Temperature and humidity test box temperature control system

Abstract

The utility model discloses a kind of temperature and humidity test box temperature control system, including first refrigeration cycle unit, first temperature control cycle unit, second refrigeration cycle unit, second temperature control cycle unit and expansion cycle unit, second refrigeration cycle unit and first refrigeration cycle unit are connected in series, first temperature control cycle unit is connected and controls first refrigeration cycle unit, second temperature control cycle unit is connected and controls second refrigeration cycle unit, expansion cycle unit is connected on first, second refrigeration cycle unit.The utility model is suitable for wide temperature range, without heater-80~60 ℃ under condition;Temperature control precision is high, temperature fluctuation degree is ≤±0.02 ℃;Temperature rising speed is fast, compared with traditional mode and improve 10%~50%;Energy efficiency ratio is high, power consumption is small, maximum can save 50% power consumption.

Description

Technical Field

[0001] This utility model relates to the field of temperature and humidity measurement technology, and in particular to a temperature control system for a temperature and humidity calibration chamber. Background Technology

[0002] Existing temperature and humidity calibration chambers typically use a constant-temperature water tank to maintain the temperature of the circulating medium. Temperature control within the chamber is achieved through secondary heat exchange, precise temperature measurement by temperature sensors, and control by an industrial programmable controller. This enables automatic temperature adjustment, temperature calibration data processing, and result printing. It offers high control and testing accuracy and provides continuous, repeatable temperature measurements.

[0003] Existing temperature control solutions include:

[0004] 1. The refrigeration solenoid valve and the heating solenoid valve switch on and off alternately, and the duty cycle is adjusted by PID to output different cooling or heating capacity. Since the compressor output cannot be adjusted according to the required temperature inside the chamber, there is a lot of circulating medium in the constant temperature bath, which affects the temperature control speed and accuracy. The temperature control accuracy is limited, with a maximum of ±0.1℃. In order to meet the maximum cooling or heating capacity to achieve the cooling and heating balance, the maximum cooling or heating capacity is limited, which affects the heating and cooling speed.

[0005] 2. By adjusting the power of the heater to balance the cooling capacity of the refrigeration system, different cooling or heating capacities can be output. This method requires a large heater power to balance the cooling capacity, resulting in high power consumption, low energy efficiency, and a huge waste of energy. In addition, it has a small applicable temperature range and poor temperature control accuracy at high and low temperatures.

[0006] Chinese patent application CN 101118445 A discloses a temperature control method and structure for a temperature and humidity calibration chamber. The method includes a working area inside the chamber, a constant-temperature water tank installed inside the chamber, and a coil connected to the constant-temperature water tank installed outside the working area. The temperature of the constant-temperature water tank is first regulated using a heater and a refrigeration compressor, and then the temperature of the working area is regulated by circulating water between the coil and the constant-temperature water tank. However, because the device provided in this patent does not adjust the compressor output and uses a constant-temperature water tank to control the temperature of the working area, the temperature control speed is slow, the equipment has a low energy efficiency ratio, and it cannot meet the needs of current calibration operations.

[0007] The applicant's earlier Chinese patent application, CN 112987832 B, discloses a temperature control device and method for a temperature and humidity calibration chamber. The device includes a cold source system and a circulation system connected to the primary and secondary sides of an evaporator, respectively. The cold source system includes a compressor, oil separator, condenser, liquid receiver, filter, regenerator, and a first flow regulating valve connected sequentially via pipelines. The circulation system includes a buffer tank, surface cooler, circulation pump, first check valve, and pipe heater connected sequentially via pipelines. This device and method offer a wide temperature control range and fast temperature control speed, and the flow regulating valve opening can be adjusted according to current operating conditions to optimize system performance. However, the medium within the circulation system limits the upper and lower limits of the chamber temperature, resulting in a narrow operating temperature range; this system uses a secondary heat exchange method, and the circulation system medium has a high specific heat capacity, leading to slow heating and cooling rates; increasing the heating and cooling speed requires increasing the refrigeration and heating power, resulting in a lower energy efficiency ratio; the circulation system medium is a consumable and needs to be replaced after reaching its service life. Utility Model Content

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a temperature control system for a temperature and humidity calibration chamber.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A temperature and humidity calibration chamber temperature control system includes a first refrigeration cycle unit, a first temperature control cycle unit, a second refrigeration cycle unit, a second temperature control cycle unit, and an expansion cycle unit. The second refrigeration cycle unit and the first refrigeration cycle unit are connected in series. The first temperature control cycle unit is connected to and controls the first refrigeration cycle unit. The second temperature control cycle unit is connected to and controls the second refrigeration cycle unit. The expansion cycle unit is connected to the first and second refrigeration cycle units.

[0011] The first refrigeration cycle unit includes a first compressor, a first oil separator, a condenser, a first filter, a first regenerator, a first flow regulating valve, and a condenser-evaporator connected in sequence via pipelines. The primary side inlet and outlet of the first regenerator are connected to the first filter and the first flow regulating valve, respectively. The primary side inlet of the condenser-evaporator is connected to the outlet of the first flow regulating valve, and the primary side outlet of the condenser-evaporator is connected to the secondary side inlet of the first regenerator. A condenser fan is fixed at the condenser. The secondary side outlet of the first regenerator is connected to the suction port of the first compressor.

[0012] The first temperature control circulation unit includes a second flow regulating valve. The inlet end of the second flow regulating valve is connected to the pipeline between the first oil separator and the condenser, and the outlet end of the second flow regulating valve is connected to the pipeline between the condenser evaporator and the first flow regulating valve.

[0013] The second refrigeration cycle unit includes a second compressor, a second oil separator, a condenser-evaporator, a second filter, a second regenerator, a third flow regulating valve, and an evaporator connected in sequence via pipelines. The secondary side inlet and outlet of the condenser-evaporator are connected to the second oil separator and the second filter, respectively. The primary side inlet and outlet of the second regenerator are connected to the second filter and the third flow regulating valve, respectively. The inlet of the evaporator is connected to the outlet of the third flow regulating valve. The outlet of the evaporator is connected to the secondary side inlet of the second regenerator. A circulating fan is fixed at the evaporator. The secondary side outlet of the second regenerator is connected to the suction port of the second compressor.

[0014] The second temperature control circulation unit includes a fourth flow regulating valve. The inlet end of the fourth flow regulating valve is connected to the pipeline between the second oil separator and the condenser-evaporator, and the outlet end of the fourth flow regulating valve is connected to the pipeline between the evaporator and the third flow regulating valve.

[0015] The expansion circulation unit includes an unloading valve and an expansion tank connected in sequence by pipelines. The inlet end of the unloading valve is connected to the pipeline between the second oil separator and the condenser-evaporator, the outlet end of the unloading valve is connected to the inlet end of the expansion tank, and the outlet end of the expansion tank is connected to the pipeline between the secondary side outlet end of the second regenerator and the suction port of the second compressor.

[0016] The evaporator is installed inside the chamber, which is also equipped with a heater and an internal temperature sensor for measuring the internal temperature.

[0017] A first evaporation temperature sensor and a first suction pressure sensor are connected to the pipeline connecting the primary side outlet of the condenser and the secondary side inlet of the first regenerator.

[0018] The opening degree of the first flow regulating valve is controlled by the first evaporation temperature sensor and the first suction pressure sensor.

[0019] A second suction pressure sensor and a second evaporation temperature sensor are installed on the pipeline connecting the outlet end of the evaporator and the secondary side inlet end of the second regenerator.

[0020] The opening degree of the third flow regulating valve is controlled by the second evaporation temperature sensor and the second suction pressure sensor.

[0021] The temperature control system also includes a controller, which connects to the various electrical components within the temperature control device.

[0022] When this utility model is in operation, when the temperature inside the chamber needs to be reduced rapidly, the second flow regulating valve and the fourth flow regulating valve are closed. The temperature and pressure values ​​are input by the first evaporation temperature sensor, the first suction pressure sensor, the second evaporation temperature sensor, and the second suction pressure sensor. After calculating the superheat, the required opening degree of the first flow regulating valve and the third flow regulating valve is calculated by PID control until the temperature inside the chamber drops to the required temperature.

[0023] When precise temperature control is required inside the chamber, the first flow regulating valve is adjusted to the opening degree corresponding to the first evaporation temperature sensor. Based on the exhaust pressure sensor, the required opening degree of the second flow regulating valve is calculated using PID control. When the opening degree of the second flow regulating valve cannot meet the current exhaust pressure requirement, the opening degree of the first flow regulating valve is adjusted to make the second flow regulating valve reach the corresponding opening degree. The third flow regulating valve is adjusted to the opening degree corresponding to the second evaporation temperature sensor. Based on the temperature inside the chamber, the required opening degree of the fourth flow regulating valve is calculated using PID control, thus achieving precise temperature control. When the opening degree of the fourth flow regulating valve cannot meet the current temperature requirement inside the chamber, the opening degree of the third flow regulating valve is adjusted to make the fourth flow regulating valve reach the corresponding opening degree.

[0024] When the temperature inside the chamber needs to be raised rapidly, close the first and third flow regulating valves, and adjust the opening of the second and fourth flow regulating valves to the maximum until the temperature inside the chamber reaches the required temperature.

[0025] The beneficial effects of this utility model are: it has a wide applicable temperature range. Based on R508B refrigerant, the boiling point at 0 bar pressure is -87.6℃. By closing the fourth flow regulator and adjusting the opening of the third flow regulator valve to the corresponding opening under the current operating conditions, the refrigerant temperature can be reduced to as low as -87℃, and the internal temperature of the chamber can reach -80℃. The compressor discharge temperature is 85~95℃. By adjusting the opening of the third flow regulator valve to the minimum and the opening of the fourth flow regulator valve to the maximum, the refrigerant temperature can be raised to 70℃, and the internal temperature of the chamber to 60℃. That is, the internal temperature range of the chamber is -80~60℃.

[0026] The system offers rapid heating and cooling, and the electronic expansion valve's opening can be adjusted according to current operating conditions to optimize system performance, resulting in an overall speed increase of 10% to 50% compared to traditional methods (capillary tubes or thermostatic expansion valves).

[0027] High temperature control accuracy; the electronic expansion valve adjusts smoothly, enabling stepless adjustment, so that the output of cold or heat is relatively balanced with the heat dissipation of the chamber, and the temperature fluctuation inside the chamber is within ±0.01℃.

[0028] It has a high energy efficiency ratio and low power consumption. Compared with the method of balancing the cooling capacity with the heater, it reduces the need for a heater and uses the heat generated by the compressor itself as a heat source, which can save up to 50% of power consumption. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the system of this utility model;

[0030] The components are as follows: 1. First compressor, 2. First oil separator, 3. Condenser, 4. Condenser fan, 5. First filter, 6. First regenerator, 7. First flow regulating valve, 8. Condenser-evaporator, 9. Second flow regulating valve, 10. Second compressor, 11. Second oil separator, 12. Second filter, 13. Second regenerator, 14. Third flow regulating valve, 15. Evaporator, 16. Circulating fan, 17. Fourth flow regulating valve, 18. Expansion tank, 19. Unloading valve, 20. Heater, 21. Discharge pressure sensor, 22. First suction pressure sensor, 23. Second suction pressure sensor, 24. First evaporation temperature sensor, 25. Second evaporation temperature sensor, 26. Internal temperature sensor, 27. Chamber. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] The structures, proportions, and sizes illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the content disclosed herein. They are not intended to limit the scope of this utility model and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, provided they do not affect the effectiveness or purpose of this utility model, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity of description and are not intended to limit the scope of this utility model. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this utility model's implementation.

[0033] like Figure 1 As shown, the temperature and humidity calibration chamber temperature control system includes a first refrigeration cycle unit, a first temperature control cycle unit, a second refrigeration cycle unit, a second temperature control cycle unit, and an expansion cycle unit. The second refrigeration cycle unit and the first refrigeration cycle unit are connected in series. The first temperature control cycle unit is connected to and controls the first refrigeration cycle unit. The second temperature control cycle unit is connected to and controls the second refrigeration cycle unit. The expansion cycle unit is connected to the first and second refrigeration cycle units.

[0034] The first circulation unit includes a first compressor 1, a first oil separator 2, a condenser 3, a first filter 5, a first regenerator 6, a first flow regulating valve 7, and a condenser-evaporator 8 connected sequentially by pipelines. The primary side inlet and outlet of the first regenerator 6 are connected to the first filter 5 and the first flow regulating valve 7, respectively. The primary side inlet of the condenser-evaporator 8 is connected to the outlet of the first flow regulating valve 7, and the primary side outlet of the condenser-evaporator 8 is connected to the secondary side inlet of the first regenerator 6. A condenser fan 4 is fixed at the condenser 3. The secondary side outlet of the first regenerator 6 is connected to the suction port of the first compressor 1.

[0035] The first temperature control circulation unit includes a second flow regulating valve 9. The inlet end of the second flow regulating valve 9 is connected to the pipeline between the first oil separator 2 and the condenser 3 (the inlet end of the second flow regulating valve 9 is connected to the inlet end of the condenser 3), and the outlet end of the second flow regulating valve 9 is connected to the pipeline between the condenser evaporator 8 and the first flow regulating valve 7.

[0036] The second refrigeration cycle unit includes a second compressor 10, a second oil separator 11, a condenser-evaporator 8, a second filter 12, a second regenerator 13, a third flow regulating valve 14, and an evaporator 15, which are connected in sequence via pipelines. The secondary side inlet and outlet of the condenser-evaporator 8 are connected to the second oil separator 11 and the second filter 12, respectively. The primary side inlet and outlet of the second regenerator 13 are connected to the second filter 12 and the third flow regulating valve 14, respectively. The inlet of the evaporator 15 is connected to the outlet of the third flow regulating valve 14. The outlet of the evaporator 15 is connected to the secondary side inlet of the second regenerator 13. A circulating fan 16 is fixed at the evaporator 15. The secondary side outlet of the second regenerator 13 is connected to the suction port of the second compressor 10.

[0037] The second temperature control circulation unit includes a fourth flow regulating valve 17. The inlet end of the fourth flow regulating valve 17 is connected to the pipeline between the second oil separator 11 and the condenser evaporator 8 (the inlet end of the fourth flow regulating valve 17 is connected to the inlet end of the condenser evaporator 8). The outlet end of the fourth flow regulating valve 17 is connected to the pipeline between the evaporator 15 and the third flow regulating valve 14.

[0038] The expansion circulation unit includes an unloading valve 19 and an expansion tank 18 connected in sequence by pipelines. The inlet end of the unloading valve 19 is connected to the pipeline between the second oil separator 11 and the condenser evaporator 8 (the inlet end of the unloading valve 19 is connected to the inlet end of the condenser evaporator 8). The outlet end of the unloading valve 19 is connected to the inlet end of the expansion tank 18. The outlet end of the expansion tank 18 is connected to the pipeline between the secondary side outlet end of the second regenerator 13 and the suction port of the second compressor 10.

[0039] The evaporator 15 is installed inside the housing 27, which also contains a heater 20 and an internal temperature sensor 26 for measuring the internal temperature.

[0040] A first evaporation temperature sensor 24 and a first suction pressure sensor 22 are connected to the pipeline connecting the primary side outlet of the condenser-evaporator 8 to the secondary side inlet of the first regenerator 6. The opening of the first flow regulating valve 7 is controlled by the first evaporation temperature sensor 24 and the first suction pressure sensor 22.

[0041] A second suction pressure sensor 23 and a second evaporation temperature sensor 25 are installed on the pipeline connecting the outlet end of the evaporator 15 to the secondary side inlet end of the second regenerator 13. The opening degree of the third flow regulating valve 14 is controlled by the second evaporation temperature sensor 25 and the second suction pressure sensor 23.

[0042] The temperature control system also includes a controller, which connects to the various electrical components within the temperature control device.

[0043] During operation, when the temperature inside the chamber needs to be reduced rapidly, the second flow regulating valve 9 and the fourth flow regulating valve 17 are closed. The temperature and pressure values ​​are input by the first evaporation temperature sensor 24, the first suction pressure sensor 22, the second evaporation temperature sensor 25, and the second suction pressure sensor 23. After calculating the superheat, the required opening degree of the first flow regulating valve 7 and the third flow regulating valve 14 is calculated by PID until the temperature inside the chamber 27 drops to the required temperature.

[0044] When precise temperature control is required inside the chamber, the first flow regulating valve 7 is adjusted to the opening degree corresponding to the first evaporation temperature sensor 24. Based on the exhaust pressure sensor 21, the required opening degree of the second flow regulating valve 9 is calculated using PID. When the opening degree of the second flow regulating valve 9 cannot meet the current exhaust pressure requirement, the opening degree of the first flow regulating valve 7 is adjusted to make the second flow regulating valve 9 reach the corresponding opening degree. The third flow regulating valve 14 is adjusted to the opening degree corresponding to the second evaporation temperature sensor 25. Based on the temperature inside the chamber 27, the required opening degree of the fourth flow regulating valve 17 is calculated using PID, thus achieving precise temperature control. When the opening degree of the fourth flow regulating valve 17 cannot meet the current temperature requirement inside the chamber, the opening degree of the third flow regulating valve 14 is adjusted to make the fourth flow regulating valve 17 reach the corresponding opening degree.

[0045] When the temperature inside the chamber needs to be raised rapidly, close the first flow regulating valve 7 and the third flow regulating valve 14, and adjust the opening of the second flow regulating valve 9 and the fourth flow regulating valve 17 to the maximum until the temperature inside the chamber 27 rises to the required temperature.

[0046] This invention has a wide applicable temperature range. Based on R508B refrigerant, its boiling point at 0 bar is -87.6℃. By closing the fourth flow regulator and adjusting the third flow regulator to the corresponding opening for the current operating condition, the refrigerant temperature can be reduced to as low as -87℃, and the internal temperature can reach -80℃. The compressor discharge temperature is 85~95℃. By adjusting the third flow regulator to its minimum opening and the fourth flow regulator to its maximum opening, the refrigerant temperature can be raised to 70℃, and the internal temperature to 60℃. That is, the internal temperature range is -80~60℃.

[0047] The system offers rapid heating and cooling, and the electronic expansion valve's opening can be adjusted according to current operating conditions to optimize system performance, resulting in an overall speed increase of 10% to 50% compared to traditional methods (capillary tubes or thermostatic expansion valves).

[0048] High temperature control accuracy; the electronic expansion valve adjusts smoothly, enabling stepless adjustment, so that the output of cold or heat is relatively balanced with the heat dissipation of the chamber, and the temperature fluctuation inside the chamber is within ±0.01℃.

[0049] It has a high energy efficiency ratio and low power consumption. Compared with the method of balancing the cooling capacity with the heater, it reduces the need for a heater and uses the heat generated by the compressor itself as a heat source, which can save up to 50% of power consumption.

[0050] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. A temperature control system for a temperature and humidity calibration chamber, characterized in that, It includes a first refrigeration cycle unit, a first temperature control cycle unit, a second refrigeration cycle unit, a second temperature control cycle unit, and an expansion cycle unit. The second refrigeration cycle unit and the first refrigeration cycle unit are connected in series. The first temperature control cycle unit is connected to and controls the first refrigeration cycle unit. The second temperature control cycle unit is connected to and controls the second refrigeration cycle unit. The expansion cycle unit is connected to the first and second refrigeration cycle units.

2. The temperature control system for the temperature and humidity calibration chamber as described in claim 1, characterized in that, The first refrigeration cycle unit includes a first compressor, a first oil separator, a condenser, a first filter, a first regenerator, a first flow regulating valve, and a condenser-evaporator connected in sequence via pipelines. The primary side inlet and outlet of the first regenerator are connected to the first filter and the first flow regulating valve, respectively. The primary side inlet of the condenser-evaporator is connected to the outlet of the first flow regulating valve, and the primary side outlet of the condenser-evaporator is connected to the secondary side inlet of the first regenerator. A condenser fan is fixed at the condenser. The secondary side outlet of the first regenerator is connected to the suction port of the first compressor.

3. The temperature control system for the temperature and humidity calibration chamber as described in claim 2, characterized in that, The first temperature control circulation unit includes a second flow regulating valve. The inlet end of the second flow regulating valve is connected to the pipeline between the first oil separator and the condenser, and the outlet end of the second flow regulating valve is connected to the pipeline between the condenser evaporator and the first flow regulating valve.

4. The temperature control system for the temperature and humidity calibration chamber as described in claim 1, characterized in that, The second refrigeration cycle unit includes a second compressor, a second oil separator, a condenser-evaporator, a second filter, a second regenerator, a third flow regulating valve, and an evaporator connected in sequence via pipelines. The secondary side inlet and outlet of the condenser-evaporator are connected to the second oil separator and the second filter, respectively. The primary side inlet and outlet of the second regenerator are connected to the second filter and the third flow regulating valve, respectively. The inlet of the evaporator is connected to the outlet of the third flow regulating valve. The outlet of the evaporator is connected to the secondary side inlet of the second regenerator. A circulating fan is fixed at the evaporator. The secondary side outlet of the second regenerator is connected to the suction port of the second compressor.

5. The temperature control system for the temperature and humidity calibration chamber as described in claim 4, characterized in that, The second temperature control circulation unit includes a fourth flow regulating valve. The inlet end of the fourth flow regulating valve is connected to the pipeline between the second oil separator and the condenser-evaporator, and the outlet end of the fourth flow regulating valve is connected to the pipeline between the evaporator and the third flow regulating valve.

6. The temperature control system for the temperature and humidity calibration chamber as described in claim 4, characterized in that, The expansion circulation unit includes an unloading valve and an expansion tank connected in sequence by pipelines. The inlet end of the unloading valve is connected to the pipeline between the second oil separator and the condenser-evaporator, the outlet end of the unloading valve is connected to the inlet end of the expansion tank, and the outlet end of the expansion tank is connected to the pipeline between the secondary side outlet end of the second regenerator and the suction port of the second compressor.

7. The temperature control system for the temperature and humidity calibration chamber as described in claim 4, characterized in that, The evaporator is installed inside the chamber, which is also equipped with a heater and an internal temperature sensor for measuring the internal temperature.

8. The temperature control system for the temperature and humidity calibration chamber as described in claim 4, characterized in that, A first evaporation temperature sensor and a first suction pressure sensor are connected to the pipeline connecting the primary side outlet of the condenser and the secondary side inlet of the first regenerator; the opening of the first flow regulating valve is controlled by the first evaporation temperature sensor and the first suction pressure sensor.

9. The temperature control system for the temperature and humidity calibration chamber as described in claim 4, characterized in that, A second suction pressure sensor and a second evaporation temperature sensor are installed on the pipeline connecting the outlet end of the evaporator and the secondary side inlet end of the second regenerator; the opening degree of the third flow regulating valve is controlled by the second evaporation temperature sensor and the second suction pressure sensor.

10. The temperature control system for the temperature and humidity calibration chamber as described in claim 1, characterized in that, The temperature control system also includes a controller, which connects to the various electrical components within the temperature control device.

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