High and low temperature alternating damp heat test box

Abstract

The utility model relates to a high and low temperature alternating damp heat test box, the temperature in a test box body is increased through cooperation of a finned evaporator and a heater, the rotating speed of a frequency conversion fan can be freely adjusted so as to adjust the temperature rise speed, and a digital low temperature compressor can reduce the temperature of the test box body so as to play a role in refrigeration. The PWM valve can adjust the energy range of the digital low-temperature compressor, so that the refrigerating system is more energy-saving, and the second pulse electronic expansion valve can synchronize an output signal of the digital low-temperature compressor to generate a pulse signal for the electronic expansion valve on the premise of playing a throttling effect, so that the stability of the refrigerating system is ensured, and the refrigerating efficiency is improved. The plurality of sensors can detect related data of each position in the refrigeration system in real time so as to monitor the working state of the refrigeration system, and the humidification circulation assembly is used for ensuring the humidity in the test box body so as to maintain the temperature and humidity state requirements of the test box body.

Description

Technical Field

[0001] The present application relates to the technical field of high and low temperature chambers, and in particular to a high and low temperature alternating humidity and heat test chamber. Background Art

[0002] With the development of science and technology, the performance and reliability requirements for various automotive parts and electronic products are becoming increasingly higher. In order to speed up the research and development of related products, a large number of environmental performance tests are required. Therefore, there is an increasing demand for high and low temperature humidity test chambers that can perform high temperature tests, low temperature tests, high and low temperature tests, and humidity and heat alternation tests.

[0003] However, the high and low temperature humidity test chambers currently on the market basically use fixed-capacity compressors, and their refrigeration capacity adjustment range is small. The demand for high and low temperature test chambers is that they require a large refrigeration capacity during the process of rapid cooling from a high temperature environment to a low temperature environment. After reaching the low temperature environment, the refrigeration capacity required to maintain the box temperature is very small, only within 10% of the refrigeration capacity under this working condition, or even only 3% to 5%. Therefore, a fixed-capacity compressor cannot achieve capacity adjustment in such a large range. Usually, the larger refrigeration capacity in the cooling process is used as the selection method. After reaching the target temperature, there are two ways to maintain the target temperature: first, electric heating is used to offset the additional refrigeration capacity to achieve constant temperature control of the target low temperature in the box. This method consumes huge energy. In addition to a high-power compressor, it also requires high-power heating. The energy efficiency ratio is very low and no longer meets the current national requirements for environmental protection and energy conservation; second, hot gas bypass is used to achieve energy regulation. Hot gas bypass replaces the load with a certain amount of exhaust gas. However, due to the large proportion that needs to be adjusted, the suction and exhaust temperatures rise sharply, resulting in application problems of other system components, such as the liquid injection pipeline adopted to cope with the rise in suction and exhaust temperatures. The difficulty in controlling the amount of liquid injection also brings about the problem of the compressor often inhaling liquid and frosting. Utility Model Content

[0004] Based on this, it is necessary to provide a high and low temperature alternating humidity and heat test chamber to address the problem that the energy efficiency ratio of existing high and low temperature humidity and heat test chambers is very low or it is difficult to control the amount of liquid sprayed, which causes the compressor to often inhale liquid and frost.

[0005] The present application provides a high and low temperature alternating humidity and heat test chamber, comprising:

[0006] The test box body is arranged to be hollow inside, and a circulating air system is arranged inside the test box body, and the circulating air system includes a variable frequency fan, a finned evaporator, a heater and a humidifying nozzle;

[0007] A humidification system, the humidification system being in communication with the test chamber body;

[0008] A refrigeration system, the refrigeration system includes a digital low-temperature compressor, a PWM valve, a first pulse electronic expansion valve, a second pulse electronic expansion valve, a liquid injection solenoid valve, a condenser, an air suction solenoid valve and multiple sensors, the first end of the PWM valve is connected to the first end of the digital low-temperature compressor, the second end of the PWM valve is connected to the second end of the digital low-temperature compressor, the first end of the condenser is connected to the test box body, the third end of the digital low-temperature compressor is connected to the second end of the condenser, the first end of the air suction solenoid valve is connected to the test box body, the second end of the second pulse electronic expansion valve is connected to the test box body, the first end of the first pulse electronic expansion valve is connected to the second end of the air suction solenoid valve, the first end of the liquid injection solenoid valve is connected to the second end of the air suction solenoid valve, the second end of the first pulse electronic expansion valve is connected to the connecting link between the digital low-temperature compressor and the second end of the condenser, and the second end of the liquid injection solenoid valve is connected to the connecting chain pipeline between the condenser and the second pulse electronic expansion valve.

[0009] The present application relates to a high and low temperature alternating humidity and heat test chamber, in which the temperature inside the test chamber body is increased by a fin-type evaporator and a heater in combination, the speed of the variable frequency fan can be freely adjusted, thereby adjusting the heating rate, and the digital low-temperature compressor can reduce the temperature of the test chamber body to achieve a cooling effect. The PWM valve can adjust the energy range of the digital low-temperature compressor, thereby making the refrigeration system more energy-efficient. The second pulse electronic expansion valve can not only achieve a throttling effect, but also synchronize the output signal of the digital low-temperature compressor to generate a pulse signal for the electronic expansion valve, thereby ensuring the stability of the refrigeration system. Multiple sensors can detect relevant data at various positions in the refrigeration system in real time, thereby monitoring the working status of the refrigeration system. The humidification cycle component is used to ensure the humidity inside the test chamber body, thereby maintaining the temperature and humidity status requirements of the test chamber body. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A schematic diagram of a process flow of a high and low temperature alternating humidity and heat test chamber provided in one embodiment of the present application.

[0011] Figure 2 This is a flow chart of a test chamber body and a humidification system in a high and low temperature alternating humidity and heat test chamber provided in one embodiment of the present application.

[0012] Figure 3 A schematic flow chart of a refrigeration system in a high and low temperature alternating humidity and heat test chamber provided in one embodiment of the present application.

[0013] Figure 4 for Figure 3 A magnified schematic diagram of area A in the middle.

[0014] Reference numerals:

[0015] 100. Test chamber body; 101. Over-temperature protection switch; 200. Circulating air system;

[0016] 201, variable frequency fan; 202, finned evaporator; 203, heater; 204, humidifying nozzle;

[0017] 300, humidification system; 301, steam generator; 302, drainage assembly; 303, water supply tank;

[0018] 303a, water inlet of the water supply tank; 303b, water filling port of the water supply tank;

[0019] 303c, a first port of the water supply tank; 303d, a second port of the water supply tank;

[0020] 303e, the third port of the water supply tank; 303f, the fourth port of the water supply tank; 304, the water filter;

[0021] 305, water pump; 305a, water inlet of the water pump; 305b, water outlet of the water pump; 306, drain valve;

[0022] 306a, first port of drain valve; 306b, second port of drain valve; 307, compressor water pan;

[0023] 308, float switch; 309, electric heating unit; 309a, first end of the electric heating unit;

[0024] 309b, a second end of the electric heating portion;

[0025] 400. Refrigeration system; 401. Digital low-temperature compressor;

[0026] 401a, a first end of a digital low-temperature compressor; 401b, a second end of a digital low-temperature compressor;

[0027] 401c, the third end of the digital low-temperature compressor; 401d, the fourth end of the digital low-temperature compressor;

[0028] 401e, the fifth end of the digital low-temperature compressor; 402, the PWM valve; 402a, the first end of the PWM valve;

[0029] 402b, the second end of the PWM valve; 403, the first pulse electronic expansion valve;

[0030] 403a, a first end of a first pulse electronic expansion valve;

[0031] 403b, the second end of the first pulse electronic expansion valve; 404, the second pulse electronic expansion valve;

[0032] 404a, a first end of a second pulse electronic expansion valve;

[0033] 404b, a second end of a second pulse electronic expansion valve;

[0034] 405, liquid spraying solenoid valve; 405a, first end of the liquid spraying solenoid valve;

[0035] 405b, the second end of the liquid injection solenoid valve; 406, the condenser; 406a, the first end of the condenser;

[0036] 406b, the second end of the condenser; 406c, the third end of the condenser; 407, the suction solenoid valve;

[0037] 407a, first end of the air suction solenoid valve; 407b, second end of the air suction solenoid valve; 408, sensor;

[0038] 409, low pressure sensor; 410, return air temperature sensor; 411, exhaust pressure sensor;

[0039] 412, exhaust temperature sensor; 413, low pressure switch; 414, high pressure switch;

[0040] 415, a temperature controller; 415a, a first terminal of the temperature controller;

[0041] 415b, a second terminal of the temperature controller; 415c, a third terminal of the temperature controller;

[0042] 416, pressure regulating valve; 417, condensing pressure constant water valve; 418, sight glass;

[0043] 500. Control system; 501. Programmable logic controller; 502. Touch screen. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0045] The present application provides a high and low temperature alternating humidity and heat test chamber using a variable capacity refrigeration system.

[0046] like Figures 1 to 4 As shown, in one embodiment of the present application, the high and low temperature alternating humidity and heat test chamber using a variable capacity refrigeration system includes a test chamber body 100 , a humidification system 300 and a refrigeration system 400 .

[0047] A circulating air system 200 is provided in the test chamber body 100 . The circulating air system 200 includes a variable frequency fan 201 , a finned evaporator 202 , a heater 203 and a humidifying nozzle 204 .

[0048] The humidification system 300 is in communication with the test chamber body 100. The refrigeration system 400 includes a digital low-temperature compressor 401, a PWM valve 402, a first pulse electronic expansion valve 403, a second pulse electronic expansion valve 404, a liquid injection solenoid valve 405, a condenser 406, an air suction solenoid valve 407, and a plurality of sensors 408. The first end 402a of the PWM valve is in communication with the first end 401a of the digital low-temperature compressor, the second end 402b of the PWM valve is in communication with the second end 401b of the digital low-temperature compressor, the first end 406a of the condenser is in communication with the test chamber body 100, and the third end 406 of the digital low-temperature compressor is in communication with the first end 401a of the PWM valve. 01c is in communication with the second end 406b of the condenser, the first end 407a of the intake solenoid valve is in communication with the test chamber body 100, the second end 404b of the second pulse electronic expansion valve is in communication with the test chamber body 100, the first end 403a of the first pulse electronic expansion valve is in communication with the second end 407b of the intake solenoid valve, the first end 405a of the liquid injection solenoid valve is in communication with the second end 407b of the intake solenoid valve, and the second end 403b of the first pulse electronic expansion valve is connected to the connection link between the digital low-temperature compressor 401 and the second end 406b of the condenser. The second end 405b of the liquid injection solenoid valve is connected to the connection link between the condenser 406 and the second pulse electronic expansion valve 404.

[0049] Specifically, the bottom surface of the variable frequency fan 201 is fixedly connected to the top surface of the test box body 100, the fin-type evaporator 202 is fixedly connected to the test box body 100, the heater 203 is arranged between the variable frequency fan 201 and the fin-type evaporator 202, and the humidification nozzle 204 passes through the box board of the test box body 100 and extends to the air treatment interlayer of the test box.

[0050] The variable frequency fan 201 mainly adjusts the temperature to further adapt to the energy regulation changes of the entire system, thereby making the system's operating conditions more stable. The humidification nozzle 204 sprays steam to the air treatment interlayer of the test chamber body to humidify the circulating air.

[0051] The first pulse electronic expansion valve 403 is a hot gas bypass pulse electronic expansion valve. The second pulse electronic expansion valve 404 is a cooling pulse electronic expansion valve.

[0052] In this embodiment, the temperature inside the test chamber body 100 is increased by cooperating with the heater 203 through the finned evaporator 202, the speed of the variable frequency fan 201 can be freely adjusted to adjust the heating speed, and the digital low-temperature compressor 401 can reduce the temperature of the test chamber body 100 to achieve a cooling effect. The PWM valve 402 can adjust the energy range of the digital low-temperature compressor 401, thereby making the refrigeration system 400 more energy-efficient. The second pulse electronic expansion valve 404 can synchronize the output signal of the digital low-temperature compressor 401 to generate a pulse signal for the electronic expansion valve while achieving a throttling effect, thereby ensuring the stability of the refrigeration system 400. Multiple sensors 408 can detect relevant data at various positions in the refrigeration system 400 in real time, thereby monitoring the working status of the refrigeration system 400. The water circulation component is used to ensure the humidity inside the test chamber body 100, thereby maintaining the temperature and humidity requirements of the test chamber body 100.

[0053] like Figure 2 As shown, in one embodiment of the present application, the humidification system 300 includes a humidification component 301, and the humidification component 301 includes a water replenishing tank 303, a water filter 304, a water pump 305 and an electric heating part 309, one end of the water filter 304 is connected to the first port 303c of the water replenishing tank, the other end of the water filter 304 is connected to the water inlet 305a of the water pump, the water outlet 305b of the water pump is connected to the test chamber body 100, the first section 309a of the electric heating part is connected to the water outlet 305a of the water pump, and the second end 309b of the electric heating part is connected to the humidification nozzle 204.

[0054] Specifically, the electric heating unit 309 includes an electric heater and a pipeline portion.

[0055] In this embodiment, since the operation of the finned evaporator 202 will cause the humidity inside the test chamber body 100 to decrease, resulting in the environment inside the test chamber body 100 becoming dry, the water in the water supply tank 303 is transported to the test chamber body 100 through the water pump 305, thereby increasing the air humidity inside the test chamber body 100 to ensure the normal operation of the finned evaporator 202.

[0056] like Figure 2 As shown, in one embodiment of the present application, the humidification system 300 further includes a drain assembly 302, which includes a drain valve 306 and a compressor water pan 307. The first end 306a of the drain valve is in communication with the second port 303d of the water makeup tank, and the second end 306b of the drain valve is in communication with the compressor water pan 307. The second end 306b of the drain valve is also in communication with the third port 303e of the water makeup tank.

[0057] Specifically, the water supply tank 303 is provided with a water inlet 303a of the water supply tank and a water filling port 303b of the water supply tank.

[0058] The water supply tank 303 further includes a float switch 308 , which is disposed between the water inlet 303 a of the water supply tank and the inner cavity of the water supply tank 303 .

[0059] In this embodiment, the water inlet 303 a of the water supply tank 303 is used to add deionized water into the water supply tank 303 , and the water addition port 303 b of the water supply tank 303 is used to add liquid water into the water supply tank 303 .

[0060] In this embodiment, the water in the water supply tank 303 is discharged to the outside through the drain valve 306.

[0061] like Figure 3 As shown, in one embodiment of the present application, the multiple sensors 408 include a low-pressure pressure sensor 409, a return air temperature sensor 410, an exhaust pressure sensor 411, and an exhaust temperature sensor 412. The low-pressure pressure sensor 409 and the return air temperature sensor 410 are disposed between the digital cryogenic compressor 401 and the intake solenoid valve 407, while the exhaust pressure sensor 411 and the exhaust temperature sensor 412 are disposed between the digital cryogenic compressor 401 and the condenser 406. In this embodiment, the low-pressure pressure between the intake solenoid valve 407 and the digital cryogenic compressor 401 is detected by the low-pressure pressure sensor 409, the return air temperature between the intake solenoid valve 407 and the digital cryogenic compressor 401 is detected by the return air temperature sensor 410, the exhaust pressure of the digital cryogenic compressor 401 is detected by the exhaust pressure sensor 411, and the exhaust temperature of the digital cryogenic compressor 401 is detected by the exhaust temperature sensor 412. The detection data of all sensors 408 are transmitted to the control system 500.

[0062] like Figure 3 As shown, in one embodiment of the present application, a low-pressure switch 413 is provided between the low-pressure pressure sensor 409 and the return air temperature sensor 410 , and a high-pressure switch 414 is provided between the exhaust pressure sensor 411 and the exhaust temperature sensor 412 .

[0063] Specifically, the high-voltage switch 414 is connected to a high-voltage meter.

[0064] In this embodiment, the fifth terminal 401e and the third terminal 401c of the digital low-temperature compressor 401 are controlled by the high-voltage switch 414 and the low-voltage switch 413 respectively.

[0065] like Figure 3As shown, in one embodiment of the present application, the refrigeration system 400 also includes a temperature controller 415, the first terminal 415a of the temperature controller is connected to the connection link between the second pulse electronic expansion valve 404 and the condenser 406, the second terminal 415b of the temperature controller is connected to the fourth terminal 401d of the digital low-temperature compressor, and the third terminal 415c of the temperature controller is connected to the fifth terminal 401e of the digital low-temperature compressor.

[0066] Specifically, the temperature controller 415 is also in communication with the control system 500 (not shown in the figure).

[0067] In this embodiment, the first terminal 415a of the temperature controller is connected to the connection link between the first end 404a of the second pulse electronic expansion valve and the first end 406a of the condenser.

[0068] like Figure 3 As shown, in one embodiment of the present application, the refrigeration system 400 further includes a pressure regulating valve 416 , and the pressure regulating valve 416 is connected in parallel to both ends of the suction solenoid valve 407 .

[0069] In this embodiment, the pressure of the air intake solenoid valve 407 is regulated by the pressure regulating valve 416 , thereby improving the working efficiency of the air intake solenoid valve 407 .

[0070] like Figure 2 As shown, in one embodiment of the present application, the high and low temperature alternating humidity and heat test chamber using a pulse electronic expansion valve also includes a control system 500, the control system 500 includes a programmable logic controller 501 and a touch screen 502, and the multiple sensors 408 are all communicatively connected to the programmable logic controller 501 (not shown in the figure), and the touch screen 502 is communicatively connected to the programmable logic controller 501.

[0071] In this embodiment, since the actual temperature of the test chamber body 100 has not reached the set temperature at the initial stage of operation, the capacity requirement of the digital low-temperature compressor 401 can be calculated through PID, and the working capacity of the digital low-temperature compressor 401 can be controlled by the programmable logic controller 501, and the PWM valve 402 is coordinated to achieve energy regulation of the digital low-temperature compressor 401 between 10% and 100%.

[0072] Since the input power of the digital low-temperature compressor 401 can be linearly adjusted according to the energy regulation range, it is suitable for the partial load energy regulation needs of the test chamber body 100 within a larger range, which greatly reduces the unnecessary input power of the refrigeration system 400 in various application stages (including constant temperature stage, rapid cooling stage, etc.), and realizes the most appropriate refrigeration capacity output of the compressor in the current stage through edge capacity control, achieving the best energy-saving effect.

[0073] like Figure 2 As shown, in one embodiment of the present application, an over-temperature protection switch 101 is further provided in the test box body 100 , and the over-temperature protection switch 101 is provided between the heater 203 and the variable frequency fan 201 .

[0074] In this embodiment, the over-temperature protection switch 101 is used to prevent the temperature inside the test box body 100 from being too high. When the temperature inside the test box body 100 is too high, the over-temperature protection switch 101 is disconnected to stop the operation of the test box body 100.

[0075] The reason for using the variable frequency fan 201 is that the variable frequency fan 201 can adjust the motor frequency of the fan according to the change of the box temperature, thereby adjusting its speed, and finally achieving adaptive changes in air volume, thereby increasing the heating speed of the test box body 100 during the heating process.

[0076] like Figure 3 As shown, in one embodiment of the present application, the third end 406 c of the condenser 406 is fixedly connected to a condensing pressure constant water valve 417 .

[0077] Specifically, the reason why a pulse electronic expansion valve is used to replace the traditional quick-opening solenoid valve and thermal expansion valve is that the pulse electronic expansion valve can simultaneously achieve two functions: controlling the flow rate by controlling the on-off time per unit time and further throttling by superheat control, thereby ensuring that the flow entering the evaporation is completely evaporated.

[0078] Since the digital low-temperature compressor 401 controls energy by pulse ratio, the simultaneous use of the digital low-temperature compressor 401 and the first pulse electronic expansion valve 403 can synchronize the same pulse ratio, thereby improving the operating efficiency of the system. In this embodiment, the digital low-temperature compressor 401 and the first pulse electronic expansion valve 403 work together to achieve energy regulation of the test chamber body 100 over a wide range. Since the regulation is directed to the refrigeration capacity of the test chamber body 100, the heat exchange rate on the condensing side will also vary over a wide range. Therefore, the condensing pressure constant water valve 417 is used to stabilize the condensing pressure of the condenser 406 when the load of the condenser 406 changes drastically, thereby avoiding the occurrence of liquid accumulation in the condenser 406, which affects the evaporation temperature.

[0079] The digital low-temperature compressor 401, the first pulse electronic expansion valve 403 and the condensing pressure constant water valve 417 enable the refrigeration system 400 to quickly and accurately reach the target temperature when the energy regulation changes in a larger range, reducing temperature fluctuations. Combined with the variable frequency fan 201, the test box body 100 can adapt to the air flow in the high temperature stage during the heating and maintaining high temperature stages, achieving better heating speed and temperature uniformity, thereby improving the reliability of the test box body 100.

[0080] like Figure 4 As shown, in one embodiment of the present application, the high and low temperature alternating humidity and heat test chamber using a pulse electronic expansion valve also includes a sight glass 418, and the sight glass 418 is connected to the connection link between the first end 404a of the second pulse electronic expansion valve and the first end 406a of the condenser.

[0081] Specifically, in this embodiment, the first terminal 415a of the temperature controller is connected to the connection link between the sight glass 418 and the first end 406a of the condenser.

[0082] The various technical features of the above-described embodiments can be combined arbitrarily, and the execution order of the method steps is not restricted. In order to make the description concise, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0083] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A high and low temperature alternating humidity test chamber, characterized in that: The high and low temperature alternating humidity test chamber comprises: The test box body is arranged to be hollow inside, and a circulating air system is arranged inside the test box body, and the circulating air system includes a variable frequency fan, a finned evaporator, a heater and a humidifying nozzle; A humidification system, the humidification system being in communication with the test chamber body; A refrigeration system, the refrigeration system includes a digital low-temperature compressor, a PWM valve, a first pulse electronic expansion valve, a second pulse electronic expansion valve, a liquid injection solenoid valve, a condenser, an air suction solenoid valve and multiple sensors, the first end of the PWM valve is connected to the first end of the digital low-temperature compressor, the second end of the PWM valve is connected to the second end of the digital low-temperature compressor, the first end of the condenser is connected to the test box body, the third end of the digital low-temperature compressor is connected to the second end of the condenser, the first end of the air suction solenoid valve is connected to the test box body, the second end of the second pulse electronic expansion valve is connected to the test box body, the first end of the first pulse electronic expansion valve is connected to the second end of the air suction solenoid valve, the first end of the liquid injection solenoid valve is connected to the second end of the air suction solenoid valve, the second end of the first pulse electronic expansion valve is connected to the connecting link between the digital low-temperature compressor and the second end of the condenser, and the second end of the liquid injection solenoid valve is connected to the connecting chain pipeline between the condenser and the second pulse electronic expansion valve.

2. The high and low temperature alternating humidity test chamber according to claim 1, characterized in that: The humidification system includes a humidification component, which includes a water supply tank, a water filter, a water pump and an electric heating part. One end of the water filter is connected to the first port of the water supply tank, the other end of the water filter is connected to the water inlet of the water pump, the water outlet of the water pump is connected to the test box body, the first section of the electric heating part is connected to the water outlet of the water pump, and the second end of the electric heating part is connected to the humidification nozzle.

3. The high and low temperature alternating humidity test chamber according to claim 2, characterized in that: The humidification system also includes a drainage assembly, which includes a drain valve and a compressor water pan. The first end of the drain valve is connected to the second port of the water make-up tank, the second end of the drain valve is connected to the compressor water pan, and the second end of the drain valve is also connected to the third port of the water make-up tank.

4. The high and low temperature alternating humidity test chamber according to claim 3, characterized in that: The multiple sensors include a low-pressure pressure sensor, a return air temperature sensor, an exhaust pressure sensor and an exhaust temperature sensor. The low-pressure pressure sensor and the return air temperature sensor are arranged between the digital low-temperature compressor and the intake solenoid valve, and the exhaust pressure sensor and the exhaust temperature sensor are arranged between the digital low-temperature compressor and the condenser.

5. The high and low temperature alternating humidity test chamber according to claim 4, characterized in that: A low-pressure switch is provided between the low-pressure pressure sensor and the return air temperature sensor, and a high-pressure switch is provided between the exhaust pressure sensor and the exhaust temperature sensor.

6. The high and low temperature alternating humidity test chamber according to claim 5, characterized in that: The refrigeration system further comprises: A temperature controller, wherein a first terminal of the temperature controller is connected to the connection link between the second pulse electronic expansion valve and the condenser, a second terminal of the temperature controller is connected to the fourth end of the digital low-temperature compressor, and a third terminal of the temperature controller is connected to the fifth end of the digital low-temperature compressor.

7. The high and low temperature alternating humidity test chamber according to claim 6, characterized in that: The refrigeration system further comprises: A pressure regulating valve is connected in parallel to both ends of the air suction solenoid valve.

8. The high and low temperature alternating humidity test chamber according to claim 1, characterized in that: Also includes: A control system includes a programmable logic controller and a touch screen, each of the sensors is communicatively connected to the programmable logic controller, and the touch screen is communicatively connected to the programmable logic controller.

9. The high and low temperature alternating humidity test chamber according to claim 8, characterized in that: The test box body is also provided with: An over-temperature protection switch is provided between the heater and the variable frequency fan.

10. The high and low temperature alternating humidity test chamber according to claim 9, characterized in that: The third end of the condenser is fixedly connected to a condensation pressure constant water valve.

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