Temperature control type evaporator suitable for damp and hot box and control method

Abstract

The invention discloses a temperature control type evaporator suitable for a damp and hot box and a control method. A high-temperature gas side and a low-temperature liquid side of a high-temperature stage system of a cascade refrigeration system enter a plate heat exchanger through pipelines respectively to provide a heat source and a cold source for an upper cooling liquid system; a cold source end pipeline of the plate heat exchanger controls a three-way proportional regulating valve through feedback of a temperature sensor on the cold source end pipeline, the flow of cooling liquid entering the refrigeration and dehumidification heat exchanger is controlled, the cooling liquid is connected to a liquid storage container through a liquid return pipe, meanwhile, the heat source end of the plate heat exchanger is connected to the liquid storage container through a liquid outlet pipe, and a circulating pump is arranged on the liquid outlet pipe. Cooling liquid in the refrigeration and dehumidification heat exchanger is blown back to the liquid storage container through the air blowing pipe on the liquid outlet pipe when refrigeration is not needed, a cold and heat source of the whole system comes from the high-temperature stage or the low-temperature stage of the cascade refrigeration system, and the temperature of the cooling liquid can be controlled through the high-temperature air side, the low-temperature liquid side and related valves. No cold and heat source of any other type needs to be added, and the controllable temperature range is wide.

Description

Technical Field

[0001] The invention belongs to the technical field of high and low temperature test chambers, and in particular relates to a temperature-controlled evaporator suitable for a wet heat chamber and a control method thereof. Background Art

[0002] Conventional high and low temperature test chambers usually use steam humidification when doing wet heat. The steam humidification temperature is high, and it will exchange sensible heat with the studio, causing the studio to heat up. Therefore, wet heat usually requires refrigeration. Due to the use of a cascade refrigeration system, a low-temperature evaporator is usually used for refrigeration and dehumidification, or a high-temperature evaporator is used for refrigeration and dehumidification (usually high-temperature dehumidification will integrate two sets of evaporators into one). The evaporation temperature of the refrigeration system is much lower than the dew point temperature of the operating point in the box, so the studio air will exchange latent heat with the evaporator, resulting in a decrease in the relative humidity of the studio. The low evaporation temperature will also cause the studio temperature to drop sharply, so it is necessary to increase the steam volume and perform heating compensation in time, that is, the power of the humidifier and the heater need to be increased. After the heating and humidification increase, the required dehumidification and cooling capacity increase. The increase in various parameters will cause large fluctuations in the temperature and humidity in the box. When heating, humidification, dehumidification, and refrigeration reach a balance, the working conditions will tend to be stable. Since these four parameters are difficult to control to the actual demand, each item will exceed the design value, thereby increasing power consumption and configuration costs. At the same time, when the test chamber is conducting high temperature / low temperature / vacuum experiments, the gas detection instrument cannot withstand high or low temperatures, and the vacuum pump cannot meet the gas detection requirements of the test chamber under low pressure. Summary of the invention

[0003] In order to overcome the above-mentioned deficiencies, the inventor of the present invention has continuously reformed and innovated through long-term exploration and attempts, multiple experiments and efforts, and proposed a temperature-controlled evaporator and control method suitable for a wet heat box. The cold and heat sources of the overall system come from the high temperature stage or low temperature stage of the cascade refrigeration system. The coolant temperature can be controlled by the high temperature gas side, the low temperature liquid side and related valves, without adding any other type of cold and heat sources, and the controllable temperature range is relatively wide.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a temperature-controlled evaporator suitable for a wet heat box. The high-temperature gas side and low-temperature liquid side of the high-temperature stage system of the cascade refrigeration system enter the plate heat exchanger through the high-temperature gas side solenoid valve, the high-temperature gas side manual valve and the low-temperature liquid side solenoid valve, and the low-temperature expansion valve respectively. The high-temperature stage system of the cascade refrigeration system provides a heat source and a cold source for the upper coolant system through the plate heat exchanger. The cold source end of the plate heat exchanger is successively provided with a temperature sensor and a three-way proportional regulating valve. The three-way proportional regulating valve is controlled by relying on the feedback of the temperature sensor. The coolant flow entering the refrigeration and dehumidification heat exchanger is controlled by proportional regulation. The remaining outlet of the three-way regulating valve is connected to the back of the refrigeration and dehumidification heat exchanger. The return liquid pipe at the end is used as a bypass, and a one-way valve is arranged between the rear end of the refrigeration and dehumidification heat exchanger and the return liquid pipe to prevent the liquid bypassed by the three-way proportional regulating valve from affecting the return flow of the refrigeration and dehumidification heat exchanger. The end of the return liquid pipe is connected to the liquid storage container, and the heat source end of the plate heat exchanger is connected to the liquid storage container through the liquid outlet pipe. A circulating pump is arranged on the liquid outlet pipe, and an air blowing pipe is connected between the circulating pump of the liquid outlet pipe and the plate heat exchanger. An air circuit solenoid valve and a throttle valve are arranged on the air blowing pipe. The air circuit solenoid valve is opened when refrigeration is not needed to blow the coolant in the refrigeration and dehumidification heat exchanger back to the liquid storage container, and the throttle valve adjusts the intake pressure.

[0005] According to the temperature-controlled evaporator suitable for a wet heat box described in the present invention, a further preferred technical solution is: a pressure relief solenoid valve and a mechanical safety valve are arranged in parallel on the pressure relief pipe of the liquid storage container, the pressure relief solenoid valve opens when the system pressure is too high, and the mechanical safety valve ensures the safety of the system when the pressure relief solenoid valve fails.

[0006] According to the temperature-controlled evaporator suitable for a wet heat box described in the present invention, a further preferred technical solution is: a filter and a liquid replenishment pump are arranged on the liquid replenishment pipe of the liquid storage container, the filter plays a filtering role when the system is injected with liquid, and the liquid replenishment pump provides power for the injection.

[0007] According to the temperature-controlled evaporator suitable for a wet heat box described in the present invention, a further preferred technical solution is that the liquid storage container is the highest point of the entire system, which provides a guarantee for the circulating liquid to fill the system and plays a role in buffering and constant pressure.

[0008] According to the temperature-controlled evaporator suitable for a wet heat box described in the present invention, a further preferred technical solution is: a liquid discharge ball valve is arranged at the bottom of the liquid storage container for replacing the solution or draining the liquid.

[0009] According to the temperature-controlled evaporator suitable for a wet heat box described in the present invention, a further preferred technical solution is: a double liquid level float switch is arranged in the liquid storage container, which is used to perform liquid replenishment operation when the coolant is lower than the low liquid level, and stop liquid replenishment when it is higher than the high liquid level.

[0010] According to the temperature-controlled evaporator suitable for a wet heat box described in the present invention, a further preferred technical solution is: a second temperature sensor is arranged on the liquid storage container to detect the temperature of the coolant in the liquid storage container.

[0011] According to the temperature-controlled evaporator suitable for a wet heat box described in the present invention, a further preferred technical solution is: a bypass pipe is connected between the liquid outlet pipe circulation pump and the plate heat exchanger to the liquid return pipe, a bypass ball valve is arranged on the liquid return pipe, and when the pump pressure is too high, the bypass ball valve is opened to prevent the pump from blocking.

[0012] According to the temperature-controlled evaporator suitable for a wet heat box described in the present invention, a further preferred technical solution is that the cold and heat sources of the system come from the high temperature stage or low temperature stage of the cascade refrigeration system.

[0013] A temperature-controlled evaporator control method suitable for a wet heat box, for wet heat test: the dew point temperature in this state is calculated by the temperature and relative humidity in the box, and the temperature of the coolant is controlled. When the coolant temperature is greater than the dew point temperature, only cooling is performed without dehumidification, and the humidification is small; when the coolant temperature is less than the dew point temperature, dehumidification is performed, and the dehumidification amount is controlled by the deviation between the coolant and the dew point temperature. The smaller the dehumidification amount, the closer the coolant temperature is to the dew point temperature. Conversely, the greater the dehumidification amount, the greater the temperature deviation. Cooling down the test chamber due to high temperature: pre-cool the cooling system through the three-way regulating valve bypass in advance. When the temperature is higher than the coolant temperature range, the coolant participates in the refrigeration. At the same time, the high temperature stage of the cascade refrigeration system controls the temperature of the coolant to stabilize the coolant temperature. When the coolant temperature is close to the temperature in the test chamber, the coolant in the heat exchanger is blown back to the liquid storage tank through the air source purge to prevent the coolant inside the heat exchanger from becoming a load. At the same time, the coolant has the effect of cold storage and refrigeration for the entire system. The test chamber continues to cool down through the low temperature stage of the cascade refrigeration system as needed; For constant temperature of the test chamber: constant temperature is achieved through the coolant system, the heat source comes from the high temperature stage or low temperature stage of the cascade refrigeration system, and the three-way proportional control valve maintains a constant temperature by adjusting the coolant flow in the heat exchanger.

[0014] Compared with the prior art, the technical solution of the present invention has the following advantages / benefits: 1. The heat and cold sources of the entire system come from the high temperature stage or low temperature stage of the cascade refrigeration system. The coolant temperature can be controlled by the high temperature gas bypass, low temperature liquid bypass and related valves. There is no need to add any other type of heat and cold sources, and the controllable temperature range is wide.

[0015] 2. When the test chamber is doing wet heat, the dew point temperature under this state is calculated through the temperature and relative humidity in the chamber. By controlling the temperature of the coolant, when the coolant temperature is greater than the dew point temperature, only cooling is performed without dehumidification, and the humidification is small. Only humidification and cooling in the chamber are involved in the control. Compared with the existing four control points, the number of control points is reduced and the humidity is easy to keep constant. When the coolant temperature is less than the dew point temperature, dehumidification is performed, and the dehumidification amount is controlled by the deviation between the coolant and the dew point temperature. That is, the smaller the dehumidification amount, the closer the coolant temperature is to the dew point temperature, and vice versa.

[0016] 3. Control the temperature of the coolant to > 0°C (frost point temperature), the refrigeration and dehumidification heat exchanger will not frost, and the refrigeration and dehumidification capacity will not decrease.

[0017] 4. The system uses a proportional control valve. When the cooling load in the test chamber changes greatly, the proportional valve opening can be adjusted quickly, and the total flow of the system remains unchanged. Compared with a single variable frequency pump control, the control valve responds more quickly, and the system flow is always at the maximum operation. The larger the circulation flow, the smaller the coolant temperature change, which can better ensure the stable operation of the test chamber.

[0018] 5. When the test chamber is cooled down from high temperature, the cooling system can be pre-cooled in advance through the three-way regulating valve bypass, which can be cooled to about -30℃. When the temperature is higher than the coolant temperature range, the coolant can participate in refrigeration (at the same time, the high temperature stage of the cascade refrigeration system can also control the coolant temperature to make the coolant temperature tend to be stable). When the coolant temperature is close to the temperature in the test chamber, the coolant in the heat exchanger is blown back to the liquid storage tank through the air source purge, thereby reducing the load of the lower low-temperature section, and the entire coolant system has the effect of cold storage and refrigeration.

[0019] 6. The test chamber is kept at a constant temperature. It can also be kept at a constant temperature through the coolant system. The heat and cold sources come from the high temperature stage or low temperature stage of the cascade refrigeration system. Opening the high temperature stage is more energy-efficient than opening two sets of compressors for constant temperature, and the temperature is constant. The three-way proportional control valve adjusts the coolant flow in the heat exchanger, which is more accurate and stable than the periodic on-off adjustment of the solenoid valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a structural schematic diagram of a temperature-controlled evaporator suitable for a wet heat box according to the present invention.

[0022] Figure 2It is a structural schematic diagram of a plate heat exchanger portion of a temperature-controlled evaporator suitable for a wet heat box according to the present invention.

[0023] The marks in the figure are: DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, it may not be further defined or explained in the subsequent drawings.

[0026] Embodiment 1: like Figure 1 Figure 2As shown, a temperature-controlled evaporator and control method suitable for a wet heat box. The high-temperature gas side and low-temperature liquid side of the high-temperature stage system of the cascade refrigeration system enter the plate heat exchanger 8 through the high-temperature gas side solenoid valve 3, the high-temperature gas side manual valve 4 and the low-temperature liquid side solenoid valve 5, and the low-temperature expansion valve 6 respectively. In the present invention, the plate heat exchanger has three heat exchange flow channels, one side is the flow channel for the coolant, and the other side has two flow channels, which are the hot gas bypass (high-temperature gas side) and the cold liquid bypass (low-temperature liquid side) of the high-temperature stage of the cascade system, which can provide heat source and cold source for the coolant system respectively, for heating or cooling the coolant. It should be noted that the coolant system uses an independent pipeline, and the cold source and heat source of the cascade refrigeration system are used to cool or heat the coolant of the coolant system; the high-temperature stage system 2 of the cascade refrigeration system provides a heat source and cold source for the upper part of the coolant system through the plate heat exchanger 8, and the cold source end of the plate heat exchanger is sequentially provided with a temperature sensor 9 and a three-way proportional regulating valve 10. The three-way proportional regulating valve 10 is controlled by feedback from the temperature sensor 9, and the flow of coolant entering the refrigeration and dehumidification heat exchanger 11 is controlled by proportional regulation. The remaining outlet of the three-way regulating valve is connected to the return pipe at the rear end of the refrigeration and dehumidification heat exchanger 11 as a bypass. A one-way valve is arranged between the rear end of the refrigeration and dehumidification heat exchanger 11 and the return pipe to prevent the liquid bypassed by the three-way proportional regulating valve 10 from affecting the refrigeration and dehumidification heat exchanger 11. The return pipe is connected to the liquid storage container 19, and the heat source end of the plate heat exchanger is connected to the liquid storage container 19 through the liquid outlet pipe. A circulating pump 23 is arranged on the liquid outlet pipe, and an air blowing pipe is connected between the circulating pump 23 of the liquid outlet pipe and the plate heat exchanger 8. An air circuit solenoid valve 14 and a throttle valve 13 are arranged on the air blowing pipe. The air circuit solenoid valve 14 is opened when refrigeration is not required to blow the coolant in the refrigeration and dehumidification heat exchanger 11 back to the liquid storage container 19, and the throttle valve 13 adjusts the intake pressure. A return gas check valve 7 is provided on the return liquid pipeline between the plate heat exchanger and the high temperature system of the cascade refrigeration system to prevent the refrigerant of the high temperature system of the cascade refrigeration system from flowing back. It should be noted that the evaporator of the present invention refers to the heat exchanger and the refrigeration evaporator integrated into one, and the heat exchanger can also be used as an independent structure alone, but usually we will refer to them as evaporators after integration, and the evaporator is used for humidity control in the environmental test chamber.

[0027] A pressure relief solenoid valve 15 and a mechanical safety valve 16 are arranged in parallel on the pressure relief pipe of the liquid storage container 19. The pressure relief solenoid valve 15 opens when the system pressure is high, and the mechanical safety valve 16 ensures the safety of the system when the pressure relief solenoid valve 15 fails.

[0028] A filter 17 and a fluid infusion pump 18 are arranged on the fluid infusion pipe of the fluid storage container 19. The filter 17 plays a filtering role when the system is infused with fluid, and the fluid infusion pump 18 provides power for the fluid infusion.

[0029] The liquid storage container 19 is the highest point of the entire system, which provides a guarantee for the circulating liquid to fill the system and also plays a role in buffering and maintaining pressure.

[0030] A liquid discharge ball valve 20 is provided at the bottom of the liquid storage container 19 for replacing the solution or discharging the liquid.

[0031] A double liquid level float switch 22 is provided in the liquid storage container 19 for performing liquid replenishment when the coolant is lower than the low liquid level and stopping liquid replenishment when the coolant is higher than the high liquid level.

[0032] A second temperature sensor 21 is provided on the liquid storage container 19 for detecting the temperature of the coolant in the liquid storage container 19 .

[0033] The liquid outlet circulation pump 23 and the plate heat exchanger 8 are connected to the liquid return pipe through a bypass pipe. A bypass ball valve 24 is arranged on the liquid return pipe. When the pump pressure is too high, the bypass ball valve 24 is opened to prevent the pump from stalling.

[0034] The cold and heat sources of the system come from the high temperature stage or low temperature stage of the cascade refrigeration system.

[0035] When the environmental chamber drops from high temperature to low temperature, the cooling rate is a key indicator. When the environmental chamber is at a constant high temperature, the coolant can be cooled to low temperature through the cascade high temperature stage, thereby performing cold storage operation. When the test chamber begins to cool down, the coolant enters the internal heat exchanger of the studio for circulation, and the cascade low temperature stage also enters the internal evaporator for refrigeration, thereby obtaining a faster cooling rate.

[0036] When the coolant temperature is close to the working room temperature, the test chamber continues to cool down (through cascading low-temperature stages), and the coolant inside the heat exchanger becomes a load. Therefore, gas purge is used to blow it out of the test chamber heat exchanger and recover it to the liquid storage tank to reduce the load of the subsequent low-temperature section.

[0037] Embodiment 2: A temperature-controlled evaporator control method suitable for a wet heat box, for wet heat test: the dew point temperature in this state is calculated by the temperature and relative humidity in the box, and the temperature of the coolant is controlled. When the coolant temperature is greater than the dew point temperature, only cooling is performed without dehumidification, and the humidification is small; when the coolant temperature is less than the dew point temperature, dehumidification is performed, and the dehumidification amount is controlled by the deviation between the coolant and the dew point temperature. The smaller the dehumidification amount, the closer the coolant temperature is to the dew point temperature. Conversely, the greater the dehumidification amount, the greater the temperature deviation. To reduce the temperature of the test chamber at high temperature: pre-cool the cooling system to -30℃ through the three-way regulating valve bypass in advance. When the temperature is higher than the coolant temperature range, the coolant can participate in the refrigeration. At the same time, the high temperature stage of the cascade refrigeration system controls the temperature of the coolant to make the coolant temperature stable. When the coolant temperature is close to the temperature in the test chamber, the coolant in the heat exchanger is blown back to the liquid storage tank through the air source purge to reduce the load of the lower low temperature section. The coolant has the effect of cold storage and refrigeration for the entire system. For constant temperature of the test chamber: constant temperature is achieved through the coolant system. The heat and cold sources come from the high temperature stage or low temperature stage of the cascade refrigeration system. The three-way proportional regulating valve maintains a constant temperature by adjusting the coolant flow in the heat exchanger.

[0038] Example 3: The system operation status at the 20℃ / 80% point (dry bulb temperature and) operating point was tested in a test chamber with high temperature and low humidity (90℃ / 20%). When the operating condition in the test chamber was 90℃ / 20%, the dew point temperature was calculated to be about 52.59℃, and the moisture content was about 100g / kg. When the operating condition in the test chamber was 20℃ / 80%, the dew point temperature was calculated to be about 16.47℃, and the moisture content was about 11.7g / kg.

[0039] The specific operation is to start the coolant system and the high-temperature system of the cascade system in advance, and detect the outlet temperature of the coolant system. At this time, the three-way regulating valve bypass is fully open, and the heat exchanger in the test chamber studio is kept fully closed all the way. The cascade high-temperature system cools the coolant temperature in the storage tank to 17°C by adjusting the gas-side and liquid-side solenoid valve expansion valves. When the coolant temperature reaches 17°C, adjust the opening of the three-way proportional regulating valve to reduce the temperature of the test chamber to 20°C. During the cooling process, adjust the proportional valve opening and control the cascade high-temperature gas-liquid solenoid valve to stabilize the coolant temperature of the plate heat exchanger at 17°C (not less than 16.47°C). When the test chamber temperature drops to 20°C, the coolant temperature is the dew point temperature of the studio, that is, 17°C. Therefore, when the dry bulb temperature is 20℃ and the dew point temperature is 17℃, the relative humidity in the box is 82.86%, which is close to the deviation of the set value in this state. In this state, the cooling temperature is slowly reduced to the dew point temperature of 16.47℃, the coolant temperature drops by about 0.5℃, and the temperature change in the experimental box is also small. In this state, the proportional valve can be slightly adjusted to ensure a constant temperature of 20℃ in the box. In this process, no humidification operation is required. The changes in other operating points are as follows. When controlling the temperature of the coolant (dew point temperature of the test box), refrigeration without dehumidification can be ensured. The cooling capacity is achieved by adjusting the opening of the proportional valve, that is, adjusting the coolant flow rate of the heat exchanger (also referred to as the temperature-controlled evaporator of the present invention) entering the working room.

[0040] Embodiment 4: The test chamber tests the system operation status at the 50℃ / 90% point (dry bulb temperature and relative humidity). When the working condition in the test chamber is 50℃ / 90%, the calculated dew point temperature is about 49.98℃ and the moisture content is about 100g / kg.

[0041] Heat the test chamber to 50°C, control the coolant temperature to ≥50°C, and then perform steam humidification. There will be no large-scale dehumidification of the heat exchanger in the test chamber. Since the difference between the coolant temperature and the test chamber is small when constant, the coolant flow rate does not need to be controlled. In this state, the dynamic balance between humidification and coolant temperature can stabilize the working condition.

[0042] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0043] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0045] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A temperature-controlled evaporator suitable for a wet heat box, characterized in that: The high-temperature gas side and low-temperature liquid side of the high-temperature stage system of the cascade refrigeration system enter the plate heat exchanger (8) through the high-temperature gas side solenoid valve (3), the high-temperature gas side manual valve (4), the low-temperature liquid side solenoid valve (5), and the low-temperature expansion valve (6) respectively. The high-temperature stage system (2) of the cascade refrigeration system provides a heat source and a cold source for the upper cooling liquid system through the plate heat exchanger (8). A temperature sensor (9) and a three-way proportional control valve (10) are sequentially arranged at the cold source end of the plate heat exchanger. The three-way proportional control valve (10) is controlled by feedback from the temperature sensor (9). The flow rate of the cooling liquid entering the refrigeration and dehumidification heat exchanger (11) is controlled by proportional regulation. The remaining outlet of the three-way control valve is connected to the return liquid pipe at the rear end of the refrigeration and dehumidification heat exchanger (11) as a bypass. A one-way valve (12) is provided between the rear end of the refrigeration and dehumidification heat exchanger (11) and the return liquid pipe to prevent the liquid bypassed by the three-way proportional regulating valve (10) from affecting the return of the refrigeration and dehumidification heat exchanger (11). The end of the return liquid pipe is connected to a liquid storage container (19). The heat source end of the plate heat exchanger is connected to the liquid storage container (19) through a liquid outlet pipe. A circulating pump (23) is provided on the liquid outlet pipe. An air blowing pipe is connected between the circulating pump (23) of the liquid outlet pipe and the plate heat exchanger (8). An air circuit solenoid valve (14) and a throttle valve (13) are provided on the air blowing pipe. When refrigeration is not required, the air circuit solenoid valve (14) is opened to blow the coolant in the refrigeration and dehumidification heat exchanger (11) back to the liquid storage container (19). The throttle valve (13) adjusts the intake pressure.

2. A temperature-controlled evaporator suitable for a wet heat box according to claim 1, characterized in that: A pressure relief solenoid valve (15) and a mechanical safety valve (16) are arranged in parallel on the pressure relief pipe of the liquid storage container (19). The pressure relief solenoid valve (15) opens when the system pressure is too high, and the mechanical safety valve (16) ensures the safety of the system when the pressure relief solenoid valve (15) fails.

3. A temperature-controlled evaporator suitable for a wet heat box according to claim 1, characterized in that: A filter (17) and a liquid infusion pump (18) are arranged on the liquid infusion pipe of the liquid storage container (19). The filter (17) plays a filtering role when the system is infused with liquid, and the liquid infusion pump (18) provides power for the liquid infusion.

4. A temperature-controlled evaporator suitable for a wet heat box according to claim 1, characterized in that: The liquid storage container (19) is the highest point of the entire system, which ensures that the circulating liquid fills the system and also plays a role in buffering and maintaining pressure.

5. The temperature-controlled evaporator suitable for a wet heat box according to claim 1, characterized in that: A liquid discharge ball valve (20) is provided at the bottom of the liquid storage container (19) for replacing the solution or discharging the liquid.

6. A temperature-controlled evaporator suitable for a wet heat box according to claim 1, characterized in that: A double liquid level float switch (22) is arranged in the liquid storage container (19) for performing liquid replenishment when the coolant is lower than a low liquid level and stopping liquid replenishment when the coolant is higher than a high liquid level.

7. A temperature-controlled evaporator suitable for a wet heat box according to claim 1, characterized in that: A second temperature sensor (21) is provided on the liquid storage container (19) for detecting the temperature of the coolant in the liquid storage container (19).

8. The temperature-controlled evaporator suitable for a wet heat box according to claim 1, characterized in that: A bypass pipe is provided between the liquid outlet circulation pump (23) and the plate heat exchanger (8) to connect to the liquid return pipe. A bypass ball valve (24) is provided on the liquid return pipe. When the pump pressure is too high, the bypass ball valve (24) is opened to prevent the pump from stalling.

9. The temperature-controlled evaporator suitable for a wet heat box according to claim 1, characterized in that: The cold and heat sources of the system come from the high temperature stage or low temperature stage of the cascade refrigeration system.

10. A temperature control type evaporator control method suitable for a wet heat box according to claim 1, characterized in that: For wet heat test: the dew point temperature in this state is calculated through the temperature and relative humidity in the box. By controlling the temperature of the coolant, when the coolant temperature is greater than the dew point temperature, only cooling is performed without dehumidification, and the humidification is small; when the coolant temperature is less than the dew point temperature, dehumidification is performed, and the dehumidification amount is controlled by the deviation between the coolant and the dew point temperature. The smaller the dehumidification amount, the closer the coolant temperature is to the dew point temperature. Conversely, the greater the dehumidification amount, the greater the temperature deviation. Cooling down the test chamber due to high temperature: pre-cool the cooling system through the three-way regulating valve bypass in advance. When the temperature is higher than the coolant temperature range, the coolant participates in the refrigeration. At the same time, the high temperature stage of the cascade refrigeration system controls the temperature of the coolant to stabilize the coolant temperature. When the coolant temperature is close to the temperature in the test chamber, the coolant in the heat exchanger is blown back to the liquid storage tank through the air source purge to prevent the coolant inside the heat exchanger from becoming a load. At the same time, the coolant has the effect of cold storage and refrigeration for the entire system. The test chamber continues to cool down through the low temperature stage of the cascade refrigeration system as needed; For constant temperature of the test chamber: constant temperature is achieved through the coolant system. The heat and cold sources come from the high temperature stage or low temperature stage of the cascade refrigeration system. The three-way proportional regulating valve maintains a constant temperature by adjusting the coolant flow in the heat exchanger.

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