Comparison test method and system for testing sealing performance of valve by using water pressure and air pressure

Abstract

According to the comparison test method for testing the sealing performance of the valve by using the water pressure and the air pressure, different leakage opening degrees are designed for the test valve under different water pressure test pressure working conditions of the test valve; a water pressure drop method sealing test device and an air pressure flow method sealing test device are respectively used for carrying out a comparison sealing test on the same leakage opening degree to obtain different leakage rates of the water and the air medium under respective test pressures under the leakage opening degree, and finally, the leakage rate conversion relation of the water and the air medium under different test pressures is analyzed and obtained. The device is used for finding out the leakage rate conversion relation of water and gas media under different test pressures, and solves the problems that the leakage rate detected by a gas pressure flow method cannot directly reflect the valve leakage condition and is lack of acceptance standards.

Description

Technical Field

[0001] The invention relates to the technical field of valve sealing test detection and maintenance, and in particular to a comparative test method and system for testing valve sealing by using water pressure and air pressure. Background Art

[0002] Gate valves are widely used in nuclear power plants. They cut off and isolate fluids in the primary and secondary system pipelines of power plants. The sealing performance of valves directly affects the safe, reliable and economical operation of nuclear power plants. At present, the leakage problem of gate valves at the isolation boundary of domestic nuclear power plants is prominent, which poses a great hidden danger to the safe and reliable operation of nuclear power plants. According to the requirements of the preventive maintenance outline of the electric gate valves of the nuclear power M310 unit, during the shutdown and maintenance of the unit, it is necessary to conduct online sealing tests on the gate valves of the containment isolation boundary, penetrations and other systems to check whether their leakage or leakage rate meets the acceptance requirements, and to carry out relevant maintenance work in a targeted manner for valves with excessive leakage or leakage rate.

[0003] At present, the sealing test of gate valves in domestic nuclear power plants mostly adopts the middle cavity water pressure drop method, that is, when the valve is closed, the pressurized water medium is injected into the valve middle cavity through the middle cavity pressure hole (or packing purge hole) on the valve body, and the sealing performance of the gate valve is directly tested by the medium pressure drop. This method has real and intuitive results, high accuracy, and clear acceptance standards; but there is an exhaust problem. Incomplete exhaust affects the accuracy of the test, and it is difficult to completely exhaust the air. The test takes a long time, and the test medium needs to be pressurized by a water pump. The equipment is large in size and weight, and it is laborious to carry on site. The middle cavity air pressure flow method is a gate valve sealing test method that nuclear power plants have tried to adopt in recent years. The constant pressure compressed gas is injected into the gate valve middle cavity pressure hole through the pressure equipment through the mass flow meter. The medium flow rate (i.e. leakage rate) leaking from the valve per unit time can be directly obtained by the flow meter. This method has no problem of medium exhaust, high data accuracy, short test time, can use the compressed air in the plant, small size and weight of the device, and good portability; but there are problems such as the test medium is different from the system, the test pressure is different from the operating pressure, the detection leakage rate cannot directly reflect the valve leakage, and there is a lack of acceptance standards, and it needs to be converted from the water pressure test standard. The above two sealing test methods have their own advantages and disadvantages. In comprehensive comparison, the air pressure flow method is more advanced in technology and is worth promoting in nuclear power plants, but the water pressure drop method is also widely used in nuclear power plants. Summary of the invention

[0004] The purpose of the present invention is to provide a comparative test method and system for testing the sealing performance of valves by using water pressure and air pressure, so as to find out the leakage rate conversion relationship between water and air media under different test pressures, thereby solving the problem that the leakage rate detection by air pressure flow method cannot directly reflect the valve leakage situation and lacks acceptance standards.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A comparative test method for testing valve sealing by using water pressure and air pressure, under different water pressure test pressure conditions of the test valve, different leakage openings are designed for the test valve, and a comparative sealing test is carried out on the same leakage opening by using a water pressure drop method sealing test device and an air pressure flow method sealing test device, respectively, to obtain different leakage rates of water and air media under their respective test pressures under the leakage opening, and finally the leakage rate conversion relationship between water and air media under different test pressures is analyzed.

[0007] Furthermore, the comparative test method specifically includes:

[0008] Step 1: Determine the test parameters of the two test methods for sealing comparison test;

[0009] Step 2: Install the water pressure and air pressure valve sealing comparison detection system;

[0010] Step 3: Adjust the test valve, set the valve leakage opening, and keep the water pressure and air pressure inlet isolation valves of the test pipeline system closed;

[0011] Step 4: Start the water pressure drop method sealing test device. After the test valve has stable water flow, the water pressure device detects the pressure drop of the test valve and automatically calculates the water pressure leakage rate;

[0012] Step 5: Close the water pressure inlet isolation valve of the test pipeline system, start the air pressure flow method sealing test device, perform an air pressure sealing test, and obtain the air pressure leakage rate under the leakage opening;

[0013] Step 6: Adjust the test valve, set the test valve to another leakage opening, keep the water pressure test pressure unchanged, and repeat steps 4-6 until the test under this pressure is completed;

[0014] Step 7: Change the water pressure test pressure, adjust the test valve, set the valve leakage opening, and repeat test steps 4-6 until all comparative tests under all test pressures are completed;

[0015] Step 8: Perform data analysis on multiple groups of water pressure and air pressure leakage rates obtained under each water pressure test pressure to obtain the leakage rate conversion relationship between water and air media under the test pressure.

[0016] In step 1, the test parameters include test pressure, test medium temperature, test time and test leakage rate range.

[0017] In step 2, the water pressure outlet of the water pressure drop method sealing test device is connected to the water pressure inlet interface of the test pipeline system through a high-pressure hose, and the air pressure outlet of the gas flow method sealing test device is connected to the air pressure inlet interface of the test pipeline system through a hose.

[0018] In step 4, when the output pressure of the water pressure drop method sealing test device rises above the water pressure test pressure and remains stable, slowly open the water pressure inlet isolation valve and wait for the test valve to discharge water stably.

[0019] In step 5, open the air pressure inlet isolation valve, use compressed air to blow out the residual water inside the test valve and pipeline, adjust the output pressure of the device to the air pressure test pressure and keep it constant during the test, and then perform an air pressure sealing test.

[0020] A comparative test system for testing valve sealing performance using water pressure and air pressure, comprising:

[0021] The hydraulic test device is used to provide the required hydraulic test pressure to the test valve in the test pipeline system, and obtain the hydraulic test leakage rate of the valve by detecting the pressure drop of the test valve;

[0022] The air pressure test device is used to provide the required constant air pressure test pressure to the test valve in the test pipeline system, and obtain the air pressure test leakage rate of the valve by detecting the gas leakage flow of the test valve;

[0023] The test pipeline system includes a test valve for simulating leakage, a water pressure inlet isolation valve and a gas pressure inlet isolation valve, and provides test medium interfaces for two sealing test devices: a water pressure drop method and a gas pressure flow method.

[0024] Compared with the prior art, the comparative test method and system for testing valve sealing performance using water pressure and air pressure provided by the present invention has the following beneficial effects:

[0025] Under different water pressure test pressure conditions of the valve, different valve leakage openings are designed, and two test methods are used to carry out sealing pressure comparison tests on the same leakage opening, so as to obtain different leakage rates of water and gas media under their respective test pressures under the leakage opening. Finally, the leakage rate conversion relationship of water and gas media under different test pressures is analyzed, so as to solve the problems that the leakage rate detected by the air pressure flow method cannot directly reflect the valve leakage situation and there is a lack of acceptance standards, so as to facilitate the promotion and application of the air pressure flow method and the flexible selection of the two methods in power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for the technical description.

[0027] Figure 1 A flow chart of a comparative test method for testing valve sealing performance using water pressure and air pressure provided by the present invention;

[0028] Figure 2 A schematic diagram of a comparative test system for testing valve sealing performance using water pressure and air pressure provided by the present invention. DETAILED DESCRIPTION

[0029] The following is further explained in detail through specific implementation methods.

[0030] The present invention provides a comparative test method for testing the sealing performance of a valve by using water pressure and air pressure. Under different water pressure test pressure conditions (e.g., 13MPa, 4.2MPa, etc.) of the test valve, different leakage openings (e.g., 25l / h, 3.5l / h, etc.) are designed for the test valve, and a comparative sealing test is performed on the same leakage opening by using a water pressure drop method sealing test device and an air pressure flow method sealing test device, respectively, to obtain different leakage rates of water and air media under their respective test pressures under the leakage opening and a leakage rate conversion relationship between water and air media. The present invention is used to find out the leakage rate conversion relationship between water and air media under different test pressures, so as to facilitate the promotion and application of the air pressure flow method and the flexible selection of the two methods in power plants.

[0031] like Figure 1 As shown, the comparative test method provided by the present invention specifically comprises the following steps:

[0032] Step 1: Determine the test parameters of the two test methods for the sealing comparison test; the test parameters include test pressure, test medium temperature, test time and test leakage rate range.

[0033] Step 2: Install the water pressure and air pressure valve sealing comparison detection system, connect the water pressure outlet of the water pressure drop method sealing test device to the water pressure inlet interface of the test pipeline system through a high-pressure hose, and connect the air pressure outlet of the gas flow method sealing test device to the air pressure inlet interface of the test pipeline system through a hose.

[0034] Step 3: Adjust the test valve, set the valve leakage opening, and keep the water pressure and air pressure inlet isolation valves of the test pipeline system closed.

[0035] Step 4: Start the water pressure drop method sealing test device. When the output pressure of the water pressure drop method sealing test device rises above the water pressure test pressure and remains stable, slowly open the water pressure inlet isolation valve. After the test valve discharges water stably, the water pressure device detects the test valve pressure drop and automatically calculates the water pressure leakage rate (the leakage rate calculation formula is derived using the ideal state equation of gas and Boyle's law. The water pressure test leakage rate can be automatically calculated through the known test pressure, test time, accumulator airbag set pressure, set volume, and the pressure drop obtained from the test).

[0036] Step 5: Close the water pressure inlet isolation valve of the test pipeline system, start the air pressure flow method sealing test device, open the air pressure inlet isolation valve, use compressed air to blow out the residual water inside the test valve and pipeline as much as possible, adjust the output pressure of the device to the air pressure test pressure and keep it constant during the test, conduct an air pressure sealing test, and obtain the air pressure leakage rate under the leakage opening.

[0037] Step 6: Adjust the test valve, set the valve (test valve) to another leakage opening, keep the water pressure test pressure unchanged, and repeat steps 4-6 until the test at this pressure is completed.

[0038] Step 7: Change the water pressure test pressure, adjust the test valve, set the valve leakage opening, and repeat test steps 4-7 until all comparative tests under all test pressures are completed.

[0039] Step 8: Perform data analysis on multiple groups of water pressure and air pressure leakage rates obtained under each water pressure test pressure to obtain the leakage rate conversion relationship between water and air media under the test pressure.

[0040] Through the above steps, the leakage rate comparison data of water and air media under different water pressure test pressures and the leakage rate conversion relationship are shown in Table 1 below.

[0041] Table 1 Comparative data of leakage rate of water and gas medium and leakage rate conversion relationship

[0042]

[0043]

[0044] It can be seen from Table 1 that the leakage rates of water and gas media under different water pressure test pressures are in a linear relationship. The leakage rate of the known water medium can be converted into the leakage rate of the gas medium, which effectively solves the problem of the lack of acceptance standards for the gas pressure flow method and facilitates the flexible selection of the two methods in power plants.

[0045] In addition, if Figure 2As shown, the present invention also provides a comparative test system for testing the sealing performance of valves by using water pressure and air pressure, including a water pressure test device 1, an air pressure test device 2 and a test pipeline system 3. The water pressure test device 1 is used to provide the required water pressure test pressure to the test valve 3-1 in the test pipeline system, and obtain the water pressure test leakage rate of the valve by detecting the pressure drop of the test valve; the air pressure test device 2 is used to provide the required constant air pressure test pressure to the test valve 3-1 in the test pipeline system, and obtain the air pressure test leakage rate of the valve by detecting the gas leakage flow of the test valve; the test pipeline system is composed of a test valve 3-1 simulating leakage, a water pressure inlet isolation valve 3-2 and an air pressure inlet isolation valve 3-3, and provides test medium interfaces 3-4 and 3-5 of two sealing test devices, the water pressure drop method and the air pressure flow method.

[0046] The present invention starts with two sealing test methods (water pressure drop method and air pressure flow method) of the gate valve cavity, designs different valve leakage openings under different water pressure test pressure conditions of the test valve, adopts two test methods to perform sealing pressure comparison tests on the same leakage opening respectively, and obtains different leakage rates of water and air media under their respective test pressures under the leakage opening. Finally, the leakage rate conversion relationship of water and air media under different test pressures is analyzed to facilitate the promotion and application of the air pressure flow method.

[0047] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A comparative test method for testing valve sealing performance using water pressure and air pressure, characterized in that: Under different water pressure test pressure conditions of the test valve, different leakage openings are designed for the test valve. The same leakage opening is subjected to comparative sealing tests using a water pressure drop method sealing test device and an air pressure flow method sealing test device. The different leakage rates of water and air media under their respective test pressures under the leakage opening are obtained. Finally, the leakage rate conversion relationship between water and air media under different test pressures is analyzed and obtained.

2. The comparative test method for testing valve sealing performance by using water pressure and air pressure according to claim 1, characterized in that: The comparative test method specifically includes: Step 1: Determine the test parameters of the two test methods for sealing comparison test; Step 2: Install the water pressure and air pressure valve sealing comparison detection system; Step 3: Adjust the test valve, set the valve leakage opening, and keep the water pressure and air pressure inlet isolation valves of the test pipeline system closed; Step 4: Start the water pressure drop method sealing test device. After the test valve has stable water flow, the water pressure device detects the pressure drop of the test valve and automatically calculates the water pressure leakage rate; Step 5: Close the water pressure inlet isolation valve of the test pipeline system, start the air pressure flow method sealing test device, perform an air pressure sealing test, and obtain the air pressure leakage rate under the leakage opening; Step 6: Adjust the test valve, set the test valve to another leakage opening, keep the water pressure test pressure unchanged, and repeat steps 4-6 until the test under this pressure is completed; Step 7: Change the water pressure test pressure, adjust the test valve, set the valve leakage opening, and repeat test steps 4-7 until all comparative tests under all test pressures are completed; Step 8: Perform data analysis on multiple groups of water pressure and air pressure leakage rates obtained under each water pressure test pressure to obtain the leakage rate conversion relationship between water and air media under the test pressure.

3. The comparative test method for testing valve sealing performance by using water pressure and air pressure according to claim 2, characterized in that: In step 1, the test parameters include test pressure, test medium temperature, test time and test leakage rate range.

4. The comparative test method for testing valve sealing performance by using water pressure and air pressure according to claim 2, characterized in that: In step 2, the water pressure outlet of the water pressure drop method sealing test device is connected to the water pressure inlet interface of the test pipeline system through a high-pressure hose, and the air pressure outlet of the gas flow method sealing test device is connected to the air pressure inlet interface of the test pipeline system through a hose.

5. The comparative test method for testing valve sealing performance by using water pressure and air pressure according to claim 2, characterized in that: In step 4, when the output pressure of the water pressure drop method sealing test device rises above the water pressure test pressure and remains stable, slowly open the water pressure inlet isolation valve and wait for the test valve to discharge water stably.

6. The comparative test method for testing valve sealing performance by using water pressure and air pressure according to claim 2, characterized in that: In step 5, open the air pressure inlet isolation valve, use compressed air to blow out the residual water inside the test valve and pipeline, adjust the output pressure of the device to the air pressure test pressure and keep it constant during the test, and then perform an air pressure sealing test.

7. A comparative test system for testing valve sealing performance using water pressure and air pressure, characterized in that: include: The hydraulic test device is used to provide the required hydraulic test pressure to the test valve in the test pipeline system, and obtain the hydraulic test leakage rate of the valve by detecting the pressure drop of the test valve; The air pressure test device is used to provide the required constant air pressure test pressure to the test valve in the test pipeline system, and obtain the air pressure test leakage rate of the valve by detecting the gas leakage flow of the test valve; The test pipeline system includes a test valve for simulating leakage, a water pressure inlet isolation valve and a gas pressure inlet isolation valve, and provides test medium interfaces for two sealing test devices: a water pressure drop method and a gas pressure flow method.

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