Test box for simulating environment

Abstract

The invention discloses a test box for simulating an environment. The test box comprises a box body, a single-stage refrigeration system, a cascade refrigeration system, an environment monitoring system and a control system. The box body comprises a testing space and a working space which are communicated, and the testing space is used for placing a to-be-tested product; the environment monitoring system is used for monitoring the temperature and humidity in the test space; when a first extreme environment of a to-be-tested product is simulated and tested, a control system firstly controls a single-stage refrigeration system to be started and a cascade refrigeration system to be closed, so that the temperature and humidity in a test space reach an intermediate critical environment; and then the control system controls the single-stage refrigeration system to be closed and the cascade refrigeration system to be started, so that the temperature and the humidity in the test space are reduced to the first extreme environment from the intermediate critical environment. According to the scheme, on the basis that the gas environment is not changed, simulation of the extreme environment can be achieved without external connection of other devices, the requirements of the to-be-tested product during environment testing are met, and the testing complexity and the testing cost are reduced.

Description

Technical Field

[0001] The invention relates to the field of testing technology, and in particular to a testing box for simulating an environment. Background Art

[0002] Before being put into use, nuclear power equipment needs to pass various appraisals to prove that the equipment can perform the required safety functions under various expected normal operation, abnormal operation and accident conditions during the life of the nuclear power plant. Therefore, nuclear power equipment appraisal technology is a necessary technical means to ensure the safe and economical operation of nuclear power plants, and is also one of the core technologies for achieving nuclear power independence.

[0003] The identification of nuclear power equipment includes environmental identification, electromagnetic compatibility (EMC) identification and seismic identification. For environmental identification, in addition to common tests (such as long-term operation tests, low temperature tests, high temperature tests, temperature change tests, alternating humidity and heat tests, etc.), it is also necessary to consider possible abnormal extreme conditions, such as temperature and humidity comprehensive abnormal environment tests. The temperature and humidity comprehensive abnormal environment test usually includes two stages: the first stage is the test under high temperature and high humidity environment, and the second stage is the test under low temperature and low humidity environment. After the first stage and before the second stage, it is necessary to realize the conversion of the test box from high temperature and high humidity environment to low temperature and low humidity environment. However, the reduction in temperature and humidity will cause frost on the evaporator surface of the test box refrigeration system, which will greatly affect the heat exchange efficiency, and thus the simulation of low temperature and low humidity environment cannot be realized.

[0004] To solve this problem, existing test chambers generally replace the air in the test chamber by connecting other equipment after completing the first phase of testing to simulate a low temperature and low humidity environment. However, connecting other equipment not only increases costs, but may also change the gas environment, which does not meet the test requirements. Summary of the invention

[0005] The present invention provides a test box for simulating an environment, which can simulate an extreme environment without changing the gas environment and without the need for other external equipment, thereby meeting the needs of a product to be tested during environmental testing and reducing test complexity and test costs.

[0006] According to one aspect of the present invention, a test box for simulating an environment is provided, the test box comprising: a box body, a single-stage refrigeration system, a cascade refrigeration system, an environmental monitoring system and a control system; the box body comprises a connected test space and a working space, the test space is used to place a product to be tested; the environmental monitoring system is arranged in the test space, for monitoring the temperature and humidity in the test space; the single-stage refrigeration system and the cascade refrigeration system are arranged in the working space; the single-stage refrigeration system, the cascade refrigeration system and the environmental monitoring system are electrically connected to the control system respectively; when simulating a first extreme environment of the product to be tested, the control system first controls the single-stage refrigeration system to be turned on and the cascade refrigeration system to be turned off, so that the temperature and humidity in the test space reach an intermediate critical environment; the control system then controls the single-stage refrigeration system to be turned off and the cascade refrigeration system to be turned on, so that the temperature and humidity in the test space drop from the intermediate critical environment to the first extreme environment.

[0007] Optionally, the single-stage refrigeration system includes: a first compressor, a side-pipe condenser, a first filter, a first evaporator, a first throttling device and a second throttling device; the outlet end of the first compressor is connected to the inlet end of the side-pipe condenser, the outlet end of the side-pipe condenser is connected to the inlet end of the first filter, the outlet end of the first filter is respectively connected to the inlet end of the first throttling device and the inlet end of the second throttling device; the outlet end of the first throttling device is connected to the inlet end of the first evaporator, the outlet end of the second throttling device and the outlet end of the first evaporator are respectively connected to the inlet end of the first compressor.

[0008] Optionally, a first refrigerant is arranged in the first compressor; the pipeline from the outlet end of the first throttling device to the inlet end of the first compressor, and the pipeline from the outlet end of the second throttling device to the inlet end of the first compressor are both wrapped with an insulation layer.

[0009] Optionally, the cascade refrigeration system includes: a second compressor, a water-cooled condenser, a second filter, a third throttling device, a plate heat exchanger, a third compressor, a coil heat exchanger, a third filter, a fourth throttling device, a fifth throttling device and a third evaporator; the outlet end of the second compressor is connected to the inlet end of the water-cooled condenser, the outlet end of the water-cooled condenser is connected to the inlet end of the second filter, the outlet end of the second filter is respectively connected to the inlet end of each third throttling device, the outlet end of each third throttling device is respectively connected to the first end of the plate heat exchanger, and the second end of the plate heat exchanger is connected to the inlet end of the second compressor; the outlet end of the third compressor is connected to the inlet end of the coil heat exchanger, the outlet end of the coil heat exchanger is connected to the third end of the plate heat exchanger, the fourth end of the plate heat exchanger is connected to the inlet end of the third filter, and the outlet end of the third filter is respectively connected to the inlet end of each fourth throttling device and the inlet end of the fifth throttling device; the outlet end of a fourth throttling device is connected to the inlet end of a third evaporator; the outlet end of each third evaporator and the outlet end of the fifth throttling device are respectively connected to the inlet end of the third compressor.

[0010] Optionally, the cascade refrigeration system also includes: a pressure relief valve, an expansion container and a sixth throttling device; the inlet end of the expansion container is connected to the outlet end of the coil heat exchanger, the outlet end of the expansion container is connected to the inlet end of the sixth throttling device, and the outlet end of the sixth throttling device is connected to the inlet end of the third compressor; the pressure relief valve is arranged between the inlet end of the expansion container and the outlet end of the coil heat exchanger.

[0011] Optionally, a first refrigerant is arranged in the second compressor, and a second refrigerant is arranged in the third compressor, wherein the boiling point of the first refrigerant is higher than the boiling point of the second refrigerant; the pipeline from the second end of the plate heat exchanger to the inlet end of the second compressor, and the pipeline from the fourth end of the plate heat exchanger to the inlet end of the third compressor are both wrapped with an insulation layer.

[0012] Optionally, the environmental monitoring system measures humidity in the range of 0% RH to 100% RH.

[0013] Optionally, the test box also includes: a heating and humidification system; the heating and humidification system is arranged in the working space and is electrically connected to the control system; when simulating the second extreme environment of the product to be tested, the control system controls the heating and humidification system to turn on so that the temperature and humidity in the test space reach the second extreme environment; the product to be tested is first tested in the second extreme environment and then tested in the first extreme environment.

[0014] Optionally, the test box also includes: a circulation system; the circulation system is electrically connected to the control system, and is used to achieve air exchange between the test space and the working space, and to balance the air pressure inside and outside the box.

[0015] Optionally, the test box also includes: a safety protection system; the safety protection system is used to protect the test box, the product to be tested and the tester.

[0016] The technical solution of the embodiment of the present invention is to design the structure of the test box so that the test box includes a box body, a single-stage refrigeration system, a cascade refrigeration system, an environmental monitoring system and a control system. The box body includes a connected test space and a workspace, the product to be tested is placed in the test space, and the single-stage refrigeration system and the cascade refrigeration system are arranged in the workspace, so as to achieve the isolation of the test area. Further, when simulating the first extreme environment of the product to be tested, the single-stage refrigeration system works first, and after the temperature and humidity in the test space reach the intermediate critical environment, the cascade refrigeration system works again until the temperature and humidity in the test space drop from the intermediate critical environment to the first extreme environment. By operating the two refrigeration systems in stages, the problem that one refrigeration system may not be able to achieve environmental simulation is solved, and the amount of frosting on the evaporator of the cascade refrigeration system is minimized. On the basis of not changing the gas environment, the simulation of the extreme environment can be achieved without external other equipment. In addition, the environmental monitoring system is used to monitor the temperature and humidity in the test space, ensuring the real-time monitoring of the temperature and humidity during the environmental simulation process, without manual confirmation, and ensuring the safety of the test personnel. This meets the needs of the product under test during environmental testing and reduces test complexity and cost.

[0017] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 is a schematic structural diagram of a test box for simulating an environment provided by an embodiment of the present invention;

[0020] Figure 2 is a structural schematic diagram of a single-stage refrigeration system provided by an embodiment of the present invention;

[0021] Figure 3 is a structural schematic diagram of a cascade refrigeration system provided by an embodiment of the present invention;

[0022] Figure 4It is a schematic diagram of the working range of a single-stage refrigeration system and a cascade refrigeration system provided in an embodiment of the present invention.

[0023] Reference numerals:

[0024] 10- box; 11- test space; 12- work space; 20- single-stage refrigeration system; 30- cascade refrigeration system; 40- environmental monitoring system; 50- heating and humidification system; 60- circulation system;

[0025] 21-first compressor; 22-bypass condenser; 23-first filter; 24-first evaporator; 25-first throttling device; 26-second throttling device; 27-solenoid valve; 28-pressure controller; 29-temperature controller;

[0026] 31-second compressor; 32-water-cooled condenser; 33-second filter; 34-third throttling device; 35-plate heat exchanger; 36-oil separator; 37-pressure gauge; 38-ball valve;

[0027] 41-third compressor; 42-coil heat exchanger; 43-third filter; 44-fourth throttling device; 45-fifth throttling device; 46-third evaporator; 47-pressure relief valve; 48-expansion container; 49-sixth throttling device. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first", "second", "third", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] Figure 1FIG. 1 is a schematic diagram of a test box for simulating an environment provided by an embodiment of the present invention. Figure 1 As shown, the test box includes: a box body 10, a single-stage refrigeration system 20, a cascade refrigeration system 30, an environmental monitoring system 40 and a control system (not shown in the figure).

[0031] The housing 10 includes a connected test space 11 and a work space 12. The test space 11 is used to place the product to be tested. In the present invention, the product to be tested can be any product that needs to be tested in an extreme environment (such as nuclear power equipment). In one test, multiple products to be tested can usually be placed in the test space 11.

[0032] For example, the size of the box 10 can be D5000×W1500×H3300mm, the inner material of the box 10 is plastic-coated cold-rolled steel plate, the thickness of the box 10 is δ100mm (the insulation material is hard urethane foam), the bottom plate of the box 10 is strengthened by δ2mm, and the load is 600kg / m 2 (Evenly distribute the load), there are water tanks on the three sides of the bottom except the door, which can discharge the condensed water generated during the environmental simulation process out of the box in time. The door is a left and right double door, the door opening is 1500×2500mm wide and high, the opening size is 1500×2400mm, the sealing material is a silicone rubber sealing strip, and an anti-lock safety push rod is installed on the inside. There is a gas balance hole on the top of the box 10, and there are 2 φ100 diameter lead holes on the side of the box 10, which can be used to pass through the product electrical performance test equipment cable.

[0033] The environment monitoring system 40 is arranged in the test space 11, and is used to monitor the temperature and humidity in the test space 11. Optionally, the environment monitoring system 40 may have a display device to display the temperature and humidity in the test space 11 in real time. Accordingly, an observation window is arranged in the corresponding area of ​​the box 10, so that the tester can view the display device of the environment monitoring system 40 from the observation window.

[0034] Exemplarily, the observation window can be a multi-layer hollow tempered glass with an anti-dew and anti-frost electric heating film on the surface, which can ensure that the situation inside the box can be clearly observed during the test. The visible size is 400×500mm and is installed on the door.

[0035] In one embodiment, an electronic temperature and humidity sensor can be used in the environment monitoring system 40 to monitor the temperature and humidity to avoid poor diffusion of steam at low temperatures. The measurement range of humidity by the environment monitoring system 40 is 0% RH to 100% RH. In this way, it can be ensured that the environment monitoring system 40 can still accurately display humidity in extreme environments (including the first extreme environment and the second extreme environment) without failure to display or error reporting.

[0036] For example, the first extreme environment is a low temperature and low humidity environment, such as a temperature of 4.4°C and a humidity of 5%RH; the second extreme environment is a high temperature and high humidity environment, such as a temperature of 60°C and a humidity of 90%RH. The environmental monitoring system 40 measures humidity in a range of 0%RH to 100%RH, and can accurately display humidity in the first extreme environment and the second extreme environment.

[0037] The single-stage refrigeration system 20 and the cascade refrigeration system 30 are arranged in the working space 12. Since the testing space 11 and the working space 12 are two independent but connected spaces, the single-stage refrigeration system 20 and the cascade refrigeration system 30 can be isolated from the product to be tested.

[0038] The single-stage refrigeration system 20, the cascade refrigeration system 30, and the environment monitoring system 40 are electrically connected to the control system and are controlled by the control system.

[0039] When simulating the first extreme environment of the product to be tested, the control system first controls the single-stage refrigeration system 20 to turn on and the cascade refrigeration system 30 to turn off, so that the temperature and humidity in the test space 11 reach the intermediate critical environment; the control system then controls the single-stage refrigeration system 20 to turn off and the cascade refrigeration system 30 to turn on, so that the temperature and humidity in the test space 11 drop from the intermediate critical environment to the first extreme environment.

[0040] The two refrigeration systems are operated in stages, which solves the problem that one refrigeration system may not be able to simulate the first extreme environment. Moreover, before the temperature and humidity in the test space 11 reach the intermediate critical environment, since the cascade refrigeration system 30 is not working, only the evaporator of the single-stage refrigeration system 20 will frost. This ensures the heat exchange efficiency after the cascade refrigeration system 30 starts working, so that the temperature and humidity in the test space 11 continue to steadily drop to the first extreme environment, and the amount of frost on the evaporator of the cascade refrigeration system 30 is minimized. On the basis of not changing the gas environment, the simulation of the first extreme environment can be achieved without connecting other external equipment.

[0041] Optional, continue to refer to Figure 1 The test box further includes a heating and humidifying system 50. The heating and humidifying system 50 is disposed in the working space 12 and is electrically connected to the control system and is controlled by the control system.

[0042] When simulating the second extreme environment of the product to be tested, the control system controls the heating and humidification system 50 to start, so that the temperature and humidity in the test space 11 reach the second extreme environment.

[0043] In one embodiment, the heating and humidification system 50 may include a heater (such as an electric heater) and a humidifier (such as a humidification boiler, an evaporator, etc.). Optionally, the heater uses a stainless heating tube with stable thermal performance, which has the characteristics of long life and safe and reliable use; the humidifier shell is formed by processing stainless steel plate and wrapped with insulation material, and the water heating tube uses a stainless steel heating tube with good insulation performance and safety and reliability. The humidifier water supply system adopts an automatic control water pump lifting method; the humidification water supply adopts an automatic water replenishment system.

[0044] It should be noted that if the product to be tested needs to be tested in both the first extreme environment and the second extreme environment, then the product to be tested is first tested in the second extreme environment and then tested in the first extreme environment.

[0045] Optional, continue to refer to Figure 1 The test box further includes a circulation system 60 . The circulation system 60 is electrically connected to the control system and is used to achieve air exchange between the test space 11 and the work space 12 , and balance the air pressure inside and outside the box 10 .

[0046] Exemplarily, the circulation system 60 can be arranged in a temperature and humidity regulating air duct in the form of a single air duct, and the air path form is upper outlet and lower return. The partition between the test space 11 and the working space 12 is formed by cold bending of stainless steel plate, and the air outlet uses adjustable shutters of aluminum profiles with surface passivation treatment. The circulation system 60 may include circulating blast blades, motors, compressors, etc. Driven by the motor, the circulating blast blades homogenize the temperature field in the test space 11. Optionally, the motor adopts a long-lasting, safe and low-noise three-phase asynchronous motor, the motor shaft is a stainless steel long shaft, and the fan blade volute is CNC machined with good symmetry and consistency.

[0047] Optional, continue to refer to Figure 1 The test box also includes a safety protection system (not shown in the figure). The safety protection system is used to protect the test box, the product to be tested and the tester.

[0048] Exemplarily, the safety protection system has at least one of the following functions: 1) Leakage protection function: When a leakage fault occurs in the test box, the leakage circuit breaker automatically cuts off the power supply to ensure the personal safety of the tester; 2) Short circuit protection function: When a short circuit occurs in the circuit, the fuse in the circuit melts to prevent device damage; 3) Fan overload protection function: When the load of the circulating fan is too large and exceeds the rated current, the control circuit will be cut off to protect the circulating fan; 4) Independent over-temperature protection function: When the temperature in the test space 11 exceeds the set temperature, the control circuit will be cut off to protect the product to be tested in the test space 11 from damage and ensure the safety of the test box; 5) Phase sequence / phase loss protection function: When the incoming power supply is phase lost / reverse, the phase sequence protector cuts off the control circuit to prevent device damage ;6) Refrigeration machine overpressure / overload protection function: When the exhaust pressure of the compressor exceeds the set value, the pressure protection device will send a signal, indicating overpressure protection, and delayed shutdown; when the load of the compressor is too large and its loop current exceeds the set value, the thermal relay will send a signal, indicating compressor overheat protection, and delayed shutdown; 7) Cooling and water shortage protection function: When the cooling water is not turned on or the flow rate is lower than the safety value, the sensor sends a signal, indicating water shortage, and the refrigeration system cannot be started; 8) Humidification water shortage protection function: When the water level in the total water tank is lower than the minimum water level, the sensor sends a signal, indicating water shortage, and delayed shutdown; 9) Anti-dry burning protection function: When the humidifier lacks water due to a malfunction and the heating tube is dry-burned, the sensor sends a signal, the heating circuit will be cut off, protecting the device and ensuring the safety of the test box.

[0049] Figure 2 Schematic diagram of a single-stage refrigeration system provided by an embodiment of the present invention. Figure 2 As shown, the single-stage refrigeration system includes: a first compressor 21, a bypass condenser 22, a first filter 23, a first evaporator 24, a first throttling device 25 and a second throttling device 26.

[0050] The outlet end of the first compressor 21 is connected to the inlet end of the bypass condenser 22, the outlet end of the bypass condenser 22 is connected to the inlet end of the first filter 23, the outlet end of the first filter 23 is connected to the inlet end of the first throttling device 25 and the inlet end of the second throttling device 26 respectively; the outlet end of the first throttling device 25 is connected to the inlet end of the first evaporator 24, the outlet end of the second throttling device 26 and the outlet end of the first evaporator 24 are connected to the inlet end of the first compressor 21 respectively.

[0051] Optionally, a second throttling device 26 may be provided between the outlet end of the first compressor 21 and the inlet end of the first compressor 21 to control the flow rate on the refrigerant recovery passage. Accordingly, a solenoid valve 27 may be provided on the pipelines where the first throttling device 25 and the second throttling device 26 are provided.

[0052] Optionally, two solenoid valves 27 may be respectively provided at the outlet end of the first compressor 21 and the inlet end of the first compressor 21, respectively serving as an exhaust stop valve and a return air stop valve of the first compressor 21. The single-stage refrigeration system may also be provided with a pressure controller 28 and a temperature controller 29 to monitor the working condition of the first compressor 21.

[0053] In one embodiment, a first refrigerant is arranged in the first compressor 21; the pipeline from the outlet end of the first throttling device 25 to the inlet end of the first compressor 21, and the pipeline from the outlet end of the second throttling device 26 to the inlet end of the first compressor 21 are both wrapped with an insulation layer.

[0054] Figure 3 Schematic diagram of a cascade refrigeration system provided by an embodiment of the present invention. Figure 3 As shown, the cascade refrigeration system includes: a second compressor 31, a water-cooled condenser 32, a second filter 33, a third throttling device 34, a plate heat exchanger 35, a third compressor 41, a coil heat exchanger 42, a third filter 43, a fourth throttling device 44, a fifth throttling device 45 and a third evaporator 46.

[0055] The outlet end of the second compressor 31 is connected to the inlet end of the water-cooled condenser 32, the outlet end of the water-cooled condenser 32 is connected to the inlet end of the second filter 33, the outlet end of the second filter 33 is respectively connected to the inlet end of each third throttling device 34, the outlet end of each third throttling device 34 is respectively connected to the first end S1 of the plate heat exchanger 35, and the second end S2 of the plate heat exchanger 35 is connected to the inlet end of the second compressor 31.

[0056] The outlet end of the third compressor 41 is connected to the inlet end of the coil heat exchanger 42, the outlet end of the coil heat exchanger 42 is connected to the third end S3 of the plate heat exchanger 35, the fourth end S4 of the plate heat exchanger 35 is connected to the inlet end of the third filter 43, the outlet end of the third filter 43 is respectively connected to the inlet end of each fourth throttling device 44 and the inlet end of the fifth throttling device 45; the outlet end of a fourth throttling device 44 is connected to the inlet end of a third evaporator 46; the outlet end of each third evaporator 46 and the outlet end of the fifth throttling device 45 are respectively connected to the inlet end of the third compressor 41.

[0057] Optionally, the cascade refrigeration system also includes: a pressure relief valve 47, an expansion container 48 and a sixth throttling device 49; the inlet end of the expansion container 48 is connected to the outlet end of the coil heat exchanger 42, the outlet end of the expansion container 48 is connected to the inlet end of the sixth throttling device 49, and the outlet end of the sixth throttling device 49 is connected to the inlet end of the third compressor 41; the pressure relief valve 47 is arranged between the inlet end of the expansion container 48 and the outlet end of the coil heat exchanger 42.

[0058] In this way, when the pressure of the third compressor 41 is too high, the pressure can be released through the pressure relief valve 47 , and the released refrigerant is received by the expansion container 48 and the sixth throttling device 49 and transported back to the third compressor 41 .

[0059] Optionally, an oil separator 36 is connected between the outlet of the second compressor 31 and the inlet of the water-cooled condenser 32, and between the outlet of the coil heat exchanger 42 and the third end S3 of the plate heat exchanger 35, and the oil separator 36 is used to remove the oil component in the refrigerant. A ball valve 38 can be provided between the outlet of the second compressor 31 and the inlet of the second compressor 31, and a ball valve 38 can be provided between the outlet of the third compressor 41 and the inlet of the third compressor 41 to control the flow rate on the refrigerant recovery passage. Correspondingly, a solenoid valve 27 can be provided on the pipelines where the ball valve 38, the third throttling device 34, the fourth throttling device 44, and the fifth throttling device 45 are provided.

[0060] Optionally, the cascade refrigeration system may also be provided with a pressure controller 28 , a temperature controller 29 and a pressure gauge 37 to monitor the working conditions of the second compressor 31 and the third compressor 41 .

[0061] In one embodiment, a first refrigerant is arranged in the second compressor 31, and a second refrigerant is arranged in the third compressor 41, wherein the boiling point of the first refrigerant is higher than the boiling point of the second refrigerant; the pipeline from the second end S2 of the plate heat exchanger 35 to the inlet end of the second compressor 31, and the pipeline from the fourth end S4 of the plate heat exchanger 35 to the inlet end of the third compressor 41 are both wrapped with an insulation layer.

[0062] The model of the first refrigerant may be R404a, and the model of the second refrigerant may be R23.

[0063] In one embodiment, crankshaft heating may be provided in the first compressor 21, the second compressor 31, and the third compressor 41. The first to sixth throttling devices may be implemented by capillary tubes.

[0064] Figure 4 Schematic diagram of the working range of a single-stage refrigeration system and a cascade refrigeration system provided by an embodiment of the present invention. Figure 4As shown, the test box can simulate the first extreme environment by setting up two independent refrigeration systems (i.e., a single-stage refrigeration system and a cascade refrigeration system). Specifically, the working principle of the single-stage refrigeration system is as follows: the low-temperature and low-pressure refrigerant vapor generated in the first evaporator 24 is compressed by the first compressor 21, and the high-temperature and high-pressure refrigerant vapor generated enters the side tube condenser 22 through a pipeline, and is condensed into a low-temperature and high-pressure refrigerant liquid. This part of the liquid is depressurized by the first throttling device 25 to form a low-temperature and low-pressure refrigerant liquid that enters the first evaporator 24, absorbs the heat of the cooling material and vaporizes, and is then sucked in and compressed by the first compressor 21 to form a refrigeration cycle. The refrigerant undergoes four processes in the system: compression, condensation, expansion, and evaporation to complete a cycle, which is called a refrigeration cycle. Continuous refrigeration can be achieved through continuous circulation.

[0065] The cascade refrigeration system usually consists of a high-temperature part and a low-temperature part, each of which is a complete refrigeration cycle. The evaporation of the refrigerant in the high-temperature part is used to condense the refrigerant in the low-temperature part; the refrigerant in the low-temperature part absorbs heat and refrigerates when evaporating. The high-temperature part and the low-temperature part are connected by a plate heat exchanger 35, which is both an evaporator of the high-temperature part and a condenser of the low-temperature part. The heat absorbed by the refrigerant in the low-temperature part is transferred to the refrigerant in the high-temperature part through the plate heat exchanger 35, and the refrigerant in the high-temperature part releases the heat to the ambient medium (water or air) through the condenser in its own system.

[0066] The two refrigeration systems are operated in stages, which solves the problem that one refrigeration system may not be able to achieve the first extreme environment simulation, and the temperature and humidity in the test space 11 reach the intermediate critical environment (i.e. Figure 4 Before the working interval of the single-stage refrigeration system and the working interval of the cascade refrigeration system intersect, since the cascade refrigeration system 30 is not working, only the evaporator of the single-stage refrigeration system 20 will frost. Thus, the heat exchange efficiency after the cascade refrigeration system 30 starts to work is guaranteed, so that the temperature and humidity in the test space 11 continue to steadily drop to the first extreme environment, and the amount of frost on the evaporator of the cascade refrigeration system 30 is minimized. On the basis of not changing the gas environment, the simulation of the first extreme environment can be achieved without connecting other external equipment.

[0067] The embodiment of the present invention provides a test box for simulating an environment, comprising: a box body, a single-stage refrigeration system, a cascade refrigeration system, an environmental monitoring system and a control system; the box body comprises a connected test space and a workspace, the test space is used to place the product to be tested; the environmental monitoring system is arranged in the test space, and is used to monitor the temperature and humidity in the test space; the single-stage refrigeration system and the cascade refrigeration system are arranged in the workspace; the single-stage refrigeration system, the cascade refrigeration system and the environmental monitoring system are respectively electrically connected to the control system; when simulating the first extreme environment of the product to be tested, the control system first controls the single-stage refrigeration system to be turned on and the cascade refrigeration system to be turned off, so that the temperature and humidity in the test space reach the intermediate critical environment; the control system then controls the single-stage refrigeration system to be turned off and the cascade refrigeration system to be turned on, so that the temperature and humidity in the test space drop from the intermediate critical environment to the first extreme environment. The technical solution of the embodiment of the present invention is to design the structure of the test box so that the test box includes a box body, a single-stage refrigeration system, a cascade refrigeration system, an environmental monitoring system and a control system. The box includes a connected test space and a working space. The product to be tested is placed in the test space. The single-stage refrigeration system and the cascade refrigeration system are arranged in the working space to achieve isolation of the test area. Furthermore, when simulating the first extreme environment of the product to be tested, the single-stage refrigeration system works first. After the temperature and humidity in the test space reach the intermediate critical environment, the cascade refrigeration system works again until the temperature and humidity in the test space drop from the intermediate critical environment to the first extreme environment. The two refrigeration systems are operated in stages to solve the problem that one refrigeration system may not be able to achieve environmental simulation, and the amount of frost on the evaporator of the cascade refrigeration system is minimized. On the basis of not changing the gas environment, the simulation of extreme environments can be achieved without external other equipment. In addition, the environmental monitoring system is used to monitor the temperature and humidity in the test space, ensuring real-time monitoring of temperature and humidity during the environmental simulation process, without manual confirmation, and ensuring the safety of testers. Thereby meeting the needs of the product to be tested when conducting environmental testing and reducing the test complexity and test cost.

[0068] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A test box for simulating an environment, characterized in that: The test box comprises: a box body, a single-stage refrigeration system, a cascade refrigeration system, an environmental monitoring system and a control system; The box body includes a connected test space and a working space, the test space is used to place the product to be tested; the environmental monitoring system is arranged in the test space, and is used to monitor the temperature and humidity in the test space; the single-stage refrigeration system and the cascade refrigeration system are arranged in the working space; the single-stage refrigeration system, the cascade refrigeration system and the environmental monitoring system are electrically connected to the control system respectively; When simulating the first extreme environment of the product to be tested, the control system first controls the single-stage refrigeration system to turn on and the cascade refrigeration system to turn off, so that the temperature and humidity in the test space reach the intermediate critical environment; the control system then controls the single-stage refrigeration system to turn off and the cascade refrigeration system to turn on, so that the temperature and humidity in the test space drop from the intermediate critical environment to the first extreme environment.

2. The test box for simulating an environment according to claim 1, characterized in that: The single-stage refrigeration system comprises: a first compressor, a bypass condenser, a first filter, a first evaporator, a first throttling device and a second throttling device; The outlet end of the first compressor is communicated with the inlet end of the bypass condenser, the outlet end of the bypass condenser is communicated with the inlet end of the first filter, and the outlet end of the first filter is communicated with the inlet end of the first throttling device and the inlet end of the second throttling device respectively; The outlet end of the first throttling device is communicated with the inlet end of the first evaporator, and the outlet end of the second throttling device and the outlet end of the first evaporator are respectively communicated with the inlet end of the first compressor.

3. The test box for simulating an environment according to claim 2, characterized in that: A first refrigerant is disposed in the first compressor; The pipeline from the outlet end of the first throttling device to the inlet end of the first compressor, and the pipeline from the outlet end of the second throttling device to the inlet end of the first compressor are both wrapped with an insulation layer.

4. The test box for simulating an environment according to claim 1, characterized in that: The cascade refrigeration system comprises: a second compressor, a water-cooled condenser, a second filter, a third throttling device, a plate heat exchanger, a third compressor, a coil heat exchanger, a third filter, a fourth throttling device, a fifth throttling device and a third evaporator; The outlet end of the second compressor is communicated with the inlet end of the water-cooled condenser, the outlet end of the water-cooled condenser is communicated with the inlet end of the second filter, the outlet end of the second filter is respectively communicated with the inlet end of each of the third throttling devices, the outlet end of each of the third throttling devices is respectively communicated with the first end of the plate heat exchanger, and the second end of the plate heat exchanger is communicated with the inlet end of the second compressor; The outlet end of the third compressor is communicated with the inlet end of the coil heat exchanger, the outlet end of the coil heat exchanger is communicated with the third end of the plate heat exchanger, the fourth end of the plate heat exchanger is communicated with the inlet end of the third filter, and the outlet end of the third filter is respectively communicated with the inlet end of each fourth throttling device and the inlet end of the fifth throttling device; The outlet end of one of the fourth throttling devices is connected to the inlet end of one of the third evaporators; the outlet end of each of the third evaporators and the outlet end of the fifth throttling device are respectively connected to the inlet end of the third compressor.

5. The test box for simulating an environment according to claim 4, characterized in that: The cascade refrigeration system further comprises: a pressure relief valve, an expansion container and a sixth throttling device; The inlet end of the expansion container is communicated with the outlet end of the coil heat exchanger, the outlet end of the expansion container is communicated with the inlet end of the sixth throttling device, and the outlet end of the sixth throttling device is communicated with the inlet end of the third compressor; The pressure relief valve is disposed between the inlet end of the expansion container and the outlet end of the coil heat exchanger.

6. The test box for simulating an environment according to claim 4 or 5, characterized in that: A first refrigerant is arranged in the second compressor, and a second refrigerant is arranged in the third compressor, wherein a boiling point of the first refrigerant is higher than a boiling point of the second refrigerant; The pipeline from the second end of the plate heat exchanger to the inlet end of the second compressor and the pipeline from the fourth end of the plate heat exchanger to the inlet end of the third compressor are both wrapped with a thermal insulation layer.

7. The test box for simulating an environment according to claim 1, characterized in that: The environmental monitoring system measures humidity in the range of 0% RH to 100% RH.

8. The test box for simulating an environment according to claim 1, characterized in that: The test box also includes: a heating and humidification system; The heating and humidification system is arranged in the working space and is electrically connected to the control system; When simulating a second extreme environment for testing the product to be tested, the control system controls the heating and humidification system to start, so that the temperature and humidity in the test space reach the second extreme environment; The product to be tested is first tested under the second extreme environment, and then tested under the first extreme environment.

9. The test box for simulating an environment according to claim 1, characterized in that: The test box also includes: a circulation system; The circulation system is electrically connected to the control system, and is used to achieve air exchange between the test space and the working space, and balance the air pressure inside and outside the box.

10. The test box for simulating an environment according to claim 1, characterized in that: The test box also includes: a safety protection system; The safety protection system is used to protect the test box, the product to be tested and the tester.

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