Method and system for detecting sealing performance of positive and negative pressure sealing equipment with high and low temperature circulation

Abstract

The invention discloses a high and low temperature circulation positive and negative pressure sealing equipment sealing performance detection method and system, and the method and system can test the sealing performance of equipment, a wireless pressure sensor is placed in to-be-detected sealing equipment, and the data of the sealing performance of the equipment in the environment is obtained through the change of the data of the wireless pressure sensor in the detection process. The system comprises a control system; a data storage and display system; a WeChat server; the controlled electromagnetic valves comprise a switching valve and a proportional valve; a controlled high temperature and high pressure generating device; a controlled low-temperature low-pressure refrigeration device; and the sealed environment box provides a test environment. The sealing performance test in normal temperature and high pressure, normal temperature and low pressure, high temperature and high pressure and low temperature and low pressure states can be realized through control, double-PID control during temperature reduction in the pressure maintaining test process in the high temperature and high pressure test environment is realized through a proportional valve, and control is relatively simple.

Description

Technical Field

[0001] The invention belongs to the technical field of sealing test, and the invention relates to a sealing detection method and system for positive and negative pressure sealing equipment with high and low temperature cycles. Background Art

[0002] The sealing test equipment with high and low temperature cycle function is a device used to evaluate the sealing performance of products in temperature changing environments. This equipment is usually used to test the sealing performance of boxes that need to be filled with nitrogen for long-term storage of special items, such as special chemicals, medicines, and cultural relics manuscripts, to ensure that they can still maintain good sealing performance under extreme temperature conditions.

[0003] At present, the sealing test equipment with high and low temperature cycle function can realize few test scenarios, generally only realizing low temperature / normal temperature alternating environment, the detection test has limitations, the function is not comprehensive, and it will also have a certain impact on the test results. And generally the control it realizes is relatively complex.

[0004] For example, the announcement number CN 116337368 discloses a method and system for testing the air tightness of gas cylinders in an ultra-low temperature / normal temperature alternating environment. The gas cylinder is placed in a liquid nitrogen tank and connected to a precooling coil placed in a precooling tank through a pipeline; the precooling coil is connected to a heat exchange coil through a pipeline, and the heat exchange coil is respectively connected to a high-pressure helium cylinder group, a medium-pressure helium cylinder group, and a low-pressure helium cylinder group C through pipelines; the precooling tank and the liquid nitrogen tank are both connected to a liquid nitrogen filling tank through pipelines, which can realize the test of the air tightness of gas cylinders in an ultra-low temperature / normal temperature alternating environment. It can only realize a low temperature / normal temperature alternating environment, and the control is relatively complex. Summary of the invention

[0005] The purpose of the present invention is to provide a method and system for detecting the sealing performance of positive and negative pressure sealing equipment with high and low temperature cycles, which can control and realize sealing performance testing under normal temperature and high pressure, normal temperature and low pressure, high temperature and high pressure, and low temperature and low pressure. A proportional valve is used to realize dual PID control when the temperature is reduced during the pressure holding test under a high temperature and high pressure test environment, and the control is relatively simple.

[0006] The technical solution to achieve the purpose of the present invention is:

[0007] A high and low temperature cycle positive and negative pressure sealing equipment sealing detection system, comprising:

[0008] Controlled high temperature and high pressure generating equipment, used to provide high temperature and high pressure gas and normal temperature and pressure gas to the sealed environment box, and circulate and heat the gas in the high pressure storage tank through the heater;

[0009] Controlled low temperature and low pressure generating equipment: Start the refrigerator, and circulate and refrigerate the gas in the sealed environment box through the circulation pump. When the refrigeration temperature reaches the lower limit, the vacuum pump will generate negative pressure to provide a low temperature and low pressure test environment for the sealed environment box. If the refrigerator is not started, a normal temperature and low pressure test environment will be provided for the sealed environment box.

[0010] A sealed environmental box, a box connected to the controlled high temperature and high pressure generating equipment, the controlled low temperature and low pressure generating equipment, and the external atmosphere, the box is provided with a temperature sensor and a pressure sensor for providing detection signals to the control system;

[0011] Controlled solenoid valves, including:

[0012] Switch valve A: a vent valve connecting the sealed environment box to the atmosphere;

[0013] Switch valve B: vent valve connecting the sealed environment box and the refrigerator;

[0014] Switch valve C: a vent valve connecting the sealed environment box to the high temperature and high pressure generating equipment;

[0015] Switch valve D: A switch valve located between the circulating pump U and the high-pressure storage tank in the high-temperature and high-pressure generating equipment;

[0016] Switch valve E: Switch valve connecting the compressor and the high-pressure storage tank;

[0017] Proportional valve Z: a ​​continuous regulating valve connecting the sealed environmental box and the refrigerator;

[0018] Proportional valve Y: a continuous regulating valve connecting the sealed environmental chamber and the heater;

[0019] Proportional valve X: a continuous regulating valve connected to the atmosphere of the sealed environment box;

[0020] Control system, used for control of switch valves, analog control of proportional valves, control of high temperature and high pressure generating equipment, control of low temperature and low pressure refrigeration equipment, calculation and transmission of sensor data, recording of QR code numbers of sealed equipment to be tested, and PID calculation of heating process and PID calculation of cooling process;

[0021] The data acquisition and storage system is installed with configuration software to display and set the current test environment data, display the current internal air pressure value of the tested equipment, store data, and transmit the absolute value data of the air pressure value change of the tested sealing equipment under the set temperature and pressure.

[0022] The preferred technical solution also includes:

[0023] The WeChat server is used to record the transmitted data and obtain the test environment information of the device and the leakage data of the sealed device in the test environment by scanning the QR code.

[0024] In the preferred technical solution, the controlled solenoid valve type also includes:

[0025] Circulation pump U: located in the controlled high temperature and high pressure generating equipment, connected to the high pressure storage tank and the heater;

[0026] Circulation pump V: located in the controlled low temperature and low pressure generating equipment, connected to the refrigerator and the sealed environmental box.

[0027] In the preferred technical solution, the controlled high temperature and high pressure generating device is used to provide two test environments, high temperature and high pressure and normal temperature and high pressure, to the sealed environmental box. The high pressure gas enters the high pressure storage tank through the compressor. When the gas pressure in the high pressure storage tank reaches the set pressure, the compressor and the switch valve E are closed;

[0028] If the test environment requires a high temperature and high pressure environment, the circulation pump U is turned on to circulate and heat the gas in the high pressure storage tank. The heating process is that the circulation pump drives the gas in the high pressure storage tank to flow through the heater and then returns to the high pressure storage tank. When a certain temperature is reached, the large flow gas heating is no longer performed.

[0029] If the test environment requires a normal temperature and high pressure environment, directly open the switch valve C and the proportional valve Y to control the gas flowing into the sealed environment box. If the set pressure is reached, close the switch valve C and the proportional valve Y.

[0030] The present invention also discloses a method for detecting the sealing performance of a positive and negative pressure sealing device with high and low temperature cycles, comprising the following steps:

[0031] S01: Input the QR code into the control system, and the control system records the code as the beginning of subsequent data;

[0032] S02: Place the sealed device to be tested into a sealed environmental chamber, place the wireless air pressure sensor in it, close the sealed device to be tested, and close the sealed environmental chamber; select the test environment on the test interface: high temperature and high pressure, normal temperature and high pressure, normal temperature and low pressure, low temperature and low pressure, and set parameters according to different test environments;

[0033] S03: If a high temperature and high pressure environment is selected, the control system starts the compressor and opens the switch valve E at the same time. The compressor presses the air into the high pressure storage tank. When the air pressure reaches the set value, the control system closes the compressor and the switch valve E.

[0034] The control system starts the circulation pump U, and simultaneously starts the heater and the switch valve D. Under the action of the circulation pump, the air in the high-pressure storage tank is heated. When the set temperature is reached, the heating is stopped.

[0035] Open the switch valve C and the proportional valve Y to allow the high-temperature and high-pressure gas to enter the sealed environment box at a certain rate. The control system sends different control quantities to the proportional valve to control the amount of hot air entering.

[0036] During the pressurization process of the sealed environment box, the control system records the pressure sensor data inside the sealed device to be tested, the temperature data and pressure data in the current sealed test box, and transmits them to the data acquisition and storage system at the same time;

[0037] When the pressure data reaches the set value, the pressure holding process begins, and the data of the wireless air pressure sensor placed in the current sealing device to be tested is recorded. If the temperature drops below the set temperature within the set time, the control system simultaneously opens proportional valve X and proportional valve Y to adjust the temperature and pressure in the sealed environment box;

[0038] When the test is completed, the control system calculates the average temperature and average pressure data of the entire insulation process, as well as the duration data within the set pressure range, the built-in wireless air pressure sensor data of the sealing device to be tested, and calculates the difference between its maximum value and the atmospheric pressure, and transmits the above data to the data acquisition and storage system;

[0039] S04: If the normal temperature and high pressure test environment is selected, the control system starts the compressor and opens the switch valve E at the same time. The compressor presses the air into the high pressure storage tank. When the air pressure reaches the set value, the control system closes the compressor and the switch valve E.

[0040] The control system opens the switch valve C and the proportional valve Y, allowing the normal temperature and high pressure gas to enter the sealed environment box at a certain rate. The control system sends different control quantities to the proportional valve to control the amount of air entering, so as to ensure the air pressure in the sealed environment box.

[0041] When the air pressure in the sealed environment box reaches the set value, the switch valve C and the proportional valve Y are closed, the pressure holding delay begins, and the data of the wireless pressure sensor placed in the sealed device to be tested is recorded;

[0042] When the test is completed, the control system calculates the highest pressure data of the whole process, as well as the duration data within the set pressure range, the built-in wireless air pressure sensor data of the sealing device to be tested, and calculates the difference between its maximum value and atmospheric pressure, and transmits the above data to the data acquisition and storage system;

[0043] S05: If the normal temperature and low pressure test environment is selected, the control system opens the switch valve B and the proportional valve Z, starts the vacuum pump, and evacuates the sealed environment box. When the required negative pressure condition is reached, the switch valve B and the proportional valve Z are closed, and the data of the wireless air pressure sensor built into the sealing device to be tested is recorded until the pressure holding process is completed; the control system calculates the above negative pressure data and duration, as well as the difference between the output of the negative pressure sensor and the atmospheric pressure, and transmits them to the data acquisition and storage system;

[0044] S06: If a low-temperature and low-pressure test environment is selected, the control system opens the switch valve B and the proportional valve Z, the circulation pump V and the refrigeration equipment. The circulation pump V continuously sends the air in the sealed environment box to the refrigeration equipment for cooling, and then flows back to the sealed environment box after cooling. During the continuous circulation process, the temperature in the sealed environment box continues to decrease until the temperature is lower than the required ambient temperature. At this time, the control system turns off the circulation pump V and turns on the vacuum pump to start evacuating the sealed environment box. When the air pressure in the sealed environment box is lower than the set value, the vacuum pump is turned off, and the data of the wireless air pressure sensor placed inside the sealed device to be tested is recorded during this process until the test is completed;

[0045] If the temperature in the sealed environment box exceeds the set temperature value during the test, the control system starts the circulation pump and controls the air flow sent to the refrigerator through the proportional valve Z to control the temperature in the sealed environment box until the temperature is lower than the set value, and then shuts down the refrigerator and the circulation pump;

[0046] S07: After the test is finished, the control system opens the switch valve A, so that the air pressure in the sealed environment box is the same as the external air pressure, the temperature in the sealed environment box is close to the external temperature, and the sealed environment box is opened.

[0047] In the preferred technical solution, the analog quantity sent by the control system to the proportional valve is obtained through PID operation, and the pressure value of the sealed environment box is controlled by controlling the opening of the proportional valve. The PID operation is as follows:

[0048]

[0049] Among them, Kp is the proportional coefficient, Ki is the integral coefficient, Kd is the differential coefficient, u(t) is the output control amount of PID, and e(t) is the deviation, that is, the difference between the air pressure data in the sealed environment box and the set value;

[0050] When PID is controlling high and low pressure processes, it is necessary to set the high pressure test process as the positive process of PID and the low pressure test process as the reverse process of PID.

[0051] The output of PID is calculated by DA in the control system, and finally sent to the corresponding proportional valve in the DA module with a standard transmission signal of 0-10V or 4-20mA, thereby completing the control of air pressure.

[0052] In the preferred technical solution, during the pressure-maintaining process in the high-temperature and high-pressure test environment, if the temperature drops below the set temperature within the set time, the control system simultaneously opens the proportional valve X and the proportional valve Y, and the PID operation of the proportional valve Y is performed with the temperature difference as input, and the PID operation of the proportional valve X is performed with the pressure difference as input.

[0053] Compared with the prior art, the present invention has the following significant advantages:

[0054] 1. It can control the sealing test under normal temperature and high pressure, normal temperature and low pressure, high temperature and high pressure and low temperature and low pressure. It can realize the test form of hot and cold cycle. It can be tested under the conditions of preset temperature, which meets the test mode of different temperature and pressure factors.

[0055] 2. By using a proportional valve to achieve dual PID control when the temperature is reduced during the pressure holding test under a high temperature and high pressure test environment, the control is relatively simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 The schematic diagram of the sealing detection system for positive and negative pressure sealing equipment with high and low temperature cycles;

[0057] Figure 2 This is the control system block diagram under normal temperature and high pressure environment;

[0058] Figure 3 This is the control system block diagram under high temperature and high pressure environment;

[0059] Figure 4 This is the control system block diagram under normal temperature and low pressure environment;

[0060] Figure 5 This is the control system block diagram in low temperature and low pressure environment;

[0061] Figure 6 This is a block diagram of a dual PID control system for reducing the temperature during the pressure holding process under high temperature and high pressure environment;

[0062] Figure 7 This is a block diagram of the control system for temperature rise during the pressure maintenance process in a low temperature and low pressure environment;

[0063] Figure 8 The present invention is a flow chart of a method for detecting the sealing performance of positive and negative pressure sealing equipment with high and low temperature cycles. DETAILED DESCRIPTION

[0064] The principle of the present invention is that it can control and realize sealing tests under normal temperature and high pressure, normal temperature and low pressure, high temperature and high pressure and low temperature and low pressure conditions, and use a proportional valve to realize dual PID control when the temperature is reduced during the pressure holding test under a high temperature and high pressure test environment, and the control is relatively simple.

[0065] Embodiment 1:

[0066] A high and low temperature cycle positive and negative pressure sealing equipment sealing detection system, the function of this system: This system is a sealing equipment sealing test system, the test system can realize the equipment sealing test under high temperature and high pressure, normal temperature and high pressure, normal temperature and low pressure, and low temperature and low pressure environments within a certain range. The test is carried out by placing a wireless pressure sensor inside the sealing equipment to be tested, and the data of the equipment sealing in this environment is obtained by the change of the wireless pressure sensor data during the detection process.

[0067] 1. If Figure 1 As shown, the composition of this system is: 1. Control system; 2. Data storage and display system; 3. WeChat server; 4. Controlled solenoid valves; 5. Controlled high temperature and high pressure generating equipment; 6. Controlled low temperature and low pressure refrigerator; 7. Sealed environmental box that provides test environment.

[0068] 1. Control system. The control system is composed of PLC, which can complete the control of switch valves, analog control of proportional valves, control of high temperature and high pressure generating equipment, control of low temperature and low pressure refrigerators, calculation and transmission of sensor data, QR code number recording of the sealed equipment to be tested, and PID calculation of heating process and PID calculation of cooling process;

[0069] 2. The data acquisition and storage system consists of a desktop or laptop computer installed with configuration software, which can display and set the current test environment data (the temperature and air pressure of the current test environment), display the current internal air pressure value of the device to be tested, and store data; it has the function of transmitting the absolute value of the air pressure change of the sealed device to be tested at the set temperature and pressure to the WeChat server (the data transmitted to the WeChat server include: the QR code of the currently tested sealing device, the highest or lowest temperature of the environment during the test, the highest or lowest pressure data, and the absolute value of the internal air pressure change of the sealing device).

[0070] 3. WeChat server, which can record the data transmitted by the above-mentioned devices. When using it, users only need to use their mobile phones to enter the WeChat public account and scan the QR code to obtain the test environment information of the device and the leakage status of the sealed device under the test environment;

[0071] 4. Controlled valves include: switch valves and proportional valves;

[0072] Switch valve A: a vent valve that connects the sealed environmental chamber to the atmosphere;

[0073] Switch valve B: vent valve connecting the sealed environment box and the refrigerator;

[0074] Switch valve C: a vent valve connecting the sealed environment box to the high temperature and high pressure generating equipment;

[0075] Switch valve D: A switch valve located between the circulation pump and the high-pressure storage tank in high-temperature and high-pressure generating equipment;

[0076] Switch valve E: Switch valve connecting the compressor and the high-pressure storage tank;

[0077] Proportional valve Z: a ​​continuous regulating valve connecting the sealed environmental box and the controlled low-temperature and low-pressure refrigerator;

[0078] Proportional valve Y: a continuous regulating valve connecting the sealed environmental chamber and the controlled high temperature and high pressure heating equipment;

[0079] Proportional valve X: a continuous regulating valve connected to the atmosphere of the sealed environment box;

[0080] Circulation pump U: Circulation pump in high temperature and high pressure equipment, connecting high pressure storage tank and heater;

[0081] Circulation pump V: Circulation pump in low temperature and low pressure equipment, connecting the refrigerator and the sealed environment box;

[0082] 5. Controlled high temperature and high pressure generating equipment: It can provide high temperature and high pressure gas and normal temperature and pressure gas to the sealed environment box; when the heater is turned on, the gas in the high pressure storage tank will be circulated and heated; when the heater is not turned on, there will be no heating effect, and the high temperature and high pressure generating equipment at this time is equivalent to a normal temperature and high pressure generating equipment;

[0083] 6. Controlled low temperature and low pressure generating equipment: It can complete the circulating refrigeration of the gas in the environmental box. The circulation process is driven by the circulating pump. When the refrigeration temperature reaches the lower limit, the vacuum pump starts to produce a negative pressure effect. If the refrigerator is turned on and the vacuum pump is started, the sealed environmental box can be provided with a low temperature and low pressure effect. If the refrigerator is not started, directly starting the vacuum pump can provide the sealed environmental box with a normal temperature and low pressure effect.

[0084] 7. Sealed environmental chamber: A box that can be connected to the controlled high temperature and high pressure generating equipment, low temperature and low pressure equipment, and the external atmosphere. The box has temperature sensors and pressure sensors to provide detection signals to the control system. During the detection process, the sealed equipment to be tested can be placed in the sealed environmental chamber for a certain period of time for sealing tests.

[0085] 2. Working principle of controlled high temperature and high pressure generating equipment

[0086] This part of the equipment can provide two test environments for the sealed environment box: high temperature and high pressure and normal temperature and high pressure. The high-pressure gas enters the high-pressure storage tank through the compressor. When the gas pressure in the high-pressure storage tank reaches the set pressure, the compressor and switch valve E will be closed;

[0087] If the test environment requires a high temperature and high pressure environment, turn on the circulation pump in the high temperature and high pressure equipment part to start circulating and heating the gas in the high pressure storage tank. The heating process is that the circulation pump drives the gas in the high pressure storage tank to flow through the heater and then returns to the high pressure storage tank. When a certain temperature is reached, large flow gas heating will no longer be performed.

[0088] If the test environment requires a normal temperature and high pressure environment, directly open the switch valve C and the proportional valve Y to control the gas flowing into the sealed environment box. If the set pressure is reached, close the switch valve C and the proportional valve Y.

[0089] 3. Working principle of controlled low temperature and low pressure equipment

[0090] This part of the equipment can provide two test environments, low temperature and low pressure and normal temperature and low pressure, to the sealed environment box. The low temperature and low pressure environment is achieved by starting the circulating pump of the refrigeration process through the equipment, allowing the air in the sealed environment box to flow through the refrigerator to complete the cooling process. When the temperature in the sealed environment box is lower than a certain value of the set temperature, the vacuum pump is started to evacuate the gas in the sealed environment box to generate negative pressure. When the negative pressure setting value is reached, the switch valve B and the proportional valve Y are closed.

[0091] 4. Description of the working process of the control system, such as Figure 8 As shown:

[0092] 1. First use a QR code scanner to input the QR code into the control system, which will record the code as the beginning of subsequent data;

[0093] 2. Place the sealed device to be tested in a sealed environmental chamber, place wireless air pressure sensors (air pressure positive pressure sensor and air pressure negative pressure sensor) in it, close the sealed device to be tested, and close the sealed environmental chamber;

[0094] 3. Select the test environment on the test interface: high temperature and high pressure, normal temperature and high pressure, normal temperature and low pressure, low temperature and low pressure;

[0095] 4. If you choose high temperature and high pressure environment, you need to set the parameters: maximum temperature (within 70 degrees Celsius), maximum pressure (within 1.0MPa); if you choose normal temperature and high pressure, you need to set the parameters: maximum pressure (within 1.0Mpa); if you choose normal temperature and low pressure, you need to set the parameters: minimum pressure (above 0.01Mpa); if you choose low temperature and low pressure, you need to set the parameters: minimum temperature (above -30 degrees Celsius), minimum pressure (above 0.01MPa);

[0096] 5. If you choose a high temperature and high pressure environment, such as Figure 3 As shown, the control system starts the compressor and opens the switch valve E at the same time. The compressor presses the air into the high-pressure storage tank. When the air pressure reaches the set value, the control system closes the compressor and the switch valve E.

[0097] 6. The control system starts the circulation pump U, and simultaneously starts the heater and the switch valve D. Under the action of the circulation pump, the air in the high-pressure storage tank is heated. When the set temperature is reached, the heating is stopped.

[0098] 7. Open the switch valve C and the proportional valve Y to allow the high-temperature and high-pressure gas to enter the sealed environment box at a certain rate. The control system sends different control quantities to the proportional valve to control the amount of hot air entering to ensure the air pressure in the sealed environment box.

[0099] 8. During the pressurization process of the sealed environment box, the pressure sensor data inside the sealed device to be tested will be recorded by the control system and transmitted to the data display and storage device. The temperature and pressure data in the current sealed test box are also recorded.

[0100] 9. When the pressure data reaches the set value, the pressure holding process begins, and the data of the wireless air pressure sensor placed in the sealing device to be tested is recorded at the same time. If the temperature drops below the set temperature within the set time, such as Figure 6 As shown, the control system will open proportional valve X and proportional valve Y at the same time. Proportional valve X is opened to release the gas with lower temperature, and proportional valve Y is opened to replenish the gas with higher temperature, thereby increasing the temperature in the sealed environment box and ensuring the pressure level in the whole process. The control amount of proportional valve Y and proportional valve X is calculated by the control system according to the set value.

[0101] 10. When the test is completed, the control system calculates the average temperature and average pressure data of the entire insulation process, as well as the time data within the set pressure range, the built-in wireless air pressure sensor data of the sealing device to be tested, and calculates the difference between its maximum value and the atmospheric pressure, and transmits the above data to the data storage and display device for storage and display.

[0102] 11. If you choose the normal temperature and high pressure test environment, such as Figure 2 As shown, the control system starts the compressor and opens the switch valve E at the same time. The compressor presses the air into the high-pressure storage tank. When the air pressure reaches the set value, the control system closes the compressor and the switch valve E.

[0103] 12. The control system opens the switch valve C and the proportional valve Y, allowing the normal temperature and high pressure gas to enter the sealed environment box at a certain rate. The control system sends different control quantities to the proportional valve, thereby controlling the amount of air entering to ensure the air pressure in the sealed environment box.

[0104] 13. When the air pressure in the sealed environment box reaches the set value, close the switch valve C and the proportional valve Y, and start the pressure maintenance delay. During this process, the data of the wireless pressure sensor placed in the sealed device to be tested will be recorded.

[0105] 14. When the test process is completed, the control system calculates the highest pressure data of the entire process, as well as the time data within the set pressure range, the built-in wireless air pressure sensor data of the sealing device to be tested, and calculates the difference between its maximum value and the atmospheric pressure, and transmits the above data to the data storage and display device for storage and display.

[0106] 15. If the normal temperature and low pressure test environment is selected, Figure 4 As shown, the control system opens the switch valve B and the proportional valve Z, starts the vacuum pump, and evacuates the sealed environment box. When the required negative pressure condition is reached, the switch valve B and the proportional valve Z are closed. During this process, the data of the wireless air pressure sensor built into the sealing device to be tested is recorded until the pressure holding process is completed; the control system calculates the above negative pressure data and duration, as well as the difference between the output of the negative pressure sensor and the atmospheric pressure, and transmits them to the data storage and display device for storage and display.

[0107] 16. If the low temperature and low pressure test environment is selected, Figure 5 As shown, the control system opens the switch valve B and the proportional valve Z, the circulation pump V and the refrigerator. The circulation pump V continuously sends the air in the sealed environment box into the refrigerator for cooling. After cooling, the air flows back into the sealed environment box. During the continuous circulation process, the temperature in the sealed environment box continues to decrease until the temperature is lower than the required ambient temperature. At this time, the control system turns off the circulation pump and turns on the vacuum pump to start vacuuming the sealed environment box. When the air pressure in the sealed environment box is lower than the set value, the vacuum pump is turned off. In this process, the data of the wireless air pressure sensor placed inside the sealed device to be tested is continuously recorded until the test is completed;

[0108] 17. If the test time is long, the temperature in the sealed environment box rises and exceeds the set temperature value. Figure 7 As shown, the control system starts the circulation pump and controls the air flow into the refrigerator through the proportional valve Z, thereby slowly controlling the temperature in the sealed environment box until the temperature is lower than the set value, and then shuts down the refrigerator and the circulation pump.

[0109] 18. If the above test is completed, the control system opens the switch valve A, so that the air pressure in the sealed environmental box is the same as the external air pressure, and the temperature in the sealed environmental box is close to the external temperature, so as to prepare for opening the sealed environmental box.

[0110] 6. Control system PID description

[0111] In the four test environments, proportional valves are used to accurately control the pressure in the sealed environment box. The analog value sent by the control system to the proportional valve is obtained by PID calculation. By controlling the opening of the proportional valve, the pressure value of the sealed environment box is controlled.

[0112]

[0113] Formula (1) is the mathematical description of PID, Kp is the proportional coefficient, Ki is the integral coefficient, Kd is the differential coefficient, u(t) is the output control quantity of PID, e(t) is the deviation, and its specific data is the difference between the air pressure data in the sealed environment box and the set value. Since high and low pressure are differences in two different directions, when PID controls high and low pressure, it is necessary to set the high pressure test process as the positive process of PID and the low pressure test process as the reverse process of PID.

[0114] The output of PID is calculated by DA in the control system, and finally sent to the corresponding proportional valve in the DA module with a standard transmission signal of 0-10V or 4-20mA, thereby completing the control of air pressure.

[0115] 7. Handling of temperature changes during testing

[0116] During the test, temperature changes occur in both high-temperature and low-temperature test states. In order to ensure the air pressure data, in the high-temperature test, if the temperature is lower than the set value under the pressure-maintaining state, the control system opens the proportional valve X connected to the sealed environmental box and the outside world and the proportional valve Y connected to the high-pressure storage tank. The PID operation of the proportional valve Y is calculated with the temperature difference as input, and the PID operation of the proportional valve X is calculated with the pressure difference as input. Figure 6 shown.

[0117] In low temperature tests, such as Figure 7 As shown, if the temperature rises under the pressure holding state and exceeds the set value, the control system starts the circulation pump and the refrigerator to perform circulation refrigeration under low pressure. When the temperature in the sealed environment box is lower than the set value again, the circulation pump and the refrigerator are turned off.

[0118] 8. Data transmitted by the control system

[0119] Before the test, the QR code of the sealing device to be tested is first input into the control system by scanning the QR code. The control system transmits the temperature and pressure data of the sealed environment box during the test and the data of the wireless air pressure positive pressure sensor and the wireless air pressure negative pressure sensor in the sealing device to be tested to the data storage and display device.

[0120] After the test is completed, the control system will calculate the parameters of the pressure holding process in the current environment: the average temperature and pressure during the pressure holding process, and the difference between the maximum output of the wireless air pressure sensor and the standard atmospheric pressure. This series of data will be stored in the WeChat server with a QR code as an index, so that subsequent users can scan and query the data in the WeChat public account.

[0121] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement modes and shall be included in the protection scope of the present invention.

Claims

1. A high and low temperature cycle positive and negative pressure sealing equipment sealing detection system, characterized in that: include: Controlled high temperature and high pressure generating equipment, used to provide high temperature and high pressure gas and normal temperature and pressure gas to the sealed environment box, and circulate and heat the gas in the high pressure storage tank through the heater; Controlled low temperature and low pressure generating equipment: Start the refrigerator, and circulate and refrigerate the gas in the sealed environment box through the circulation pump. When the refrigeration temperature reaches the lower limit, the vacuum pump generates negative pressure to provide a low temperature and low pressure test environment for the sealed environment box. If the refrigerator is not started, a normal temperature and low pressure test environment is provided for the sealed environment box. A sealed environmental box, a box connected to the controlled high temperature and high pressure generating equipment, the controlled low temperature and low pressure generating equipment, and the external atmosphere, the box is provided with a temperature sensor and a pressure sensor for providing detection signals to the control system; Controlled solenoid valves, including: Switch valve A: a vent valve connecting the sealed environment box to the atmosphere; Switch valve B: vent valve connecting the sealed environment box and the refrigerator; Switch valve C: a vent valve connecting the sealed environment box to the high temperature and high pressure generating equipment; Switch valve D: A switch valve located between the circulating pump U and the high-pressure storage tank in the high-temperature and high-pressure generating equipment; Switch valve E: Switch valve connecting the compressor and the high-pressure storage tank; Proportional valve Z: a ​​continuous regulating valve connecting the sealed environmental box and the refrigerator; Proportional valve Y: a continuous regulating valve connecting the sealed environmental chamber and the heater; Proportional valve X: a continuous regulating valve connected to the atmosphere of the sealed environment box; Control system, used for control of switch valves, analog control of proportional valves, control of high temperature and high pressure generating equipment, control of low temperature and low pressure refrigeration equipment, calculation and transmission of sensor data, recording of QR code numbers of sealed equipment to be tested, and PID calculation of heating process and PID calculation of cooling process; The data acquisition and storage system is installed with configuration software to display and set the current test environment data, display the current internal air pressure value of the tested equipment, store data, and transmit the absolute value data of the air pressure value change of the tested sealing equipment under the set temperature and pressure.

2. The high and low temperature cycle positive and negative pressure sealing equipment sealing detection system according to claim 1 is characterized in that: Also includes: The WeChat server is used to record the transmitted data and obtain the test environment information of the device and the leakage data of the sealed device in the test environment by scanning the QR code.

3. The high and low temperature cycle positive and negative pressure sealing equipment sealing detection system according to claim 1 is characterized in that: The controlled solenoid valve class also includes: Circulation pump U: located in the controlled high temperature and high pressure generating equipment, connected to the high pressure storage tank and the heater; Circulation pump V: located in the controlled low temperature and low pressure generating equipment, connected to the refrigerator and the sealed environmental box.

4. The high and low temperature cycle positive and negative pressure sealing equipment sealing detection system according to claim 3 is characterized in that: The controlled high temperature and high pressure generating equipment is used to provide two test environments, high temperature and high pressure and normal temperature and high pressure, to the sealed environment box. The high pressure gas enters the high pressure storage tank through the compressor. When the gas pressure in the high pressure storage tank reaches the set pressure, the compressor and the switch valve E are closed; If the test environment requires a high temperature and high pressure environment, the circulation pump U is turned on to circulate and heat the gas in the high pressure storage tank. The heating process is that the circulation pump drives the gas in the high pressure storage tank to flow through the heater and then returns to the high pressure storage tank. When a certain temperature is reached, the large flow gas heating is no longer performed. If the test environment requires a normal temperature and high pressure environment, directly open the switch valve C and the proportional valve Y to control the gas flowing into the sealed environment box. If the set pressure is reached, close the switch valve C and the proportional valve Y.

5. A method for detecting the sealing performance of positive and negative pressure sealing equipment with high and low temperature cycles, characterized in that: The following steps are involved: S01: Input the QR code into the control system, and the control system records the code as the beginning of subsequent data; S02: Place the sealed device to be tested into a sealed environmental chamber, place the wireless air pressure sensor in it, close the sealed device to be tested, and close the sealed environmental chamber; select the test environment on the test interface: high temperature and high pressure, normal temperature and high pressure, normal temperature and low pressure, low temperature and low pressure, and set parameters according to different test environments; S03: If a high temperature and high pressure environment is selected, the control system starts the compressor and opens the switch valve E at the same time. The compressor presses the air into the high pressure storage tank. When the air pressure reaches the set value, the control system closes the compressor and the switch valve E. The control system starts the circulation pump U, and simultaneously starts the heater and the switch valve D. Under the action of the circulation pump, the air in the high-pressure storage tank is heated. When the set temperature is reached, the heating is stopped. Open the switch valve C and the proportional valve Y to allow the high-temperature and high-pressure gas to enter the sealed environment box at a certain rate. The control system sends different control quantities to the proportional valve to control the amount of hot air entering. During the pressurization process of the sealed environment box, the control system records the pressure sensor data inside the sealed device to be tested, the temperature data and pressure data in the current sealed test box, and transmits them to the data acquisition and storage system at the same time; When the pressure data reaches the set value, the pressure holding process begins, and the data of the wireless air pressure sensor placed in the current sealing device to be tested is recorded. If the temperature drops below the set temperature within the set time, the control system simultaneously opens proportional valve X and proportional valve Y to adjust the temperature and pressure in the sealed environment box; When the test is completed, the control system calculates the average temperature and average pressure data of the entire insulation process, as well as the duration data within the set pressure range, the built-in wireless air pressure sensor data of the sealing device to be tested, and calculates the difference between its maximum value and the atmospheric pressure, and transmits the above data to the data acquisition and storage system; S04: If the normal temperature and high pressure test environment is selected, the control system starts the compressor and opens the switch valve E at the same time. The compressor presses the air into the high pressure storage tank. When the air pressure reaches the set value, the control system closes the compressor and the switch valve E. The control system opens the switch valve C and the proportional valve Y, allowing the normal temperature and high pressure gas to enter the sealed environment box at a certain rate. The control system sends different control quantities to the proportional valve to control the amount of air entering, so as to ensure the air pressure in the sealed environment box. When the air pressure in the sealed environment box reaches the set value, the switch valve C and the proportional valve Y are closed, the pressure holding delay begins, and the data of the wireless pressure sensor placed in the sealed device to be tested is recorded; When the test is completed, the control system calculates the highest pressure data of the whole process, as well as the duration data within the set pressure range, the built-in wireless air pressure sensor data of the sealing device to be tested, and calculates the difference between its maximum value and atmospheric pressure, and transmits the above data to the data acquisition and storage system; S05: If the normal temperature and low pressure test environment is selected, the control system opens the switch valve B and the proportional valve Z, starts the vacuum pump, and evacuates the sealed environment box. When the required negative pressure condition is reached, the switch valve B and the proportional valve Z are closed, and the data of the wireless air pressure sensor built into the sealing device to be tested is recorded until the pressure holding process is completed; the control system calculates the above negative pressure data and duration, as well as the difference between the output of the negative pressure sensor and the atmospheric pressure, and transmits them to the data acquisition and storage system; S06: If a low-temperature and low-pressure test environment is selected, the control system opens the switch valve B and the proportional valve Z, the circulation pump V and the refrigeration equipment. The circulation pump V continuously sends the air in the sealed environment box to the refrigeration equipment for cooling, and then flows back to the sealed environment box after cooling. During the continuous circulation process, the temperature in the sealed environment box continues to decrease until the temperature is lower than the required ambient temperature. At this time, the control system turns off the circulation pump V and turns on the vacuum pump to start evacuating the sealed environment box. When the air pressure in the sealed environment box is lower than the set value, the vacuum pump is turned off, and the data of the wireless air pressure sensor placed inside the sealed device to be tested is recorded during this process until the test is completed; If the temperature in the sealed environment box exceeds the set temperature value during the test, the control system starts the circulation pump and controls the air flow sent to the refrigerator through the proportional valve Z to control the temperature in the sealed environment box until the temperature is lower than the set value, and then shuts down the refrigerator and the circulation pump; S07: After the test is finished, the control system opens the switch valve A, so that the air pressure in the sealed environment box is the same as the external air pressure, the temperature in the sealed environment box is close to the external temperature, and the sealed environment box is opened.

6. The method for detecting the sealing performance of the positive and negative pressure sealing equipment with high and low temperature cycles according to claim 5 is characterized in that: The analog quantity sent by the control system to the proportional valve is obtained through PID operation. By controlling the opening of the proportional valve, the pressure value of the sealed environment box is controlled. The PID operation is as follows: Among them, K p is the proportionality coefficient, K i is the integration coefficient, K d is the differential coefficient, u(t) is the output control amount of PID, and e(t) is the deviation, that is, the difference between the air pressure data in the sealed environment box and the set value; When PID is controlling high and low pressure processes, it is necessary to set the high pressure test process as the positive process of PID and the low pressure test process as the reverse process of PID. The output of PID is calculated by DA in the control system, and finally sent to the corresponding proportional valve in the DA module with a standard transmission signal of 0-10V or 4-20mA, thereby completing the control of air pressure.

7. The method for detecting the sealing performance of the positive and negative pressure sealing equipment for high and low temperature cycles according to claim 5, characterized in that: During the pressure holding process in a high temperature and high pressure test environment, if the temperature drops below the set temperature within the set time, the control system opens proportional valve X and proportional valve Y at the same time. The PID operation of proportional valve Y is performed with the temperature difference as input, and the PID operation of proportional valve X is performed with the pressure difference as input.

Images