end of the drive device being connected to the input end of the input shaft, the drive device being used to drive the input shaft to rotate; a magnetic fluid sealing device sleeved on the input shaft, and at least a portion of the magnetic fluid sealing device being located within the first housing, the magnetic fluid sealing device being fixedly connected relative to the first housing; the drive device being located on the side of the magnetic fluid sealing device away from the first housing; the magnetic fluid sealing device being filled with magnetic fluid, the magnetic fluid being located on the outer wall of the input shaft to seal the input shaft by magnetic fluid; and a control device for acquiring a current first pressure value within the first housing and a current second pressure value outside the first housing, to adaptively adjust the magnetic field strength of the magnetic fluid according to the current first pressure value and the current second pressure value.

[0008] Furthermore, the magnetic fluid sealing device includes: a second housing, which is inserted into a first housing, with at least a portion of the second housing located within the first housing; the second housing and the first housing are fixedly connected relative to each other; the second housing has a first placement cavity and a second placement cavity, both extending along the axial direction of the input shaft; the first placement cavity is nested within the second placement cavity; the first placement cavity is filled with magnetic fluid; an electromagnet assembly is disposed within the second placement cavity to adjust the magnetic field strength of the magnetic fluid by switching the electromagnet assembly on and off; the electromagnet assembly is connected to a control device, which adaptively controls the on / off state of the electromagnet assembly according to a current first pressure value and a current second pressure value.

[0009] Furthermore, the second placement cavity is an annular chamber, and the electromagnet assembly includes at least two electromagnets, each electromagnet being sequentially sleeved on the outer wall of the first placement cavity along the extension direction of the second placement cavity; wherein, the control device adaptively controls the on / off state of each electromagnet according to the current first pressure value and the current second pressure value.

[0010] Furthermore, the magnetic fluid sealing device also includes: a permanent magnet assembly, which is disposed in the second placement cavity and sleeved on the outer wall of the first placement cavity; and an electromagnet assembly nested within the permanent magnet assembly.

[0011] Furthermore, the permanent magnet assembly includes: at least two permanent magnet rings, each permanent magnet ring being arranged sequentially along the extension direction of the second placement cavity; the magnetic poles of two adjacent permanent magnet rings in each permanent magnet ring are arranged in opposite directions; and the electromagnet assembly is nested within at least one of the permanent magnet rings.

[0012] Furthermore, the compressor also includes: a first pressure detection device, which is disposed on the magnetic fluid sealing device and located inside the first housing; the first pressure detection device is used to detect a first pressure value inside the first housing; the first pressure detection device is connected to a control device and sends the detected first pressure value inside the first housing to the control device.

[0013] Furthermore, the compressor also includes: a second pressure detection device, which is disposed on the magnetic fluid sealing device and located outside the first housing; the second pressure detection device is used to detect a second pressure value outside the first housing; the second pressure detection device is connected to the control device and sends the detected second pressure value outside the first housing to the control device.

[0014] Furthermore, the magnetic fluid sealing device includes: a second housing, the second housing having a first placement cavity, a flow cavity, and an inlet and an outlet respectively communicating with the flow cavity; the first placement cavity is nested within the flow cavity, and both the first placement cavity and the flow cavity extend along the axial direction of the input shaft; the first placement cavity is filled with magnetic fluid; the flow cavity is used for the flow of refrigerant, and the refrigerant enters the flow cavity through the inlet to exchange heat with the magnetic fluid; the refrigerant, after absorbing heat, flows out from the outlet.

[0015] Furthermore, the compressor body has a first suction port and a second suction port; the compressor also includes: a circulation pump, the input end of which is connected to the first suction port of the compressor body, and the output end of which is connected to the inlet; the circulation pump is used to extract refrigerant from the first suction port of the compressor body; the extracted refrigerant enters the flow chamber through the output end and the inlet of the circulation pump.

[0016] Furthermore, the compressor also includes: an electromagnetic expansion valve disposed between the circulating pump and the inlet, the output end of the circulating pump being connected to the inlet via the electromagnetic expansion valve; the electromagnetic expansion valve being used to regulate the flow rate and velocity of the refrigerant; and / or, a first pipeline connected to the outlet and the second suction port respectively, wherein the refrigerant flowing out from the outlet sequentially enters the compressor body through the first pipeline and the second suction port.

[0017] According to another aspect of the present invention, a control method is provided, which is applied to the compressor described above. The control method includes: acquiring a current first pressure value inside a first housing and a current second pressure value outside the first housing; and adaptively adjusting the magnetic field strength of the magnetic fluid in the magnetic fluid sealing device according to the current first pressure value and the current second pressure value.

[0018] Furthermore, the control method is applied to the compressor described above; the method for adaptively adjusting the magnetic field strength of the magnetic fluid within the magnetic fluid sealing device according to the current first pressure value and the current second pressure value includes: calculating the pressure difference between the current first pressure value and the current second pressure value, and controlling the on / off state of the electromagnet assembly according to the pressure difference; if the pressure difference is less than a first preset value, controlling the electromagnet assembly to be in an off state to maintain the current magnetic field strength of the magnetic fluid; if the pressure difference is greater than or equal to the first preset value, controlling at least a portion of the electromagnet assembly to switch to an on state, so as to adjust the magnetization intensity of the magnetic fluid through at least a portion of the electromagnet assembly in the on state.

[0019] Further, if the electromagnet assembly has N electromagnets, N≥2; each electromagnet is arranged sequentially along the axial direction of the input shaft; if the pressure difference is greater than a first preset value, control at least a portion of the electromagnet assembly to switch to an energized state, so as to adjust the magnetization intensity of the magnetic fluid by means of at least a portion of the electromagnet assembly in the energized state, the method includes: if the pressure difference is greater than or equal to the first preset value, adaptively controlling the number of electromagnets energized according to the pressure difference; wherein the number of electromagnets energized is proportional to the pressure difference.

[0020] Furthermore, the method for adaptively adjusting the magnetic field strength of the magnetic fluid within the magnetic fluid sealing device based on the current first pressure value and the current second pressure value further includes: if the pressure difference changes frequently within a first preset time period, controlling the electromagnet assembly to switch to an energized state, so as to adjust the magnetization intensity of the magnetic fluid through the energized electromagnet assembly.

[0021] Furthermore, the control method is applied to the compressor described above, and the control method further includes: calculating the pressure difference between the current first pressure value and the current second pressure value, so as to control the electromagnetic expansion valve according to the pressure difference; if the pressure difference is less than a first preset value, controlling the opening of the electromagnetic expansion valve to maintain at a preset opening; if the pressure difference is greater than or equal to the first preset value, increasing the opening of the electromagnetic expansion valve according to the pressure difference; wherein, controlling the opening of the electromagnetic expansion valve is proportional to the pressure difference.

[0022] Beneficial effects:

[0023] The compressor provided by this invention, using the technical solution of the present invention, includes: a compressor body, a drive device, a magnetic fluid sealing device, and a control device. The compressor body has a first housing and an input shaft, wherein the input end of the input shaft is located outside the first housing, the drive device is located on one side of the compressor body, and the drive end of the drive device is connected to the input end of the input shaft, thereby driving the rotation of the input shaft to complete the compression of the refrigerant by the compressor. Simultaneously, a magnetic fluid sealing device is provided on the side of the first housing near the drive device. The magnetic fluid sealing device is sleeved on the input shaft and inserted into the first housing, such that a portion of the magnetic fluid sealing device is located inside the first housing. The magnetic fluid sealing device is fixedly connected to the first housing, and the drive device is located on the side of the magnetic fluid sealing device away from the first housing. The magnetic fluid sealing device is filled with magnetic fluid forming a dynamic seal. The magnetic fluid is located on the outer wall of the input shaft, i.e., the magnetic fluid surrounds the portion of the input shaft located inside the magnetic fluid sealing device, ensuring that the magnetic fluid seals the input shaft, thereby preventing refrigerant leakage along the outer wall of the input shaft. Furthermore, the control device is connected to the magnetohydrodynamic (MHD) sealing device, and the control device is used to acquire the current first pressure value inside the first housing and the current second pressure value outside the first housing, so as to adaptively adjust the magnetic field strength of the MHD based on the current first pressure value and the current second pressure value. Thus, the MHD sealing device, through a dynamic sealing mechanism, ensures a tight seal between the input shaft and the first housing, effectively preventing refrigerant leakage and avoiding leakage of lubricating oil from the compressor body when the drive device rotates at high speed, thereby improving system reliability. Moreover, the positioning design of the MHD sealing device effectively seals the interface between the input shaft and the first housing. In addition, the MHD, as a liquid seal, forms a contact seal with the input shaft, avoiding direct friction between the input shaft and the seal, reducing additional load. Simultaneously, by acquiring the current first pressure value inside the first housing and the current second pressure value outside the first housing, and adaptively adjusting the magnetic field strength of the MHD based on the current first pressure value and the current second pressure value, this process effectively controls the magnetic field strength in the MHD movement space, ensuring the stability and reliability of the dynamic seal, and ensuring that the sealing layer is always in optimal condition to meet the needs of different operating conditions. Furthermore, by providing a magnetohydrodynamic sealing device on the side of the first housing near the drive unit, the problem of frequent replacement of the sealing shaft ring is avoided, reducing maintenance costs and thus improving the compressor's energy efficiency and equipment lifespan. The compressor of this invention effectively solves the technical problem of poor sealing performance of the input shaft in existing open-type screw compressors, which may lead to refrigerant leakage. Attached Figure Description

[0024] Figure 1 A first-view structural schematic diagram of an embodiment of the compressor of the present invention is shown;

[0025] Figure 2 A second-view structural schematic diagram of an embodiment of the compressor of the present invention is shown;

[0026] Figure 3 A schematic diagram of the magnetic fluid sealing device in an embodiment of the compressor of the present invention is shown;

[0027] Figure 4 A flowchart illustrating an embodiment of the control method of the present invention is shown.

[0028] The above figures include the following reference numerals:

[0029] 1. Compressor body; 11. First housing; 12. Input shaft; 13. First suction port; 14. Second suction port; 15. Compression component; 2. Drive unit; 21. Drive body; 22. Drive shaft; 3. Magnetohydrodynamic sealing device; 31. Second housing; 311. First placement chamber; 312. Second placement chamber; 313. Flow chamber; 314. Inlet; 315. Outlet; 33. Electromagnet assembly; 331. Electromagnet; 34. Permanent magnet assembly; 341. Permanent magnet ring; 4. First pressure detection device; 5. Second pressure detection device; 6. Circulation pump; 7. Electromagnetic expansion valve; 8. First pipeline; 9. Coupling. Detailed Implementation

[0030] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0031] Please see Figures 1 to 3As shown in the embodiment of the present invention, the present invention provides a compressor, including: a compressor body 1, a drive device 2, a magnetic fluid sealing device 3, and a control device. The compressor body 1 has a first housing 11 and an input shaft 12, the input end of the input shaft 12 being located outside the first housing 11; the drive end of the drive device 2 is connected to the input end of the input shaft 12, and the drive device 2 is used to drive the input shaft 12 to rotate; the magnetic fluid sealing device 3 is sleeved on the input shaft 12, and at least a portion of the magnetic fluid sealing device 3 is located inside the first housing 11, and the magnetic fluid sealing device 3 is fixedly connected to the first housing 11; the drive device 2 is located on the side of the magnetic fluid sealing device 3 away from the first housing 11; the magnetic fluid sealing device 3 is filled with magnetic fluid, and the magnetic fluid is located on the outer wall of the input shaft 12 to seal the input shaft 12 by means of magnetic fluid; the control device is used to obtain a current first pressure value inside the first housing 11 and a current second pressure value outside the first housing 11, so as to adaptively adjust the magnetic field strength of the magnetic fluid according to the current first pressure value and the current second pressure value.

[0032] As can be seen, the compressor provided by the present invention includes: a compressor body 1, a drive device 2, a magnetic fluid sealing device 3, and a control device. The compressor body 1 has a first housing 11 and an input shaft 12, wherein the input end of the input shaft 12 is located outside the first housing 11, the drive device 2 is located on one side of the compressor body 1, and the drive end of the drive device 2 is connected to the input end of the input shaft 12, thereby driving the rotation of the input shaft 12 to complete the compression of the refrigerant by the compressor. Meanwhile, a magnetic fluid sealing device 3 is provided on the side of the first housing 11 near the drive device 2. The magnetic fluid sealing device 3 is sleeved on the input shaft 12 and inserted into the first housing 11, such that a portion of the magnetic fluid sealing device 3 is located inside the first housing 11. The magnetic fluid sealing device 3 is fixedly connected to the first housing 11, and the drive device 2 is located on the side of the magnetic fluid sealing device 3 away from the first housing 11. The magnetofluid sealing device 3 is filled with magnetofluid to form a dynamic seal. The magnetofluid is located on the outer wall of the input shaft 12 (i.e., the magnetofluid surrounds the portion of the input shaft 12 located within the magnetofluid sealing device 3), ensuring that the input shaft 12 is sealed by the magnetofluid, thereby preventing refrigerant leakage along the outer wall of the input shaft 12. Furthermore, a control device is connected to the magnetofluid sealing device 3, and the control device is used to acquire a current first pressure value within the first housing 11 and a current second pressure value outside the first housing 11, so as to adaptively adjust the magnetic field strength of the magnetofluid based on the current first pressure value and the current second pressure value.

[0033] Therefore, the magnetic fluid sealing device 3, through a dynamic sealing mechanism, ensures a tight seal between the input shaft 12 and the first housing 11, effectively preventing refrigerant leakage and avoiding lubricant leakage from the compressor body 1 when the drive unit 2 rotates at high speed, thereby improving system reliability. Furthermore, the positional design of the magnetic fluid sealing device 3 effectively seals the interface between the input shaft 12 and the first housing 11. In addition, the magnetic fluid, acting as a liquid seal, forms a contact seal with the input shaft 12, avoiding direct friction between the input shaft and the seal, reducing additional load. Simultaneously, the control device acquires the current first pressure value inside the first housing 11 and the current second pressure value outside the first housing 11. Based on these values, the magnetic field strength of the magnetic fluid is adaptively adjusted. This process effectively controls the magnetic field strength in the magnetic fluid movement space, ensuring the stability and reliability of the dynamic seal and guaranteeing that the sealing layer is always in optimal condition to adapt to different operating conditions. Furthermore, by placing the magnetic fluid sealing device 3 on the side of the first housing 11 near the drive unit, the problem of frequent replacement of the sealing ring is avoided, reducing maintenance costs and thus improving the compressor's energy efficiency and equipment lifespan. The compressor of the present invention effectively solves the technical problem of poor sealing performance of the input shaft of the existing open screw compressor, which may lead to refrigerant leakage.

[0034] Optionally, the compressor is an open-type screw compressor.

[0035] Optionally, the magnetohydrodynamic seal utilizes the principle of dynamic sealing, which can actively adjust the sealing strength according to the system's operating state. This dynamic characteristic allows the magnetohydrodynamic seal device 3 to maintain a stable sealing effect under different operating conditions, adapting to conditions such as high-speed compressor rotation.

[0036] Magnetofluid is a liquid material that, under the influence of an external magnetic field, forms a liquid sealing layer between the input shaft and the housing. This sealing layer not only effectively prevents refrigerant leakage but also prevents lubricating oil escape. Due to the fluidity and adjustability of the magnetofluid, it can simultaneously surround and isolate two fluids in a liquid-sealed mode.

[0037] Furthermore, the drive device 2 includes a drive body 21 and a drive shaft 22. The two ends of the drive shaft 22 are respectively connected to the drive body 21 and the input end of the input shaft 12. The end of the drive shaft 22 close to the input shaft 12 forms the drive end of the drive device 2.

[0038] Optionally, the axis of the drive shaft 22 is set to coincide with the axis of the input shaft 12 (i.e., the drive shaft 22 and the input shaft 12 are coaxial and collinear). This design ensures precise transmission between the drive unit 2 and the compressor body 1, reduces mechanical vibration and wear, and improves the stability and efficiency of the system.

[0039] Optionally, the drive unit 2 is a motor.

[0040] Furthermore, the compressor also includes a coupling 9, the drive end of the drive unit 2 being connected to the input end of the input shaft 12 via the coupling 9.

[0041] Furthermore, the compressor body 1 also includes a compression component 15, which is located within the first housing 11 and is used to compress the refrigerant. The input end of the input shaft 12 is connected to the compression component 15. When the drive device 2 drives the input shaft 12 to rotate, the rotation of the input shaft 12 drives the compression component 15 to move, thereby realizing the compression of the refrigerant.

[0042] Specifically, such as Figure 1 and Figure 3 As shown, the magnetohydrodynamic sealing device 3 includes: a second housing 31 and an electromagnet assembly 33. The second housing 31 is inserted into the first housing 11, and at least a portion of the second housing 31 is located within the first housing 11. The second housing 31 is fixedly connected to the first housing 11. The second housing 31 has a first placement cavity 311 and a second placement cavity 312, both extending along the axial direction of the input shaft 12. The first placement cavity 311 is nested within the second placement cavity 312. The first placement cavity 311 is filled with magnetohydrodynamic fluid. The electromagnet assembly 33 is disposed within the second placement cavity 312 to adjust the magnetic field strength of the magnetohydrodynamic fluid by switching the electromagnet assembly 33 on and off. The electromagnet assembly 33 is connected to a control device, which adaptively controls the on / off state of the electromagnet assembly 33 according to the current first pressure value and the current second pressure value. With this structural arrangement, the second housing 31 has a first placement cavity 311 and a second placement cavity 312 inside, wherein the first placement cavity 311 is nested within the second placement cavity 312. This design facilitates effective isolation between the magnetofluid and the electromagnet assembly 33. Furthermore, by placing the electromagnet assembly 33 within the second placement cavity 312, the magnetic field strength of the magnetofluid can be enhanced when the electromagnet assembly 33 is partially energized, thereby increasing the saturation magnetization of the magnetofluid. This ensures more stable sealing performance of the magnetofluid sealing device 3.

[0043] Electromagnets generate magnetic fields through current-carrying conductors. When current flows through the electromagnet coil, a magnetic field is formed around it, and the strength of the magnetic field is proportional to the magnitude of the current and the number of turns of the coil. Magnetofluids are liquids containing ferromagnetic particles that exhibit magnetism under the influence of an external magnetic field. Their saturation magnetization represents the maximum magnetic effect achievable by a magnetofluid under a strong magnetic field. A stronger external magnetic field can cause the magnetic particles in the magnetofluid to align more effectively, thereby improving its magnetic field-based performance. Magnetofluids circulate under the influence of a strong magnetic field, thus forming a physical seal.

[0044] Therefore, even with partial energization, the magnetic field generated by the electromagnet assembly 33 when energized is sufficient to enhance the arrangement of particles within the magnetofluid, thereby increasing its saturation magnetization. This means that the magnetofluid's ability to resist external influences is enhanced under the influence of an external magnetic field, thus improving the sealing effect.

[0045] Meanwhile, the magnetofluid sealing device 3 relies on the magnetism of the magnetofluid to form a reliable seal. Under the influence of a stronger magnetic field, the retention and pressure-bearing capacity of the magnetofluid are enhanced, effectively preventing liquid or gas leakage. Furthermore, the increased saturation magnetization ensures that the sealing performance remains stable under different operating conditions (such as temperature and pressure changes), making it less susceptible to external influences.

[0046] Optionally, the second housing 31 is a cylindrical annular housing, and both the first placement cavity 311 and the second placement cavity 312 are annular cavities, with the first placement cavity 311 nested inside the second placement cavity 312.

[0047] Optionally, the second housing 31 is made of non-magnetic bronze.

[0048] Optionally, when the magnetohydrodynamic sealing device 3 is mounted on the input shaft 12, a portion of the input shaft 12 is located within the first placement cavity 311.

[0049] Specifically, such as Figure 3As shown, the second placement cavity 312 is an annular chamber. The electromagnet assembly 33 includes at least two electromagnets 331, each electromagnet 331 being sequentially sleeved on the outer wall of the first placement cavity 311 along the extension direction of the second placement cavity 312. The control device adaptively controls the on / off state of each electromagnet 331 based on the current first and second pressure values. With this structural arrangement, the control device automatically adjusts the on / off state of each electromagnet 331 according to the current first and second pressure values, thereby ensuring that the magnetic field strength of the magnetic fluid is always at its optimal state, thus enabling the magnetic fluid sealing device 3 to adapt to different working conditions. Furthermore, it can control the number of electromagnets energized according to actual conditions, thereby reducing unnecessary energy consumption and improving system energy efficiency. In addition, dynamically adjusting the number of electromagnets 331 energized reduces excessive load on mechanical components, lowers the risk of wear, and extends the service life of the equipment. It also allows for more precise magnetic field strength adjustment, ensuring the stability and reliability of the sealing layer.

[0050] Optionally, the control device may select to energize or de-energize all electromagnets 331 based on the current first pressure value and the current second pressure value, or it may select to energize only some of the electromagnets 331. In other words, the control device will control the number of electromagnets 331 energized according to the actual situation.

[0051] Specifically, such as Figure 2 As shown, the magnetofluid sealing device 3 further includes: a permanent magnet assembly 34, which is disposed within the second placement cavity 312 and sleeved on the outer wall of the first placement cavity 311; and an electromagnet assembly 33 nested within the permanent magnet assembly 34. This structural arrangement, by incorporating the permanent magnet assembly 34, provides a constant magnetic field for the magnetofluid, helping to maintain the optimal working state of the magnetofluid when the electromagnet assembly 33 is not energized, thereby ensuring the stability of the sealing effect. The nested design of the permanent magnet assembly 34 and the electromagnet assembly 33 makes the overall structure more compact, helping to reduce the size of the device while improving system reliability and ease of maintenance. Simultaneously, when a rapid restoration or change in the magnetofluid state is required, the permanent magnet assembly 34 can respond instantly, combined with the rapid changes in the electromagnet assembly 33, providing support for the system to quickly adjust the sealing effect of the magnetofluid. Furthermore, by effectively utilizing the static magnetic field, the permanent magnet assembly 34 reduces the current input requirement, saving energy and improving system energy efficiency. Furthermore, the combination of the permanent magnet assembly 34 and the electromagnet assembly 33 enhances the magnetic field effect of the magnetofluid when the electromagnet assembly 33 is energized. This synergistic effect increases the saturation magnetization of the magnetofluid, further enhancing the sealing effect and reducing the risk of liquid or gas leakage.

[0052] Specifically, such as Figure 2 As shown, the permanent magnet assembly 34 includes at least two permanent magnet rings 341, which are sequentially arranged along the extension direction of the second placement cavity 312; the magnetic poles of adjacent permanent magnet rings 341 are arranged in opposite directions; and an electromagnet assembly 33 is nested within at least one of the permanent magnet rings 341. Each permanent magnet ring 341 is fitted onto the outer wall of the first placement cavity 311. This structural arrangement, with the opposite orientation of adjacent permanent magnet rings 341, effectively enhances the density and uniformity of the magnetic field, forming a stronger comprehensive magnetic field, which is crucial for improving the saturation magnetization and sealing performance of the magnetic fluid. By setting multiple permanent magnet rings 341, the influence of magnetic field changes on equipment performance can be effectively dispersed, enhancing the stability of the magnetic fluid sealing device 3 under harsh environments such as high temperature and high pressure. Furthermore, the nested design of the electromagnet assembly 33 allows it to quickly respond to external signals with the assistance of the permanent magnetic field, thereby adjusting the sealing effect in a timely manner and adapting to rapidly changing working environments.

[0053] Optionally, each permanent magnet ring 341 is made of permanent magnet material, and each extreme end is attached to a magnetic pole made of No. 45 steel. This combination forms a "magnetic source" of a pole segment. Each group of "magnetic sources" is connected in series axially with NN and SS directions in opposite directions.

[0054] Specifically, such as Figure 1 As shown, the compressor also includes: a first pressure detection device 4, which is mounted on the magnetic fluid sealing device 3 and located inside the first housing 11; the first pressure detection device 4 is used to detect a first pressure value inside the first housing 11; the first pressure detection device 4 is connected to the control device and sends the detected first pressure value inside the first housing 11 to the control device. With this structural arrangement, the first pressure detection device 4 can monitor the pressure changes inside the first housing 11 in real time and promptly feed the data back to the control device, ensuring that the control system always has the latest operating condition information. Based on the accurate data provided by the first pressure detection device 4, the control device precisely adjusts the on / off state of the electromagnet assembly 33 to ensure that the magnetic field strength of the magnetic fluid is always at its optimal state, improving sealing performance.

[0055] Specifically, such as Figure 1As shown, the compressor also includes a second pressure detection device 5, which is mounted on the magnetic fluid sealing device 3 and located outside the first housing 11. The second pressure detection device 5 is used to detect a second pressure value outside the first housing 11. The second pressure detection device 5 is connected to the control device and sends the detected second pressure value outside the first housing 11 to the control device. With this structural arrangement, the second pressure detection device 5 can monitor pressure changes outside the first housing 11 in real time and promptly feed the data back to the control device, ensuring that the control system always has the latest operating condition information. Based on the internal and external pressure difference data, the control device precisely adjusts the on / off state of the electromagnet assembly 33 to ensure that the magnetic field strength of the magnetic fluid is always at its optimal state, improving sealing performance. Furthermore, based on the internal and external pressure difference data, the control system can dynamically adjust the number of electromagnets energized according to actual needs, achieving intelligent adjustment to adapt to different operating conditions.

[0056] Optionally, the first pressure detection device 4 and the second pressure detection device 5 are spaced apart on the magnetic fluid sealing device 3 along the axial direction of the input shaft 12.

[0057] Furthermore, when the control device acquires the first pressure value and the second pressure value, it determines whether to energize based on the pressure difference between the first pressure value and the second pressure value, so that at least a portion of the electromagnet assembly 33 is in an energized state.

[0058] Optionally, since the internal pressure of the compressor body 1 (i.e., the first pressure inside the first housing 11) is much greater than the external pressure (i.e., the second pressure outside the first housing 11), the liquid in the compressor body 1 will be more easily thrown out during the rotation of the input shaft 12. Therefore, it is necessary to control at least part of the electromagnet assembly 33 to be in an energized state, thereby further enhancing the magnetic field strength of the magnetic fluid. The magnetic fluid experiences greater force in the magnetic field, its movement speed is faster, and the formed liquid seal will be more stable.

[0059] Optionally, the outer wall of each permanent magnet ring 341 abuts against the inner wall of the second placement cavity 312, thereby fixing each permanent magnet ring 341 inside the second placement cavity 312.

[0060] Specifically, such as Figure 3As shown, the magnetohydrodynamic sealing device 3 includes: a second housing 31, which has a first placement cavity 311, a flow cavity 313, and an inlet 314 and an outlet 315 respectively communicating with the flow cavity 313; the first placement cavity 311 is nested within the flow cavity 313, and both the first placement cavity 311 and the flow cavity 313 extend along the axial direction of the input shaft 12; the first placement cavity 311 is filled with magnetohydrodynamic fluid; the flow cavity 313 is used for the flow of refrigerant, which enters the flow cavity 313 through the inlet 314 to exchange heat with the magnetohydrodynamic fluid; the refrigerant, after absorbing heat, flows out from the outlet 315. With this structural arrangement, the flow cavity 313 facilitates the flow of refrigerant, realizes heat exchange between the refrigerant and the magnetohydrodynamic fluid, thereby reducing the temperature of the magnetohydrodynamic fluid, reducing magnetic field fluctuations that may be caused by temperature increases, and thus improving the stability of the magnetohydrodynamic magnetic field. The magnetohydrodynamic sealing device 3 has a simple structure, is easy to install and replace, reduces the compressor assembly time, and improves working efficiency. The magnetohydrodynamic sealing device 3 is more suitable for large commercial units such as open-type screw compressors.

[0061] Optionally, the movement of the magnetohydrodynamic fluid generates heat, which can affect the stability of the magnetic field. Therefore, by introducing refrigerant into the flow cavity 313 and circulating the refrigerant, the heat generated during the movement of the magnetohydrodynamic fluid is carried away, thereby maintaining the stability of the magnetohydrodynamic magnetic field.

[0062] Optionally, the first placement cavity 311 is nested within the second placement cavity 312, which in turn is nested within the flow cavity 313. Refrigerant flows into the flow cavity 313 to exchange heat with the permanent magnet assembly 34 and the electromagnet assembly 33. Furthermore, the heat generated when the electromagnet is energized can be effectively absorbed.

[0063] Optionally, the second housing 31 is a cylindrical annular housing and adopts a double-layer hollow design, with the hollow part in the middle forming a flow cavity 313.

[0064] Specifically, such as Figure 2As shown, the compressor body has a first suction port 13 and a second suction port 14. The compressor also includes a circulation pump 6, whose input end is connected to the first suction port 13 of the compressor body 1, and whose output end is connected to an inlet 314. The circulation pump 6 is used to draw refrigerant from the first suction port 13 of the compressor body 1. The drawn refrigerant enters the flow chamber 313 through the output end of the circulation pump 6 and the inlet 314. With this structural arrangement, by setting up the circulation pump 6, the refrigerant can be introduced into the flow chamber 313, enhancing the working environment stability of the magnetic fluid sealing device 3, ensuring that the magnetic fluid works in optimal condition, and improving the sealing effect. The introduction of the circulation pump 6 allows the refrigerant to circulate effectively within the system. By precisely controlling the flow path of the refrigerant, the coordinated work between various components is ensured, optimizing the performance and reliability of the entire compressor system. Furthermore, by connecting the circulation pump 6 to the first suction port 13, it is convenient to introduce low-temperature refrigerant (uncompressed refrigerant) into the flow chamber 313, thereby effectively reducing the temperature of the magnetic fluid.

[0065] Specifically, such as Figure 2 As shown, the compressor also includes an electromagnetic expansion valve 7, which is located between the circulating pump 6 and the inlet 314. The output end of the circulating pump 6 is connected to the inlet 314 via the electromagnetic expansion valve 7. The electromagnetic expansion valve 7 is used to regulate the flow rate and velocity of the refrigerant. This structural arrangement allows for precise adjustment of the refrigerant flow rate and velocity according to actual needs, ensuring the system is always in optimal operating condition and improving system stability and reliability. Precise control of the refrigerant flow rate and velocity ensures smooth refrigerant flow within the magnetohydrodynamic sealing device 3, enhancing the sealing effect and reducing the risk of leakage. Furthermore, precise adjustment of the refrigerant flow rate and velocity helps optimize system efficiency, reduce unnecessary energy consumption, and improve system energy efficiency. In addition, the electromagnetic expansion valve 7 can flexibly adjust the refrigerant flow rate and velocity according to different operating conditions, enabling the system to better adapt to various operating conditions and improving system flexibility and applicability.

[0066] Furthermore, the electromagnetic expansion valve 7 is connected to a control device, which adaptively adjusts the opening of the electromagnetic expansion valve 7 according to the current first pressure value and the current second pressure value.

[0067] Optionally, if the pressure difference between the current first pressure value and the current second pressure value is too large, the heat generated by the magnetofluid will increase significantly. In order to effectively dissipate heat and maintain the stable operation of the system, the control device controls the electromagnetic expansion valve 7 to increase its opening, thereby increasing the refrigerant flow rate and volume. In this way, more refrigerant is introduced into the flow chamber 313, quickly carrying away the heat generated by the magnetofluid and the electromagnet 331 after energization, thereby maintaining the stable operation of the magnetic field.

[0068] Specifically, such as Figure 2 As shown, the compressor also includes a first pipe 8, which is connected to an outlet 315 and a second suction port 14. The refrigerant flowing out of the outlet 315 passes through the first pipe 8 and the second suction port 14 in sequence and enters the compressor body 1. With this structural arrangement, the design of the first pipe 8 ensures that the refrigerant can circulate efficiently within the system, avoiding refrigerant stagnation in the magnetohydrodynamic sealing device 3 and improving the system's refrigeration efficiency.

[0069] This invention provides a control method, which is applied to the compressor in the above embodiments, such as... Figure 4 As shown, the control methods include:

[0070] S11, obtain the current first pressure value inside the first housing 11 and the current second pressure value outside the first housing 11;

[0071] S12, to adaptively adjust the magnetic field strength of the magnetic fluid within the magnetic fluid sealing device 3 according to the current first pressure value and the current second pressure value.

[0072] By adopting this control method, the magnetic field strength of the magnetofluid is adaptively adjusted according to the current first pressure value and the current second pressure value. This process can effectively control the magnetic field strength in the magnetofluid movement space, ensure the stability and reliability of the dynamic seal, and ensure that the sealing layer is always in the best condition to meet the needs of different working conditions.

[0073] Specifically, the method for adaptively adjusting the magnetic field strength of the magnetic fluid within the magnetic fluid sealing device 3 based on the current first pressure value and the current second pressure value includes: calculating the pressure difference between the current first pressure value and the current second pressure value, and controlling the on / off state of the electromagnet assembly 33 according to the pressure difference; if the pressure difference is less than a first preset value, controlling the electromagnet assembly 33 to be in an off-state to maintain the current magnetic field strength of the magnetic fluid; if the pressure difference is greater than or equal to the first preset value, controlling at least a portion of the electromagnet assembly 33 to switch to an energized state, so as to adjust the magnetization intensity of the magnetic fluid through at least a portion of the energized electromagnet assembly 33. This control method dynamically adjusts the magnetic field strength of the magnetic fluid according to the actual pressure difference, ensuring optimal sealing performance under different operating conditions and effectively preventing refrigerant leakage. Furthermore, by real-time monitoring and automatic adjustment of the on / off state of the electromagnet assembly according to the pressure difference, the magnetic field strength of the magnetic fluid is always kept at its optimal state, improving the system's reliability and response speed. Simultaneously, when the pressure difference is small, the electromagnet assembly remains in an off-state, reducing unnecessary energy consumption and improving the system's energy efficiency.

[0074] The first preset value refers to a pre-set pressure difference threshold, which is used to determine whether the on / off state of the electromagnet assembly needs to be adjusted.

[0075] Optionally, when the pressure difference is less than the first preset value, it indicates that the pressure inside the compressor body 1 is not significantly different from the pressure outside the compressor body 1, and the liquid inside the compressor body 1 is unlikely to leak out. In this case, maintaining the magnetic field strength of the permanent magnet is sufficient. When the pressure difference is greater than or equal to the first preset value, it indicates that the pressure inside the compressor body 1 is too different from the pressure outside the compressor body 1, and the liquid inside the compressor body 1 is easily thrown out. Therefore, it is necessary to control at least a portion of the electromagnet assembly 33 to be in an energized state, thereby further enhancing the magnetic field strength of the magnetic fluid. The magnetic fluid experiences greater force in the magnetic field, its movement speed is faster, and the formed liquid seal will be more stable.

[0076] Specifically, if the electromagnet assembly 33 has N electromagnets 331, where N≥2; each electromagnet 331 is sequentially arranged along the axial direction of the input shaft 12; if the pressure difference is greater than or equal to a first preset value, at least a portion of the electromagnet assembly 33 is controlled to switch to an energized state, and the magnetization intensity of the magnetic fluid is adjusted by the at least portion of the electromagnet assembly 33 in the energized state, the method includes: if the pressure difference is greater than or equal to the first preset value, adaptively controlling the number of electromagnets 331 energized according to the pressure difference; wherein the number of electromagnets 331 energized is proportional to the pressure difference. Using this control method, when the pressure difference is greater than or equal to the first preset value, the number of electromagnets energized is automatically adjusted according to the actual pressure difference, thereby ensuring that the magnetic field strength of the magnetic fluid is always in an optimal state, thus improving the reliability and response speed of the system. Furthermore, dynamically adjusting the number of electromagnets energized reduces unnecessary energy consumption and improves the energy efficiency of the system. Also, it achieves finer magnetic field strength adjustment, ensuring the stability and reliability of the sealing layer. The system's overall safety is enhanced through effective pressure difference monitoring and magnetic field strength adjustment mechanisms. Furthermore, the system can flexibly adjust the magnetic field strength according to different operating conditions, thereby improving its applicability and flexibility.

[0077] Furthermore, if the pressure difference is greater than or equal to the first preset value, the number of electromagnets 331 energized will also increase as the pressure difference increases.

[0078] For example, there are three electromagnets 331. When the pressure difference is greater than or equal to a first preset value, and less than a second preset value, one electromagnet 331 is energized, thus putting it in an on-state. If the pressure difference is greater than or equal to the second preset value and less than a third preset value, two electromagnets 331 are energized. If the pressure difference is greater than or equal to the third preset value, all electromagnets 331 are energized. When the pressure difference is less than the first preset value, all electromagnets 331 are de-energized. The first preset value is less than the second preset value, and the second preset value is less than the third preset value.

[0079] Specifically, the method for adaptively adjusting the magnetic field strength of the magnetic fluid within the magnetic fluid sealing device 3 based on the current first pressure value and the current second pressure value further includes: if the pressure difference changes frequently within a first preset time period, controlling the electromagnet assembly 33 to switch to an energized state, so as to adjust the magnetization intensity of the magnetic fluid by means of the energized electromagnet assembly 33. Using this control method, in the case of frequent pressure difference changes, by timely adjusting the energization state of the electromagnet assembly 33, a stable magnetic field strength is effectively maintained, improving the overall stability of the system. It also enables rapid response to frequently changing pressure differences, ensuring that the magnetization intensity of the magnetic fluid is always kept at an optimal state, preventing seal failure due to pressure fluctuations. Simultaneously, by real-time monitoring and automatically adjusting the energization state of the electromagnet assembly 33 according to changes in pressure difference, the magnetic field strength of the magnetic fluid is always kept at an optimal state, improving the reliability and response speed of the system.

[0080] Furthermore, if the pressure difference changes frequently within the first preset time, all electromagnets 331 are controlled to be energized to adjust the magnetic field strength of the magnetic fluid to the maximum, thereby ensuring optimal sealing.

[0081] Specifically, the control method further includes: calculating the pressure difference between the current first pressure value and the current second pressure value, and controlling the electromagnetic expansion valve 7 according to the pressure difference; if the pressure difference is less than a first preset value, controlling the opening of the electromagnetic expansion valve 7 to maintain a preset opening; if the pressure difference is greater than or equal to the first preset value, increasing the opening of the electromagnetic expansion valve 7 according to the pressure difference; wherein, the opening of the electromagnetic expansion valve 7 is proportional to the pressure difference. Using this control method, the opening of the electromagnetic expansion valve 7 is dynamically adjusted according to the actual pressure difference, ensuring that the refrigerant flow rate and velocity are always at their optimal state, thus improving the stability and reliability of the system. When the pressure difference is less than the first preset value, maintaining the electromagnetic expansion valve 7 at the preset opening reduces unnecessary energy consumption and improves the system's energy efficiency. When the pressure difference is greater than or equal to the first preset value, increasing the opening of the electromagnetic expansion valve 7 increases the refrigerant velocity and flow rate, thereby allowing more refrigerant to be introduced into the flow chamber 313, quickly carrying away the heat generated by the magnetic fluid and electromagnet 331 after energization, thus effectively dissipating heat and maintaining stable system operation and magnetic field operation.

[0082] Furthermore, if the pressure difference is greater than or equal to the first preset value, the opening of the electromagnetic expansion valve 7 will be gradually increased as the pressure difference increases.

[0083] Optionally, the compressor control process is as follows:

[0084] The magnetohydrodynamic sealing device has multiple permanent magnet rings 341 and multiple electromagnets 331.

[0085] Step 1: When the compressor is working, the drive device 2 drives the input shaft 12 to rotate, thereby driving the compression component of the compressor body 1 to move, so as to compress the refrigerant. At the same time, when the compressor is working, the first pressure detection device 4 and the second pressure detection device 5 respectively detect the first pressure value inside the first housing 11 and the second pressure value outside the first housing 11 in real time, and send the detected first pressure value and second pressure value to the control device.

[0086] Step 2: After acquiring the first and second pressure values, the control device calculates the pressure difference between them and compares it with a first preset value. If the pressure difference is less than the first preset value, a stable magnetic field is provided to the magnetofluid through the permanent magnet assembly 34, and all electromagnets 331 are de-energized. If the pressure difference is greater than or equal to the first preset value, the number of electromagnets 331 to be energized is determined based on the calculated pressure difference, and then the corresponding number of electromagnets 331 are energized. Specifically, as the pressure difference increases, the number of energized electromagnets 331 increases accordingly.

[0087] Step 3: If the pressure difference changes frequently within the first preset time, control each electromagnet 331 to be energized, thereby increasing the magnetic field strength of the magnetofluid to the maximum.

[0088] Step 4: After the compressor is turned on, the circulation pump 6 starts, adjusting the opening of the electromagnetic expansion valve 7 to the preset opening. The refrigerant at low temperature at the first suction port 13 passes sequentially through the circulation pump 6, the electromagnetic expansion valve 7, and the inlet 314 into the flow chamber 313. Then, the refrigerant exchanges heat with the magnetic fluid, absorbing the heat generated by the magnetic fluid. The refrigerant, after absorbing heat, flows out through the outlet 315, and then enters the compressor body 1 (i.e., the compression component 15) through the first pipe 8 and the second suction port 14.

[0089] Step 5: During operation, if the pressure difference is less than the first preset value, the opening of the electromagnetic expansion valve 7 is maintained at the preset opening. If the pressure difference is greater than or equal to the first preset value, the opening of the electromagnetic expansion valve 7 is determined based on the calculated pressure difference. Then, the opening of the electromagnetic expansion valve 7 is adjusted. Specifically, as the pressure difference increases, the opening of the electromagnetic expansion valve 7 is gradually increased.

[0090] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0091] Optionally, specific examples in this embodiment can refer to the examples described in the above embodiments, and will not be repeated here.

[0092] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0093] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0094] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A compressor, characterized in that, include: The compressor body (1) and the drive device (2) are provided. The compressor body (1) has a first housing (11) and an input shaft (12). The input end of the input shaft (12) is located outside the first housing (11). The drive end of the drive device (2) is connected to the input end of the input shaft (12). The drive device (2) is used to drive the input shaft (12) to rotate. A magnetic fluid sealing device (3) is sleeved on the input shaft (12), and at least a portion of the magnetic fluid sealing device (3) is located inside the first housing (11). The magnetic fluid sealing device (3) is fixedly connected to the first housing (11). The driving device (2) is located on the side of the magnetic fluid sealing device (3) away from the first housing (11). The magnetic fluid sealing device (3) is filled with magnetic fluid, which is located on the outer wall of the input shaft (12) to seal the input shaft (12) through the magnetic fluid. A control device for acquiring a current first pressure value inside the first housing (11) and a current second pressure value outside the first housing (11) to adaptively adjust the magnetic field strength of the magnetofluid based on the current first pressure value and the current second pressure value. The magnetic fluid sealing device (3) includes: a second housing (31), the second housing (31) having a first placement cavity (311), a flow cavity (313), and an inlet (314) and an outlet (315) respectively communicating with the flow cavity (313); the first placement cavity (311) is nested in the flow cavity (313), and both the first placement cavity (311) and the flow cavity (313) extend along the axial direction of the input shaft (12); the first placement cavity (311) is filled with the magnetic fluid; the flow cavity (313) is used for the flow of refrigerant, and the refrigerant enters the flow cavity (313) through the inlet (314) to exchange heat with the magnetic fluid; the refrigerant, after absorbing heat, flows out from the outlet (315); The compressor body has a first suction port (13) and a second suction port (14); the compressor also includes a circulation pump (6), the input end of which is connected to the first suction port (13) of the compressor body (1), and the output end of which is connected to the inlet (314); the circulation pump (6) is used to extract the refrigerant at the first suction port (13) of the compressor body (1); the extracted refrigerant enters the flow chamber (313) through the output end of the circulation pump (6) and the inlet (314).

2. The compressor according to claim 1, characterized in that, The magnetic fluid sealing device (3) includes: A second housing (31) is inserted into the first housing (11), and at least a portion of the second housing (31) is located inside the first housing (11). The second housing (31) is fixedly connected to the first housing (11). The second housing (31) has a first placement cavity (311) and a second placement cavity (312) inside. Both the first placement cavity (311) and the second placement cavity (312) extend along the axial direction of the input shaft (12). The first placement cavity (311) is nested inside the second placement cavity (312). The first placement cavity (311) is filled with the magnetic fluid. An electromagnet assembly (33) is disposed in the second placement cavity (312) to adjust the magnetic field strength of the magnetic fluid by switching the electromagnet assembly (33) on and off; the electromagnet assembly (33) is connected to the control device to adaptively control the on and off state of the electromagnet assembly (33) according to the current first pressure value and the current second pressure value.

3. The compressor according to claim 2, characterized in that, The second placement cavity (312) is an annular chamber, and the electromagnet assembly (33) includes: At least two electromagnets (331) are provided, and each of the electromagnets (331) is sequentially sleeved on the outer wall of the first placement cavity (311) along the extension direction of the second placement cavity (312); The control device adaptively controls the on / off state of each of the electromagnets (331) according to the current first pressure value and the current second pressure value.

4. The compressor according to claim 2, characterized in that, The magnetic fluid sealing device (3) further includes: a permanent magnet assembly (34), which is disposed in the second placement cavity (312) and sleeved on the outer wall of the first placement cavity (311); and an electromagnet assembly (33) is nested in the permanent magnet assembly (34).

5. The compressor according to claim 4, characterized in that, The permanent magnet assembly (34) includes: at least two permanent magnet rings (341), each of the permanent magnet rings (341) being arranged sequentially along the extension direction of the second placement cavity (312); the magnetic poles of two adjacent permanent magnet rings (341) are arranged in opposite directions; the electromagnet assembly (33) is nested within at least one of the permanent magnet rings (341).

6. The compressor according to claim 1, characterized in that, The compressor further includes: a first pressure detection device (4), which is disposed on the magnetic fluid sealing device (3) and located inside the first housing (11); the first pressure detection device (4) is used to detect a first pressure value inside the first housing (11); the first pressure detection device (4) is connected to the control device and sends the detected first pressure value inside the first housing (11) to the control device.

7. The compressor according to claim 1, characterized in that, The compressor also includes: The second pressure detection device (5) is disposed on the magnetic fluid sealing device (3) and is located outside the first housing (11); the second pressure detection device (5) is used to detect a second pressure value outside the first housing (11); the second pressure detection device (5) is connected to the control device and sends the detected second pressure value outside the first housing (11) to the control device.

8. The compressor according to claim 1, characterized in that, The compressor also includes: An electromagnetic expansion valve (7) is disposed between the circulating pump (6) and the inlet (314), the output end of the circulating pump (6) being connected to the inlet (314) via the electromagnetic expansion valve (7); the electromagnetic expansion valve (7) is used to regulate the flow rate and velocity of the refrigerant; and / or, The first pipeline (8) is connected to the outlet (315) and the second suction port (14) respectively. The refrigerant flowing out from the outlet (315) enters the compressor body (1) through the first pipeline (8) and the second suction port (14) in sequence.

9. A control method, characterized in that, The control method is applied to the compressor according to any one of claims 1 to 8, and the control method includes: Obtain the current first pressure value inside the first housing (11) and the current second pressure value outside the first housing (11); The magnetic field strength of the magnetic fluid in the magnetic fluid sealing device (3) is adaptively adjusted according to the current first pressure value and the current second pressure value.

10. The control method according to claim 9, characterized in that, The control method is applied to the compressor of claim 2; the method for adaptively adjusting the magnetic field strength of the magnetic fluid within the magnetic fluid sealing device (3) according to the current first pressure value and the current second pressure value includes: Calculate the pressure difference between the current first pressure value and the current second pressure value, and control the on / off state of the electromagnet assembly (33) according to the pressure difference; If the pressure difference is less than the first preset value, the electromagnet assembly (33) is controlled to be in a de-energized state in order to maintain the current magnetic field strength of the magnetic fluid; If the pressure difference is greater than or equal to a first preset value, at least a portion of the electromagnet assembly (33) is controlled to switch to an energized state, so as to adjust the magnetization intensity of the magnetic fluid by at least a portion of the electromagnet assembly (33) in the energized state.

11. The control method according to claim 10, characterized in that, If the electromagnet assembly (33) has N electromagnets (331), N≥2; each of the electromagnets (331) is arranged sequentially along the axial direction of the input shaft (12); the method of controlling at least a portion of the electromagnet assembly (33) to switch to an energized state if the pressure difference is greater than or equal to a first preset value, so as to adjust the magnetization intensity of the magnetic fluid by means of at least a portion of the electromagnet assembly (33) in the energized state, includes: If the pressure difference is greater than or equal to a first preset value, the amount of electromagnet (331) energized is adaptively controlled according to the pressure difference. The number of electromagnets (331) energized is proportional to the pressure difference.

12. The control method according to claim 10, characterized in that, The method for adaptively adjusting the magnetic field strength of the magnetic fluid within the magnetic fluid sealing device (3) based on the current first pressure value and the current second pressure value further includes: If the pressure difference changes frequently within a first preset time period, the electromagnet assembly (33) is controlled to switch to the energized state so as to adjust the magnetization intensity of the magnetic fluid by means of the electromagnet assembly (33) in the energized state.

13. The control method according to claim 10, characterized in that, The control method is applied to the compressor of claim 8, and the control method further includes: Calculate the pressure difference between the current first pressure value and the current second pressure value, and control the electromagnetic expansion valve (7) based on the pressure difference. If the pressure difference is less than the first preset value, the opening degree of the electromagnetic expansion valve (7) is controlled to be maintained at the preset opening degree; If the pressure difference is greater than or equal to the first preset value, the opening degree of the electromagnetic expansion valve (7) is increased according to the pressure difference; The opening degree of the electromagnetic expansion valve (7) is proportional to the pressure difference.

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