Cascade refrigerating system for cold therapy instrument

Abstract

The invention relates to the technical field of ultralow-temperature treatment equipment, in particular to a cascade refrigeration system for a cold therapy instrument, which comprises a first-stage compression cycle module, a second-stage compression cycle module, a third-stage compression cycle module, a fourth-stage compression cycle module, a fifth-stage compression cycle module and a sixth-stage compression cycle module, the first-stage compression circulation module is connected with the second-stage compression circulation module in parallel through the first heat exchanger, and a second heat exchanger and a composite evaporator are arranged on the second-stage compression circulation module; and the third-stage compression circulation module is connected with the second-stage compression circulation module in parallel through the second heat exchanger, and the third-stage compression circulation module is communicated with the composite evaporator. The air conditioner has the effect of increasing the refrigerating temperature range.

Description

Technical Field

[0001] This application relates to the technical field of cryotherapy equipment, and in particular to a cascade refrigeration system for cryotherapy instruments. Background Technology

[0002] Currently, the field of cryotherapy equipment technology has developed rapidly in recent years. Cryotherapy, as an important treatment method, plays a crucial role in medical rehabilitation and sports injury recovery. Cryotherapy instruments can stimulate human tissues using a low-temperature environment, promoting blood circulation, reducing inflammation and pain, and showing significant effects in the treatment of some chronic diseases and acute injuries. With the deepening of medical research and the increasing demand for health, the performance requirements for cryotherapy instruments are also becoming higher, especially in terms of cooling efficiency and temperature control range. The development of low-temperature and ultra-low-temperature refrigeration technology has provided strong support for the upgrading of cryotherapy instruments.

[0003] In related technologies, in order to meet the refrigeration requirements of ultra-low temperature cryotherapy equipment, a single-stage compressor is usually used for refrigeration. Single-stage compressor refrigeration is achieved by compressing the refrigerant with the compressor, causing it to release heat and liquefy in the condenser, and then reducing the pressure through a throttling device and absorbing heat and vaporizing in the evaporator. However, due to the limitations of its compression ratio and refrigerant characteristics, the refrigeration temperature range is relatively narrow.

[0004] Therefore, there is an urgent need for a cascade refrigeration system for cryotherapy devices. Summary of the Invention

[0005] In order to increase the cooling temperature range, this application provides a cascade cooling system for cryotherapy instruments.

[0006] This application provides a cascade cooling system for cryotherapy instruments, which adopts the following technical solution: A cascade cooling system for cryotherapy devices, comprising: A primary compression cycle module, wherein a first heat exchanger is provided on the primary compression cycle module; A two-stage compression cycle module, wherein the first-stage compression cycle module is connected in parallel with the second-stage compression cycle module through the first heat exchanger, and the second-stage compression cycle module is respectively provided with a second heat exchanger and a combined evaporator; The three-stage compression cycle module is connected in parallel with the two-stage compression cycle module through the second heat exchanger, and is connected to the composite evaporator.

[0007] By adopting the above technical solution, the primary, secondary, and tertiary compression cycle modules are connected in parallel via a first and second heat exchanger to form a cascade refrigeration system. The primary compression cycle module first cools the refrigerant, then transfers the cooling energy to the refrigerant in the secondary compression cycle module via the first heat exchanger. The refrigerant vaporizes upon passing through the composite evaporator, absorbing heat from the environment, thus initially lowering the temperature inside the cryotherapy chamber. At this point, the first heat exchanger functions as an evaporator in the primary compression cycle module and as a condenser in the secondary compression cycle module. Furthermore, the cooling energy generated by the refrigerant in the secondary compression cycle module can be transferred to the refrigerant in the tertiary compression cycle module via the second heat exchanger. The refrigerant in the tertiary compression cycle module vaporizes upon passing through the composite evaporator, further lowering the temperature inside the cryotherapy chamber, thereby enabling the production of even lower temperatures and expanding the cooling temperature range, making it suitable for cryotherapy instruments requiring ultra-low temperatures.

[0008] Optionally, the primary compression cycle module includes a primary compressor, a condenser, a first capillary tube, and a first gas-liquid separator, wherein the primary compressor, the condenser, the first capillary tube, the first heat exchanger, and the first gas-liquid separator are connected end to end in sequence via pipelines.

[0009] By employing the above technical solution, the first-stage compressor compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure superheated gas. This superheated gas then comes into contact with the outside air through a condenser, causing the refrigerant to release heat and gradually cool and liquefy into a high-pressure, room-temperature liquid state. The high-pressure, room-temperature liquid refrigerant then passes through the first capillary tube. Due to the narrow channel of the first capillary tube, the refrigerant pressure drops sharply, and some of the liquid refrigerant rapidly vaporizes, entering the first heat exchanger as a low-temperature, low-pressure mist mixture. Inside the first heat exchanger, the refrigerant completely vaporizes into a low-temperature, low-pressure gas, with a temperature that can drop to -40°C. Afterward, it passes through the first gas-liquid separator, becoming a saturated gaseous refrigerant that returns to the first-stage compressor for recirculation. This single-stage compression cycle module configuration realizes the circulation of refrigerant and the refrigeration process.

[0010] Optionally, the two-stage compression cycle module includes a two-stage compressor, a first oil separator, a first liquid storage tank, a second capillary tube, and a second gas-liquid separator. The two-stage compressor, the first oil separator, the first heat exchanger, the first liquid storage tank, the second capillary tube, the composite evaporator, and the second gas-liquid separator are connected end to end in sequence through pipelines. A bypass pipeline connects the first liquid storage tank and the second capillary tube. The bypass pipeline is connected to the second heat exchanger. The second heat exchanger is connected to the second gas-liquid separator. Solenoid valves are respectively installed between the bypass pipeline and the second capillary tube and on the bypass pipeline. A third capillary tube is installed on the bypass pipeline.

[0011] By adopting the above technical solution, the two-stage compressor draws in and compresses the low-temperature, low-pressure gaseous refrigerant. After passing through the first oil separator, it releases heat and liquefies in the first heat exchanger. Then, after passing through the first liquid storage tank, it circulates in two paths. One path enters the compound evaporator through the second capillary tube, where the refrigerant is completely vaporized into a low-temperature, low-pressure gas, lowering the temperature to -80°C before entering the cryotherapy chamber. It then returns to the two-stage compressor through the second gas-liquid separator, thus achieving the cooling of the cryotherapy chamber. The other path enters the second heat exchanger through the third capillary tube via a bypass pipe, and then returns to the second gas-liquid separator. This path exchanges heat with the three-stage compression cycle module, achieving parallel operation of the two-stage refrigeration system. Simultaneously, the solenoid valve on the bypass pipe controls the refrigerant flow, adjusting it to meet different cooling needs. Moreover, the entire secondary compression cycle module works in conjunction with the primary and tertiary compression cycle modules to form a cascade refrigeration system. Compared with the two-stage cascade refrigeration cycle, it is more suitable for producing low temperatures below -80°C, providing a lower temperature refrigeration environment for cryotherapy instruments and meeting the needs of ultra-low temperature cryotherapy.

[0012] Optionally, the three-stage compression cycle module includes a three-stage compressor, a second oil separator, a second liquid storage tank, a regenerative heat exchanger, and a fourth capillary tube. The three-stage compressor, the second oil separator, the second heat exchanger, the second liquid storage tank, and the regenerative heat exchanger are connected end to end in sequence through pipelines. The regenerative heat exchanger, the fourth capillary tube, and the composite evaporator are also connected end to end in sequence through pipelines.

[0013] By adopting the above technical solution, the high-temperature, high-pressure gaseous refrigerant compressed by the three-stage compressor sequentially passes through the second oil separator, the second heat exchanger, and the second liquid storage tank before reaching the regenerating heat exchanger. In the regenerating heat exchanger, it exchanges heat with the low-temperature, low-pressure gaseous refrigerant returning from the compound evaporator. This lowers the temperature and enthalpy of the refrigerant liquid before entering the fourth capillary tube, achieving liquid subcooling. Simultaneously, it superheats the vapor exiting the compound evaporator, improving the refrigerant's cooling capacity and thus enhancing the overall refrigeration efficiency of the refrigeration system. Furthermore, the refrigerant, after being throttled by the fourth capillary tube before entering the compound evaporator, further reduces the temperature within the compound evaporator. Combined with the first-stage and second-stage compression cycle modules, this allows for the creation of even lower temperatures for the cryotherapy device, meeting its requirements for a low-temperature environment.

[0014] Optionally, a drying filter is provided between the first capillary tube and the condenser, between the bypass pipeline and the first liquid storage tank, and between the regenerative heat exchanger and the fourth capillary tube.

[0015] By adopting the above technical solution, dryer filters are respectively installed between the first capillary tube and the condenser, between the bypass pipeline and the first liquid storage tank, and between the regenerative heat exchanger and the fourth capillary tube. This removes moisture from the refrigerant in the refrigeration system, thereby helping to ensure the purity of the refrigerant, ensuring the smooth flow of components such as the capillary tube in the refrigeration system, enabling the refrigerant to circulate stably in the system, and thus improving the operational stability and reliability of the refrigeration system, further ensuring the refrigeration effect.

[0016] Optionally, a third heat exchanger is provided between the three-stage compressor and the second oil separator. The third heat exchanger is connected to a first pipeline and a second pipeline. The end of the first pipeline away from the third heat exchanger is connected between the first heat exchanger and the first gas-liquid separator. The end of the second pipeline away from the third heat exchanger is connected between the first capillary tube and the condenser. A fifth capillary tube and a solenoid valve are respectively provided on the second pipeline.

[0017] By adopting the above technical solution, when the three-stage compressor starts, the solenoid valve on the second pipeline is opened. The high-pressure, room-temperature liquid refrigerant condensed in the condenser of the first-stage compression cycle module can be vaporized through the fifth capillary tube and connected to the third heat exchanger through the second pipeline. This allows it to exchange heat with the high-temperature, high-pressure gaseous refrigerant compressed by the third-stage compressor in the third heat exchanger, thus pre-cooling the high-temperature, high-pressure gaseous refrigerant. Afterward, the refrigerant from the first-stage compression cycle module returns to the first-stage compression cycle module through the first pipeline to continue participating in the cycle, which helps to improve the refrigeration efficiency of the entire cascade refrigeration system.

[0018] Optionally, the composite evaporator includes mutually isolated evaporators A and B. Evaporator A is connected to the second capillary and the second gas-liquid separator, respectively, and evaporator B is connected to the fourth capillary and the regenerative heat exchanger, respectively.

[0019] By adopting the above technical solution, evaporator A is connected to the second capillary tube and the second gas-liquid separator, and evaporator B is connected to the fourth capillary tube and the regenerative heat exchanger. This allows the refrigerant in the secondary and tertiary compression cycle modules to independently undergo vaporization and heat absorption processes within their respective evaporators, avoiding mutual interference between refrigerants from different cycle modules and ensuring the stability and efficiency of the refrigeration process. Furthermore, the independent chambers allow the secondary and tertiary compression cycle modules to more precisely control the evaporation and state changes of the refrigerant according to their respective refrigeration needs and characteristics, thereby more effectively achieving different levels of refrigeration temperatures to meet the requirements of cryotherapy instruments for different low-temperature environments. For example, the secondary compression cycle module can achieve a refrigeration temperature of -80°C, and the tertiary compression cycle module can achieve a refrigeration temperature of -110°C.

[0020] Optionally, a third pipeline is connected to the first oil separator, the third pipeline being connected between the A evaporator and the second capillary tube, and a solenoid valve is installed on the third pipeline.

[0021] By adopting the above technical solution, during the operation of the two-stage compression cycle module, when frost forms on evaporator A, the solenoid valve on the third pipeline is opened. The high-temperature, high-pressure gaseous refrigerant, compressed by the two-stage compressor and separated by the first oil separator, enters evaporator A through the third pipeline. The heat from the high-temperature, high-pressure gaseous refrigerant defrosts evaporator A, ensuring the normal operation of the composite evaporator, and thus ensuring the stable operation and cooling effect of the entire cascade refrigeration system.

[0022] Optionally, a fourth pipeline is connected to the second oil separator, the fourth pipeline being connected between the regenerative heat exchanger and the B evaporator, and a solenoid valve is installed on the fourth pipeline.

[0023] By adopting the above technical solution, when the solenoid valve is opened, the high-temperature and high-pressure gaseous refrigerant in the second oil separator can enter the B evaporator through the fourth pipeline, which can defrost the B evaporator, avoid the composite evaporator from being affected by frost, ensure the stable operation of the refrigeration system, and thus ensure the normal use of the cryotherapy instrument.

[0024] Optionally, the composite evaporator is equipped with an electric heater.

[0025] By adopting the above technical solution and installing electric heating inside the composite evaporator, additional heat can be provided to the composite evaporator when needed, avoiding situations such as frost formation on the composite evaporator that affect the cooling effect, ensuring the stable operation of the cascade refrigeration system and improving cooling efficiency.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. By cooperating with the primary compression cycle module, the secondary compression cycle module, the tertiary compression cycle module, the first heat exchanger, the second heat exchanger, and the composite evaporator, the problem of the relatively narrow cooling temperature range of the single-stage compressor is solved, and lower temperatures can be produced to increase the cooling temperature range, making it suitable for cryotherapy instruments that require ultra-low temperatures. 2. The regenerative heat exchanger allows the refrigerant liquid at the heat exchanger outlet to exchange heat with the refrigerant vapor at the compound evaporator outlet, thereby reducing the temperature and enthalpy of the refrigerant liquid, achieving liquid subcooling and vapor superheating, and improving refrigeration efficiency; 3. The hot gas bypass of the two-stage and three-stage compression refrigeration cycles, switched by a solenoid valve, allows the high-temperature and high-pressure gaseous refrigerant to defrost the composite evaporator. Attached Figure Description

[0027] Figure 1This is a schematic diagram of the overall structure of a cascade refrigeration system for a cryotherapy device according to an embodiment of this application.

[0028] Figure 2 This is a schematic diagram of the structure of the first-level compression loop module in the embodiment of this application.

[0029] Figure 3 This is a schematic diagram of the structure of the secondary compression loop module in the embodiments of this application.

[0030] Figure 4 This is a schematic diagram of the three-stage compression loop module in an embodiment of this application.

[0031] Explanation of reference numerals in the attached figures: 1. First-stage compression cycle module; 11. First heat exchanger; 12. First-stage compressor; 13. Condenser; 14. First capillary tube; 15. First gas-liquid separator; 2. Second-stage compression cycle module; 21. Second heat exchanger; 22. Second-stage compressor; 23. First oil separator; 231. Third pipeline; 24. First liquid storage tank; 25. Second capillary tube; 26. Second gas-liquid separator; 27. Bypass pipeline; 28. Third capillary tube 3. Three-stage compression cycle module; 31. Three-stage compressor; 32. Second oil separator; 321. Fourth pipeline; 33. Second liquid storage tank; 34. Regenerative heat exchanger; 35. Fourth capillary tube; 36. Third heat exchanger; 361. First pipeline; 362. Second pipeline; 363. Fifth capillary tube; 4. Compound evaporator; 41. A evaporator; 42. B evaporator; 43. Electric heating; 5. Dryer filter; 6. Solenoid valve. Detailed Implementation

[0032] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0033] This application discloses a cascade refrigeration system for cryotherapy instruments.

[0034] It should be noted that, in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] Reference Figure 1A cascade refrigeration system for cryotherapy instruments includes a primary compression cycle module 1, a secondary compression cycle module 2, and a tertiary compression cycle module 3. The primary compression cycle module 1 is equipped with a first heat exchanger 11 and is connected in parallel with the secondary compression cycle module 2 through the first heat exchanger 11. The secondary compression cycle module 2 is equipped with a second heat exchanger 21 and a composite evaporator 4, and the secondary compression cycle module 2 and the tertiary compression cycle module 3 are connected in parallel through the second heat exchanger 21. The tertiary compression cycle module 3 is connected to the composite evaporator 4. This parallel structure enables the primary compression cycle module 1, the secondary compression cycle module 2, and the tertiary compression cycle module 3 to work together to gradually reduce the temperature and achieve the effect of ultra-low temperature refrigeration.

[0036] Reference Figure 1 and Figure 2 The primary compression cycle module 1 includes a primary compressor 12, a condenser 13, a first capillary tube 14, and a first gas-liquid separator 15. The primary compressor 12, condenser 13, first capillary tube 14, first heat exchanger 11, and first gas-liquid separator 15 are connected end to end by pipelines to form a complete circulation loop.

[0037] The first-stage compressor 12 is used to draw in low-temperature, low-pressure gaseous refrigerant and compress it into high-temperature, high-pressure superheated gas. In this embodiment, the first-stage compressor 12 is typically a reciprocating compressor or a scroll compressor. In other embodiments, the first-stage compressor 12 may also be other types of compressors.

[0038] The condenser 13 is a finned air-cooled condenser, which is composed of many heat dissipation fins and pipes. The refrigerant flows in the pipes and exchanges heat with the outside air through the fins, releasing heat and gradually cooling and liquefying into a high-pressure room temperature liquid.

[0039] The first capillary tube 14 is a long and narrow pipe. When high-pressure, room-temperature liquid refrigerant passes through it, the pressure drops sharply, and some of the liquid refrigerant vaporizes rapidly. The first gas-liquid separator 15 is used to separate the gaseous and liquid refrigerant, turning the refrigerant into saturated gaseous refrigerant which returns to the first-stage compressor 12 for circulation.

[0040] In this embodiment, the first heat exchanger 11 is provided with an A end and a B end, and the A end and the B end are respectively provided with an inlet and an outlet. The first capillary tube 14 is connected to the inlet of the A end of the first heat exchanger 11 through a pipe. The first gas-liquid separator 15 is connected to the outlet of the A end of the first heat exchanger 11 through a pipe. A temperature sensor is provided at the outlet of the A end of the first heat exchanger 11 to detect the cooling temperature.

[0041] When the first-stage compressor 12 is working, it compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure superheated gas. The superheated gas exchanges heat with the outside air through the condenser 13, causing it to release heat and gradually cool and liquefy into a high-pressure, room-temperature liquid. The high-pressure, room-temperature liquid refrigerant passes through the first capillary tube 14, where it is depressurized and vaporized. This causes the refrigerant to enter the first heat exchanger 11 as a low-temperature, low-pressure mist mixture. In the first heat exchanger 11, it is further vaporized and cooled. Finally, it passes through the first gas-liquid separator 15, causing the refrigerant to become a saturated gaseous refrigerant and return to the first-stage compressor 12. This cycle repeats to achieve initial cooling, reducing the temperature to -40°C.

[0042] A dryer filter 5 is installed between the first capillary tube 14 and the condenser 13 to remove moisture from the refrigerant entering the first capillary tube 14. The presence of moisture can cause blockage of the first capillary tube 14, affect the flow performance of the refrigerant, and lead to system corrosion. Removing moisture ensures the purity of the refrigerant, guarantees the unobstructed flow of components such as the capillary tube in the refrigeration system, and allows the refrigerant to circulate stably within the system. This improves the operational stability and reliability of the refrigeration system, further ensuring the cooling effect.

[0043] Reference Figure 1 and Figure 3 The secondary compression cycle module 2 includes a secondary compressor 22, a first oil separator 23, a first liquid storage tank 24, a second capillary tube 25, and a second gas-liquid separator 26. The secondary compressor 22, the first oil separator 23, the first heat exchanger 11, the first liquid storage tank 24, the second capillary tube 25, the composite evaporator 4, and the second gas-liquid separator 26 are connected end-to-end via pipelines to form a complete circulation loop. The first oil separator 23 is connected to the B-end inlet of the first heat exchanger 11 via a pipeline, and the first liquid storage tank 24 is connected to the B-end outlet of the first heat exchanger 11 via a pipeline.

[0044] The secondary compressor 22 is used to draw in and compress the low-temperature, low-pressure gaseous refrigerant for the secondary cycle. In this embodiment, the secondary compressor 22 can also be a reciprocating or scroll compressor. In other embodiments, the secondary compressor 22 can also be other types of compressors.

[0045] The first oil separator 23 separates lubricating oil from the refrigerant, ensuring the purity of the refrigerant and the normal operation of the refrigeration system. The first liquid receiver 24 stores liquid refrigerant, stabilizing the refrigerant flow rate. The second capillary tube 25 functions similarly to the first capillary tube 14, causing a sudden drop in refrigerant pressure and partial vaporization. The second gas-liquid separator 26 separates gaseous and liquid refrigerant.

[0046] The second heat exchanger 21 has a similar structure to the first heat exchanger 11. A bypass pipe 27 is connected between the first liquid storage tank 24 and the second capillary tube 25. The bypass pipe 27 is connected to the A-end inlet of the second heat exchanger 21, and the A-end outlet of the second heat exchanger 21 is connected to the second gas-liquid separator 26. Solenoid valves 6 are respectively installed between the bypass pipe 27 and the second capillary tube 25 and on the bypass pipe 27 to facilitate the control of the opening and closing of the pipeline.

[0047] A third capillary tube 28 is provided on the bypass pipe 27. The third capillary tube 28 is located on the side of the solenoid valve 6 near the second heat exchanger 21, and the function of the third capillary tube 28 is similar to that of the first capillary tube 14.

[0048] When the temperature sensor detects that the temperature of the first heat exchanger 11 has dropped to -40°C, the second-stage compressor 22 starts, the solenoid valve 6 opens, and the second-stage cycle begins. The second-stage compressor 22 draws in the low-temperature, low-pressure gaseous refrigerant for the second-stage cycle, and the refrigerant sequentially passes through the second-stage compressor 22, the first oil separator 23, the first heat exchanger 11, and the first liquid receiver 24. In the second-stage compressor 22, the refrigerant is compressed, heated, and pressurized. In the first oil separator 23, lubricating oil is separated. In the first heat exchanger 11, heat is released, and the refrigerant is cooled and liquefied into a high-pressure, room-temperature liquid. Then, a portion of the refrigerant passes through the bypass pipe 27, is depressurized and vaporized through the third capillary tube 28, and enters the second heat exchanger 21. Another portion of the refrigerant passes through the second capillary tube 25, is depressurized and vaporized, and enters the compound evaporator 4. In the compound evaporator 4, the refrigerant is completely vaporized into a low-temperature, low-pressure gas, causing the temperature to drop to -80°C before entering the cryotherapy chamber. The gaseous refrigerant then returns to the second-stage compressor 22 via the second gas-liquid separator 26 for further circulation.

[0049] In this embodiment, a dryer filter 5 is also provided between the bypass pipe 27 and the first liquid storage tank 24 to remove moisture from the refrigerant entering the second capillary tube 25 and the bypass pipe 27.

[0050] Reference Figure 1 and Figure 4 The three-stage compression cycle module 3 includes a three-stage compressor 31, a second oil separator 32, a second liquid storage tank 33, a regenerative heat exchanger 34, a fourth capillary tube 35, and a third heat exchanger 36. The three-stage compressor 31, the third heat exchanger 36, the second oil separator 32, the second heat exchanger 31, the second liquid storage tank 33, and the regenerative heat exchanger 34 are connected end-to-end via pipelines. The regenerative heat exchanger 34, the fourth capillary tube 35, and the composite evaporator 4 are also connected end-to-end via pipelines.

[0051] The three-stage compressor 31 is used to draw in and compress the low-temperature, low-pressure gaseous refrigerant for the three-stage cycle. In this embodiment, the three-stage compressor 31 can also be a reciprocating or scroll compressor. In other embodiments, the three-stage compressor 31 can also be other types of compressors.

[0052] The third heat exchanger 36 has a similar structure to the first heat exchanger 11. The three-stage compressor 31 is connected to the A-end inlet of the third heat exchanger 36 via a pipe. The second oil separator 32 is connected to the A-end outlet of the third heat exchanger 36 and the B-end inlet of the second heat exchanger 21 via pipes. The second liquid receiver 33 is connected to the B-end outlet of the second heat exchanger 21 via a pipe. The second oil separator 32 is used to separate the lubricating oil from the refrigerant in the three-stage cycle. The second liquid receiver 33 stores liquid refrigerant.

[0053] In this embodiment, the regenerative heat exchanger 34 is also provided with an A end and a B end respectively. The inlet of the A end of the regenerative heat exchanger 34 is connected to the second liquid storage tank 33, the outlet of the A end of the regenerative heat exchanger 34 is connected to the fourth capillary tube 35, the inlet of the B end of the regenerative heat exchanger 34 is connected to the composite evaporator 4, and the outlet of the B end of the regenerative heat exchanger 34 is connected to the three-stage compressor 31.

[0054] The regenerative heat exchanger 34 exchanges heat between the refrigerant liquid flowing out of the second liquid storage tank 33 and the refrigerant vapor at the outlet of the compound evaporator 4, causing the temperature and enthalpy of the refrigerant liquid to decrease. This achieves both subcooling of the liquid and superheating of the vapor, thereby improving refrigeration efficiency. A dryer filter 5 is also installed between the regenerative heat exchanger 34 and the fourth capillary tube 35 to filter impurities and moisture from the refrigerant.

[0055] The fourth capillary tube 35 functions similarly to the first capillary tube 14, causing a sudden drop in refrigerant pressure and partial vaporization. A temperature sensor is also installed on the composite evaporator 4 to monitor the temperature inside the cryotherapy chamber.

[0056] When the temperature sensor detects that the temperature of the cryotherapy chamber has dropped to -80°C, the solenoid valve 6 on the bypass line 27 is closed, and the three-stage compressor 31 is started simultaneously, initiating the three-stage cycle. The three-stage compressor 31 draws in the low-temperature, low-pressure gaseous refrigerant for the three-stage cycle, and the refrigerant sequentially passes through the three-stage compressor 31, the third heat exchanger 36, the second oil separator 32, the second heat exchanger 21, the second liquid receiver 33, the regenerating heat exchanger 34, the fourth capillary tube 35, the compound evaporator 4, and the regenerating heat exchanger 34, finally returning to the three-stage compressor 31.

[0057] In this process, the refrigerant is compressed, heated, and pressurized in the three-stage compressor 31, separated from the lubricating oil in the second oil separator 32, released heat and cooled to liquefy into a high-pressure, room-temperature liquid in the second heat exchanger 21, undergoes heat exchange in the regenerating heat exchanger 34, depressurizes and vaporizes in the fourth capillary tube 35, and finally completely vaporizes into a low-temperature, low-pressure gas in the composite evaporator 4, lowering the temperature to -110°C and entering the cryotherapy chamber. The gaseous refrigerant then re-enters the three-stage compressor 31 for circulation.

[0058] Reference Figure 1 The inlet of the third heat exchanger 36 at end B is connected to a first pipe 361, and the outlet of the third heat exchanger 36 at end B is connected to a second pipe 362. The end of the first pipe 361 away from the third heat exchanger 36 is connected between the first heat exchanger 11 and the first gas-liquid separator 15. The end of the second pipe 362 away from the third heat exchanger 36 is connected between the first capillary tube 14 and the condenser 13. A fifth capillary tube 363 and a solenoid valve 6 are respectively installed on the second pipe 362.

[0059] When the temperature sensor detects that the temperature of the cryotherapy chamber has dropped to -80°C, the solenoid valve 6 on the three-stage compressor 31 and the second pipeline 362 is opened. At this time, the high-pressure, room-temperature liquid refrigerant condensed by the first-stage compression cycle module 1 flows through the first pipeline 361 and the second pipeline 362 in the third heat exchanger 36, and vaporizes through the fifth capillary tube 363. It exchanges heat with the high-temperature, high-pressure gaseous refrigerant compressed by the three-stage compressor 31 in the third heat exchanger 36, thus playing a pre-cooling role.

[0060] Reference Figure 1 The first oil separator 23 is connected to a third pipe 231, which connects the composite evaporator 4 and the second capillary tube 25. A solenoid valve 6 is installed on the third pipe 231, so that the high-temperature and high-pressure gaseous refrigerant separated by the first oil separator 23 after being compressed by the second-stage compressor 22 will enter the composite evaporator 4 through the third pipe 231, so as to use the heat brought by the high-temperature and high-pressure gaseous refrigerant to defrost the composite evaporator 4.

[0061] The second oil separator 32 is connected to a fourth pipe 321, which connects the fourth capillary tube 35 to the composite evaporator 4. A solenoid valve 6 is installed on the fourth pipe 321. When the solenoid valve 6 is open, the high-temperature, high-pressure gaseous refrigerant separated by the second oil separator 32 can enter the composite evaporator 4 through the fourth pipe 321 to defrost the composite evaporator 4. This prevents the composite evaporator 4 from being affected by frost buildup, ensuring the stable operation of the refrigeration system and thus guaranteeing the normal use of the cryotherapy instrument.

[0062] Reference Figure 1 In this embodiment, the composite evaporator 4 includes mutually isolated evaporators A 41 and B evaporator 42. Evaporator A 41 is connected to the second capillary tube 25 and the second gas-liquid separator 26 via pipes, while evaporator B 42 is connected to the fourth capillary tube 35 and the regenerative heat exchanger 34 via pipes. This allows the refrigerants in the secondary compression cycle module 2 and the tertiary compression cycle module 3 to undergo independent vaporization and heat absorption processes in their respective evaporators, avoiding mutual interference between the refrigerants of different cycle modules and ensuring the stability and efficiency of the refrigeration process.

[0063] The third pipe 231 is connected to evaporator A 41, so that the high-temperature and high-pressure gaseous refrigerant in the secondary compression cycle module 2 can enter evaporator A 41 through the third pipe 231 to defrost evaporator A 41.

[0064] The fourth pipe 321 is connected to the B evaporator 42, so that the high-temperature and high-pressure gaseous refrigerant in the three-stage compression cycle module 3 can enter the B evaporator 42 through the fourth pipe 321 to defrost the B evaporator 42.

[0065] The compound evaporator 4 is also equipped with an electric heater 43, which can provide additional heat to the compound evaporator 4 when needed, further preventing the compound evaporator 4 from frosting or other situations that affect the cooling effect, ensuring the stable operation of the cascade refrigeration system and improving the cooling efficiency.

[0066] The surface of the composite evaporator 4 is also equipped with a temperature sensor. When the temperature sensor detects that the temperature has reached a certain value, the third pipe 231 and the fourth pipe 321 are turned on first to use hot air for defrosting, and then the electric heater 43 is turned on for further defrosting.

[0067] The implementation principle of this embodiment is as follows: the cascade refrigeration system uses a parallel connection of a primary compression cycle module 1, a secondary compression cycle module 2, and a tertiary compression cycle module 3. Each module refrigerates for different temperature ranges, gradually reducing the temperature to achieve ultra-low temperature refrigeration from -160°C to -40°C, meeting the needs of application scenarios such as ultra-low temperature cryotherapy chambers and local cryotherapy devices.

[0068] Meanwhile, the different levels of compression cycle modules work together to fully utilize their respective cooling capabilities. Compared with single-stage compressor refrigeration systems, it has a wider cooling temperature range, higher cooling efficiency, and is safe and reliable. It does not require the use of liquid nitrogen, solving the problem of narrow cooling temperature range in existing technologies and providing a more efficient refrigeration solution in the field of cryogenic therapy equipment technology.

[0069] It should be noted that in this embodiment, the refrigerants used in the primary compression cycle module 1, the secondary compression cycle module 2, and the tertiary compression cycle module 3 are different, and each module uses a single pure component or an azeotropic mixture of refrigerants, which are thermally coupled through a heat exchanger, thereby making the temperature stages of the overall system clear. In addition, the different modules operate relatively independently with little mutual interference, which is beneficial to improving the operational stability of the overall system.

[0070] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A cascade cooling system for cryotherapy instruments, characterized in that, include: A primary compression cycle module (1) is provided with a first heat exchanger (11). The secondary compression cycle module (2) is connected in parallel with the primary compression cycle module (1) through the first heat exchanger (11). The secondary compression cycle module (2) is provided with a second heat exchanger (21) and a composite evaporator (4). The three-stage compression cycle module (3) is connected in parallel with the two-stage compression cycle module (2) through the second heat exchanger (21), and the three-stage compression cycle module (3) is connected to the composite evaporator (4).

2. The cascade refrigeration system for cryotherapy instruments according to claim 1, characterized in that: The primary compression cycle module (1) includes a primary compressor (12), a condenser (13), a first capillary tube (14), and a first gas-liquid separator (15). The primary compressor (12), the condenser (13), the first capillary tube (14), the first heat exchanger (11), and the first gas-liquid separator (15) are connected end to end by pipelines.

3. The cascade refrigeration system for cryotherapy instruments according to claim 2, characterized in that: The secondary compression cycle module (2) includes a secondary compressor (22), a first oil separator (23), a first liquid storage tank (24), a second capillary tube (25), and a second gas-liquid separator (26). The secondary compressor (22), the first oil separator (23), the first heat exchanger (11), the first liquid storage tank (24), the second capillary tube (25), the composite evaporator (4), and the second gas-liquid separator (26) are connected end to end by pipelines. A bypass pipeline (27) is connected between the first liquid storage tank (24) and the second capillary tube (25). The bypass pipeline (27) is connected to the second heat exchanger (21). The second heat exchanger (21) is connected to the second gas-liquid separator (26). A solenoid valve (6) is provided between the bypass pipeline (27) and the second capillary tube (25) and on the bypass pipeline (27). A third capillary tube (28) is provided on the bypass pipeline (27).

4. The cascade refrigeration system for cryotherapy instruments according to claim 3, characterized in that: The three-stage compression cycle module (3) includes a three-stage compressor (31), a second oil separator (32), a second liquid storage tank (33), a regenerative heat exchanger (34), and a fourth capillary tube (35). The three-stage compressor (31), the second oil separator (32), the second heat exchanger (21), the second liquid storage tank (33), and the regenerative heat exchanger (34) are connected end to end in sequence through pipelines. The regenerative heat exchanger (34), the fourth capillary tube (35), and the composite evaporator (4) are connected end to end in sequence through pipelines.

5. The cascade refrigeration system for cryotherapy instruments according to claim 4, characterized in that: A drying filter (5) is provided between the first capillary tube (14) and the condenser (13), between the bypass pipeline (27) and the first liquid storage tank (24), and between the regenerative heat exchanger (34) and the fourth capillary tube (35).

6. The cascade refrigeration system for cryotherapy instruments according to claim 4, characterized in that: A third heat exchanger (36) is provided between the three-stage compressor (31) and the second oil separator (32). The third heat exchanger (36) is connected to a first pipeline (361) and a second pipeline (362). The end of the first pipeline (361) away from the third heat exchanger (36) is connected between the first heat exchanger (11) and the first gas-liquid separator (15). The end of the second pipeline (362) away from the third heat exchanger (36) is connected between the first capillary tube (14) and the condenser (13). A fifth capillary tube (363) and a solenoid valve (6) are provided on the second pipeline (362).

7. The cascade refrigeration system for cryotherapy instruments according to claim 4, characterized in that: The composite evaporator (4) includes an A evaporator (41) and a B evaporator (42) that are isolated from each other. The A evaporator (41) is connected to the second capillary (25) and the second gas-liquid separator (26) respectively, and the B evaporator (42) is connected to the fourth capillary (35) and the regenerative heat exchanger (34) respectively.

8. The cascade refrigeration system for cryotherapy instruments according to claim 7, characterized in that: The first oil separator (23) is connected to a third pipeline (231), which is connected between the A evaporator (41) and the second capillary tube (25). A solenoid valve (6) is installed on the third pipeline (231).

9. The cascade refrigeration system for cryotherapy instruments according to claim 7, characterized in that: The second oil separator (32) is connected to a fourth pipeline (321), which is connected between the regenerative heat exchanger (34) and the B evaporator (42). A solenoid valve (6) is installed on the fourth pipeline (321).

10. The cascade refrigeration system for a cryotherapy instrument according to claim 1, characterized in that: The composite evaporator (4) is equipped with an electric heater (43).

Images