An environmental simulation test device for high-temperature and high-pressure liquid level switch

Abstract

The present application belongs to the technical field of liquid level measurement, and particularly relates to an environmental simulation test device for a high-temperature and high-pressure liquid level switch. The device comprises a water tank, wherein the top of the water tank is connected with a cooler, the water tank is connected with a plunger pump, the plunger pump is connected with a second pressure stabilizer and one end of a regenerator, the other end of the regenerator is connected with a preheater through a pipeline and a valve, the preheater is connected with the pressure stabilizer, the pressure stabilizer is connected with a saturated water tank through a liquid level adjusting valve, the pressure stabilizer is connected with a back pressure adjusting valve, and the back pressure adjusting valve is connected with the cooler. The present application has the beneficial effects that it can meet the harsh working conditions of nuclear power sites, meet the operating environment of high-temperature and high-pressure saturated steam, continuously change and control the liquid level, and be suitable for simulation and test of various systems.

Description

Technical Field

[0001] This invention belongs to the field of liquid level measurement technology, specifically relating to an environmental simulation test device for a high-temperature and high-pressure liquid level switch. Background Technology

[0002] In nuclear power plants, a large number of level switches are used to accurately detect the liquid levels in various systems. The most common type is the float level switch, where the float's position changes with the liquid level. When the float rises or falls to a certain height, the switch activates and triggers an alarm. Therefore, level switches are extremely important for the safe operation of nuclear power plants. However, due to the high temperature and high pressure characteristics of the liquids in various nuclear power systems, level switches are highly susceptible to damage even during operation. Replacing these switches is not easy, and every opportunity for repair or replacement is extremely valuable. Therefore, environmental simulation tests are necessary to ensure the reliability and durability of the level switches.

[0003] Ordinary environmental simulation test devices cannot replicate the operating environment conditions of high-temperature and high-pressure liquid level switches, nor can they simulate the operation of high-temperature and high-pressure liquid level switches under special conditions, thus failing to guarantee the accuracy and effectiveness of the tests. Therefore, it is necessary to design corresponding environmental simulation test devices based on the actual operating environment of each system in a nuclear power plant, and to complete environmental simulation tests of the liquid level switches before their application at the nuclear power plant site.

[0004] High-temperature and high-pressure liquid level switches are widely used in nuclear power plants. However, due to their harsh operating conditions and stringent accuracy requirements, there is currently no suitable environmental simulation test device for their verification. Existing devices have the following shortcomings: 1) Nuclear power plant operating cycles are long, and ordinary environmental test devices are generally affected by environmental constraints and complex operating conditions, making it impossible to provide a high-temperature and high-pressure steam environment for extended periods. Furthermore, continuous liquid level changes lead to unstable temperature and pressure throughout the device, failing to meet the needs of long-term testing simulating the operating conditions of liquid level switches in the field. 2) Existing test devices are not designed specifically for nuclear power plant operating conditions; the operating conditions and interfaces of the entire equipment cannot match the testing requirements of various liquid level switches. 3) Existing test devices cannot accurately measure liquid levels under harsh conditions; ordinary calibration instruments and liquid level measuring instruments cannot calibrate and standardize the liquid level switches. 4) Existing devices cannot automatically measure the opening and closing of liquid level switch circuits under high-temperature and high-pressure environments. Therefore, a calibration device needs to be designed that can simulate the operating conditions of liquid level switches in the field, is fully adaptable to the field, and completes the verification work before the liquid level switches are put into operation. Summary of the Invention

[0005] The purpose of this invention is to provide an environmental simulation test device for high-temperature and high-pressure liquid level switches, which can meet the simulation test requirements of liquid level switches in the high-temperature and high-pressure saturated steam working environment of nuclear power plants. It can effectively reflect the usage environment of nuclear power sites and solve the problem that high-temperature and high-pressure liquid level switches cannot be used on-site due to verification difficulties.

[0006] The technical solution of the present invention is as follows: An environmental simulation test device for a high-temperature and high-pressure liquid level switch includes a water tank, a cooler connected to the top of the water tank, a plunger pump connected to the water tank, a second pressure regulator connected to one end of a regenerator connected to the plunger pump, the other end of the regenerator connected to a preheater via a pipeline and a valve, the preheater connected to a pressure regulator, the pressure regulator connected to a saturated water tank via a liquid level regulating valve, the pressure regulator connected to a back pressure regulating valve, and the pressure regulating valve connected to the cooler.

[0007] A pressure reducing valve is also installed on the pipeline between the preheater and the pressure regulator.

[0008] The back pressure regulating valve and the cooler are connected to the two ends of the regenerator through two separate pipes.

[0009] The saturated water tank is connected to a differential pressure level gauge.

[0010] The saturated water tank is equipped with three level switches.

[0011] The lower part of the saturated water tank is connected to a first liquid level switch.

[0012] A second liquid level switch is connected in the middle of the saturated water tank.

[0013] A third liquid level switch is connected to the upper part of the saturated water tank.

[0014] The beneficial effects of this invention are as follows: 1. It can meet the harsh operating conditions of nuclear power plant sites, satisfy the operating environment of high temperature and high pressure saturated steam, continuously change and control the liquid level, and is suitable for simulation and testing of various systems. 2. It has standard measuring instruments that can be compared and verified with the liquid level switch, and the test device meets the testing requirements of the liquid level switch, improving the accuracy of the entire test. 3. The entire device can automatically measure the opening and closing of the switch, requiring minimal human intervention during the entire test process, thus reducing the labor costs of the entire test and ensuring safety. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of an environmental simulation test device for a high-temperature and high-pressure liquid level switch provided by the present invention.

[0016] In the diagram: 1. Water tank, 2. Piston pump, 3. Regenerator, 4. Preheater, 5. Pressure reducing valve, 6. Saturated water tank, 7. Liquid level regulating valve, 8. Communicator, 9. Back pressure regulating valve, 10. Cooler, 11. Pressure stabilizer, 12. Second pressure stabilizer, 13. First liquid level switch, 14. Second liquid level switch, 15. Third liquid level switch, 16. Differential pressure level gauge. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] The maximum working pressure of the environmental simulation test device is 18MPa, and the maximum working temperature is 350℃.

[0019] like Figure 1 As shown, an environmental simulation test device for a high-temperature and high-pressure liquid level switch includes: a water tank 1, a plunger pump 2, a regenerator 3, a preheater 4, a pressure reducing valve 5, a saturated water tank 6, a liquid level regulating valve 7, a communicating vessel 8, a back pressure regulating valve 9, a cooler 10, a pressure stabilizer 11, a second pressure stabilizer 12, a first liquid level switch 13, a second liquid level switch 14, a third liquid level switch 15, and a differential pressure level gauge 16. The top of the water tank 1 is connected to the lower part of the cooler 10 via valves and pipes. The bottom of the water tank 1 is connected to the plunger pump 2 via pipes and valves. The plunger pump 2 is connected to the bottom of the second pressure stabilizer 12 and one end of the regenerator 3 via pipes and valves. The other end is connected to the preheater 4 through pipes and valves. The preheater 4 is connected to the bottom of the pressure regulator 11 through pipes and valves. A pressure reducing valve 5 is also installed on the pipe between the preheater 4 and the pressure regulator. The pressure regulator 11 is connected to the saturated water tank 6 through the liquid level regulating valve 7. The lower part of the saturated water tank 6 is connected to the first liquid level switch 13, the middle part is connected to the second liquid level switch 14, and the upper part is connected to the third liquid level switch 15. A differential pressure level gauge 16 is also connected to the saturated water tank 6. The top of the pressure regulator 11 is connected to the back pressure regulating valve 9 through pipes and valves. The back pressure regulating valve is connected to the cooler 10. The pipe between the back pressure regulating valve 9 and the cooler 10 is connected to both ends of the regenerator 3 through two pipes.

[0020] The working process of this invention is as follows:

[0021] Deionized water at normal temperature and pressure is pressurized from the normal water tank 1 by a plunger pump 2, while simultaneously recovering some heat from the high-temperature water at the cooler inlet for preheating, before entering the regenerator 3. A pressure regulator 11 ensures stable water pressure before entering the regenerator. The water in the regenerator 3 is heated to a high-temperature, high-pressure state by an electric heater in the preheater, ensuring the required temperature and pressure. A pressure reducing valve 5 lowers the pressure to the required working pressure under test conditions, converting the water into a mixture of saturated water and saturated vapor with a certain vapor content, which is then fed into the saturated water tank. Under gravity, a certain liquid level is formed in the downstream saturated water tank. The saturated water tank represents the liquid level in the simulated working system, and its level plane is kept consistent with the interface of the level switch via a communicating vessel principle. The container is equipped with a standard level gauge and the level switch to be tested. A downstream back pressure regulating valve stabilizes the pressure in the saturated water tank, ensuring that the simulated system operating conditions can be consistently met by the switch. By using a level regulating valve and adjusting the valve on the container's outlet pipe to control the liquid level changes within the container, the liquid level in the saturated water tank and the communicating vessel can be repeatedly raised and lowered, triggering the level switch to continuously operate and simulating long-term working conditions. The hot water eventually returns to the water tank after being cooled by the cooler, completing the liquid circulation throughout the entire test bench.

[0022] The container level is continuously measured using a differential pressure transmitter, and this measurement serves as a standard level parameter to validate the operation of the level switch. The differential pressure value measured by the transmitter is input to the analog input module of the controller. By measuring the pressure and temperature inside the container, the densities of water and vapor are calculated. Combining the differential pressure value and density, the standard level is calculated.

[0023] The level switch actuates in response to the rise and fall of the liquid level, converting the signal into an ON-OFF switching signal. This signal is then input to the controller's digital input module for measurement. The standard liquid level obtained from the differential pressure level gauge and the binary variable of the level switch can both be continuously stored, archived, and exported within the control system.

[0024] During or after the experiment, the standard liquid level value and the binary variable of the level switch over a period of time can be exported. Both have the same time coordinate. By determining the moment when the binary variable of the level switch changes from 0 to 1 or from 1 to 0, the standard liquid level value at that moment can be obtained. Finally, the standard liquid level can be compared with the set operating level of the level switch to determine the difference and verify the performance of the level switch under long-term operating conditions.

[0025] The entire experimental setup is mainly divided into two parts: The first part is a generator that simulates the actual working environment of the liquid level switch system measured on the conventional island of a nuclear power plant. The main design of the entire generator is to benchmark against the most severe operating conditions of the conventional island system, ensuring that the test product can operate smoothly under the harsh conditions of a nuclear power plant for an extended period. Products that can operate successfully under these conditions are those that meet the requirements. To ensure stable operation in this environment, multiple pressure stabilizing devices and circulation devices are installed. The second part tests the operation of the liquid level switch as the liquid level changes. To ensure the safety of the entire experimental process and avoid the risks of high-temperature, high-pressure steam, the entire setup uses more intelligent detection equipment. The entire recording process requires no manual intervention, automatically recording the switch's operating status and the actual liquid position, improving experimental efficiency and accuracy.

[0026] This invention relates to an environmental simulation test device for liquid level switches in the conventional island of nuclear power plants. Specifically designed for the operating conditions of liquid level switches in nuclear power plants, it meets the environmental requirements of high-temperature, high-pressure saturated steam. The simulated operating environment of the entire test device is consistent with the actual working environment of the liquid level switch, allowing the liquid level switches tested to be directly put into operation at the nuclear power plant site. The entire device features water and heat recycling, with a water and heat circulation system reducing energy consumption and system reaction time. It can automatically collect and record the operating status of the liquid level switch, using a standard liquid level gauge for comparison. Records for the entire test process are automatically generated, requiring minimal human intervention.

[0027] The simulation of temperature, pressure, and operating conditions of the high-temperature, high-pressure liquids in each system is fundamental to simulating the working environment of level switches in nuclear power plants. This device can control the temperature and pressure within the operating range of the level switch, matching the working environment of a nuclear power plant while not exceeding the limits that the level switch can withstand. It simulates the adjustment and changes in the high-temperature, high-pressure liquid levels in each system and the feedback signals caused by these changes. The device can adjust the position of the high-temperature, high-pressure liquid by regulating the valves in the container's outlet pipe and the cooling system. Simultaneously, the level switch's movement in response to the rise and fall of the liquid level can be converted into a switching signal, which is then statistically analyzed and measured through the digital input module of the controller. The level switch monitors the liquid level directly using a high-precision level gauge, whose accuracy is higher than that of the level switch itself. The actual liquid level position is used to compare and correct the actual operating condition of the level switch, features currently lacking in nuclear power plant level switch environmental simulation test devices.

Claims

1. An environmental simulation test device for a high-temperature and high-pressure liquid level switch, characterized in that: The system includes a water tank. The top of the water tank is connected to the lower part of the cooler, and the bottom of the water tank is connected to a plunger pump. The plunger pump is connected to the bottom of the second pressure regulator and one end of the regenerator. The other end of the regenerator is connected to a preheater, which is connected to the bottom of the first pressure regulator. A pressure reducing valve is installed on the pipeline between the preheater and the first pressure regulator. The first pressure regulator is connected to a saturated water tank through a liquid level regulating valve. The top of the first pressure regulator is connected to a back pressure regulating valve, which is connected to the cooler. The pipeline between the back pressure regulating valve and the cooler is connected to both ends of the regenerator through two separate pipelines. Deionized water at ambient temperature and pressure is pressurized from the water tank by the plunger pump, and simultaneously recovers some heat from the high-temperature water at the cooler inlet for preheating before entering the regenerator. The water in the regenerator is heated to a high temperature by the preheater. The high-pressure state ensures that the temperature and pressure meet the requirements. The pressure reducing valve lowers the pressure to the working pressure required by the test conditions, converting the water into a saturated water and saturated steam mixture with a certain vapor content, which is then input into the saturated water tank. A certain liquid level is formed in the downstream saturated water tank, which is the liquid level in the simulated working system. The liquid level regulating valve is used to adjust the valve of the container's outlet pipe to regulate the changes in the liquid level in the container, controlling the liquid level in the saturated water tank to rise and fall repeatedly, triggering the liquid level switch to work continuously, simulating long-term working conditions. The test device is divided into two parts: the first part is a device that simulates the actual working environment of the system measured by the liquid level switch on the conventional island of a nuclear power plant, and the second part is a device for testing the working condition of the liquid level switch as the liquid level changes.

2. The environmental simulation test device for a high-temperature and high-pressure liquid level switch as described in claim 1, characterized in that: The saturated water tank is connected to a differential pressure level gauge.

3. The environmental simulation test device for a high-temperature and high-pressure liquid level switch as described in claim 1, characterized in that: The saturated water tank is equipped with three level switches.

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