A nitrogen replenishing device and method for a fire-fighting gas cylinder with an upper chamber pressure-sealed type of cylinder head valve

Abstract

The present invention belongs to the field of nuclear power plant safety design, and specifically relates to a nitrogen replenishing device and method for a cylinder head valve upper chamber air pressure sealed fire cylinder. The device includes a nitrogen cylinder and a main pipeline, as well as an outlet and inlet pressure gauge and a pressure reducing valve. The main pipeline is connected to the bottle mouth valve spray port and the cylinder head valve standard start port through a parallel pipeline. After the nitrogen cylinder is opened, the nitrogen filling pipeline is vented. After the fire cylinder is in the spraying state, the corresponding valve on the nitrogen filling pipeline is operated to seal and fill with nitrogen. After completion, the relevant interface is removed to complete the nitrogen filling. The device and method can realize the nitrogen filling operation of the pressure-sealed fire cylinder with the upper chamber of the cylinder head valve that has lost pressure at the fire cylinder installation site, thereby improving the timely availability and reliability of the fire protection system.

Description

Technical Field

[0001] The invention belongs to the field of nuclear power plant safety design, and in particular relates to a nitrogen replenishing device and an operating method. Background Art

[0002] A total of 292 fire-fighting gas cylinders are installed in the conventional island and nuclear island of a nuclear power plant. These gas cylinders are pressure-sealed fire-fighting gas cylinders with upper chambers of bottle head valves. The discharge port of this type of fire-fighting gas cylinder is located on the side of the bottle head valve. The upper surface area of ​​the piston inside the bottle head valve is larger than the lower surface area of ​​the piston. There is a small channel connecting the upper and lower chambers of the piston inside the piston. When the fire-fighting gas cylinder is not started, the pressure in the upper chamber of the bottle head valve is equal to the pressure inside the fire-fighting gas cylinder. Therefore, the piston is at the lower part of the piston chamber of the bottle head valve. The discharge port of the bottle head valve is in a closed state through the piston seal. A valve core with a self-sealing function is provided at the top of the bottle head valve. When the solenoid valve at the top of the bottle head valve is energized, the solenoid valve ejector presses the self-sealing valve core of the bottle head valve, causing the pressure in the upper chamber of the bottle head valve to be released, and the piston of the bottle head valve moves up, causing the fire-fighting gas cylinder to be discharged. The low-pressure alarm switch and pressure switch wiring installed on the bottle head valve are both threaded, and the internal pressure of the fire-fighting gas cylinder is measured. The low-pressure alarm switch and pressure switch joints are more likely to leak nitrogen. When the pressure is lower than 20 bar, a low pressure alarm will be triggered, and the fire-fighting gas cylinder needs to be weighed and refilled with nitrogen (nitrogen is refilled while ensuring that the weight has not decreased, that is, the agent has not leaked). If the gas fire-fighting device is returned to the factory for nitrogen replenishment, it will take at least one week. Since the gas fire-fighting device needs to be restored within 72 hours after a fault alarm, a large number of spare gas cylinders need to be purchased.

[0003] The existing fire-fighting gas cylinders have a simple structure. To fill the gas cylinder with nitrogen, one only needs to unscrew the pressure gauge and connect the nitrogen pipeline through the check valve at the pressure gauge to directly fill the gas cylinder with nitrogen. Therefore, the existing fire-fighting gas cylinder nitrogen replenishing tool cannot be used to replenish nitrogen for the upper chamber air pressure sealed fire-fighting gas cylinder.

[0004] According to the target requirements of nuclear power plants, the structure of the fire cylinder head valve is that the pressure gauge is a copper threaded connection, and there is no check valve at the interface. After the pressure gauge is removed, the nitrogen and reagent in the fire cylinder will be lost, and frequent disassembly and assembly of the pressure gauge joint will cause the copper thread to fail to seal. In order to ensure the reliability of the sealing of each interface of the bottle head valve and avoid the loss of reagents during the nitrogen filling process, nitrogen can only be filled from the discharge port of the fire cylinder. During the nitrogen filling process, the cylinder is in a discharge state, and the nitrogen filling operation is difficult to implement. Therefore, it is impossible to use general nitrogen filling tools to replenish nitrogen on existing fire cylinders. If the pressure of the fire cylinder is reduced, it can only be sent to a specific agency to refill the fire cylinder. Summary of the invention

[0005] The purpose of the present invention is to provide a nitrogen replenishing device and method for fire-fighting gas cylinders with air pressure sealing in the upper cavity of a cylinder head valve, which can realize the replenishment of nitrogen at the discharge port of the fire-fighting gas cylinder, is safe and reliable during operation, and effectively avoids industrial safety risks caused by the fire-fighting gas cylinders not spraying.

[0006] The technical solution of the present invention is as follows:

[0007] A nitrogen replenishing device for fire-fighting gas cylinders with air pressure sealing type on a bottle head valve comprises a nitrogen bottle and a main pipeline connected with the nitrogen bottle, wherein an outlet pressure gauge and a pressure reducing valve are arranged in sequence on the main pipeline along the direction of gas flow, an inlet pressure gauge is installed above the pressure reducing valve, and the main pipeline is respectively connected with a bottle mouth valve discharge port and a bottle head valve standard start port through parallel pipelines; one of the parallel pipelines is a nitrogen filling pipeline, wherein a nitrogen filling valve 1, a nitrogen filling valve 2 and a bottle head valve connector are arranged in sequence along the direction of gas flow, and the pipeline where the nitrogen filling valve 2 is located is perpendicular to the nitrogen filling pipeline; the other parallel pipeline is a locking pipeline, wherein a locking valve 1, a locking valve 2 and a quick connector are arranged in sequence along the direction of gas flow, and the pipeline where the locking valve 2 is located is perpendicular to the locking pipeline; the locking pipeline and the nitrogen filling pipeline are combined at the outlet of the pressure reducing valve on the main pipeline.

[0008] The main pipeline is connected to the spray port of the bottle mouth valve through a bottle head valve connector; the main pipeline is connected to the standard start port of the bottle head valve through a quick connector.

[0009] The outlet pressure gauge has a measuring range of 20 to 35 MPa.

[0010] The inlet pressure gauge range is 2-3 times the standard pressure value inside the nitrogen cylinder.

[0011] A method for replenishing nitrogen in a fire-fighting gas cylinder with an upper pressure-sealed gas cylinder head valve, based on the nitrogen replenishing device for a fire-fighting gas cylinder with an upper pressure-sealed gas cylinder head valve, comprises the following specific steps:

[0012] Step 1. Close the pressure reducing valve, nitrogen charging valve 2, nitrogen charging valve 1, locking valve 2 and locking valve 1;

[0013] Step 2. Check whether the range of the outlet pressure gauge and the range of the inlet pressure gauge meet the requirements. If they do, proceed to step 3. If not, replace the pressure gauge.

[0014] Step 3. Connect the main pipeline to the outlet of the nitrogen bottle through the nitrogen bottle connector, and connect the nitrogen filling pipeline to the bottle head valve discharge port through the bottle head valve connector;

[0015] Step 4. Open the gas outlet of the nitrogen bottle, open the nitrogen filling valve 1 on the nitrogen filling pipeline, and open the pressure reducing valve on the main pipeline until the pressure display on the pressure reducing valve remains at the pressure value when the bottle head valve is opened;

[0016] Step 5. Open the nitrogen filling valve 2 on the nitrogen filling pipeline to exhaust, and close the nitrogen filling valve 1 and the nitrogen filling valve 2;

[0017] Step 6. Open the pressure reducing valve on the main pipeline until the inlet pressure reading remains at the standard pressure inside the nitrogen cylinder;

[0018] Step 7. Expel the gas from the upper cavity of the piston inside the head valve of the fire cylinder, move the piston inside the head valve upward, and the fire cylinder is in a spraying state;

[0019] Step 8. Open the nitrogen filling valve 1. When the reading on the outlet pressure gauge reaches the standard pressure inside the nitrogen cylinder, close the pressure reducing valve and then close the nitrogen filling valve 1;

[0020] Step 9. Connect the quick connector to the standard start port of the bottle head valve;

[0021] Step 10. Open the lock valve 1 on the lock pipeline, open the pressure reducing valve on the main pipeline, until the inlet pressure indication on it remains at the opening pressure value of the bottle head valve, close the lock valve 1, and then close the pressure reducing valve;

[0022] Step 11. Open the pressure reducing valve on the main pipeline until the inlet pressure reading remains 3-5 times the flat head valve opening pressure value;

[0023] Step 12. Fully open the locking valve 1 on the locking pipeline until the piston inside the bottle head valve moves down to the bottom of the piston chamber of the bottle head valve, then close the locking valve 1, and then close the pressure reducing valve on the main pipeline;

[0024] Step 13. Close the nitrogen bottle, open the second nitrogen filling valve on the nitrogen filling pipeline, wait until no gas is discharged, and then close the second nitrogen filling valve;

[0025] Step 14. Open the second locking valve on the locking pipeline until no gas is discharged, open the locking valve one, and close the locking valve one and the locking valve two when no gas is discharged;

[0026] Step 15. Remove the connection between the quick connector and the standard starting port of the fire cylinder valve, remove the connection between the nitrogen filling pipeline and the discharge port of the fire cylinder, and remove the connection between the main pipeline and the nitrogen cylinder.

[0027] Step 16. The process of filling the gas cylinder with nitrogen is completed.

[0028] In the step 5, exhaust is performed for 5-10 seconds.

[0029] In step 6, fully open the locking valve on the locking pipeline and hold it for 3-5 seconds.

[0030] Repeat step 12 several times to ensure that the piston inside the bottle head valve moves down to the bottom of the bottle head valve piston chamber; this can be done 3 to 5 times.

[0031] The remarkable effects of the present invention are as follows:

[0032] Since the bottle head valve discharge port is connected by using the bottle head valve connector and the nitrogen filling valve, the bottle head valve quick connector and the locking valve are connected to the bottle head valve start port, and the filled nitrogen can enter the fire cylinder through the bottle head valve discharge port, the device can realize the nitrogen filling operation of the pressure-sealed fire cylinder with the upper chamber of the bottle head valve that has lost pressure at the fire cylinder installation site, thereby improving the timely availability and reliability of the fire protection system;

[0033] The nitrogen pressure in the nitrogen cylinder used on site is greater than the medium pressure inside the fire cylinder, and the discharge port of the fire cylinder valve is connected to the nitrogen cylinder. Therefore, during the nitrogen filling operation, the industrial safety risks caused by the fire cylinder spraying can be effectively avoided;

[0034] After the pressure of the upper chamber air pressure sealed fire cylinder is reduced, if there is no special nitrogen replenishing tool, it can only be returned to the factory for processing. Since the time of returning to the factory for maintenance is too long, the on-site fire protection system will be unavailable, so it is necessary to use a spare cylinder to replace the defective fire cylinder in time. By using this nitrogen replenishing device, it is possible to use a micro nitrogen cylinder to replenish the nitrogen of the upper chamber air pressure sealed fire cylinder on site, effectively avoiding the return of the on-site fire cylinder to the factory for maintenance after the pressure is reduced, thereby effectively reducing the use of on-site spare fire cylinders;

[0035] By using the nitrogen replenishing device, the fire-fighting gas cylinder can be replenished with nitrogen through the discharge port of the fire-fighting gas cylinder head valve, thereby avoiding the frequent disassembly of the fire-fighting gas cylinder pressure gauge and improving the sealing reliability of the fire-fighting gas cylinder;

[0036] The nitrogen replenishing device is provided with a pressure reducing valve to set the outlet pressure of the nitrogen cylinder before the nitrogen replenishing operation. The nitrogen replenishing device is also provided with an exhaust valve. During the nitrogen replenishing operation, when the nitrogen pressure in the internal pipeline of the nitrogen replenishing device is too high or the internal pressure of the fire cylinder is too high, the internal pressure of the fire cylinder can be adjusted through the exhaust valve. Therefore, the pressure in the fire cylinder can be accurately replenished to a given pressure, avoiding the need to fine-tune the internal pressure of the fire cylinder again after the nitrogen replenishing operation;

[0037] The device can be operated by a single person, which can effectively reduce the labor intensity of the staff, shorten the equipment maintenance time and improve work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the principle of the nitrogen replenishing device for fire-fighting gas cylinders with air pressure sealing in the upper chamber of the cylinder head valve;

[0039] Figure 2 This is a schematic diagram of the structure of a nitrogen replenishing device for a fire-fighting gas cylinder with an upper chamber air pressure seal of a cylinder head valve;

[0040] In the figure: 1. Nitrogen bottle connector; 2. Outlet pressure gauge; 3. Pressure reducing valve; 4. Inlet pressure gauge; 5. Nitrogen charging valve 1; 6. Nitrogen charging valve 2; 7. Bottle head valve connector; 8. Nitrogen charging pipeline; 9. Quick connector; 10. Locking valve 2; 11. Locking valve 1; 12. Locking pipeline; 13. Main pipeline; 14. Nitrogen bottle; 15. Bottle mouth valve spray port; 16. Bottle head valve standard start port. DETAILED DESCRIPTION

[0041] The present invention will be further described below through the accompanying drawings and specific implementation methods.

[0042] like Figure 1 and Figure 2 As shown, the nitrogen for the nitrogen replenishment operation comes from a nitrogen bottle 14, which is connected to a main pipeline 13 through a nitrogen bottle connector 1. An outlet pressure gauge 2 and a pressure reducing valve 3 are arranged in sequence on the main pipeline 13 along the direction of gas flow, and an inlet pressure gauge 4 is installed above the pressure reducing valve 3.

[0043] The range of the outlet pressure gauge 2 is 25MPa, and the range of the inlet pressure gauge 4 is 2-3 times the standard pressure value inside the nitrogen cylinder 14;

[0044] The main pipeline 13 is connected to the bottle mouth valve discharge port 15 and the bottle head valve standard start port 16 respectively through parallel pipelines;

[0045] The bottle mouth valve discharge port 15 and the bottle head valve standard start port 16 are the input ports of the equipment that needs to be supplemented with nitrogen in the nuclear power plant;

[0046] The main pipeline 13 is connected to the bottle mouth valve discharge port 15 through the bottle head valve connector 7; the main pipeline 13 is connected to the bottle head valve standard start port through the quick connector 9;

[0047] One of the parallel pipelines is the nitrogen charging pipeline 8, which is the pipeline connecting the main pipeline 13 and the bottle valve discharge port 15, and is installed with nitrogen charging valve 1 5, nitrogen charging valve 2 6 and bottle head valve connector 7 in sequence along the direction of gas flow, wherein the pipeline where the nitrogen charging valve 2 6 is located is perpendicular to the nitrogen charging pipeline 8;

[0048] The other parallel pipeline is the locking pipeline 12, which refers to the pipeline connecting the main pipeline 13 and the standard start port 16 of the bottle head valve, and is installed with the locking valve 11, the locking valve 2 10 and the quick connector 9 in sequence along the direction of gas flow, wherein the pipeline where the locking valve 2 10 is located is perpendicular to the locking pipeline 12;

[0049] The lock pipeline 12 and the nitrogen filling pipeline 8 are combined at the outlet of the pressure reducing valve 3 on the above-mentioned main pipeline 13.

[0050] The above device is used to replenish nitrogen in fire-fighting cylinders. The specific operations are as follows:

[0051] Step 1. Close the pressure reducing valve 3, the nitrogen charging valve 2 6, the nitrogen charging valve 1 5, the locking valve 2 10 and the locking valve 1 11;

[0052] Step 2. Check whether the range of the outlet pressure gauge 2 and the range of the inlet pressure gauge 4 meet the requirements. If they do, proceed to step 3. If not, replace the pressure gauges.

[0053] Step 3. Connect the main pipeline 13 to the outlet of the nitrogen bottle 14 through the nitrogen bottle connector 1, and connect the nitrogen filling pipeline 8 to the bottle head valve discharge port 15 through the bottle head valve connector 7;

[0054] Step 4. Open the gas outlet of the nitrogen cylinder to be charged, open the nitrogen charging valve 5 on the nitrogen charging pipeline 8, and open the pressure reducing valve 3 on the main pipeline 13 until the pressure display on the pressure reducing valve 3 remains at the pressure value when the cylinder head valve is opened;

[0055] Step 5. Open the nitrogen filling valve 2 6 on the nitrogen filling pipeline 8 to exhaust. After exhausting for 5-10 seconds, close the nitrogen filling valve 1 5 and the nitrogen filling valve 2 6;

[0056] Step 6. Open the pressure reducing valve 3 on the main pipeline 13 until the reading of the inlet pressure gauge 4 thereof remains at the standard pressure inside the nitrogen cylinder 14;

[0057] Step 7. Expel the gas from the upper cavity of the piston inside the head valve of the fire cylinder, move the piston inside the head valve upward, and the fire cylinder is in a spraying state;

[0058] Step 8. Open the nitrogen filling valve 5. When the reading on the outlet pressure gauge 2 reaches the standard pressure inside the nitrogen cylinder, close the pressure reducing valve 3, and then close the nitrogen filling valve 5;

[0059] Step 9. Connect the quick connector 9 to the standard start port 16 of the bottle head valve;

[0060] Step 10. Open the locking valve 11 on the locking pipeline 12, open the pressure reducing valve 3 on the main pipeline 13, until the reading of the inlet pressure gauge 4 on it remains at the opening pressure value of the bottle head valve, close the locking valve 11, and then close the pressure reducing valve 3;

[0061] Step 11. Open the pressure reducing valve 3 on the main pipeline 13 until the reading on the inlet pressure gauge 4 remains 3-5 times the value of the flat head valve opening pressure;

[0062] Step 12. Fully open the locking valve 11 on the locking pipeline 12 and hold it for 3-5 seconds until the piston inside the bottle head valve moves down to the bottom of the piston chamber of the bottle head valve, then close the locking valve 11, and then close the pressure reducing valve 3 on the main pipeline 13;

[0063] Step 13. Repeat step 12 to ensure that the piston inside the bottle head valve moves down to the bottom of the piston chamber of the bottle head valve;

[0064] Step 14. Close the nitrogen bottle 14, open the nitrogen filling valve 2 6 on the nitrogen filling pipeline 8, until no gas is discharged, and close the nitrogen filling valve 2 6;

[0065] Step 15. Open the second locking valve 10 on the locking pipeline 12, open the locking valve 1 11 until no gas is discharged, and close the locking valve 1 11 and the locking valve 2 10 when no gas is discharged;

[0066] Step 16. Remove the connection between the quick connector 9 and the standard starting port 16 of the fire cylinder head valve, remove the connection between the nitrogen filling pipeline 8 and the fire cylinder discharge port 15, and remove the connection between the main pipeline 13 and the nitrogen cylinder 14.

[0067] Step 17. The process of filling the gas cylinder with nitrogen is completed.

Claims

1. A nitrogen replenishing device for fire-fighting gas cylinders with an upper chamber pressure-sealed cylinder head valve, comprising a nitrogen cylinder (14) and a main pipeline (13) connected to the nitrogen cylinder (14), characterized in that: The main pipeline (13) is provided with an outlet pressure gauge (2) and a pressure reducing valve (3) in sequence along the direction of gas flow, an inlet pressure gauge (4) is installed above the pressure reducing valve (3), and the main pipeline (13) is connected to the bottle head valve discharge port (15) and the bottle head valve standard start port (16) respectively through parallel pipelines; one of the parallel pipelines is a nitrogen filling pipeline (8), and a nitrogen filling valve 1 (5), a nitrogen filling valve 2 (6) and a bottle head valve connector (7) are arranged in sequence along the direction of gas flow, and the pipeline where the nitrogen filling valve 2 (6) is located is perpendicular to the nitrogen filling pipeline (8); the other parallel pipeline is a locking pipeline (12), and a locking valve 1 (11), a locking valve 2 (10) and a quick connector (9) are arranged in sequence along the direction of gas flow, and the pipeline where the locking valve 2 (10) is located is perpendicular to the locking pipeline (12); the locking pipeline (12) and the nitrogen filling pipeline (8) are combined at the outlet of the pressure reducing valve (3) on the main pipeline (13); The main pipeline (13) is connected to the bottle head valve discharge port (15) via the bottle head valve connector (7); the main pipeline (13) is connected to the bottle head valve standard start port (16) via a quick connector (9); The outlet pressure gauge (2) has a measuring range of 20-35 MPa; The measuring range of the inlet pressure gauge (4) is 2-3 times the internal standard pressure value of the nitrogen cylinder (14).

2. A method for replenishing nitrogen in a fire-fighting gas cylinder with an upper pressure-sealed cylinder head valve, characterized in that: The nitrogen replenishing device for fire-fighting gas cylinders with air pressure sealing on the upper chamber of the bottle head valve according to claim 1 comprises the following specific steps: Step 1. Close the pressure reducing valve (3), nitrogen charging valve 2 (6), nitrogen charging valve 1 (5), locking valve 2 (10) and locking valve 1 (11); Step 2. Check whether the range of the outlet pressure gauge (2) and the range of the inlet pressure gauge (4) meet the requirements. If they do, proceed to step (3). If not, replace the pressure gauges. Step 3. Connect the main pipeline (13) to the outlet of the nitrogen bottle (14) through the nitrogen bottle connector (1), and connect the nitrogen filling pipeline (8) to the bottle head valve discharge port (15) through the bottle head valve connector (7); Step 4. Open the gas outlet of the nitrogen bottle (14), open the nitrogen filling valve 1 (5) on the nitrogen filling pipeline (8), and open the pressure reducing valve (3) on the main pipeline (13) until the pressure indicator on the pressure reducing valve (3) remains at the pressure value when the bottle head valve is opened; Step 5. Open the nitrogen charging valve 2 (6) on the nitrogen charging pipeline (8) to exhaust, and close the nitrogen charging valve 1 (5) and the nitrogen charging valve 2 (6); Step 6. Open the pressure reducing valve (3) on the main pipeline (13) until the reading on the inlet pressure gauge (4) remains at the standard pressure inside the nitrogen cylinder (14); Step 7. Expel the gas from the upper cavity of the piston inside the head valve of the fire cylinder, move the piston inside the head valve upward, and the fire cylinder is in a spraying state; Step 8. Open the nitrogen filling valve 1 (5). When the reading on the outlet pressure gauge (2) reaches the standard pressure inside the nitrogen cylinder, close the pressure reducing valve (3), and then close the nitrogen filling valve 1 (5). Step 9. Connect the quick connector (9) to the standard start port (16) of the bottle head valve; Step 10. Open the first locking valve (11) on the locking pipeline (12), open the pressure reducing valve (3) on the main pipeline (13), until the reading on the inlet pressure gauge (4) remains at the opening pressure value of the bottle head valve, close the first locking valve (11), and then close the pressure reducing valve (3); Step 11. Open the pressure reducing valve (3) on the main pipeline (13) until the reading on the inlet pressure gauge (4) remains 3-5 times the opening pressure of the flat head valve; Step 12. Fully open the locking valve 1 (11) on the locking pipeline (12) until the piston inside the bottle head valve moves down to the bottom of the piston chamber of the bottle head valve, then close the locking valve 1 (11), and then close the pressure reducing valve (3) on the main pipeline (13); Step 13. Close the nitrogen bottle (14), open the second nitrogen filling valve (6) on the nitrogen filling pipeline (8), wait until no gas is discharged, and then close the second nitrogen filling valve (6); Step 14. Open the second locking valve (10) on the locking pipeline (12), open the locking valve (11) until no gas is discharged, and close the locking valve (11) and the locking valve (10) until no gas is discharged; Step 15. Remove the connection between the quick connector (9) and the standard start port (16) of the fire cylinder valve, remove the connection between the nitrogen filling pipeline (8) and the discharge port (15) of the cylinder valve, and remove the connection between the main pipeline (13) and the nitrogen cylinder (14); Step 16. The process of filling the gas cylinder with nitrogen is completed.

3. A method for replenishing nitrogen in a fire-fighting gas cylinder with an upper chamber pressure-sealed cylinder head valve as claimed in claim 2, characterized in that: In the step 5, exhaust is performed for 5-10 seconds.

4. A method for replenishing nitrogen in a fire-fighting gas cylinder with an upper chamber pressure-sealed cylinder head valve as claimed in claim 2, characterized in that: In step 6, fully open the lock valve 1 (11) on the lock line (12) and hold it for 3-5 seconds.

5. A method for replenishing nitrogen in a fire-fighting gas cylinder with an upper chamber pressure-sealed cylinder head valve as claimed in claim 2, characterized in that: Repeat step 12 several times to ensure that the piston inside the bottle head valve moves down to the bottom of the bottle head valve piston chamber.

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