A compressor, a refrigeration system and a control method

Abstract

The present invention belongs to the technical field of compressors, and particularly relates to a compressor, a refrigeration system and a control method. The pump body assembly includes a first cylinder and a second cylinder. The compressor has a first working mode, a second mode and a third working mode. The first working mode is a working mode in which the first cylinder and the second cylinder respectively perform primary compression. The second working mode is a working mode in which the first cylinder performs primary compression and the second cylinder performs secondary compression. The third working mode is a working mode in which the first cylinder performs primary compression, the second cylinder performs secondary compression and has gas injection and enthalpy increase. The compressor is provided with a switching mechanism, and the switching mechanism is used to switch the compressor between the first working mode, the second working mode and the third working mode. The compressor of the present invention can not only expand the cooling capacity range but also expand the operating condition range.

Description

Technical Field

[0001] The present invention belongs to the technical field of compressors, and in particular relates to a compressor, a refrigeration system and a control method. Background Art

[0002] The two-cylinder two-stage compressor is efficient and stable in low-temperature environments. However, when operating under light working conditions, the pressure ratio and pressure difference are low, and the second cylinder of the two-cylinder compressor is wasted and not fully utilized. The cooling capacity range of the two-cylinder single-stage compressor can be further expanded under light working conditions compared to the two-cylinder two-stage compressor, but the reliability of the compressor is greatly affected in low-temperature environments. Therefore, it is necessary to provide a compressor that can achieve both the expansion of the cooling capacity range and the expansion of the working condition range.

[0003] In view of this, the present invention is proposed. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a compressor, a refrigeration system and a control method that can achieve both expansion of the cooling capacity range and expansion of the operating condition range.

[0005] In order to solve the above technical problems, the present invention provides a compressor in a first aspect, comprising a housing, wherein a pump assembly is arranged in the housing; the pump assembly comprises a first cylinder and a second cylinder; the compressor is provided with a first working mode, a second mode and a third working mode, wherein

[0006] The first working mode is a working mode in which the first cylinder and the second cylinder respectively perform one-stage compression;

[0007] The second working mode is a working mode in which the first cylinder performs one-stage compression and the second cylinder performs two-stage compression;

[0008] The third working mode is a working mode in which the first cylinder performs one-stage compression and the second cylinder performs two-stage compression with air supplement and enthalpy increase;

[0009] The compressor is provided with a switching mechanism, and the switching mechanism is used to switch the compressor among the first working mode, the second working mode and the third working mode.

[0010] Further optionally, a first air inlet and a second air inlet are formed on one side of the pump body assembly, a first exhaust port and an air supply port are formed on the other side of the pump body assembly, and a second exhaust port is provided on the top of the shell; the first cylinder includes a first compression chamber, and the second cylinder includes a second compression chamber;

[0011] The first air inlet is used to introduce air into the first compression chamber, and the first air outlet is used to exhaust air from the first compression chamber; the second air inlet is used to introduce air into the second compression chamber, the second air outlet is used to exhaust air from the second compression chamber, and the air supplement port is used to supplement air to the second compression chamber.

[0012] Further optionally, the pump body assembly is sequentially provided with the second cylinder, the second partition plate, the first partition plate, the first cylinder, and the lower flange assembly from top to bottom;

[0013] The first air inlet is formed on the first cylinder;

[0014] The first air outlet is formed on the lower flange assembly;

[0015] A mixing chamber is formed between the first partition plate and the second partition plate. The second air inlet and the air supplement port are respectively communicated with the mixing chamber. The mixing chamber is communicated with the second compression chamber. The second air inlet and the air supplement port are respectively formed on the first partition plate.

[0016] Further optionally, a first air inlet pipe is connected to the first air inlet, a second air inlet pipe is connected to the second air inlet, a supplementary air pipe is connected to the air supplement port, a first exhaust pipe is connected to the first air outlet, a second exhaust pipe is connected to the second air outlet, and a connecting pipe is provided between the first air outlet and the second air inlet;

[0017] The switching mechanism enables the compressor to switch between the first working mode, the second working mode, and the third working mode by controlling the on-off of the first air inlet pipe, the second air inlet pipe, the first exhaust pipe, the second exhaust pipe, the supplementary air pipe, and the connecting pipe.

[0018] Further optionally, a first liquid distributor is connected between the first air inlet pipe and the first air inlet; a second liquid distributor is connected between the second air inlet pipe and the second air inlet; and an air supplement and enthalpy-increasing liquid distributor is connected between the air supplement port and the supplementary air pipe.

[0019] Further optionally, the switching mechanism includes:

[0020] A first control valve, disposed on the second air inlet pipe;

[0021] A second control valve, disposed on the connecting pipe;

[0022] A third control valve, disposed on the supplementary air pipe;

[0023] A fourth control valve, disposed on the first exhaust pipe.

[0024] Further optionally, the inlet of the connecting pipe communicates with the first exhaust pipe, and the outlet communicates with the second intake pipe; the switching mechanism further includes:

[0025] A first three-way valve that connects the second intake pipe to the connecting pipe;

[0026] A second three-way valve that connects the first exhaust pipe to the connecting pipe;

[0027] The first control valve is located on the second intake pipe between the inlet of the second intake pipe and the first three-way valve;

[0028] The fourth control valve is located on the first exhaust pipe between the second three-way valve and the outlet of the first exhaust port.

[0029] A second aspect of the present invention provides a refrigeration system, which includes a first heat exchanger, a second heat exchanger, a flash evaporator, and the compressor provided in the first aspect;

[0030] The first end of the first heat exchanger communicates with the first end of the flash evaporator, the second end of the flash evaporator communicates with the first end of the second heat exchanger, the second end of the second heat exchanger communicates with the first intake pipe and the second intake pipe respectively, and the second end of the first heat exchanger communicates with the first exhaust pipe and the second exhaust pipe respectively; the third end of the flash evaporator communicates with the make-up air pipe.

[0031] Further optionally, the refrigeration system further includes a first throttle valve and a second throttle valve. The first throttle valve is provided between the first end of the first heat exchanger and the first end of the flash evaporator, and the second throttle valve is provided between the second end of the flash evaporator and the second end of the second heat exchanger.

[0032] A third aspect of the present invention provides a control method for the refrigeration system provided in the second aspect of the claims. The control method includes:

[0033] Controlling the compressor to switch between the first operating mode, the second operating mode, and the third operating mode.

[0034] Further optionally, the control method includes:

[0035] When the compressor is in the first operating mode, controlling the switching mechanism to respectively conduct the first intake pipe, the first exhaust pipe, the second intake pipe, and the second exhaust pipe, and disconnect the make-up air pipe and the connecting pipe;

[0036] When the compressor is in the second working mode, the switching mechanism is controlled to connect the first air intake pipe, the second air exhaust pipe and the connecting pipe, and disconnect the second air intake pipe, the first air exhaust pipe and the air supply pipe;

[0037] When the compressor is in the third working mode, the switching mechanism is controlled to connect the first air intake pipe, the second exhaust pipe, the air supply pipe, and the connecting pipe, respectively, and disconnect the second air intake pipe and the first exhaust pipe.

[0038] Further optionally, when the switching mechanism includes a first control valve provided on the second intake pipe, a second control valve provided on the connecting pipe, a third control valve provided on the air supply pipe, and a fourth control valve provided on the first exhaust pipe, the control method includes:

[0039] When the compressor is in a first working mode, the first control valve and the fourth control valve are controlled to be opened, and the second control valve and the third control valve are controlled to be closed;

[0040] When the compressor is in the second working mode, the first control valve, the third control valve and the fourth control valve are controlled to be closed, and the second control valve is controlled to be opened;

[0041] When the compressor is in the third working mode, the first control valve and the fourth control valve are controlled to be closed, and the second control valve and the third control valve are controlled to be opened.

[0042] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0043] The present invention reasonably designs the pump assembly structure through a single compressor to realize multiple suction and exhaust channels, which can realize the first working mode of a double-cylinder double-suction single-stage cycle in which the first cylinder performs one-stage compression and the second cylinder performs two-stage compression, and can also realize the second working mode of a double-cylinder single-suction two-stage without enthalpy increase cycle in which the first cylinder performs one-stage compression and the second cylinder performs two-stage compression, and the third working mode of a double-cylinder single-suction two-stage with enthalpy increase cycle in which the first cylinder performs one-stage compression and the second cylinder performs two-stage compression with air supplement and enthalpy increase. The present invention can realize the switching of multiple modes by using one compressor, reduce the installation space, and reduce the cost.

[0044] The present invention can further expand the operating range of the compressor by switching between multiple working modes. The cooling capacity range of the twin-cylinder double-intake single-stage mode is wider than that of the twin-cylinder single-intake two-stage with enthalpy increase cycle. The twin-cylinder single-intake two-stage with enthalpy increase cycle can operate at a lower evaporating temperature than the twin-cylinder double-intake single-stage mode, thereby expanding the operating range of the compressor.

[0045] The following further describes in detail the specific embodiments of the present invention with reference to the accompanying drawings. Description of the Drawings

[0046] The accompanying drawings, as part of the present invention, are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention, but do not constitute an improper limitation to the present invention. Obviously, the drawings in the following description are only some embodiments, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts. In the drawings:

[0047] Figure 1 : Structural diagram of the compressor according to an embodiment of the present invention.

[0048] Figure 2 : Top view of the whole compressor according to an embodiment of the present invention.

[0049] Figure 3 : Cross-sectional view of the pump body assembly according to an embodiment of the present invention.

[0050] Figure 4 : Refrigeration system diagram according to an embodiment of the present invention.

[0051] Figure 5 : Schematic diagram of the refrigerant flow direction when the compressor is in the first working mode in the refrigeration system according to an embodiment of the present invention.

[0052] Figure 6 : Schematic diagram of the refrigerant flow direction when the compressor is in the second working mode in the refrigeration system according to an embodiment of the present invention.

[0053] Figure 7 : Schematic diagram of the refrigerant flow direction when the compressor is in the third working mode in the refrigeration system according to an embodiment of the present invention.

[0054] Wherein: 1 - compressor; 2 - first heat exchanger; 3 - first throttle valve; 4 - flash tank; 5 - second throttle valve; 6 - second heat exchanger; 7 - first control valve; 8 - second control valve; 9 - third control valve; 10 - fourth control valve; 20 - housing; 21 - first liquid distributor; 211 - first inlet pipe; 22 - second liquid distributor; 221 - second inlet pipe; 23 - motor; 24 - upper cover assembly; 241 - second exhaust port; 25 - second exhaust pipe; 26 - pump body assembly; 27 - enthalpy-increasing liquid distributor; 28 - first exhaust pipe; 30 - crankshaft; 31 - upper flange assembly; 32 - second cylinder; 33 - second partition; 34 - first partition; 35 first cylinder; 36 - lower flange assembly; 37 - lower flange cover plate; 351 - first intake port; 361 - first exhaust port; 341 - second intake port; 342 - gas supplement port; 41 - connecting pipe; 42 - gas supplement pipe;

[0055] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but are intended to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0056] In the description of the present invention, it should be noted that the terms "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0057] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "contacted", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] This embodiment provides a compressor 1, such as Figures 1 - 3 , including a shell 20, in which a motor 23 and a pump body assembly 26 are arranged; the pump body assembly 26 includes a crankshaft 30, a first cylinder 35 and a second cylinder 32; the compressor 1 includes a first working mode in which the first cylinder 35 and the second cylinder 32 respectively perform one-stage compression, a second working mode in which the first cylinder 35 performs one-stage compression and the second cylinder 32 performs two-stage compression, and a third working mode in which the first cylinder 35 performs one-stage compression and the second cylinder 32 performs two-stage compression with air supplement and enthalpy increase; the compressor 1 also includes a switching mechanism, which is used to switch the compressor 1 between the first working mode, the second working mode and the third working mode.

[0059] In this embodiment, a single compressor is used to reasonably design the pump assembly structure to realize multiple suction and exhaust channels, which can realize the first working mode of a double-cylinder double-suction single-stage cycle in which the first cylinder performs one-stage compression and the second cylinder performs two-stage compression, and can also realize the second working mode of a double-cylinder single-suction two-stage cycle without enthalpy increase in which the first cylinder performs one-stage compression and the second cylinder performs two-stage compression, and the third working mode of a double-cylinder single-suction two-stage cycle with enthalpy increase in which the first cylinder performs one-stage compression and the second cylinder performs two-stage compression and supplements air enthalpy increase. In this embodiment, one compressor is used to realize the switching of multiple modes, reduce the installation space, and reduce the cost. At the same time, the switching of multiple working modes can further expand the operating range of the compressor. The double-cylinder double-suction single-stage mode has a wider cooling capacity range than the double-cylinder single-suction two-stage cycle with enthalpy increase, and the double-cylinder single-suction two-stage cycle with enthalpy increase can operate at a lower evaporation temperature than the double-cylinder double-suction single-stage mode, thereby expanding the operating range of the compressor. The compressor 1 of this embodiment can optionally be a rotary compressor 1.

[0060] Alternatively, see Figure 1 and Figure 3 A first air inlet 351 and a second air inlet 341 are formed on one side of the pump body assembly 26, a first exhaust port 361 and an air supply port 342 are formed on the other side of the pump body assembly 26, a second exhaust port 241 is provided on the top of the shell 20, optionally, an upper cover assembly 24 is provided on the top of the shell 20, and the second exhaust hole is located on the upper cover assembly 24; the first cylinder 35 includes a first compression chamber, and the second cylinder 32 includes a second compression chamber; the first air inlet 351 is used to intake air into the first compression chamber, and the first exhaust port 361 is used to exhaust air from the first compression chamber; the second air inlet 341 is used to intake air into the second compression chamber, the second exhaust port 241 is used to exhaust air from the second compression chamber, and the air supply port 342 is used to replenish air into the second compression chamber.

[0061] Alternatively, see Figure 3, the pump body assembly 26 is sequentially provided with an upper flange assembly 31, a second cylinder 32, a second partition plate 33, a first partition plate 34, a first cylinder 35, a lower flange assembly 36, and a lower flange group cover plate 37 from top to bottom; a first air inlet 351 is formed on the first cylinder 35; a first air outlet 361 is formed on the lower flange assembly 31; a mixing chamber is formed between the first partition plate 34 and the second partition plate 33, a second air inlet 341 and a gas supplement port 342 are respectively communicated with the mixing chamber, the mixing chamber is communicated with a second compression chamber, and the second air inlet 341 and the gas supplement port 342 are respectively formed on the first partition plate 34. In this embodiment, the gas path structure formed between the upper flange assembly 31, the first cylinder, the first air inlet 351, and the first air outlet 361, and the gas path structure formed between the second cylinder, the lower flange assembly, the second air inlet 341, and the second air outlet 241 all belong to the well-known compressor gas path structure in the art. Exemplarily, on the premise that there is no upper muffler, the refrigerant discharged from the upper flange assembly 31 is directly discharged into the lower cavity of the motor, and then passes through the gap between the stator and the rotor or the flow holes on the stator and the rotor to the upper cavity of the motor, and then is discharged from the compressor housing through the second air outlet 241. If there is an upper muffler, it is first discharged into the muffler chamber, then into the lower cavity of the motor, then into the upper cavity of the motor, and then discharged to the outside of the housing through the second exhaust pipe. In addition, air holes are provided on the flange, and crescent grooves are provided on the cylinder, and the air holes correspond to the crescent grooves. When the pressure in the compression chamber is higher than the back pressure of the valve plate, that is, the pressure in the lower cavity of the motor, the valve plate is pushed open, and then exhaust is realized.

[0062] A mixing chamber is formed between the first intermediate partition plate and the second intermediate partition plate assembly in this embodiment, realizing the gas supplement and enthalpy increase of the low-pressure cycle, reducing the exhaust temperature of the low-pressure cycle, increasing the refrigerating capacity per unit mass, and thus improving the refrigeration efficiency of the low-temperature cycle; at the same time, the mixing chamber also forms the air inlet chamber of the second cylinder 32, realizing the double-cylinder double-suction cycle.

[0063] Further optionally, referring to Figure 4 , a first intake pipe 211 is connected to the first air inlet 351, a second intake pipe 221 is connected to the second air inlet 341, a gas supplement pipe 42 is connected to the gas supplement port 342, a first exhaust pipe 28 is connected to the first air outlet 361, a second exhaust pipe 25 is connected to the second air outlet 241, and a connecting pipe 41 is provided between the first air outlet 361 and the second air inlet 341; the switching mechanism enables the compressor 1 to switch between a first working mode, a second working mode, and a third working mode by controlling the on-off of the first intake pipe 211, the second intake pipe 221, the first exhaust pipe 28, the second exhaust pipe 25, the gas supplement pipe 42, and the connecting pipe 41. Optionally, a first liquid distributor 21 is connected between the first intake pipe 211 and the first air inlet 351; a second liquid distributor 22 is connected between the second intake pipe 221 and the second air inlet 341; a gas supplement and enthalpy increase liquid distributor 27 is connected between the gas supplement port 342 and the gas supplement pipe 42.

[0064] Further optionally, referring to Figure 4 , the switching mechanism includes: a first control valve 7 provided on the second intake pipe 221; a second control valve 8 provided on the connecting pipe 41; a third control valve 9 provided on the supplementary air pipe 42; and a fourth control valve 10 provided on the first exhaust pipe 28.

[0065] Further optionally, referring to Figure 4 , the inlet of the connecting pipe 41 communicates with the first exhaust pipe 28, and the outlet communicates with the second intake pipe 221; the switching mechanism further includes: a first three-way valve and a second three-way valve, the first three-way valve connects the second intake pipe 221 with the connecting pipe 41; the second three-way valve connects the first exhaust pipe 28 with the connecting pipe 41; the first control valve 7 is provided on the second intake pipe 221 between the inlet of the second intake pipe 221 and the first three-way valve; the fourth control valve 10 is provided on the first exhaust pipe 28 between the second three-way valve and the outlet of the first exhaust port 361.

[0066] The compressor 1 of this embodiment can realize the switching of three working modes. Different working modes can be adapted to different application environments. The first working mode (double-cylinder double-suction single-stage cycle) can maximize the utilization of the cylinder volume of the compressor 1. When this mode is adopted under light working conditions, the displacement of the compressor 1 is the sum of the volumes of the upper and lower cylinders, and the cooling capacity range of the compressor 1 is further improved in this mode. The third working mode (double-cylinder double-stage with enthalpy-increasing mode) is suitable for the case where the outdoor environment is relatively harsh. The compressor 1 can reduce the exhaust temperature of the compressor 1 and increase the refrigerating capacity per unit mass, thereby improving the performance and service life of the compressor 1. The second working mode (double-cylinder double-stage enthalpy-increasing off mode) is used as a transition mode.

[0067] This embodiment also proposes a refrigeration system, referring to Figure 4 , which includes a first heat exchanger 2, a second heat exchanger 6, a flash evaporator 4 and the above-mentioned compressor 1; the first end of the first heat exchanger 2 communicates with the first end of the flash evaporator 4, the second end of the flash evaporator 4 communicates with the first end of the second heat exchanger 6, the second end of the second heat exchanger 6 communicates with the first intake pipe 211 and the second intake pipe 221 respectively, and the second end of the first heat exchanger 2 communicates with the first exhaust pipe 28 and the second exhaust pipe 25 respectively; the third end of the flash evaporator 4 communicates with the supplementary air pipe 42.

[0068] Further optionally, the refrigeration system further includes a first throttling valve 3 and a second throttling valve 5. The first throttling valve 3 is provided between the first end of the first heat exchanger 2 and the first end of the flash evaporator 4, and the second throttling valve 5 is provided between the second end of the flash evaporator 4 and the second end of the second heat exchanger 6.

[0069] This embodiment also proposes a control method for the above refrigeration system. The control method includes:

[0070] Control the compressor 1 to switch between the first working mode, the second working mode and the third working mode.

[0071] Further optionally, the control method includes: when the compressor 1 is in the first working mode, controlling the switching mechanism to conduct the first intake pipe 211, the first exhaust pipe 28, the second intake pipe 221, and the second exhaust pipe 25 respectively, and disconnect the supplementary air pipe 42 and the connecting pipe 41; when the compressor 1 is in the second working mode, controlling the switching mechanism to conduct the first intake pipe 211, the second exhaust pipe 25, and the connecting pipe 41, and disconnect the second intake pipe 221, the first exhaust pipe 28, and the supplementary air pipe 42; when the compressor 1 is in the third working mode, controlling the switching mechanism to conduct the first intake pipe 211, the second exhaust pipe 25, the supplementary air pipe 42, and the connecting pipe 41 respectively, and disconnect the second intake pipe 221 and the first exhaust pipe 28.

[0072] Further optionally, when the switching mechanism includes a first control valve 7 provided on the second intake pipe 221, a second control valve 8 provided on the connecting pipe 41, a third control valve 9 provided on the supplementary air pipe 42, and a fourth control valve 10 provided on the first exhaust pipe 28, the control method includes:

[0073] When the compressor 1 is in the first working mode, control the first control valve 7 and the fourth control valve 10 to open, and control the second control valve 8 and the third control valve 9 to close; when the compressor 1 is in the second working mode, control the first control valve 7, the third control valve 9, and the fourth control valve 10 to close, and control the second control valve 8 to open; when the compressor 1 is in the third working mode, control the first control valve 7 and the fourth control valve 10 to close, and control the second control valve 8 and the third control valve 9 to open.

[0074] The control of the three control modes of the compressor of the refrigeration system in this embodiment will be described in detail below:

[0075] The first working mode (double-cylinder double-suction single-stage cycle): Refer to Figure 5, at this time, the first control valve and the fourth control valve are open, while the second control valve and the third control valve are closed. The low-temperature and low-pressure refrigerant from the second heat exchanger 6 enters the first cylinder 35 and the second cylinder 32 respectively through the first liquid distributor 21 and the second liquid distributor 22 for compression. The refrigerant compressed by the first cylinder 32 is first discharged into the exhaust cavity of the lower flange assembly formed by the lower flange assembly 36 and the lower flange assembly cover plate 37, and then discharged outside the compressor housing through the first exhaust pipe 28. After passing through the fourth control valve, it is mixed with the refrigerant discharged through the second exhaust pipe 25 after being compressed by the second cylinder 32. After mixing, it enters the first heat exchanger 2, and then condenses into a high-temperature and high-pressure subcooled refrigerant in the first heat exchanger 2. The high-temperature and high-pressure subcooled refrigerant is throttled and depressurized by the throttle valve to become a low-temperature and low-pressure gas-liquid mixed refrigerant, and then absorbs heat and evaporates in the second heat exchanger 6, and then returns to the first liquid distributor 21 and the second liquid distributor 22 and returns to the compressor to complete a cycle.

[0076] The second working mode (double-cylinder single-suction two-stage without enthalpy-increasing mode), see Figure 6 , at this time, the first control valve, the third control valve and the fourth control valve are closed, while the second control valve is open. The low-temperature and low-pressure refrigerant from the second heat exchanger 6 enters the first cylinder 35 through the first liquid distributor 21. The refrigerant compressed by the first cylinder 35 is first discharged into the exhaust cavity of the lower flange assembly formed by the lower flange assembly 36 and the lower flange assembly cover plate 37, and then discharged outside the compressor housing through the first exhaust pipe 28. Then it passes through the second control valve and enters the second liquid distributor 22, and then enters the mixing cavity formed by the second intermediate partition 33 and the first intermediate partition 34 and then enters the second cylinder 32 and is discharged from the compressor after compression through the second exhaust pipe. The high-temperature and high-pressure refrigerant condenses into a high-temperature and high-pressure subcooled refrigerant in the first heat exchanger 2. The high-temperature and high-pressure subcooled refrigerant is throttled and depressurized by the first throttle valve 3 and then enters the flash tank 4. The liquid refrigerant at the bottom of the flash tank 4 becomes a low-temperature and low-pressure gas-liquid mixture through the second-stage throttle valve 5 and enters the second heat exchanger 6. After absorbing heat and vaporizing in the second heat exchanger 6, it returns to the first liquid distributor 21 to complete a cycle.

[0077] The third working mode (double-cylinder single-suction two-stage with enthalpy-increasing mode): see Figure 7, at this time, the first control valve and the fourth control valve are closed, while the second control valve and the third control valve are open. The low-temperature and low-pressure refrigerant from the second heat exchanger 6 enters the first cylinder 35 through the first liquid distributor 21. The refrigerant compressed by the first cylinder 35 is first discharged into the exhaust cavity of the lower flange assembly formed by the lower flange assembly 36 and the lower flange assembly cover plate 37, and then discharged outside the compressor housing through the first exhaust pipe 28. Then it enters the second liquid distributor 22 through the second control valve, and then enters the second intermediate partition 33 and the first intermediate partition 34 to be mixed with the refrigerant from the flash evaporator 4, which plays a role in reducing the exhaust temperature of the first stage of the compressor. The refrigerant mixed in the mixing cavity formed by the intermediate partitions enters the second cylinder and is discharged from the compressor through the second exhaust pipe 25 after compression. The high-temperature and high-pressure refrigerant becomes a high-temperature and high-pressure subcooled refrigerant after being condensed by the first heat exchanger 2. The high-temperature and high-pressure subcooled refrigerant enters the flash evaporator 4 after being throttled and depressurized by the first throttle valve 3. In the flash evaporator 4, it is divided into two streams. The liquid refrigerant at the bottom of the flash evaporator 4 becomes a low-temperature and low-pressure gas-liquid mixture through the second-stage throttle valve 5 and enters the second heat exchanger 6. After absorbing heat and vaporizing in the second heat exchanger 6, it returns to the first liquid distributor 21 to complete a cycle. The gaseous refrigerant in the second heat exchanger 6 enters the mixing cavity formed by the second intermediate partition 33 and the first intermediate partition 34 through the enthalpy-increasing liquid distributor 27 to be mixed with the medium-temperature and medium-pressure refrigerant from the lower cavity, and then enters the second cylinder 32 to complete the cycle. This mode enables the compressor to achieve a wider operating range and a higher pressure ratio. Under high pressure ratio conditions, it can reduce the exhaust temperature and increase the refrigerating capacity per unit mass, thereby improving the compression performance.

[0078] The above are only the preferred embodiments of the present invention, and there is no any form of limitation to the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art of this patent, without departing from the scope of the technical solution of the present invention, can make some changes or modifications using the technical content prompted above as equivalent embodiments of equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A compressor, characterized in that, it includes a housing, and a pump body assembly is provided inside the housing; the pump body assembly includes a first cylinder and a second cylinder; the compressor has a first working mode, a second working mode, and a third working mode, wherein the first working mode is a working mode in which the first cylinder and the second cylinder respectively perform primary compression; the second working mode is a working mode in which the first cylinder performs primary compression and the second cylinder performs secondary compression; the third working mode is a working mode in which the first cylinder performs primary compression, the second cylinder performs secondary compression and has gas injection and enthalpy increase; the compressor is provided with a switching mechanism, and the switching mechanism is used to switch the compressor between the first working mode, the second working mode, and the third working mode; a first air inlet and a second air inlet are formed on one side of the pump body assembly, a first exhaust port and a gas injection port are formed on the other side of the pump body assembly, and a second exhaust port is provided at the top of the housing; the first cylinder includes a first compression chamber, and the second cylinder includes a second compression chamber; the first air inlet is used for admitting air into the first compression chamber, and the first exhaust port is used for exhausting air from the first compression chamber; the second air inlet is used for admitting air into the second compression chamber, the second exhaust port is used for exhausting air from the second compression chamber, and the gas injection port is used for injecting gas into the second compression chamber; the pump body assembly includes a first partition plate and a second partition plate, a mixing chamber is formed between the first partition plate and the second partition plate, the second air inlet and the gas injection port are respectively communicated with the mixing chamber, and the mixing chamber is communicated with the second compression chamber.

2. The compressor according to claim 1, characterized in that, the pump body assembly is sequentially provided with the second cylinder, the second partition plate, the first partition plate, the first cylinder, and a lower flange assembly from top to bottom; the first air inlet is formed on the first cylinder; the first exhaust port is formed on the lower flange assembly; the second air inlet and the gas injection port are respectively formed on the first partition plate.

3. The compressor according to claim 1, characterized in that, a first inlet pipe is connected to the first air inlet, a second inlet pipe is connected to the second air inlet, a gas injection pipe is connected to the gas injection port, a first exhaust pipe is connected to the first exhaust port, a second exhaust pipe is connected to the second exhaust port, and a connecting pipe is provided between the first exhaust port and the second air inlet; the switching mechanism switches the compressor between the first working mode, the second working mode, and the third working mode by controlling the on-off of the first inlet pipe, the second inlet pipe, the first exhaust pipe, the second exhaust pipe, the gas injection pipe, and the connecting pipe.

4. The compressor according to claim 3, characterized in that, a first liquid separator is connected between the first inlet pipe and the first air inlet; a second liquid separator is connected between the second inlet pipe and the second air inlet; a gas injection and enthalpy increase liquid separator is connected between the gas injection port and the gas injection pipe.

5. The compressor according to claim 3 or 4, characterized in that, The switching mechanism includes: A first control valve, which is arranged on the second intake pipe; A second control valve, which is arranged on the connecting pipe; A third control valve, which is arranged on the supplementary air pipe; A fourth control valve, which is arranged on the first exhaust pipe.

6. A compressor according to claim 5, wherein, The inlet of the connecting pipe is communicated with the first exhaust pipe, and the outlet is communicated with the second intake pipe; the switching mechanism further includes: A first three-way valve, which communicates the second intake pipe with the connecting pipe; A second three-way valve, which communicates the first exhaust pipe with the connecting pipe; The first control valve is located on the second intake pipe between the inlet of the second intake pipe and the first three-way valve; The fourth control valve is located on the first exhaust pipe between the second three-way valve and the outlet of the first exhaust port.

7. A refrigeration system, wherein, It includes a first heat exchanger, a second heat exchanger, a flash evaporator and the compressor according to any one of claims 1-6; The first end of the first heat exchanger is communicated with the first end of the flash evaporator, the second end of the flash evaporator is communicated with the first end of the second heat exchanger, the second end of the second heat exchanger is respectively communicated with the first intake pipe and the second intake pipe, and the second end of the first heat exchanger is respectively communicated with the first exhaust pipe and the second exhaust pipe; the third end of the flash evaporator is communicated with the supplementary air pipe.

8. A refrigeration system according to claim 7, wherein, The refrigeration system further includes a first throttling valve and a second throttling valve. The first throttling valve is arranged between the first end of the first heat exchanger and the first end of the flash evaporator, and the second throttling valve is arranged between the second end of the flash evaporator and the second end of the second heat exchanger.

9. A control method for the refrigeration system according to claim 7 or 8, wherein, The control method includes: Controlling the compressor to switch between the first working mode, the second working mode and the third working mode.

10. A control method for the refrigeration system according to claim 9, wherein, When the refrigeration system includes the compressor according to any one of claims 3-6, the control method includes: When the compressor is in the first working mode, controlling the switching mechanism to respectively conduct the first intake pipe, the first exhaust pipe, the second intake pipe and the second exhaust pipe, and disconnect the supplementary air pipe and the connecting pipe; When the compressor is in the second working mode, controlling the switching mechanism to conduct the first intake pipe, the second exhaust pipe and the connecting pipe, and disconnect the second intake pipe, the first exhaust pipe and the supplementary air pipe; When the compressor is in the third working mode, controlling the switching mechanism to respectively conduct the first intake pipe, the second exhaust pipe, the supplementary air pipe and the connecting pipe, and disconnect the second intake pipe and the first exhaust pipe.

11. A control method for the refrigeration system according to claim 10, wherein, When the switching mechanism includes a first control valve provided on the second intake pipe, a second control valve provided on the connecting pipe, a third control valve provided on the supplementary air pipe, and a fourth control valve provided on the first exhaust pipe, the control method includes: When the compressor is in the first working mode, control the first control valve and the fourth control valve to open, and control the second control valve and the third control valve to close; When the compressor is in the second working mode, control the first control valve, the third control valve, and the fourth control valve to close, and control the second control valve to open; When the compressor is in the third working mode, control the first control valve and the fourth control valve to close, and control the second control valve and the third control valve to open.

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