High and low temperature circulation control method

Abstract

The invention discloses a high and low temperature cycle control method, relates to the technical field of semiconductor tests, and aims at solving the problems that an existing refrigeration and heating system is small in temperature range and low in temperature control precision. Comprising the following steps that S1, a refrigerating system is operated, and the temperature interval where the set liquid outlet temperature is located is judged; s2, according to the set temperature interval where the liquid outlet temperature is located, temperature control strategies corresponding to the temperature interval are executed; according to the temperature control strategy, opening and closing of all the electromagnetic valves are adjusted according to the current liquid outlet temperature, and the power of the heater and the opening degree of the electronic expansion valve are adjusted by judging whether the current liquid outlet temperature is smaller than the set liquid outlet temperature or not; and S3, if the current liquid outlet temperature can be kept the same as the preset liquid outlet temperature, the current state operation is kept. According to the high and low temperature cycle control method, the heat exchanger set of the refrigerating system can be used for heat exchange, and segmented temperature control of different temperature segments is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor testing, and particularly relates to a high and low temperature cycle control method. Background Art

[0002] After the production of semiconductor components is completed, considering the service life and reliability of semiconductor components, high and low temperature tests need to be carried out on semiconductor components. At present, the temperature range of the refrigeration and heating system is small, and the temperature control accuracy is low.

[0003] For the Chinese patent with the publication number CN117433176A, although it can improve the refrigeration and heating efficiency of the system, it cannot solve the problems of the small temperature adjustment range and low temperature control accuracy of the above refrigeration and heating system. Summary of the Invention

[0004] The present invention solves the problems of the small temperature range and low temperature control accuracy of the current refrigeration and heating system, and proposes a high and low temperature cycle control method, which can use the heat exchanger group of the refrigeration system for heat exchange to achieve segmented temperature control in different temperature segments.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A high and low temperature cycle control method includes the following steps: S1. Run the refrigeration system and determine the temperature range where the set outlet temperature is located; S2. According to the temperature range where the set outlet temperature is located, execute the temperature control strategy corresponding to the temperature range; The temperature control strategy adjusts the opening and closing of each solenoid valve according to the current outlet temperature, and adjusts the power of the heater and the opening of the electronic expansion valve by judging whether the current outlet temperature is less than the set outlet temperature; S3. If the current outlet temperature can be kept the same as the preset outlet temperature, keep the current state running.

[0006] In this technical solution, first start the refrigeration system, turn on the compressor and the refrigeration fan in the refrigeration system, and then judge which temperature range the set outlet temperature is in, and execute the specific temperature control strategy according to the temperature range where the outlet temperature is located. The temperature control strategy mainly includes the first temperature control strategy to the sixth temperature control strategy. By adjusting the solenoid valve and the heater power, segmented temperature control in different temperature segments is realized, which is beneficial to achieve precise temperature control.

[0007] The present invention is further set as follows: The step S1 includes: Start the compressor and the refrigeration fan, and open each electronic expansion valve to a preset opening, and then determine which temperature range the set outlet temperature specifically belongs to, so as to adaptively adjust the solenoid valve switch.

[0008] In this technical solution, the refrigeration system starts to operate. Specifically, the compressor in the refrigeration system is started, and then the refrigeration fan is started. The first electronic expansion valve, the second electronic expansion valve, the third electronic expansion valve, and the fourth electronic expansion valve are opened to a preset opening degree, and then the temperature range where the preset liquid outlet temperature is located is determined.

[0009] The present invention is further set as follows: when the first temperature control strategy is executed, only the solenoid valve of the circulation system is opened, the current liquid outlet temperature is obtained, and it is judged whether the current liquid outlet temperature is less than the set liquid outlet temperature. If so, the power of the heater is increased and the rotational speed of the circulation fan is decreased; if not, the power of the heater is decreased and the rotational speed of the circulation fan is increased.

[0010] In this technical solution, when the set liquid outlet temperature is between 40 degrees and 300 degrees, the first temperature control strategy is executed. In this case, only the solenoid valve in the circulation system is opened, and then the obtained current liquid outlet temperature is compared with the set liquid outlet temperature, and the heater and the circulation fan are adjusted.

[0011] The present invention is further set as follows: when the second temperature control strategy is executed, it is judged whether the current liquid outlet temperature is greater than the maximum temperature value of the second temperature range. If so, the solenoid valves of the circulation system and the first heat exchanger are opened; if not, the solenoid valve of the first heat exchanger is opened alone, and then it is judged whether the current liquid outlet temperature is less than the set liquid outlet temperature. If so, the power of the heater is increased and the opening degree of the electronic expansion valve is adjusted; if not, the power of the heater is decreased and the opening degree of the electronic expansion valve is adjusted.

[0012] In this technical solution, when the set liquid outlet temperature is between 25 degrees and 40 degrees, the second temperature control strategy is executed. Different from the first temperature control strategy, the second temperature control strategy also needs to judge whether the current liquid outlet temperature is greater than the maximum temperature value of the second temperature range to determine whether to open the second solenoid valve of the circulation system, and the subsequent judgment process is the same as that of the first temperature control strategy.

[0013] The present invention is further set as follows: when the third temperature control strategy is executed, it is judged whether the current liquid outlet temperature is greater than the maximum temperature value of the third temperature range. If so, the solenoid valves of the circulation system and the first heat exchanger are opened; if not, the solenoid valve of the second heat exchanger is opened alone, and then it is judged whether the current liquid outlet temperature is less than the set liquid outlet temperature. If so, the power of the heater is increased and the opening degree of the electronic expansion valve is adjusted; if not, the power of the heater is decreased and the opening degree of the electronic expansion valve is adjusted.

[0014] In this technical solution, when the set liquid outlet temperature is between -30 degrees and 25 degrees, the third temperature control strategy is executed.

[0015] The present invention is further configured such that when the fourth temperature control strategy is executed, according to the relationship between the current liquid outlet temperature and the maximum temperature value of the fourth temperature range, the solenoid valves of the circulation system, the first heat exchanger, and the second heat exchanger are opened, or only the solenoid valve of the third heat exchanger is opened.

[0016] In this technical solution, when the set liquid outlet temperature is between -70°C and -30°C, the fourth temperature control strategy is executed.

[0017] The present invention is further configured such that when the fifth temperature control strategy is executed, according to the relationship between the current liquid outlet temperature and the maximum temperature value of the fifth temperature range, the solenoid valves of the circulation system, the first heat exchanger to the third heat exchanger are opened, or only the solenoid valve of the fourth heat exchanger is opened.

[0018] In this technical solution, when the set liquid outlet temperature is between -110°C and -70°C, the fifth temperature control strategy is executed.

[0019] The present invention is further configured such that when the sixth temperature control strategy is executed, according to the relationship between the current liquid outlet temperature and the maximum temperature value of the sixth temperature range, the solenoid valves of the circulation system, the first heat exchanger to the fourth heat exchanger are opened, or only the solenoid valve of the fifth heat exchanger is opened.

[0020] In this technical solution, when the set liquid outlet temperature is between -150°C and -110°C, the sixth temperature control strategy is executed.

[0021] The present invention is further configured such that the step S3 further includes: if the current liquid outlet temperature is not the same as the preset liquid outlet temperature, continue to adjust the power of the heater and the opening degree of the electronic expansion valve.

[0022] The present invention is further configured such that the current liquid outlet temperature is detected by a temperature sensor provided at the liquid outlet, and the temperature sensor transmits the real-time detection data to the system controller, and the system controller makes a judgment and comparison based on the real-time detection data.

[0023] In this technical solution, the real-time current liquid outlet temperature is obtained through the temperature sensor, so as to facilitate the comparison and judgment of the system controller.

[0024] The present invention can bring the following beneficial effects: A high and low temperature cycle control method related to the present invention can achieve temperature adjustment from -150°C to 300°C, and has high temperature control accuracy and convenient adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a partial flow schematic diagram of a high and low temperature cycle control method of the present application.

[0026] Figure 2It is another part of the process schematic diagram of a high and low temperature cycle control method of this application.

[0027] Figure 3 It is the schematic diagram of the system adopted by a high and low temperature cycle control method of this application.

[0028] Reference numerals: 1. Compressor; 2. Oil separator; 3. Condenser; 4. Refrigeration fan; 5. Dry filter; 6. First heat exchanger; 7. Second heat exchanger; 8. Third heat exchanger; 9. Fourth heat exchanger; 10. Fifth heat exchanger; 11. First gas-liquid separator; 12. Second gas-liquid separator; 13. Third gas-liquid separator; 14. First electronic expansion valve; 15. Second electronic expansion valve; 16. Third electronic expansion valve; 17. Fourth electronic expansion valve; 18. Solenoid valve; 19. Expansion vessel; 20. Fifth capillary; 21. First pressure sensor; 22. First temperature sensor; 23. Second temperature sensor; 24. Third temperature sensor; 25. Fourth temperature sensor; 26. Second pressure sensor; 27. Fifth temperature sensor; 30. Water tank; 31. Heater; 32. Water pump; 33. First solenoid valve; 34. Second solenoid valve; 35. Third heat exchanger; 36. Circulation fan; 37. Third solenoid valve; 38. Fourth solenoid valve; 39. Fifth solenoid valve; 40. Sixth solenoid valve; 41. Seventh solenoid valve; 42. Eighth solenoid valve; 43. Ninth solenoid valve; 44. Tenth solenoid valve; 45. Eleventh solenoid valve; 46. Twelfth solenoid valve; 47. Thirteenth solenoid valve; 48. Fourteenth solenoid valve; 49. Check valve; 50. Third pressure sensor; 51. Sixth temperature sensor; 52. Fourth pressure sensor; 53. Seventh temperature sensor; 54. Fifteenth solenoid valve. Detailed implementation manners

[0029] To make the purpose, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific implementation manners described herein are only the best embodiments of the present invention, which are only used to explain the present invention and do not limit the protection scope of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0030] Embodiment 1 This embodiment proposes a high and low temperature cycle control method, referring to Figure 1 and Figure 2 , which mainly includes the following several steps.

[0031] Step S1: First, run the refrigeration system, and then determine the temperature range where the set outlet temperature is located. Specifically, start the compressor 1 and the refrigeration fan 4 in the refrigeration system, open the corresponding electronic expansion valves of the refrigeration system to the preset opening degree, and determine in which range the set outlet temperature SV is specifically, so as to decide the opening and closing of each solenoid valve.

[0032] In this technical solution, the refrigeration system starts to run. Specifically, start the compressor 1 in the refrigeration system, and then start the refrigeration fan 4. The first electronic expansion valve 14, the second electronic expansion valve 15, the third electronic expansion valve 16, and the fourth electronic expansion valve 17 are opened to the preset opening degree, and then determine the temperature range where the preset outlet temperature is located.

[0033] Step S2: Based on Step S1, according to the temperature range to which the set outlet temperature belongs, execute different temperature control strategies respectively.

[0034] More specifically, the temperature control strategy mainly controls and adjusts the opening and closing of each solenoid valve according to the current outlet temperature, and adjusts the power of the heater 31 and the opening degree of the electronic expansion valve according to the comparison result between the current outlet temperature and the set outlet temperature.

[0035] In this technical solution, the temperature control strategy mainly includes the first temperature control strategy, the second temperature control strategy, the third temperature control strategy, the fourth temperature control strategy, the fifth temperature control strategy, and the sixth temperature control strategy.

[0036] For the first temperature control strategy, when executing this strategy, only open the solenoid valve of the circulation system. The system obtains the current outlet temperature, and determines whether to adjust the heater power by judging whether the current outlet temperature is less than the set outlet temperature. Specifically, if the current outlet temperature is less than the set outlet temperature, increase the heater power and decrease the rotation speed of the circulation fan; if the current outlet temperature is not less than the set outlet temperature, decrease the heater power and increase the rotation speed of the circulation fan.

[0037] In this embodiment, the preset outlet temperature range for executing the first temperature control strategy is 40°C < SV < 300°C. In this case, the second solenoid valve 34, the third solenoid valve 37, the fifth solenoid valve 39, the seventh solenoid valve 41, the ninth solenoid valve 43, the eleventh solenoid valve 45, and the thirteenth solenoid valve 47 are opened, and the rest of the solenoid valves are closed. The system obtains the temperature value PV of the current outlet temperature sensor, and judges the size of the current outlet temperature PV and the set outlet temperature SV: if the current outlet temperature PV < the set temperature SV, increase the power P value of the heater 31, and at the same time decrease the rotation speed of the circulation fan 36 until the current outlet temperature PV = the set temperature PV; if the current outlet temperature PV > the set temperature SV, decrease the power P value of the heater 31, and at the same time increase the rotation speed of the circulation fan 36 until the current outlet temperature PV = the set temperature PV.

[0038] For the second temperature control strategy, when implementing this strategy, first determine whether the current liquid outlet temperature is greater than the maximum temperature value of the second temperature range. If the current liquid outlet temperature is greater than the maximum temperature value of the second temperature range, then open the solenoid valves of the circulation system and the first heat exchanger; if the current liquid outlet temperature is not greater than the maximum temperature value of the second temperature range, then only open the solenoid valve of the first heat exchanger. After that, determine whether the current liquid outlet temperature is less than the set liquid outlet temperature. If the current liquid outlet temperature is less than the set liquid outlet temperature, then increase the power of the heater and adjust the opening degree of the electronic expansion valve. If the current liquid outlet temperature is not less than the set liquid outlet temperature, then decrease the power of the heater and adjust the opening degree of the electronic expansion valve.

[0039] In this embodiment, the temperature range for implementing the second temperature control strategy is 25°C < SV < 40°C. The system obtains the temperature value PV of the current liquid outlet temperature sensor and determines whether the current liquid outlet temperature PV is greater than 40°C. If the current liquid outlet temperature PV > 40°C, then the second solenoid valve 34, the third solenoid valve 37, the fourth solenoid valve 38, the sixth solenoid valve 40, the seventh solenoid valve 41, the ninth solenoid valve 43, the eleventh solenoid valve 45, and the thirteenth solenoid valve 47 are opened, and the other solenoid valves are closed. Increase the rotational speed of the circulation fan 36, and at the same time adjust the opening degree of the first electronic expansion valve 14 until the current liquid outlet temperature PV < 40°C.

[0040] If the current liquid outlet temperature < 40°C, then the fifteenth solenoid valve 54, the fourth solenoid valve 38, the sixth solenoid valve 40, the seventh solenoid valve 41, the ninth solenoid valve 43, the eleventh solenoid valve 45, and the thirteenth solenoid valve 47 are opened, and the other solenoid valves are closed. Determine the magnitudes of the current liquid outlet temperature PV and the set liquid outlet temperature SV: If the current liquid outlet temperature PV < the set temperature SV, then increase the power P value of the heater 31 and adjust the opening degree of the first electronic expansion valve 14 until the current liquid outlet temperature PV = the set temperature PV; if the current liquid outlet temperature PV > the set temperature SV, then decrease the power P value of the heater 31 and adjust the opening degree of the first electronic expansion valve 14 until the current liquid outlet temperature PV = the set temperature PV.

[0041] For the third temperature control strategy, when implementing this strategy, first, determine whether the current liquid outlet temperature is greater than the maximum temperature value of the third temperature range. If the current liquid outlet temperature is greater than the maximum temperature value of the third temperature range, then open the solenoid valves of the circulation system and the first heat exchanger. If the current liquid outlet temperature is not greater than the maximum temperature value of the third temperature range, then only open the solenoid valve of the second heat exchanger. After that, determine whether the current liquid outlet temperature is less than the set liquid outlet temperature. If the current liquid outlet temperature is less than the set liquid outlet temperature, then it is necessary to increase the power of the heater and adjust the opening degree of the electronic expansion valve. Otherwise, it is necessary to decrease the power of the heater and adjust the opening degree of the electronic expansion valve.

[0042] In this embodiment, the temperature range for implementing the third temperature control strategy is -30°C < SV < 25°C. The system obtains the temperature value PV of the current liquid outlet temperature sensor and determines whether the current liquid outlet temperature PV is greater than 25°C. If the current liquid outlet temperature PV > 25°C, then the second solenoid valve 34, the third solenoid valve 37, the fourth solenoid valve 38, the sixth solenoid valve 40, the seventh solenoid valve 41, the ninth solenoid valve 43, the eleventh solenoid valve 45, and the thirteenth solenoid valve 47 are opened, and the remaining solenoid valves are closed. The rotational speed of the circulation fan 36 is increased and the opening degree of the first electronic expansion valve 14 is adjusted until the current liquid outlet temperature.

[0043] If the current liquid outlet temperature PV < 25°C, then the fifteenth solenoid valve 54, the fifth solenoid valve 39, the sixth solenoid valve 40, the eighth solenoid valve 42, the ninth solenoid valve 43, the eleventh solenoid valve 45, and the thirteenth solenoid valve 47 are opened, and the remaining solenoid valves are closed. The magnitudes of the current liquid outlet temperature PV and the set liquid outlet temperature SV are judged: If the current liquid outlet temperature PV < the set temperature SV, then the power P value of the heater 31 is increased and the opening degree of the first electronic expansion valve 14 is adjusted until the current liquid outlet temperature PV = the set temperature PV; if the current liquid outlet temperature PV > the set temperature SV, then the power P value of the heater 31 is decreased and the opening degree of the first electronic expansion valve 14 is adjusted until the current liquid outlet temperature PV = the set temperature PV.

[0044] For the fourth temperature control strategy, it specifically opens the solenoid valves of the circulation system, the first heat exchanger, and the second heat exchanger, or only opens the solenoid valve of the third heat exchanger according to the relationship between the current liquid outlet temperature and the maximum temperature value of the fourth temperature range.

[0045] In this embodiment, the temperature range for implementing the fourth temperature control strategy is -70°C < SV < -30°C. The system obtains the temperature value PV of the current liquid outlet temperature sensor and determines whether the current liquid outlet temperature PV is greater than -30°C. If the current liquid outlet temperature PV > -30°C, then the second solenoid valve 34, the third solenoid valve 37, the fourth solenoid valve 38, the eighth solenoid valve 42, the ninth solenoid valve 43, the eleventh solenoid valve 45, and the thirteenth solenoid valve 47 are opened, and the remaining solenoid valves are closed. The rotational speed of the circulation fan 36 is increased and the opening degrees of the first electronic expansion valve 14 and the second electronic expansion valve 15 are adjusted until the current liquid outlet temperature < -30°C.

[0046] If the current liquid outlet temperature PV < -30°C, the fifteenth solenoid valve 54, the fifth solenoid valve 39, the seventh solenoid valve 41, the eighth solenoid valve 42, the tenth solenoid valve 44, the eleventh solenoid valve 45, and the thirteenth solenoid valve 47 are opened, and the rest of the solenoid valves are closed. Then, judge the magnitudes of the current liquid outlet temperature PV and the set liquid outlet temperature SV: If the current liquid outlet temperature PV < the set temperature SV, increase the power P value of the heater 31 and simultaneously adjust the opening degree of the second electronic expansion valve 15 until the current liquid outlet temperature PV = the set temperature PV; if the current liquid outlet temperature PV > the set temperature SV, decrease the power P value of the heater 31 and simultaneously adjust the opening degree of the second electronic expansion valve 15 until the current liquid outlet temperature PV = the set temperature PV.

[0047] For the fifth temperature control strategy, based on the relationship between the current liquid outlet temperature and the maximum temperature value of the fifth temperature range, it opens the solenoid valves of the circulation system, the first heat exchanger, the second heat exchanger, and the third heat exchanger, or only opens the solenoid valve of the fourth heat exchanger.

[0048] In this embodiment, the temperature range for implementing the fifth temperature control strategy is -110°C < SV < -70°C. The system obtains the temperature value PV of the current liquid outlet temperature sensor and judges whether the current liquid outlet temperature PV is greater than -70°C. If the current liquid outlet temperature PV > -70°C, the second solenoid valve 34, the third solenoid valve 37, the fourth solenoid valve 38, the tenth solenoid valve 44, the eleventh solenoid valve 45, and the thirteenth solenoid valve 47 are opened, and the rest of the solenoid valves are closed. Increase the rotational speed of the circulation fan 36 and simultaneously adjust the opening degrees of the first electronic expansion valve 14, the second electronic expansion valve 15, and the third electronic expansion valve 16 until the current liquid outlet temperature < -70°C.

[0049] If the current liquid outlet temperature PV < -70°C, the fifteenth solenoid valve 54, the fifth solenoid valve 39, the seventh solenoid valve 41, the ninth solenoid valve 43, the tenth solenoid valve 44, the twelfth solenoid valve 46, and the thirteenth solenoid valve 47 are opened, and the rest of the solenoid valves are closed. Then, judge the magnitudes of the current liquid outlet temperature PV and the set liquid outlet temperature SV: If the current liquid outlet temperature PV < the set temperature SV, increase the power P value of the heater 31 and simultaneously adjust the opening degree of the third electronic expansion valve 16 until the current liquid outlet temperature PV = the set temperature PV; if the current liquid outlet temperature PV > the set temperature SV, decrease the power P value of the heater 31 and simultaneously adjust the opening degree of the third electronic expansion valve 16 until the current liquid outlet temperature PV = the set temperature PV.

[0050] For the sixth temperature control strategy, based on the relationship between the current liquid outlet temperature and the maximum temperature value of the fifth temperature range, it opens the solenoid valves of the circulation system, the first heat exchanger, the second heat exchanger, the third heat exchanger, and the fourth heat exchanger, or only opens the solenoid valve of the fifth heat exchanger.

[0051] In this embodiment, the temperature range for implementing the sixth temperature control strategy is -150°C < SV < -110°C. The system obtains the temperature value PV of the current liquid outlet temperature sensor and determines whether the current liquid outlet temperature PV is greater than -110°C. If the current liquid outlet temperature PV > -110°C, then the second solenoid valve 34, the third solenoid valve 37, the fourth solenoid valve 38, and the thirteenth solenoid valve 47 are opened, and the remaining solenoid valves are closed. The rotational speed of the circulation fan 36 is increased while the opening degrees of the first electronic expansion valve 14, the second electronic expansion valve 15, the third electronic expansion valve 16, and the fourth electronic expansion valve 17 are adjusted until the current liquid outlet temperature < -110°C.

[0052] If the current liquid outlet temperature PV < -110°C, then the fifteenth solenoid valve 54, the fifth solenoid valve 39, the seventh solenoid valve 41, the ninth solenoid valve 43, the eleventh solenoid valve 45, the twelfth solenoid valve 46, and the fourteenth solenoid valve 48 are opened, and the remaining solenoid valves are closed. The magnitudes of the current liquid outlet temperature PV and the set liquid outlet temperature SV are judged: If the current liquid outlet temperature PV < the set temperature SV, then the power P value of the heater 31 is increased while the opening degree of the fourth electronic expansion valve 17 is adjusted until the current liquid outlet temperature PV = the set temperature PV; if the current liquid outlet temperature PV > the set temperature SV, then the power P value of the heater 31 is decreased while the opening degree of the fourth electronic expansion valve 17 is adjusted until the current liquid outlet temperature PV = the set temperature PV.

[0053] Embodiment 2 Reference Figure 3 For the system based on the above high and low temperature circulation control method, it mainly includes a refrigeration system and a circulation system connected to the refrigeration system. The refrigeration system includes a compressor 1 and a heat exchanger group, and a gas-liquid separator is arranged and connected between adjacent heat exchangers in the heat exchanger group; the circulation system mainly includes a water tank 30, a heater 31, a water pump 32, and multiple solenoid valves; the water tank 30 can be connected to the heater 31, the heater 31 is connected to the water pump 32, the water pump 32 is successively connected to multiple solenoid valves, the circulation system can segmentally adjust the circulation liquid flow path of different temperature segments, and the refrigeration system can achieve ultra-low temperature refrigeration through automatic partial condensation of the mixed refrigeration medium.

[0054] An oil separator 2, a condenser 3, a refrigeration fan 4, and a drying filter 5 are respectively arranged between the heat exchanger group and the compressor 1; wherein, one end of the oil separator 2 is connected to the compressor 1, the other end of the oil separator 2 is provided and connected with the condenser 3, and a refrigeration fan 4 is arranged on one side of the condenser 3; the other end of the condenser 3 is connected to the drying filter 5, and the other end of the drying filter 5 is connected to the heat exchanger group.

[0055] A first pressure sensor 21 and a second temperature sensor 22 are arranged between the compressor 1 and the oil separator 2, and a second temperature sensor 23 is arranged between the drying filter 5 and the heat exchanger group.

[0056] For the heat exchanger group, it includes at least five heat exchangers connected in sequence. A corresponding gas-liquid separator is provided between adjacent heat exchangers. One end of the gas-liquid separator is connected to one of the heat exchangers, and the other end of the gas-liquid separator is connected to an electronic expansion valve, and the electronic expansion valve is also connected to other heat exchangers.

[0057] The heat exchanger group includes a first heat exchanger 6, a second heat exchanger 7, a third heat exchanger 8, a fourth heat exchanger 9, and a fifth heat exchanger 10.

[0058] In this technical solution, multiple heat exchangers in the heat exchanger group can perform staged cooling and separation on refrigerants with different boiling points.

[0059] In the circulation system, one end of the water pump 32 far from the heater 31 is connected to the user end. A first solenoid valve 33 is provided at the inlet and outlet positions of the user end. The other end of the first solenoid valve 33 is respectively connected to a second solenoid valve 34 and a fifteenth solenoid valve 54. The other end of the second solenoid valve 34 is sequentially connected to a sixth heat exchanger 35 and a third solenoid valve 37, and the third solenoid valve 37 is also connected to the other end of the fifteenth solenoid valve 54.

[0060] In this technical solution, when the corresponding solenoid valve is opened, the circulating liquid returning from the user end flows into the sixth heat exchanger 35 through the second solenoid valve 34 and is forcibly air-cooled by the circulating fan 36.

[0061] The third solenoid valve 37 is also respectively connected to a fourth solenoid valve 38 and a fifth solenoid valve 39. The fourth solenoid valve 38 is connected to the first heat exchanger 6. The other end of the fifth solenoid valve 39 is respectively connected to a sixth solenoid valve 40 and a seventh solenoid valve 41. The sixth solenoid valve 40 is respectively connected to the first heat exchanger 6 and the second heat exchanger 7.

[0062] On this basis, the fifth solenoid valve 39 is sequentially connected to the seventh solenoid valve 41, the ninth solenoid valve 43, the eleventh solenoid valve 45, and the thirteenth solenoid valve 47. The other end of the thirteenth solenoid valve 47 is respectively connected to a check valve 49 between the water tank 30 and the heater 31 and a fourteenth solenoid valve 48. The other end of the fourteenth solenoid valve 48 is connected to the fifth heat exchanger 10. And an eighth solenoid valve 42 is provided between the seventh solenoid valve 41 and the ninth solenoid valve 43. The other end of the eighth solenoid valve 42 is respectively connected to the second heat exchanger 7 and the third heat exchanger 8. Similarly, a tenth solenoid valve 44 is respectively connected to the third heat exchanger 8 and the fourth heat exchanger 9, and a twelfth solenoid valve 46 is respectively connected to the fourth heat exchanger 9 and the fifth heat exchanger 10.

[0063] In a refrigeration system, the gas-liquid separator includes a first gas-liquid separator 11. The first gas-liquid separator 11 includes multiple channels. The third channel 113 of the first gas-liquid separator 11 is connected to the first electronic expansion valve 14. The second channel 112 of the first gas-liquid separator 11 is connected to the second heat exchanger 7. The first channel 111 of the first gas-liquid separator 11 is connected to the first heat exchanger 6.

[0064] In this technical solution, the connection relationships of the second gas-liquid separator 12 and the third gas-liquid separator 13 are similar to those of the above-mentioned first gas-liquid separator 11.

[0065] For the first heat exchanger 6, the first channel 61 of the first heat exchanger 6 is connected to the compressor 1. The second channel 62 of the first heat exchanger 6 is connected to the second heat exchanger 7. The third channel 63 of the first heat exchanger 6 is connected to the circulation system. The fourth channel 64 of the first heat exchanger 6 is respectively connected to the circulation system and the second heat exchanger 7. The fifth channel 65 of the first heat exchanger 6 is connected to the condenser 3. The first heat exchanger 6 is specifically connected to the first gas-liquid separator 11 through its sixth channel 66.

[0066] The channel connection relationships of the second heat exchanger 7, the third heat exchanger 8, the fourth heat exchanger 9, and the fifth heat exchanger 10 are similar to those of the above-mentioned first heat exchanger 6. For more detailed content, reference can be made to Figure 1 the schematic diagram of the connection relationship.

[0067] The second heat exchanger 7 is connected to the second gas-liquid separator 12. The second gas-liquid separator 12 is connected to the second electronic expansion valve 15. The third heat exchanger 8 is connected to the third gas-liquid separator 13. The third gas-liquid separator 13 is connected to the third electronic expansion valve 16.

[0068] The other end of the compressor 1 is also connected to the capillary tube 20. The capillary tube 20 is also connected to the expansion vessel 19. The other end of the expansion vessel 19 is connected to the solenoid valve 18. The other end of the solenoid valve 18 is connected to the third gas-liquid separator 13.

[0069] In addition, a third temperature sensor 24 is connected to one end of the fifth heat exchanger 5. A fifth temperature sensor 25 is provided between the fifth heat exchanger 5 and the third electronic expansion valve 16. A second pressure sensor 26 and a fifth temperature sensor 27 are provided between the first heat exchanger 5 and the compressor 1.

[0070] For the refrigeration system, it includes the following working process.

[0071] A variety of mixed refrigerants at low temperature and low pressure (three or more refrigerants with different boiling points at different temperatures) are sucked in through the suction port of the compressor 1. After compression, the mixed gas becomes a high-temperature and high-pressure mixed gas. The oil in the gas is separated by the oil separator 2, and the separated oil returns to the compressor. The mixed gas after being separated by the oil separator enters the condenser 3 and is forced to dissipate heat and condense into a low-temperature and high-pressure gas-liquid mixture (the high-boiling refrigerant condenses into a liquid) through the refrigeration fan 4.

[0072] The gas-liquid mixture enters the first heat exchanger 6 to further cool the high-boiling refrigerant into a liquid. The gas-liquid mixture after being cooled by the first heat exchanger 6 enters the first gas-liquid separator 11 to separate the gas-liquid two phases of the gas-liquid mixture.

[0073] The high-boiling liquid refrigerant exits from the third channel 113 of the first gas-liquid separator 11. After throttling and depressurizing through the first electronic expansion valve 14, the high-boiling liquid refrigerant is mixed with the refrigerant after returning from the third heat exchanger 8.

[0074] The medium- and low-boiling gaseous mixed refrigerant enters the second heat exchanger 7 through the second channel 112 of the first gas-liquid separator 11 for heat exchange. In the second heat exchanger 7, the medium-boiling refrigerant in the medium- and low-boiling gaseous mixture is condensed into a liquid.

[0075] The medium- and low-boiling gas-liquid mixed refrigerant coming out of the second heat exchanger 7 enters the second gas-liquid separator 12 for separation. The medium-boiling liquid refrigerant exits from the channel 123. After throttling and depressurizing through the second electronic expansion valve 15, the medium-boiling liquid refrigerant is mixed with the refrigerant after returning from the fourth heat exchanger 9.

[0076] The low-boiling refrigerant exits from the channel 122 and enters the third heat exchanger 8. In the third heat exchanger 8, the low-boiling refrigerant is further condensed into a lower temperature, and the mixed medium- and high-boiling refrigerants in the low-boiling refrigerant are further cooled into a low-temperature liquid, making the low-temperature refrigerant purer.

[0077] The refrigerant after heat exchange in the third heat exchanger 8 enters the third gas-liquid separator 13. In the third gas-liquid separator, the separated liquid medium- and high-boiling refrigerants exit from the channel 133 and are throttled by the third electronic expansion valve 16 and then mixed with the refrigerant after returning from the second heat exchanger 7.

[0078] After the gaseous refrigerant with a low boiling point enters the fourth heat exchanger 9 and is further condensed into a liquid refrigerant, it enters the fifth heat exchanger 10, exchanges heat and becomes a subcooled liquid. The subcooled liquid after heat exchange in the fifth heat exchanger 10 passes through the fourth electronic expansion valve 17 for throttling and pressure reduction and then becomes a gas-liquid mixture with low temperature and low pressure, and then returns to the fifth heat exchanger 10 to exchange heat with the circulating liquid (channels 103, 104) and the low-boiling-point subcooled liquid (channels 101, 102). The low-boiling-point gas-liquid mixture absorbs the heat of the compressed air and the subcooled liquid and then becomes a gas with low temperature and low pressure. Thus, the temperature of the circulating liquid and the low-boiling-point subcooled liquid decreases. The low-boiling-point refrigerant gas coming out from channel 105 returns to the fourth heat exchanger 9. Similarly, the low-boiling-point low-temperature refrigerant returning from channel 105 to channel 95 exchanges heat with the refrigerant channels 93, 94 and the circulating liquid in channels 91, 92 respectively.

[0079] The refrigerant returning from the fourth heat exchanger 9 is mixed with the medium-boiling-point refrigerant after throttling by the second electronic expansion valve 15 and then enters the third heat exchanger. The mixed refrigerant exchanges heat with the circulating liquid in the refrigerant channels 83, 84 of channels 81, 82 in the third heat exchanger 8. The mixed refrigerant from channel 85 of the third heat exchanger 8 is mixed with the high-boiling-point refrigerant after throttling by the first electronic expansion valve 14 and then enters the second heat exchanger 7. The mixed refrigerant exchanges heat with the circulating liquid in the refrigerant channels 73, 74 of channels 71, 72 in the second heat exchanger 7.

[0080] The mixed working medium from channel 75 of the second heat exchanger 7 is mixed with the refrigerant after throttling by the third electronic expansion valve 16 and then enters the first heat exchanger 6. The mixed refrigerant after heat exchange in the first heat exchanger 6 comes out from channel 63 and returns to the suction port of the compressor 1.

[0081] This embodiment can bring the following technical effects: the temperature control range is large, and the temperature can be controlled within the range from -150°C to +300°C; the heat exchangers at all levels of the refrigeration system are fully utilized for heat exchange to achieve segmented temperature control in different temperature segments, and a single-stage system can achieve mixed refrigeration with four or more refrigerants; automatic partial condensation of multiple mixed refrigerants realizes high and low temperature cycles; it can achieve rapid cooling from high temperature, greatly reducing the cooling time.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. Although the present invention has been described in detail with reference to the embodiments, those of ordinary skill in the art should understand that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A high and low temperature cycle control method, characterized in that: The following steps are involved: S1, running the refrigeration system and determining the temperature range in which the set liquid outlet temperature is located; S2, according to the temperature range in which the liquid outlet temperature is set, respectively execute the temperature control strategy corresponding to the temperature range; The temperature control strategy adjusts the switches of each solenoid valve according to the current outlet liquid temperature, and adjusts the power of the heater and the opening of the electronic expansion valve by judging whether the current outlet liquid temperature is lower than the set outlet liquid temperature; S3: If the current outlet liquid temperature can be maintained the same as the preset outlet liquid temperature, the current state is maintained.

2. A high and low temperature cycle control method according to claim 1, characterized in that: The step S1 comprises: Start the compressor and refrigeration fan, and open each electronic expansion valve to the preset opening, then determine the temperature range within which the set liquid outlet temperature belongs to, and adaptively adjust the solenoid valve switch.

3. A high and low temperature cycle control method according to claim 1, characterized in that: When executing the first temperature control strategy, only the solenoid valve of the circulation system is opened to obtain the current liquid outlet temperature, and determine whether the current liquid outlet temperature is lower than the set liquid outlet temperature. If so, the heater power is increased and the circulation fan speed is reduced; if not, the heater power is reduced and the circulation fan speed is increased.

4. A high and low temperature cycle control method according to claim 1, 2 or 3, characterized in that: When executing the second temperature control strategy, determine whether the current liquid outlet temperature is greater than the maximum temperature value of the second temperature range. If so, open the solenoid valves of the circulation system and the first heat exchanger; if not, open the solenoid valve of the first heat exchanger alone, and then determine whether the current liquid outlet temperature is less than the set liquid outlet temperature. If so, increase the heater power and adjust the opening of the electronic expansion valve; if not, reduce the heater power and adjust the opening of the electronic expansion valve.

5. A high and low temperature cycle control method according to claim 4, characterized in that: When executing the third temperature control strategy, determine whether the current liquid outlet temperature is greater than the maximum temperature value of the third temperature range. If so, open the solenoid valves of the circulation system and the first heat exchanger; if not, open the solenoid valve of the second heat exchanger alone, and then determine whether the current liquid outlet temperature is less than the set liquid outlet temperature. If so, increase the heater power and adjust the opening of the electronic expansion valve; if not, reduce the heater power and adjust the opening of the electronic expansion valve.

6. A high and low temperature cycle control method according to claim 5, characterized in that: When the fourth temperature control strategy is executed, the solenoid valves of the circulation system, the first heat exchanger and the second heat exchanger are opened, or only the solenoid valve of the third heat exchanger is opened according to the relationship between the current liquid outlet temperature and the maximum temperature value of the fourth temperature range.

7. A high and low temperature cycle control method according to claim 5 or 6, characterized in that: When the fifth temperature control strategy is executed, the solenoid valves of the circulation system, the first heat exchanger to the third heat exchanger, or only the solenoid valve of the fourth heat exchanger are opened according to the relationship between the current liquid outlet temperature and the maximum temperature value of the fifth temperature range.

8. A high and low temperature cycle control method according to claim 5 or 6, characterized in that: When the sixth temperature control strategy is executed, the solenoid valves of the circulation system, the first to fourth heat exchangers, or only the solenoid valve of the fifth heat exchanger are opened according to the relationship between the current liquid outlet temperature and the maximum temperature value of the sixth temperature range.

9. A high and low temperature cycle control method according to claim 1, characterized in that: The step S3 further includes: if the current liquid outlet temperature is different from the preset liquid outlet temperature, continuing to adjust the power of the heater and the opening of the electronic expansion valve.

10. A high and low temperature cycle control method according to claim 1 or 2, characterized in that: The current liquid outlet temperature is detected by a temperature sensor provided at the liquid outlet. The temperature sensor transmits real-time detection data to the system controller, and the system controller makes a judgment and comparison based on the real-time detection data.

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