A temperature-controlled evaporator applicable to a humidity and heat chamber and a control method thereof

Abstract

The present invention discloses a temperature-controlled evaporator applicable to a humidity and heat chamber and a control method. The high-temperature gas bypass and the low-temperature liquid bypass of the high-temperature stage system of the cascade refrigeration system respectively enter a plate heat exchanger through pipelines to provide a heat source and a cold source for the upper part of the coolant system. The pipeline at the cold source end of the plate heat exchanger controls a three-way proportional regulating valve based on the feedback of a temperature sensor thereon, controls the coolant flow rate entering the refrigeration and dehumidification heat exchanger. The coolant is connected to a liquid storage container through a return pipe. At the same time, the heat source end of the plate heat exchanger is connected to the liquid storage container through an outlet pipe, and a circulation pump is arranged on the outlet pipe. When refrigeration is not required, the coolant in the refrigeration and dehumidification heat exchanger is blown back to the liquid storage container through a blowing pipe on the outlet pipe. The cold and heat sources of the overall system come from the high-temperature stage or the low-temperature stage of the cascade refrigeration system. The coolant temperature can be controlled through the high-temperature gas bypass, the low-temperature liquid bypass and related valve parts, without adding any other types of cold and heat sources, and the controllable temperature range is wide.

Description

Technical Field

[0001] The present invention belongs to the technical field of high and low temperature test chambers, and particularly relates to a temperature-controlled evaporator applicable to a humidity test chamber and a control method therefor. Background Art

[0002] In a conventional high and low temperature test chamber, during the humidity test, steam humidification is usually adopted. The temperature of the steam humidification is relatively high, and it will exchange sensible heat with the working chamber, resulting in the temperature rise of the working chamber. Therefore, refrigeration is usually required during the humidity test. Since a cascade refrigeration system is adopted, usually the low-temperature stage evaporator is used for refrigeration and dehumidification, or the high-temperature stage evaporator is used for refrigeration and dehumidification (usually when using high-temperature stage dehumidification, the two sets of evaporators are integrated into one). The evaporation temperature of the refrigeration system is much lower than the dew point temperature of the working condition point in the chamber. Therefore, the air in the working chamber will exchange latent heat with the evaporator, resulting in a decrease in the relative humidity of the working chamber. Since the evaporation temperature is relatively low, it will also cause a sudden drop in the temperature of the working chamber, so it is necessary to increase the steam volume to perform heating compensation in a timely manner, that is, it is necessary to increase the power of the humidifier and the power of the heater. After the heating and humidification are increased, the required dehumidification amount and refrigeration amount are increased. After all parameters are increased, the temperature and humidity fluctuations in the chamber will be relatively large. When heating, humidifying, dehumidifying, and refrigerating reach equilibrium, the working condition will tend to be stable. Since these four parameters are difficult to control to the actual required values, each item will exceed the design value, thus increasing the power consumption and configuration cost. At the same time, when the test chamber conducts experiments such as high temperature / low temperature / vacuum, the gas detection instrument cannot withstand relatively high or low temperatures, and the air pump cannot meet the gas detection of the test chamber under low pressure. Summary of the Invention

[0003] To overcome the above deficiencies, the inventors of the present invention have made long-term exploration and attempts, as well as multiple experiments and efforts, continuously reforming and innovating, and proposed a temperature-controlled evaporator applicable to a humidity test chamber and a control method therefor. The cold and heat sources of the overall system come from the high-temperature stage or the low-temperature stage of the cascade refrigeration system. The temperature of the coolant can be controlled through the high-temperature gas bypass, the low-temperature liquid bypass, and related valve components, without adding any other types of cold and heat sources, and the controllable temperature range is relatively wide.

[0004] The technical solution adopted by the present invention to achieve the above object is: to provide a temperature-controlled evaporator applicable to a humidity and heat chamber. The high-temperature gas bypass and the low-temperature liquid bypass of the high-temperature stage system of the cascade refrigeration system respectively enter the plate heat exchanger through the high-temperature gas bypass solenoid valve, the high-temperature gas bypass manual valve, the low-temperature liquid bypass solenoid valve, and the low-temperature expansion valve. The high-temperature stage system of the cascade refrigeration system provides a heat source and a cold source for the upper part of the coolant system through the plate heat exchanger. A temperature sensor and a three-way proportional regulating valve are sequentially arranged at the cold source end of the plate heat exchanger. The three-way proportional regulating valve is controlled by relying on the feedback of the temperature sensor. The coolant flow rate entering the refrigeration and dehumidification heat exchanger is controlled through proportional regulation. The remaining outlet of the three-way regulating valve is connected to the liquid return pipe at the rear end of the refrigeration and dehumidification heat exchanger as a bypass. A check valve is arranged between the rear end of the refrigeration and dehumidification heat exchanger and the liquid return pipe to prevent the liquid in the bypass of the three-way proportional regulating valve from affecting the reflux of the refrigeration and dehumidification heat exchanger. The end of the liquid return pipe is connected to a liquid storage container. The heat source end of the plate heat exchanger is connected to the liquid storage container through a liquid outlet pipe. A circulation pump is arranged on the liquid outlet pipe. A blow pipe is connected between the circulation pump on the liquid outlet pipe and the plate heat exchanger. An air path solenoid valve and a throttle valve are arranged on the blow pipe. The air path solenoid valve is opened when refrigeration is not required to blow the coolant in the refrigeration and dehumidification heat exchanger back to the liquid storage container, and the throttle valve regulates the intake pressure.

[0005] For a temperature-controlled evaporator applicable to a humidity and heat chamber according to 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 is opened 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] For a temperature-controlled evaporator applicable to a humidity and heat chamber according to the present invention, a further preferred technical solution is: a filter and a liquid filling pump are arranged on the liquid filling pipe of the liquid storage container. The filter plays a filtering role when the system is filled with liquid, and the liquid filling pump provides power for liquid filling.

[0007] For a temperature-controlled evaporator applicable to a humidity and heat chamber according to the present invention, a further preferred technical solution is: the liquid storage container is the highest point of the entire system, which ensures that the circulating liquid fills the system and plays a role in buffering and constant pressure.

[0008] For a temperature-controlled evaporator applicable to a humidity and heat chamber according to the present invention, a further preferred technical solution is: a drain ball valve is arranged at the bottom of the liquid storage container for replacing the solution or draining the liquid.

[0009] For a temperature-controlled evaporator applicable to a humidity and heat chamber according to the present invention, a further preferred technical solution is: a double-level float switch is arranged in the liquid storage container for performing liquid filling operations when the coolant is below the low level and stopping liquid filling when it is above the high level.

[0010] A temperature-controlled evaporator applicable to a humidity and heat chamber according to the present invention, a further preferred technical solution thereof is: a second temperature sensor is provided on the liquid storage container for detecting the temperature of the coolant in the liquid storage container.

[0011] A temperature-controlled evaporator applicable to a humidity and heat chamber according to the present invention, a further preferred technical solution thereof is: a bypass pipe is connected between the liquid outlet pipe circulation pump and the plate heat exchanger to the return pipe, and a bypass ball valve is provided on the return pipe. When the pump pressure is too high, the bypass ball valve is opened to prevent the pump from stalling.

[0012] A temperature-controlled evaporator applicable to a humidity and heat chamber according to the present invention, a further preferred technical solution thereof is: the cold and heat source of the system comes from the high temperature stage or the low temperature stage of the cascade refrigeration system.

[0013] A control method for a temperature-controlled evaporator applicable to a humidity and heat chamber, for humidity and heat tests: the dew point temperature in this state is calculated through the temperature and relative humidity in the chamber. By controlling the temperature of the coolant, when the coolant temperature > dew point temperature, only refrigeration is performed without dehumidification, and the humidification is small; when the coolant temperature < 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 temperature deviation, the greater the dehumidification amount;

[0014] For the high temperature to low temperature reduction of the test chamber: pre-cool the cooling system in advance through the bypass of the three-way regulating valve. Within the range higher than the coolant temperature, the coolant participates in refrigeration, and at the same time, the high temperature stage of the cascade refrigeration system controls the temperature of the coolant 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 gas purge to avoid the coolant inside the heat exchanger becoming a load. At the same time, the coolant has a cold storage and refrigeration effect on the whole system. The test chamber continues to cool down as needed through the low temperature stage of the cascade refrigeration system;

[0015] For the constant temperature of the test chamber: constant temperature is achieved through the coolant system. The cold and heat source comes from the high temperature stage or the low temperature stage of the cascade refrigeration system. The three-way proportional regulating valve keeps the temperature constant by adjusting the coolant flow rate in the heat exchanger..

[0016] Compared with the prior art, the technical solution of the present invention has the following advantages / beneficial effects:

[0017] 1. The cold and heat source of the whole system comes from the high temperature stage or the low temperature stage of the cascade refrigeration system. The coolant temperature can be controlled through the high temperature gas bypass, low temperature liquid bypass and related valve parts, without adding any other type of cold and heat source, and the controllable temperature range is relatively wide.

[0018] 2. When the test chamber is doing damp heat test, the dew point temperature under this state is calculated through the temperature and relative humidity inside the chamber. By controlling the temperature of the coolant, when the coolant temperature > dew point temperature, only refrigeration is carried out without dehumidification, the humidification is small, and only humidification and refrigeration inside the chamber participate in the control. Compared with the existing four control points, the number of control points is reduced and the humidity is easier to be constant. When the coolant temperature < dew point temperature, dehumidification is carried out, and the amount of dehumidification is controlled by the deviation between the coolant temperature and the dew point temperature, that is, the smaller the amount of dehumidification, the closer the coolant temperature is to the dew point temperature, and vice versa, the greater the temperature deviation.

[0019] 3. Control the coolant temperature > 0°C (frost point temperature), the refrigeration and dehumidification heat exchanger will not frost, and the refrigeration and dehumidification capacity will not decrease.

[0020] 4. The system adopts a proportional regulating valve. When the cooling load inside the test chamber changes greatly, the opening of the proportional valve can be quickly adjusted, and the total flow of the system remains unchanged. Compared with the single variable frequency pump control, the regulating valve responds more quickly, and the system flow is always at the maximum operation. The greater the circulation flow, the smaller the change in the coolant temperature, so as to better ensure the stable operation of the test chamber.

[0021] 5. When the test chamber changes from high temperature to low temperature, the cooling system can be pre-cooled in advance through the bypass of the three-way regulating valve, and it can be cooled to about -30°C. Within the range higher than the coolant temperature, 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 inside the test chamber, the coolant in the heat exchanger is blown back to the liquid storage tank through the gas source purge, so as to reduce the load of the lower low temperature section, and the entire coolant system plays the role of cold storage and refrigeration.

[0022] 6. When the test chamber is at a constant temperature, it can also be kept at a constant temperature through the coolant system. The cold and heat source comes from the high temperature stage or the low temperature stage of the cascade refrigeration system. This way of turning on the high temperature stage is more energy-saving than turning on two sets of compressors for constant temperature, and the temperature is constant. The three-way proportional regulating valve adjusts the coolant flow inside the heat exchanger, which is more accurate and stable than the periodic on-off adjustment of the solenoid valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, so they should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a schematic structural diagram of a temperature control type evaporator applicable to a damp heat chamber of the present invention.

[0025] Figure 2It is a schematic structural diagram of the plate heat exchanger part of a temperature-controlled evaporator applicable to a humidity and heat box according to the present invention.

[0026] The markings in the figure are respectively:

[0027] Specific embodiments

[0028] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to 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 selected embodiments of the present invention.

[0029] It should be noted that similar reference numerals and letters denote similar items in the following figures. Therefore, once an item is defined in one figure, it may not be further defined and explained in subsequent figures.

[0030] Example 1:

[0031] As Figure 1 Figure 2As shown in the figure, a temperature-controlled evaporator applicable to a humidity chamber and a control method thereof. The high-temperature gas bypass and the low-temperature liquid bypass of the high-temperature stage system of the cascade refrigeration system respectively enter the plate heat exchanger 8 through the high-temperature gas bypass solenoid valve 3, the high-temperature gas bypass manual valve 4, the low-temperature liquid bypass solenoid valve 5, and the low-temperature expansion valve 6. In the present invention, the plate heat exchanger has three heat exchange channels. One side is the flow channel of the coolant, and the other side has two channels, namely the hot gas bypass (high-temperature gas bypass) and the cold liquid bypass (low-temperature liquid bypass) of the high-temperature stage of the cascade system, which can respectively provide heat sources and cold sources for the coolant system for heating or cooling the coolant. It should be noted that the coolant system adopts 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 heat sources and cold sources for the upper part of the coolant system through the plate heat exchanger 8. A temperature sensor 9 and a three-way proportional regulating valve 10 are sequentially arranged at the cold source end of the plate heat exchanger. The three-way proportional regulating valve 10 is controlled by the feedback of the temperature sensor 9. The flow rate of the 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 flowing back to the refrigeration and dehumidification heat exchanger 11. The return pipe is connected to the liquid storage container 19. The heat source end of the plate heat exchanger is connected to the liquid storage container 19 through an outlet pipe. A circulation pump 23 is arranged on the outlet pipe. A blow pipe is connected between the circulation pump 23 on the outlet pipe and the plate heat exchanger 8. An air path solenoid valve 14 and a throttle valve 13 are arranged on the blow pipe. The air path 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. The throttle valve 13 regulates the intake pressure. A return air one-way valve 7 is arranged on the return pipe of the plate heat exchanger and the high-temperature stage system of the cascade refrigeration system to prevent the refrigerant of the high-temperature stage system of the cascade refrigeration system from flowing back. It should be noted that the evaporator of the present invention refers to the integration of the heat exchanger and the refrigeration evaporator into one. The heat exchanger can also be used as an independent structure alone, but usually our practice is to collectively call it an evaporator after integration. The evaporator is used for humidity control in the environmental test chamber.

[0032] 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 is opened 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.

[0033] A filter 17 and a liquid filling pump 18 are arranged on the liquid filling pipe of the liquid storage container 19. The filter 17 plays a filtering role when the system is filled with liquid, and the liquid filling pump 18 provides power for liquid filling.

[0034] The liquid storage container 19 is the highest point of the entire system, which ensures that the circulating liquid fills the system and plays a role in buffering and constant pressure.

[0035] A drain ball valve 20 is provided at the bottom of the liquid storage container 19 for replacing the solution or draining the liquid.

[0036] A double-level float switch 22 is provided in the liquid storage container 19 for replenishing the coolant when it is below the low level and stopping the replenishment when it is above the high level.

[0037] 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.

[0038] A bypass pipe is connected between the liquid outlet pipe circulation pump 23 and the plate heat exchanger 8 to the return pipe, and a bypass ball valve 24 is provided on the return pipe. When the pump pressure is too high, the bypass ball valve 24 is opened to prevent the pump from stalling.

[0039] The cold and heat sources of the system come from the high-temperature stage or the low-temperature stage of the cascade refrigeration system.

[0040] When the environmental chamber is cooled from high temperature to low temperature, the cooling rate is a key index. When the environmental chamber is at a constant high temperature, the coolant can be cooled to a low temperature through the cascade high-temperature stage for cold storage operation. When the test chamber starts to cool, the coolant enters the internal heat exchanger of the working chamber for circulation, and the cascade low-temperature stage also enters the internal evaporator for refrigeration to obtain a faster cooling rate.

[0041] When the coolant temperature is close to the working chamber temperature, the test chamber continues to cool (through the cascade low-temperature stage). The coolant inside the heat exchanger will become a load, so gas purging is used to blow it out of the internal heat exchanger of the test chamber and recycle it to the liquid storage tank to reduce the load in the subsequent low-temperature section.

[0042] Embodiment 2:

[0043] A temperature control type evaporator control method applicable to a damp heat chamber, for damp heat tests: the dew point temperature in this state is calculated through the temperature and relative humidity inside the chamber. By controlling the temperature of the coolant, when the coolant temperature > dew point temperature, only refrigeration is performed without dehumidification, and the humidification is small; when the coolant temperature < dew point temperature, dehumidification is performed, and the amount of dehumidification is controlled by the deviation between the coolant and the dew point temperature. The smaller the amount of dehumidification, the closer the coolant temperature is to the dew point temperature. Conversely, the larger the temperature deviation, the larger the amount of dehumidification.

[0044] For the test chamber to cool from high temperature to low temperature: the cooling system is pre-cooled to -30°C in advance through the bypass of the three-way regulating valve. Above the coolant temperature range, the coolant can participate in refrigeration, and at the same time, the high-temperature stage of the cascade refrigeration system controls the temperature of the coolant to make the coolant temperature tend to be stable. When the coolant temperature is close to the temperature inside the test chamber, the coolant inside the heat exchanger is blown back to the liquid storage tank through gas purging to reduce the load in the lower low-temperature section. The coolant plays the role of cold storage and refrigeration for the entire system.

[0045] For the constant temperature of the test chamber: The constant temperature is achieved through the coolant system. The cold and heat sources come from the high-temperature stage or the low-temperature stage of the cascade refrigeration system. The three-way proportional regulating valve maintains a constant temperature by adjusting the coolant flow rate in the heat exchanger.

[0046] Example 3: Test the system operation at the 20°C / 80% (dry bulb temperature and relative humidity) operating point when the test chamber is at high temperature and low humidity (90°C / 20%). When the conditions inside the test chamber are 90°C / 20%, calculate the dew point temperature to be approximately 52.59°C and the moisture content to be approximately 100 g / kg. When the conditions inside the test chamber are 20°C / 80%, calculate the dew point temperature to be approximately 16.47°C and the moisture content to be approximately 11.7 g / kg.

[0047] The specific operation is to pre-start the coolant system and the high-temperature stage system of the cascade system, and detect the outlet temperature of the coolant system. At this time, the bypass of the three-way regulating valve is fully open, and the path connecting to the heat exchanger inside the working chamber of the test chamber remains fully closed. The high-temperature stage system of the cascade adjusts the gas bypass and liquid bypass solenoid valves and expansion valves to cool the coolant temperature in the liquid storage tank to 17°C. When the coolant temperature reaches 17°C, adjust the opening of the three-way proportional regulating valve to lower the temperature of the experimental chamber to 20°C. During the cooling process, adjust the opening of the proportional valve and control the gas-liquid bypass solenoid valves of the cascade high-temperature stage to keep the coolant temperature in the plate heat exchanger stable at 17°C (not lower than 16.47°C). When the temperature of the test chamber drops to 20°C, the coolant temperature is the dew point temperature of the working chamber, which is 17°C. Therefore, when the dry bulb temperature is 20°C and the dew point temperature is 17°C, the relative humidity inside the chamber is 82.86%. In this state, it is already within the deviation range close to the set value. Slowly reduce the cooling temperature to the dew point temperature of 16.47°C in this state. The coolant temperature drops by about 0.5°C, and the temperature change inside the experimental chamber is also small. In this state, the proportional valve can slightly adjust the opening to ensure a constant temperature of 20°C inside the chamber. During this process, no humidification operation is required. The same is true for other operating point changes. When controlling the temperature of the coolant (dew point temperature of the test chamber), it can ensure that refrigeration does not dehumidify. The refrigeration capacity is achieved by adjusting the opening of the proportional valve, that is, adjusting the coolant flow rate into the heat exchanger inside the working chamber (also referring to the temperature-controlled evaporator of the present invention).

[0048] Example 4:

[0049] Test the system operation at the 50°C / 90% (dry bulb temperature and relative humidity) operating point of the test chamber. When the conditions inside the test chamber are 50°C / 90%, calculate the dew point temperature to be approximately 49.98°C and the moisture content to be approximately 100 g / kg.

[0050] Heat the test chamber to 50°C, control the coolant temperature to ≥50°C, and then perform steam humidification. There will be no significant dehumidification phenomenon of the heat exchanger in the test chamber. Since the temperature difference between the coolant and the test chamber is small at a constant state, the coolant flow rate does not need to be controlled. Under this condition, ensuring the dynamic balance between humidification and coolant temperature can stabilize this working condition.

[0051] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0052] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below" and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.

[0054] The above are only the preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as a limitation of the present invention. The protection scope of the present invention should be subject to the scope defined by the claims. For those of ordinary skill in the art, without departing from the spirit and scope of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as within the protection scope of the present invention.

Claims

1. A temperature-controlled evaporator applicable to a humidity and heat chamber, characterized in that, The high-temperature gas bypass and low-temperature liquid bypass of the high-temperature stage system of the cascade refrigeration system respectively enter the plate heat exchanger (8) through the high-temperature gas bypass solenoid valve (3), high-temperature gas bypass manual valve (4), low-temperature liquid bypass solenoid valve (5), and low-temperature expansion valve (6). The high-temperature stage system (2) of the cascade refrigeration system provides heat and cold sources for the upper part of the coolant system through the plate heat exchanger (8). A temperature sensor (9) and a three-way proportional regulating valve (10) are sequentially arranged at the cold source end of the plate heat exchanger. The three-way proportional regulating valve (10) is controlled by relying on the feedback of the temperature sensor (9). The coolant flow rate 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 check valve (12) is arranged between the rear end of the refrigeration and dehumidification heat exchanger (11) and the return pipe to prevent the liquid in the bypass of the three-way proportional regulating valve (10) from affecting the backflow of the refrigeration and dehumidification heat exchanger (11). The end of the return pipe is connected to the liquid storage container (19). The heat source end of the plate heat exchanger is connected to the liquid storage container (19) through an outlet pipe. A circulation pump (23) is arranged on the outlet pipe. A blow pipe is connected between the outlet pipe circulation pump (23) and the plate heat exchanger (8). An air path solenoid valve (14) and a throttle valve (13) are arranged on the blow pipe. The air path 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). The throttle valve (13) regulates the intake pressure.

2. The temperature control type evaporator applicable to a humidity and heat box according to claim 1, wherein 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) is opened when the system pressure is too high. The mechanical safety valve (16) ensures the safety of the system when the pressure relief solenoid valve (15) fails.

3. A temperature-controlled evaporator applicable to a humidity and heat chamber according to claim 1, characterized in that, A filter (17) and a liquid filling pump (18) are arranged on the liquid filling pipe of the liquid storage container (19). The filter (17) plays a filtering role during system liquid filling, and the liquid filling pump (18) provides power for liquid filling.

4. A temperature-controlled evaporator applicable to a humidity and heat chamber 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 plays a role in buffering and constant pressure.

5. A temperature-controlled evaporator applicable to a humidity and heat chamber, characterized in that, A drain ball valve (20) is arranged at the bottom of the liquid storage container (19) for replacing the solution or draining the liquid.

6. A temperature-controlled evaporator applicable to a humidity and heat chamber according to claim 1, characterized in that, A double-level float switch (22) is arranged in the liquid storage container (19) for performing liquid filling operations when the coolant is below the low level and stopping liquid filling when it is above the high level.

7. A temperature-controlled evaporator applicable to a humidity and heat chamber according to claim 1, characterized in that, A second temperature sensor (21) is arranged on the liquid storage container (19) for detecting the temperature of the coolant in the liquid storage container (19).

8. A temperature-controlled evaporator applicable to a humidity and heat chamber according to claim 1, characterized in that, A bypass pipe is connected between the outlet pipe circulation pump (23) and the plate heat exchanger (8) to the return pipe. A bypass ball valve (24) is arranged on the return pipe. When the pump pressure is too high, the bypass ball valve (24) is opened to prevent the pump from jamming.

9. A temperature-controlled evaporator applicable to a humidity and heat chamber, characterized in that, The heat and cold sources of the system come from the high-temperature stage or low-temperature stage of the cascade refrigeration system.

10. The temperature control type evaporator control method applicable to a humidity and heat test chamber according to claim 1, characterized in that For the damp heat test: Calculate the dew point temperature in this state based on the temperature and relative humidity inside the chamber. By controlling the temperature of the coolant, when the coolant temperature > dew point temperature, only refrigeration is carried out without dehumidification, and the humidification is small; when the coolant temperature < dew point temperature, dehumidification is carried out, and the amount of dehumidification is controlled by the deviation between the coolant and the dew point temperature. The smaller the amount of dehumidification, the closer the coolant temperature is to the dew point temperature. Conversely, the larger the amount of dehumidification, the greater the temperature deviation. For the high temperature to low temperature change of the test chamber: Pre-cool the cooling system through the bypass of the three-way regulating valve in advance. Within the range higher than the coolant temperature, the coolant participates in refrigeration, and at the same time, the high-temperature stage of the cascade refrigeration system controls the temperature of the coolant to make the coolant temperature tend to be stable. When the coolant temperature is close to the temperature inside the test chamber, the coolant in the heat exchanger is blown back to the liquid storage tank through gas purging to avoid the coolant inside the heat exchanger becoming a load. At the same time, the coolant plays a role in cold storage and refrigeration for the whole system. The test chamber continues to cool down as needed through the low-temperature stage of the cascade refrigeration system. For the constant temperature of the test chamber: Keep the temperature constant through the coolant system. The cold and heat sources come from the high-temperature stage or the low-temperature stage of the cascade refrigeration system. The three-way proportional regulating valve keeps the temperature constant by adjusting the coolant flow rate in the heat exchanger.

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