A stop-check valve non-return leakage rate testing system and testing method

Abstract

The present invention relates to the field of valve technology, and more particularly to a stop-check valve non-return leakage rate testing system and testing method. The present invention provides a stop-check valve non-return leakage rate system, which meets the non-return sealing requirements when testing its operation in a shallow water area of ​​0-500mm and a deep water area of ​​several hundred meters, and measures the leakage rates in the shallow water area and the deep water area after life tests. The non-return leakage rate of deep water and shallow water stop-check valves is measured under the same system, and PLC control is adopted. The system integrates high-precision measurement of low pressure difference and a measurement method of pressure difference measurement by a pressure sensor, and realizes a high degree of automation of life tests. The problem of no pressure sensor with a suitable range in the shallow water test system is solved, and automatic data collection is realized. The leakage rate measured by the system is close to the actual working condition requirements and has high precision.

Description

Technical Field

[0001] The invention relates to the field of valve technology, and in particular to a system and method for testing the non-return leakage rate of a stop check valve. Background Art

[0002] A stop-check valve is a multi-purpose valve that has both stop valve and check valve functions. Its structure is similar to that of a stop valve, but the valve stem and valve disc are not fixedly connected. When the valve stem descends and presses the valve disc against the valve seat, it acts as a stop valve; when the valve stem rises, it acts as a check valve. On pipelines where both stop valves (or gate valves) and check valves need to be installed (such as the outlet of a water pump), or in places where the installation position is restricted (such as ships), the use of stop-check valves can save installation costs and space.

[0003] The stop check valve tested by this system is used in shallow water areas of 0-500mm and deep water areas of several hundred meters. The performance requirements of the stop check valve must meet the requirements of the non-return leakage rate under two different pressure conditions. At present, a test system is needed to detect the non-return performance and life of the stop check valve in shallow water areas and deep water areas. Therefore, a method and system that can simultaneously detect the non-return leakage rate of the stop check valve in deep water areas and shallow water areas is urgently needed. Summary of the invention

[0004] In order to solve the problems and shortcomings in the above-mentioned prior art, the present invention proposes a stop-check valve non-return leakage rate test system and detection method in shallow water areas of 0-500mm and deep water areas of several hundred meters.

[0005] Since the pressure sensor with a measurement range below 500mm cannot meet the accuracy of the pressure difference 1mm accuracy level at present, the shallow water check test in this paper adopts the water column method. However, for deep water tests at a depth of several hundred meters, the water column method has harsh conditions and unreasonable economic benefits. The pressure sensor at a depth of several hundred meters can meet the accuracy requirements. Therefore, this test method adopts the water column method for shallow water tests below half a meter, and the water column plus air pressure method for deep water tests at a depth of several hundred meters. An automatic control system is designed to automatically control the test set parameters through valves and test devices to achieve the purpose of the test.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows:

[0007] A stop-check valve non-return leakage rate test system comprises a forward medium electric valve 1, a water storage tank 17 and a nitrogen cylinder 24, wherein the forward medium electric valve 1 is connected to a flow meter 2, an exhaust valve group 3, a temperature sensor 4, a pressure sensor 5, a drain valve 6 and a collection valve 7 in sequence through pipelines, wherein the collection valve 7 is connected to one end of an electric stop-check valve 9, and the other end of the electric stop-check valve 9 is provided with two branches, one of which is connected to a discharge solenoid valve 12, and the other is connected to a shallow water tank 10 through a test water inlet solenoid valve 11, and a liquid level sensor 14 is provided on the diving tank 10; the water storage tank 17 is provided with two flow paths, one of which flows to the shallow water tank 10 through a water supply solenoid valve 15, and the other flows to the shallow water tank 10 through a water supply valve 16; the nitrogen cylinder 24 is connected to a pressure regulating tank 21 through an air supply solenoid valve 22 and an air supply hand valve 23 in sequence, and the pressure regulating tank 21 is connected to the shallow water tank 10 through a test air inlet solenoid valve 18.

[0008] Furthermore, a pressure sensor 19 and a regulating valve 20 are provided above the pressure stabilizing tank 21 .

[0009] Furthermore, a measuring cylinder 8 is provided below the collection valve 7 for measuring the liquid flowing out through the collection valve 7 .

[0010] Furthermore, the system is equipped with PLC control and counting is performed by PLC.

[0011] Furthermore, the height difference between the flange on the tested stop check valve 9 and the liquid level of the shallow water tank is 0-500 mm.

[0012] The present invention provides a method for testing the non-return leakage rate of a stop check valve with a depth of 0-500 mm, comprising the following steps:

[0013] A. Preparation: The test stop check valve 9 is electrically open, the forward fluid medium is ready, the drain valve 16 is opened to fill the shallow water tank with water, the water level of each water tank is at the normal level, and the gauge pressure of the nitrogen cylinder is 8MPa high;

[0014] B. Forward fluid medium opens stop check valve 9: valve 12 opens, the pressure behind stop check valve 9 is normal pressure, valve 1 opens after 10S, the forward fluid medium pushes the stop check valve open, flow meter 2 displays the flow, and records the flow after 5S, pressure 5 and temperature 4. After valve 1 is opened for 8S, the stop check valve opens, valve 1 is closed, and the pressure relief at the outlet behind stop check valve 9 is completed after a delay of 2S. Valve 12 is closed, valve 6 is opened for 5S, and the pressure relief and water discharge in front of stop check valve 9 provide conditions for the non-return test. The opening action is completed, and the counter statistics are not displayed;

[0015] C. After 10 seconds, reverse set water level check test: valve 13 is opened, the shallow water tank is connected to air, valve 11 is opened, and normal temperature water is injected into the stop check valve 9 in the reverse direction. Wait for the liquid level gauge 14 to send a signal that the liquid level reaches the set value. If the liquid level is lower than the set value, valve 15 is opened by a jog, and the water in the water storage tank 17 replenishes the liquid level of the shallow water tank 10. Wait for 5 seconds, the pressure is stable, and the stop check valve 9 completes the check action. When the check closing action is completed, the counter counts 1 time on / off

[0016] 100 on-off cycles constitute one group. After each group is completed, the test will be paused and a prompt tone will be sounded. The pressure will be maintained for 10 minutes to measure the leakage rate.

[0017] D. Leakage rate test with 10-minute pressure maintenance: Valve 7 is opened, and no water drips within 3 minutes, and the water in front of the stop check valve 9 is removed. Keep valve 7 open, place the measuring cylinder 8 at the drain outlet, valve 13 is opened, the shallow water tank is connected to air, valve 11 is opened, and normal temperature water is injected into the stop check valve 9 in the reverse direction, and the liquid level meter 14 sends a signal that the liquid level reaches the set value. If the liquid level is lower than the set value, valve 15 is opened in a jog motion, and the water in the water storage tank 17 replenishes the liquid level of the shallow water tank 10. Wait for 5S, the pressure is stable, and the stop check valve 9 completes the reverse action. After 10 minutes of timing, read the volume of water in the measuring cylinder and record it, and calculate the leakage rate according to the formula (the formula is: leakage rate = the volume of water in the measuring cylinder read in 10 minutes × (60 minutes / 10 minutes), the unit of leakage rate is m³ / h), and close valve 11;

[0018] E. After testing the leakage rate, click Continue, the counting continues, and operations B, C, and D are repeated every 10 seconds until the number of check times required by the test is reached.

[0019] The present invention provides a method for testing the non-return leakage rate of a deepwater stop check valve, comprising the following steps:

[0020] A. Preparation: The test stop check valve 9 is electrically open, the forward fluid medium is ready, the drain valve 16 is opened to fill the shallow water tank with water, the water level of each water tank is at the normal level, and the gauge pressure of the nitrogen cylinder is 8MPa high;

[0021] B. Forward fluid medium opens stop check valve 9: valve 12 opens, the pressure behind stop check valve 9 is normal pressure, valve 1 opens after 10S, the forward fluid medium pushes the stop check valve open, flow meter 2 displays the flow, and records the flow after 5S, pressure 5 and temperature 4. After valve 1 is opened for 8S, the stop check valve opens, valve 1 is closed, and the pressure relief at the outlet behind stop check valve 9 is completed after a delay of 2S. Valve 12 is closed, valve 6 is opened for 5S, and the pressure relief and water discharge in front of stop check valve 9 provide conditions for the non-return test. The opening action is completed, and the counter statistics are not displayed;

[0022] C. After 10 seconds, reverse the water level setting + nitrogen pressure, and test the non-return stop check valve 9:

[0023] Valve 11 is opened, and normal temperature water is injected into stop check valve 9 in the reverse direction. When liquid level meter 14 sends a signal that the liquid level reaches the set value, if the liquid level is lower than the set value, valve 15 is opened by a jog, and the water in water storage tank 17 replenishes the liquid level of shallow water tank 10. Valve 13 is closed, and the shallow water tank is sealed;

[0024] The valve 23 remains in the open state, the gas source is ready, and the pressure sensor 19 displays the set value in MPa. If the pressure is lower than the set value, the valve 22 is opened in a jog motion, and the nitrogen bottle 24 charges the pressure regulating tank 21. If the pressure exceeds the set value, an alarm is triggered, and the valve 20 is manually opened to exhaust and reduce the pressure, and the set pressure is re-established.

[0025] Open valve 18, reverse water column + nitrogen pressurization, check valve 9, after 2S, the pressure is stable, record the reading of pressure sensor 19, that is, the check pressure value, the valve closing action is completed, valve 18 is opened for 3S, the recording is completed, valve 18 is closed, count the opening / closing once, 100 switching cycles are a group, pause after each group is completed and issue a prompt sound, and do a leakage rate test by maintaining pressure for 10 minutes;

[0026] D. Reverse water column + nitrogen boost, non-return stop check valve 9, leakage rate measurement:

[0027] Valve 7 is opened, and no water drips within 3 minutes, and the water in front of the stop check valve 9 is removed. Keep valve 7 open, place the measuring cylinder 8 at the drain outlet; valve 11 is opened, and normal temperature water is injected into the stop check valve 9 in the reverse direction, and wait for the liquid level meter 14 to send a signal that the liquid level reaches the set value (if the liquid level is lower than the set value, valve 15 is opened in a jog, and the water in the water storage tank 17 replenishes the liquid level of the shallow water tank 10). Valve 13 is closed, and the shallow water tank is closed; valve 23 is kept open, and the gas source is ready. The pressure sensor 19 displays the set value in MPa. If the pressure is lower than the set value, valve 22 is opened in a jog, and the nitrogen bottle 24 is pressurized for the pressure regulating tank 21; if the pressure exceeds the set value, an alarm is issued, and valve 20 is manually opened to exhaust and reduce the pressure, and the set value pressure is re-established; valve 18 is opened, and the reverse water column + nitrogen is pressurized, and the stop check valve 9 is checked. After 10 minutes of timing, the volume of water in the measuring cylinder is read and recorded. Calculate the leakage rate according to the formula: leakage rate = the volume of water in the measuring cylinder read in 10 minutes × (60 minutes / 10 minutes), the unit of leakage rate is m³ / h, close valve 11;

[0028] E. After testing the leakage rate, click Continue, the counting continues, and operations B, C, and D are repeated every 10 seconds until the number of check times required by the test is reached.

[0029] Beneficial effects of the invention: The invention provides a stop check valve non-return leakage rate system, which meets the non-return sealing requirements when tested in shallow water areas of 0-500mm and deep water areas of several hundred meters, and measures the leakage rates in shallow water areas and deep water areas after life tests. The non-return leakage rate measurement of deep water and shallow water stop check valves is realized under the same system, and PLC control is adopted.

[0030] This system integrates the high-precision measurement of low pressure difference and the measurement method of pressure difference by pressure sensor, and realizes the high automation of life test. It solves the problem of no pressure sensor with suitable range in shallow water test system and realizes automatic data collection. The leakage rate measured by this system is close to the actual working condition requirements and has high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Attached Figure 1 This is a diagram of the stop check valve non-return leakage rate test system for this application.

[0032] Among them, the forward medium electric valve 1, the flow meter 2, the exhaust valve group 3, the temperature sensor 4, the pressure sensor 5, the drain valve 6, the collection valve 7, the measuring cylinder 8, the test stop check valve 9, the shallow water tank 10, the test water inlet solenoid valve 11, the discharge solenoid valve 12, the ventilation solenoid valve 13, the liquid level sensor 14, the water replenishment solenoid valve 15, the water supply valve 16, the water storage tank 17, the test air intake solenoid valve 18, the pressure sensor 19, the regulating valve 20, the pressure regulating tank 21, the air replenishment solenoid valve 22, the air replenishment manual valve 23, and the nitrogen cylinder 24. DETAILED DESCRIPTION

[0033] Example 1.

[0034] A stop-check valve non-return leakage rate test system comprises a forward medium electric valve 1, a water storage tank 17 and a nitrogen cylinder 24, wherein the forward medium electric valve 1 is connected to a flow meter 2, an exhaust valve group 3, a temperature sensor 4, a pressure sensor 5, a drain valve 6 and a collection valve 7 in sequence through pipelines, wherein the collection valve 7 is connected to one end of an electric stop-check valve 9, and the other end of the electric stop-check valve 9 is provided with two branches, one of which is connected to a discharge solenoid valve 12, and the other is connected to a shallow water tank 10 through a test water inlet solenoid valve 11, and a liquid level sensor 14 is provided on the diving tank 10; the water storage tank 17 is provided with two flow paths, one of which flows to the shallow water tank 10 through a water supply solenoid valve 15, and the other flows to the shallow water tank 10 through a water supply valve 16; the nitrogen cylinder 24 is connected to a pressure regulating tank 21 through an air supply solenoid valve 22 and an air supply hand valve 23 in sequence, and the pressure regulating tank 21 is connected to the shallow water tank 10 through a test air inlet solenoid valve 18.

[0035] A pressure sensor 19 and a regulating valve 20 are arranged above the pressure stabilizing tank 21 .

[0036] A measuring cylinder 8 is provided below the collection valve 7 for measuring the liquid flowing out through the collection valve 7 .

[0037] Example 2. Method for determining leakage rate in shallow water non-return test.

[0038] A. Preparation: The test stop check valve 9 is electrically open, the forward fluid medium is ready, the drain valve 16 is opened to fill the shallow water tank with water, the water level in the shallow water tank reaches the set value, the water level in the water storage tank is within the set range, and the gauge pressure of the nitrogen cylinder is 8MPa high;

[0039] B. Forward fluid medium opens stop check valve 9: valve 12 opens, the pressure behind stop check valve 9 is normal pressure, valve 1 opens after 10S, the forward fluid medium pushes the stop check valve open, flow meter 2 displays the flow, and records the flow after 5S, pressure 5 and temperature 4 are recorded, valve 1 opens for 8S, the stop check valve opens, valve 1 closes, and the pressure relief at the outlet behind stop check valve 9 is completed after 2S, valve 12 closes, valve 6 opens for 5S, the pressure relief and water discharge in front of stop check valve 9 are discharged, providing conditions for the non-return test, the opening action is completed, and the counter statistics are not displayed; the forward medium is fresh water, sea water, etc.;

[0040] C. After 10 seconds, reverse set water level check test: valve 13 is opened, the shallow water tank is connected to air, valve 11 is opened, and normal temperature water is injected into the stop check valve 9 in the reverse direction. Wait for the liquid level gauge 14 to send a signal that the liquid level reaches the set value. If the liquid level is lower than the set value, valve 15 is opened by a jog, and the water in the water storage tank 17 replenishes the liquid level of the shallow water tank 10. Wait for 5 seconds, the pressure is stable, and the stop check valve 9 completes the check action. When the check closing action is completed, the counter counts 1 time on / off

[0041] 100 on-off cycles constitute one group. After each group is completed, the test will be paused and a prompt tone will be sounded. The pressure will be maintained for 10 minutes to measure the leakage rate.

[0042] D. Leakage rate test with 10-minute pressure maintenance: Valve 7 is opened, and no water drips within 3 minutes, and the water in front of the stop check valve 9 is removed. Keep valve 7 open, place the measuring cylinder 8 at the drain outlet, valve 13 is opened, the shallow water tank is connected to air, valve 11 is opened, and normal temperature water is injected into the stop check valve 9 in the reverse direction, and wait for the liquid level gauge 14 to send a signal that the liquid level reaches the set value. If the liquid level is lower than the set value, valve 15 is opened in a jog motion, and the water in the water storage tank 17 replenishes the liquid level of the shallow water tank 10. Wait for 5S, the pressure is stable, and the stop check valve 9 completes the non-return action. After 10 minutes of timing, read the volume of water in the measuring cylinder and record it, and calculate the leakage rate according to the formula. The formula is: leakage rate = the volume of water in the measuring cylinder read in 10 minutes × (60 minutes / 10 minutes), the unit of leakage rate is m³ / h, and close valve 11;

[0043] E. After testing the leakage rate, click Continue, the counting continues, and operations B, C, and D are repeated every 10 seconds until the number of check times required by the test is reached.

[0044] Embodiment 3: A method for testing the non-return leakage rate of a stop-check valve in deep water areas.

[0045] A. Preparation: The test stop check valve 9 is electrically open, the forward fluid medium is ready, the drain valve 16 is opened to fill the shallow water tank with water, the water level in the shallow water tank reaches the set value, the water level in the water storage tank is within the set range, and the gauge pressure of the nitrogen cylinder is 8MPa high;

[0046] B. Forward fluid medium opens stop check valve 9: valve 12 opens, the pressure behind stop check valve 9 is normal pressure, valve 1 opens after 10S, the forward fluid medium pushes the stop check valve open, flow meter 2 displays the flow, and records the flow after 5S, pressure 5 and temperature 4 are recorded, valve 1 opens for 8S, the stop check valve opens, valve 1 closes, and the pressure relief at the outlet behind stop check valve 9 is completed after 2S, valve 12 closes, valve 6 opens for 5S, the pressure relief and water discharge in front of stop check valve 9 are discharged, providing conditions for the non-return test, the opening action is completed, and the counter statistics are not displayed; the forward medium is fresh water, sea water, etc.;

[0047] C. After 10 seconds, reverse the water level setting + nitrogen pressure, and test the non-return stop check valve 9:

[0048] Valve 11 is opened, and normal temperature water is injected into stop check valve 9 in the reverse direction. When liquid level meter 14 sends a signal that the liquid level reaches the set value, if the liquid level is lower than the set value, valve 15 is opened by a jog, and the water in water storage tank 17 replenishes the liquid level of shallow water tank 10. Valve 13 is closed, and the shallow water tank is sealed;

[0049] The valve 23 remains in the open state, the gas source is ready, and the pressure sensor 19 displays the set value in MPa. If the pressure is lower than the set value, the valve 22 is opened in a jog motion, and the nitrogen bottle 24 charges the pressure regulating tank 21. If the pressure exceeds the set value, an alarm is triggered, and the valve 20 is manually opened to exhaust and reduce the pressure, and the set pressure is re-established.

[0050] Open valve 18, reverse water column + nitrogen pressurization, check valve 9, after 2S, the pressure is stable, record the reading of pressure sensor 19, that is, the check pressure value, the valve closing action is completed, valve 18 is opened for 3S, the recording is completed, valve 18 is closed, count the opening / closing once, 100 switching cycles are a group, pause after each group is completed and issue a prompt sound, and do a leakage rate test by maintaining pressure for 10 minutes;

[0051] D. Reverse water column + nitrogen boost, non-return stop check valve 9, leakage rate measurement:

[0052] Valve 7 is opened, and no water drips within 3 minutes, and the water in front of the stop check valve 9 is removed. Keep valve 7 open, place the measuring cylinder 8 at the drain outlet; valve 11 is opened, and normal temperature water is injected into the stop check valve 9 in the reverse direction, and wait for the liquid level meter 14 to send a signal that the liquid level reaches the set value (if the liquid level is lower than the set value, valve 15 is opened in a jog, and the water in the water storage tank 17 replenishes the liquid level of the shallow water tank 10). Valve 13 is closed, and the shallow water tank is closed; valve 23 is kept open, and the gas source is ready. The pressure sensor 19 displays the set value in MPa. If the pressure is lower than the set value, valve 22 is opened in a jog, and the nitrogen bottle 24 is pressurized for the pressure regulating tank 21; if the pressure exceeds the set value, an alarm is issued, and valve 20 is manually opened to exhaust and reduce the pressure, and the set value pressure is re-established; valve 18 is opened, and the reverse water column + nitrogen is pressurized, and the stop check valve 9 is checked. After 10 minutes of timing, the volume of water in the measuring cylinder is read and recorded. Calculate the leakage rate according to the formula: leakage rate = the volume of water in the measuring cylinder read in 10 minutes × (60 minutes / 10 minutes), the unit of leakage rate is m³ / h, close valve 11;

[0053] E. After testing the leakage rate, click Continue, the counting continues, and operations B, C, and D are repeated every 10 seconds until the number of check times required by the test is reached.

Claims

1. A stop check valve non-return leakage rate test system, comprising a forward medium electric valve (1), a water storage tank (17) and a nitrogen cylinder (24), characterized in that: The forward medium electric valve (1) is connected to the flow meter (2), the exhaust valve group (3), the temperature sensor (4), the first pressure sensor (5), the drain valve (6), and the collection valve (7) in sequence through pipelines. The collection valve (7) is connected to one end of the test stop check valve (9). The other end of the test stop check valve (9) is provided with two branches, one of which is connected to the discharge electromagnetic valve (12), and the other is connected to the shallow water tank (10) through the test water inlet electromagnetic valve (11). The box (10) is provided with a ventilation solenoid valve (13) and a liquid level sensor (14); the water storage tank (17) is provided with two flow paths, one of which flows to the shallow water tank (10) through the water supply solenoid valve (15), and the other flows to the shallow water tank (10) through the water supply valve (16); the nitrogen cylinder (24) is connected to the pressure regulating tank (21) through the air supply solenoid valve (22) and the air supply manual valve (23) in sequence, and the pressure regulating tank (21) is connected to the shallow water tank (10) through the test air intake solenoid valve (18).

2. A stop-check valve non-return leakage rate testing system according to claim 1, characterized in that: A second pressure sensor (19) and a regulating valve (20) are arranged above the pressure stabilizing tank (21).

3. A stop-check valve non-return leakage rate testing system according to claim 1, characterized in that: A measuring cylinder (8) is provided below the collection valve (7) and is used to measure the liquid flowing out through the collection valve (7).

4. A stop-check valve non-return leakage rate testing system according to claim 1, characterized in that: This system is equipped with PLC control and counting is done through PLC.

5. A stop-check valve non-return leakage rate testing system according to claim 1, characterized in that: The height difference between the flange on the tested stop check valve (9) and the liquid level in the shallow water tank (10) is 0-500 mm.

6. A method for testing the non-return leakage rate of a stop check valve at a depth of 0-500 mm, using the test system according to any one of claims 1-5, characterized in that: It includes the following steps: A. Preparation: The stop check valve (9) under test is electrically opened, the forward fluid medium is ready, the water supply valve (16) is opened to fill the shallow water tank (10), the water level in the shallow water tank (10) reaches the set value, the water level in the water storage tank (17) is within the set range, and the gauge pressure of the nitrogen cylinder (24) is 8 MPa higher; B. The positive fluid medium opens the stop check valve (9) under test: the discharge solenoid valve (12) opens, and the pressure behind the stop check valve (9) under test is normal. After 10 seconds, the positive fluid medium electric valve (1) opens, and the stop check valve (9) under test is pushed open by the positive fluid medium. The flow meter (2) displays the flow rate. After 5 seconds, the flow rate is recorded, and the pressure and temperature are recorded. After the positive fluid medium electric valve (1) opens for 8 seconds, the opening action of the stop check valve (9) under test is completed. The positive fluid medium electric valve (1) closes, and the pressure relief at the outlet behind the stop check valve (9) under test is completed after a delay of 2 seconds. The discharge solenoid valve (12) is closed, and the drain valve (6) is opened for 5 seconds. The pressure relief and drainage in front of the stop check valve (9) under test are drained, providing conditions for the non-return test. The opening action is completed, and the counter statistics are not displayed. C. After 10 seconds, reverse set water level check test: the ventilation solenoid valve (13) is opened, the shallow water tank (10) is connected to air, the test water inlet solenoid valve (11) is opened, and normal temperature water is injected into the test stop check valve (9) in the reverse direction. When the liquid level sensor (14) sends a signal that the liquid level reaches the set value, if the liquid level is lower than the set value, the water replenishment solenoid valve (15) is opened by jogging, and the water in the water storage tank (17) replenishes the liquid level of the shallow water tank (10). Wait for 5 seconds, the pressure is stable, and the check action of the test stop check valve (9) is completed. When the check closing action is completed, the counter counts 1 opening / closing. 100 opening and closing cycles constitute a group. After each group is completed, a pause is made and a prompt sound is sounded. The pressure is maintained for 10 minutes to measure the leakage rate. D. Leakage rate test with 10-minute pressure maintenance: The sampling valve (7) is opened until no water drops within 3 minutes, and the water in front of the test stop check valve (9) is drained; the sampling valve (7) is kept open, and the measuring cylinder (8) is placed at the drain port. The ventilation solenoid valve (13) is opened, and the shallow water tank (10) is connected to air. The test water inlet solenoid valve (11) is opened, and normal temperature water is injected into the test stop check valve (9) in the reverse direction. When the liquid level sensor (14) sends a signal that the liquid level reaches the set value, if When the liquid level is lower than the set value, the water replenishment solenoid valve (15) is opened by jogging, and the water in the water storage tank (17) replenishes the liquid level of the shallow water tank (10). After waiting for 5 seconds, the pressure is stable, and the non-return action of the test stop check valve (9) is completed. After timing for 10 minutes, the volume of water in the measuring cylinder (8) is read and recorded, and the leakage rate is calculated according to the formula: leakage rate = the volume of water in the measuring cylinder read in 10 minutes × (60 minutes / 10 minutes), and the test water inlet solenoid valve (11) is closed; E. After testing the leakage rate, click Continue, the counting continues, and operations B, C, and D are repeated every 10 seconds until the number of check times required by the test is reached.

7. A method for testing the non-return leakage rate of a deepwater stop-check valve, using the test system according to any one of claims 1 to 5, characterized in that: It includes the following steps: A. Preparation: The stop check valve (9) under test is electrically opened, the forward fluid medium is ready, the water supply valve (16) is opened to fill the shallow water tank (10), the water level in the shallow water tank (10) reaches the set value, the water level in the water storage tank (17) is within the set range, and the gauge pressure of the nitrogen cylinder (24) is 8 MPa higher; B. The positive fluid medium opens the stop check valve (9) under test: the discharge solenoid valve (12) opens, and the pressure behind the stop check valve (9) under test is normal. After 10 seconds, the positive fluid medium electric valve (1) opens, and the positive fluid medium pushes the stop check valve open. The flow meter (2) displays the flow rate. After 5 seconds, the flow rate is recorded, and the pressure and temperature are recorded. After the positive fluid medium electric valve (1) opens for 8 seconds, the opening action of the stop check valve (9) under test is completed. The positive fluid medium electric valve (1) closes. After a delay of 2 seconds, the pressure at the outlet behind the stop check valve (9) under test is released. The discharge solenoid valve (12) is closed, and the drain valve (6) is opened for 5 seconds. The pressure in front of the stop check valve (9) under test is released and the water is drained, providing conditions for the non-return test. The opening action is completed, and the counter statistics are not displayed. C. After 10 seconds, reverse the water level setting + nitrogen pressure, and test the stop check valve (9): The test water inlet solenoid valve (11) is opened, and normal temperature water is injected into the test stop check valve (9) in the reverse direction. When the liquid level sensor (14) sends a signal that the liquid level reaches the set value, if the liquid level is lower than the set value, the water supply solenoid valve (15) is opened by jogging, and the water in the water storage tank (17) replenishes the liquid level of the shallow water tank (10). The ventilation solenoid valve (13) is closed, and the shallow water tank (10) is sealed; the air supply manual valve (23) remains in the open state, the air source is ready, and the second pressure sensor (19) displays the set value in MPa. If the pressure is lower than the set value, the air supply solenoid valve (22) is opened by jogging, and the nitrogen bottle (24) is pressurized for the pressure regulating tank (21); if the pressure exceeds the set value, an alarm is triggered, and the regulating valve (20) is manually opened to exhaust and reduce the pressure, and the set value pressure is re-established; The test air intake solenoid valve (18) is opened, and the reverse water column + nitrogen gas is used to pressurize the test stop check valve (9). After 2 seconds, the pressure is stable, and the reading of the second pressure sensor (19), i.e. the check pressure value, is recorded. The closing action of the test stop check valve (9) is completed. After the test air intake solenoid valve (18) is opened for 3 seconds, the recording is completed, and the test air intake solenoid valve (18) is closed. The opening / closing is counted as 1 time. 100 switching cycles constitute a group. After each group is completed, a pause is made and a prompt sound is sounded. The pressure is maintained for 10 minutes to measure the leakage rate. D. Reverse water column + nitrogen pressurization, test the leakage rate of the stop check valve (9): open the sampling valve (7), wait until no water drops within 3 minutes, drain the water in front of the stop check valve (9) of the test, keep the sampling valve (7) open, and place the measuring cylinder (8) at the drain outlet; open the test water inlet solenoid valve (11), and inject normal temperature water into the reverse direction of the stop check valve (9) of the test, wait until the liquid level sensor (14) sends a signal that the liquid level reaches the set value (if the liquid level is lower than the set value, the water replenishment solenoid valve (15) is opened in a momentary manner, and the water in the water storage tank (17) replenishes the liquid level of the shallow water tank (10), then close the ventilation solenoid valve (13), and seal the shallow water tank (10); keep the air supply hand valve (23) open, and the air source After the preparation is completed, the second pressure sensor (19) displays the set value in MPa. If the pressure is lower than the set value, the air supply solenoid valve (22) is opened by jogging, and the nitrogen bottle (24) is used to pressurize the pressure regulating tank (21). If the pressure exceeds the set value, an alarm is triggered, and the regulating valve (20) is manually opened to exhaust and reduce the pressure, and the set pressure is re-established. The test air intake solenoid valve (18) is opened, and the reverse water column + nitrogen gas is used to pressurize the test stop check valve (9). After 10 minutes of timing, the volume of water in the measuring cylinder (8) is read and recorded, and the leakage rate is calculated according to the formula: leakage rate = the volume of water in the measuring cylinder (8) read in 10 minutes × (60 minutes / 10 minutes), and the test water intake solenoid valve (11) is closed. E. After testing the leakage rate, click Continue, the counting continues, and operations B, C, and D are repeated every 10 seconds until the number of check times required by the test is reached.

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