Automatic nitrogen charging device for low-temperature electrical and signal isolation bin
The automatic nitrogen filling device enables automatic pressure control of the electrical and signal isolation chambers of the LNG cryogenic pump, solving the sealing failure problem caused by manual nitrogen filling and improving the safety and reliability of equipment operation.
Patent Information
- Application Number
- CN202520427612.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-12
- Publication Date
- 2025-12-12
- Estimated Expiration
- 2035-03-12
AI Technical Summary
In existing technologies, the electrical and signal isolation chambers of LNG cryogenic pumps require manual nitrogen filling, which leads to random sealing failures, easily causing overpressure or leakage, increasing the workload of operators, and posing an explosion risk.
Design an automatic nitrogen filling device that utilizes a pressure regulator, needle valve, check valve, two-position three-way solenoid valve, and pressure transmitter. Through a control system, it can automatically detect and control the nitrogen pressure to ensure that the pressure inside the isolation chamber is within a reasonable range and avoid overpressure or leakage.
It enables automatic adjustment of the isolation chamber pressure, reduces the workload of operators, avoids overpressure and leakage caused by human error, and improves the safety and reliability of equipment operation.
Smart Images
Figure CN223663126U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to an automatic nitrogen filling device for a cryogenic electrical and signal isolation chamber. Background Technology
[0002] LNG cryogenic pumps are critical equipment in liquefied natural gas (LNG) receiving terminals. Failure to operate these pumps can lead to reduced or even halted production. Therefore, timely and accurate protective measures are essential. In addition to electrical protection at the substation, vibration signal detection of the pump itself is particularly important in the protection of LNG cryogenic pumps.
[0003] Due to the unique operating conditions of LNG cryogenic pumps, they need to be immersed in cryogenic LNG during normal operation. Their power cables and vibration detection signal cables require special equipment to transmit power to the downstream substation and vibration management system. Considering the possibility of maintenance and disassembly of the LNG cryogenic pump, the electrical and signal connectors need to be designed to be detachable, necessitating the use of a dedicated electrical and signal isolation chamber. During normal operation, one end of this isolation chamber is filled with cryogenic natural gas, while the other end is exposed to the atmosphere. To ensure the proper functioning of the isolation chamber, it needs to be filled with dry nitrogen at a pressure significantly higher than that of the cryogenic natural gas. This effectively isolates the possibility of explosive gases entering the isolation chamber and also prevents cryogenic conduction, which could affect the equipment's insulation performance.
[0004] In large LNG receiving terminals, LNG is typically stored at atmospheric pressure in its large storage tanks. These tanks usually have top openings, so when LNG needs to be exported, it must be pressurized and lifted out of the tanks by cryogenic pumps before being delivered to downstream equipment. The isolation chamber is installed on the electrical and vibration signal transmission cables of the cryogenic pump and has detachable terminals inside. One end of the isolation chamber connects to the cryogenic pump well, and the other end connects to the electrical control cabinet or vibration transmitter junction box. It is responsible for transmitting kinetic energy or vibration detection signals to the cryogenic pump and is a critical piece of equipment for the safe operation of the cryogenic pump. See [link to relevant documentation]. Figure 3 As shown.
[0005] The isolation chamber is a cylindrical structure with flange connections at both ends. It adopts a pressure-bearing and sealing design to isolate the internal space of the isolation chamber from the atmospheric environment. After the isolation chamber is filled with pressurized nitrogen, it can isolate the cryogenic natural gas from the cryogenic pump well from the internal air of the cable conduit.
[0006] Currently, the most common method for replenishing nitrogen is manual replenishment, which is carried out by operators on-site by opening a manual valve. LNG cryogenic pumps are generally installed in remote locations, and the sealing measures of the isolation chamber are not easy to achieve a stable seal. Therefore, the depressurization of the isolation chamber occurs frequently and randomly, without a fixed pattern, which brings unpredictable workload to the operators.
[0007] In actual operation, to protect the LNG low-pressure pump, if the isolation chamber seal fails, leading to flammable gas leakage into the isolation chamber, it could potentially cause an explosion. Therefore, it is necessary to configure the logic for interlocking the LNG cryogenic pump tripping due to overpressure in the isolation chamber. Consequently, during manual nitrogen charging, a slight oversight by the operator can easily result in the nitrogen charging valve not closing in time, leading to excessive nitrogen filling and overpressure in the isolation chamber, which in turn causes the LNG cryogenic pump to trip, resulting in unnecessary trouble. Utility Model Content
[0008] In response to the long-standing problems in this field, the inventors conducted in-depth research and developed an automatic nitrogen replenishment device that can automatically replenish nitrogen without human intervention, reducing the workload of operators and avoiding overfilling caused by human error.
[0009] This application is achieved through the following technical solution:
[0010] An automatic nitrogen filling device for a cryogenic electrical and signal isolation chamber includes an electrical and signal isolation chamber. A pressure regulator, a needle valve, a check valve, a two-position three-way solenoid valve, and a pressure transmitter are sequentially installed on the nitrogen main pipe connecting the electrical and signal isolation chamber.
[0011] The two-position three-way solenoid valve includes a first port A, a second port B, and a third port C. The first port A and the second port B are respectively connected to the nitrogen main pipe. The third port C of the two-position three-way solenoid valve is connected to an vent pipe. A two-position two-way solenoid valve is installed on the vent pipe. A pressure transmitter is installed on the nitrogen replenishment line between the two-position three-way solenoid valve and the electrical and signal isolation chamber. It is used to detect the pressure in the electrical and signal isolation chamber. The control system is communicatively connected to the two-position three-way solenoid valve, the two-position two-way solenoid valve, and the pressure transmitter. It controls the opening and closing of the two-position three-way solenoid valve and the two-position two-way solenoid valve according to the detected pressure.
[0012] Furthermore, the electrical and signal isolation chamber is equipped with an air inlet and an exhaust outlet. The air inlet is connected to a nitrogen replenishment pipeline to replenish nitrogen to the isolation chamber; the exhaust outlet is sealed with a sealing flange (or threaded plug) to reduce nitrogen leakage.
[0013] Furthermore, when the pressure transmitter detects a pressure lower than the set value (generally 0.5±0.1MPa, preferably 0.5MPa), the control system outputs a signal to open the two-position three-way solenoid valve, with ports A and B open and ports B and C closed. When ports A and B are connected, the nitrogen source is connected to the isolation chamber, thus pressurizing the electrical and signal isolation chambers.
[0014] Furthermore, when the pressure detected by the pressure transmitter is higher than the required value of the isolation chamber (generally 0.8±0.1MPa, preferably 0.8MPa), the control system outputs a signal to close the two-position three-way solenoid valve, closing ports A and B, and opening ports B and C, connecting the isolation chamber to the exhaust port and stopping the gas supply.
[0015] Furthermore, when the pressure detected by the pressure transmitter is higher than the maximum allowable pressure of the isolation chamber (generally 1.0±0.1MPa, preferably 1.0MPa), the control system outputs a signal to close the two-position three-way solenoid valve, with ports A and B closed and ports B and C open, connecting the isolation chamber to the exhaust port. At the same time, the two-position two-way solenoid valve is opened to discharge the overpressure gas from the isolation chamber, preventing the system overpressure from affecting the safety of the isolation chamber.
[0016] Furthermore, in the event of active venting of the isolation chamber (when the discharge solenoid valve (two-position two-way solenoid valve) is opened), the control system issues an alarm signal to alert the operator and prompt them to conduct an on-site inspection to check for gas leaks in the electrical and signal isolation chambers. If a gas leak is detected, the cryogenic pump must be stopped immediately, and the isolation chamber with the gas leak must be replaced promptly.
[0017] In this application, the electrical and signal isolation compartment includes an electrical isolation compartment and a signal isolation compartment.
[0018] This utility model further provides an automatic nitrogen filling method for a cryogenic electrical and signal isolation chamber using the above-mentioned device, the method comprising:
[0019] In the process, dry, room-temperature nitrogen is introduced into the nitrogen main pipe and reduced to a safe pressure (generally 0.6~0.8 MPaG) by a self-regulating pressure regulator. Then, it passes through a needle valve. By adjusting the opening of the needle valve, the flow rate of nitrogen entering the isolation chamber can be regulated to ensure that the time for the isolation chamber to be filled with nitrogen from zero to full is controlled within 6~12 minutes, preferably within 8~10 minutes. This avoids the impact of rapid nitrogen filling on the equipment and also avoids the safety interlock action of the cryogenic pump caused by pressure fluctuations due to rapid nitrogen filling. Then, a check valve is connected to ensure that nitrogen can only flow from the nitrogen main pipe to the electrical and signal isolation chamber. After exiting the check valve, the nitrogen enters in sequence through a two-position three-way solenoid valve, a pressure transmitter, and the cryogenic electrical and signal isolation chamber. The pressure transmitter detects the nitrogen pressure in the cryogenic electrical and signal isolation chamber.
[0020] When the pressure transmitter detects a pressure lower than the set value (generally 0.5±0.1MPa, preferably 0.5MPa), the control system outputs a signal to open the two-position three-way solenoid valve, opening ports A and B and closing ports B and C. The nitrogen source is then connected to the isolation chamber to replenish the pressure of the electrical and signal isolation chambers.
[0021] When the pressure detected by the pressure transmitter is higher than the required value of the isolation chamber (generally 0.8±0.1MPa, preferably 0.8MPa), the control system outputs a signal to close the two-position three-way solenoid valve, closing ports A and B, and opening ports B and C, connecting the isolation chamber to the exhaust port and stopping the gas supply.
[0022] When the pressure detected by the pressure transmitter is higher than the maximum allowable pressure of the isolation chamber (generally 1.0±0.1MPa, preferably 1.0MPa), the control system outputs a signal to close the two-position three-way solenoid valve (ports A and B are closed, ports B and C are open), and at the same time opens the two-position two-way solenoid valve to discharge the overpressure gas from the isolation chamber, so as to avoid the system overpressure affecting the safety of the isolation chamber.
[0023] In the event of a gas leak or excessive nitrogen filling in the isolation chamber, to prevent the system from becoming dangerous due to overpressure, the overpressure medium in the isolation chamber needs to be actively released. When the isolation chamber is actively released (when the discharge solenoid valve is opened), the control system will issue an alarm signal to alert the operator and prompt them to conduct an on-site inspection to check for a gas leak in the isolation chamber. If a gas leak is detected, the cryogenic pump should be stopped immediately, and the isolation chamber with the gas leak should be replaced promptly. Two-position three-way solenoid valves can switch freely between filling and venting the isolation chamber. However, to vent the isolation chamber, it is not enough to only activate the two-position three-way solenoid valve; the two-position two-way solenoid valve must also activate to achieve venting. This improves system reliability and prevents automatic venting due to a single solenoid valve failure, which could affect the safe operation of the isolation chamber. This solution uses two-position two-way solenoid valves, ensuring that venting will not occur if only the two-position three-way solenoid valve is activated. Venting can only be achieved when both two-position two-way solenoid valves are activated in conjunction. The series connection of one two-position three-way solenoid valve and one two-position two-way solenoid valve improves the availability and safety of the entire isolation chamber nitrogen supply system, ensuring the safety of the entire system.
[0024] By installing this device, the workload of operators can be reduced, and the automatic nitrogen filling control process of the electrical and signal isolation chamber can be realized. At the same time, it can also prevent the cryogenic pump from tripping due to overcharging of the isolation chamber. It can also vent the LNG cryogenic pump isolation chamber in time in case of overpressure, realize the overpressure venting function of the LNG cryogenic pump isolation chamber, and generate an alarm signal to remind the operators to pay attention and troubleshoot in time, so as to prevent the system overpressure from affecting the safety of the isolation chamber.
[0025] In this application, the nitrogen source for the nitrogen main is generally liquid nitrogen vaporization or an air-pressurized nitrogen device.
[0026] Beneficial effects of this utility model
[0027] (1) By monitoring pressure changes in real time through the control system, the system automatically determines whether the isolation chamber needs pressurization, thus reducing the workload of operators;
[0028] (2) By monitoring the pressure of the isolation chamber in real time through the control system, leakage and overpressure in the isolation chamber can be detected in a timely manner, and active discharge measures can be adopted to improve the safety of the system;
[0029] (3) Avoid system tripping caused by excessive nitrogen filling;
[0030] (4) By activating the discharge valve, the health status of the isolation chamber can be understood in a timely manner to avoid the equipment from operating with defects and causing serious accidents.
[0031] In summary, the advantages of using this automatic air replenishment device are: it achieves automated control, reduces the workload of operators, and reduces interlock trips caused by human error; through automated detection and control, it improves the safety of equipment operation, saves energy and reduces consumption, and ensures a safe and stable control process. Attached Figure Description
[0032] Figure 1 A schematic diagram of a nitrogen replenishment device for an existing electrical and signal isolation chamber.
[0033] Figure 2 This is a schematic diagram of the automatic nitrogen filling device for the cryogenic electrical and signal isolation chamber in this application.
[0034] Figure 3 This is a schematic diagram of a cryogenic storage tank.
[0035] Explanation of reference numerals in the attached figures:
[0036] L1: Nitrogen main pipe; 1: Pressure regulator; V1: Check valve; V2: No. 1 switch valve; P1: Pressure transmitter; 2: Control system; 3: Electrical and signal isolation compartment; V3: No. 2 switch valve; V4: Needle valve; V5: Two-position three-way solenoid valve; V6: Two-position two-way solenoid valve; 4: Sealing flange; 10: Cryogenic storage tank; 11: In-tank cryogenic pump; 12: Inner tank wall; 13: Cryogenic pump barrel; 14: Cryogenic pump hoisting cable; 15: Inner tank ceiling; 16: Power cable; 17: Vibration signal cable; 31: Electrical isolation compartment; 32: Signal isolation compartment; 40: Electrical control cabinet; 50: Vibration signal junction box. Detailed Implementation
[0037] The present invention will be further described below with reference to specific embodiments and accompanying drawings.
[0038] Figure 3This is a schematic diagram of a cryogenic storage tank. A cryogenic pump barrel 13 is installed inside the cryogenic storage tank 10, extending to near the bottom of the tank. The cryogenic pump 11 is lowered to the bottom of the cryogenic pump barrel 13 via a cryogenic pump hoisting cable 14. The power cable 16 of the cryogenic pump connects to an electrical isolation chamber 31 and an electrical control cabinet 40. A vibration signal cable 17 connects to a signal isolation chamber 32 and a vibration signal junction box 50. Both the electrical isolation chamber 31 and the signal isolation chamber 32 are connected to a dry nitrogen source. One end of the electrical isolation chamber and the signal isolation chamber is connected to the cryogenic pump well, and the other end is connected to the electrical control cabinet or vibration transmitter junction box. They are responsible for transmitting kinetic energy or vibration detection signals to the cryogenic pump and are key equipment for the safe operation of the cryogenic pump. The isolation chamber has a cylindrical structure and adopts a pressure-bearing and sealed design to isolate the internal space of the isolation chamber from the atmospheric environment. After being filled with pressurized nitrogen, the cryogenic natural gas from the cryogenic pump well is isolated from the air inside the cable conduit. The sealing measures of the isolation chamber are not easy to achieve a stable seal, so depressurization of the isolation chamber occurs frequently, requiring operators to manually replenish nitrogen by opening valves on-site. In actual operation, to protect the LNG low-pressure pump, if the isolation chamber seal fails and flammable gas leaks into the isolation chamber, it could potentially cause an explosion. Therefore, an overpressure interlock logic for tripping the LNG cryogenic pump is required. Thus, during manual nitrogen filling, slight operator inattention can easily lead to the nitrogen filling valve not closing in time, resulting in excessive nitrogen filling and overpressure in the isolation chamber, causing the LNG cryogenic pump to trip and resulting in unnecessary trouble.
[0039] like Figure 2 As shown, this application discloses an automatic nitrogen filling device for a cryogenic electrical and signal isolation chamber, which includes an electrical and signal isolation chamber 3. A pressure regulator 1, a needle valve V4, a check valve V1, a two-position three-way solenoid valve V5, and a pressure transmitter P1 (the pressure transmitter P1 is located on the side closer to the electrical and signal isolation chamber 3) are sequentially arranged on the nitrogen main pipe L1 connected to the electrical and signal isolation chamber.
[0040] The two-position three-way solenoid valve V5 includes a first port A, a second port B, and a third port C. The first port A and the second port B are respectively connected to the nitrogen main pipe. The third port C of the two-position three-way solenoid valve is connected to the vent pipe L2. The two-position two-way solenoid valve V6 is installed on the vent pipe L2. The pressure transmitter P1 is installed on the nitrogen replenishment line between the two-position three-way solenoid valve V5 and the electrical and signal isolation chamber 3. It is used to detect the pressure in the electrical and signal isolation chamber 3. The control system 2 is communicatively connected to the two-position three-way solenoid valve V5, the two-position two-way solenoid valve V6, and the pressure transmitter P1. The control system 2 controls the opening and closing of the two-position three-way solenoid valve and the two-position two-way solenoid valve according to the pressure detected by the pressure transmitter P1.
[0041] The electrical and signal isolation chamber is equipped with one air inlet and one air outlet. The air inlet is connected to a nitrogen replenishment pipeline to replenish nitrogen to the isolation chamber; the air outlet is sealed with a sealing flange 4 (or a threaded plug) to reduce nitrogen leakage.
[0042] When the pressure transmitter detects a pressure lower than the set value (generally 0.5±0.1MPa, preferably 0.5MPa), the control system outputs a signal to open the two-position three-way solenoid valve. Ports A and B are open, while ports B and C are closed. When ports A and B are connected, the nitrogen source is connected to the isolation chamber, thus pressurizing the electrical and signal isolation chambers.
[0043] When the pressure detected by the pressure transmitter is higher than the required value of the isolation chamber (generally 0.8±0.1MPa, preferably 0.8MPa), the control system outputs a signal to close the two-position three-way solenoid valve. Ports A and B are closed, while ports B and C are open. The isolation chamber is connected to the exhaust solenoid valve V6, and the air supply is stopped (the exhaust port of the isolation chamber is sealed and discarded. Instead, the solenoid valve V6 is connected to the air inlet of the isolation chamber, so that the exhaust function of the isolation chamber is controlled by the solenoid valve V6. The air inlet of the isolation chamber also functions as the air outlet).
[0044] When the pressure detected by the pressure transmitter is higher than the maximum allowable pressure of the isolation chamber (generally 1.0±0.1MPa, preferably 1.0MPa), the control system outputs a signal to close the two-position three-way solenoid valve, with ports A and B closed and ports B and C open. The isolation chamber is connected to the exhaust solenoid valve V6, and at the same time, the two-position two-way solenoid valve V6 is opened to discharge the overpressure gas from the isolation chamber, thus preventing the system overpressure from affecting the safety of the isolation chamber.
[0045] When the isolation chamber is actively vented (when the discharge solenoid valve (two-position two-way solenoid valve) is opened), the control system will issue an alarm signal to alert the operator and prompt them to conduct an on-site inspection to check whether there is a gas leak in the electrical and signal isolation chambers. If so, the cryogenic pump should be stopped immediately and the isolation chamber with the gas leak should be replaced promptly. Example 1
[0046] In this process, dry nitrogen is introduced into the main nitrogen pipe and reduced to a safe pressure (typically 0.6~0.8 MPaA) via a self-regulating pressure regulator 1. Then, it passes through a needle valve V4. By adjusting the opening of the needle valve, the flow rate of nitrogen entering the isolation chamber can be regulated, ensuring that the time for the isolation chamber to be filled from zero to full is controlled within 8~10 minutes. This avoids the impact of rapid nitrogen filling on the equipment and also prevents pressure fluctuations caused by rapid nitrogen filling from triggering the safety interlock of the cryogenic pump. A one-way valve V1 is then connected to ensure that nitrogen can only flow from the main nitrogen pipe to the electrical and signal isolation chamber. A two-position three-way solenoid valve V5 and a pressure transmitter P1 are sequentially installed on the pipeline after the one-way valve V1, finally connecting to the inlet of the electrical and signal isolation chamber 3.
[0047] The two-position three-way solenoid valve V5 includes a first port A, a second port B, and a third port C. The first port A and the second port B are respectively connected to the nitrogen main pipe. The third port C of the two-position three-way solenoid valve is connected to the vent pipe L2. The two-position two-way solenoid valve V6 is installed on the vent pipe L2. The pressure transmitter P1 is installed on the nitrogen replenishment line between the two-position three-way solenoid valve V5 and the electrical and signal isolation chamber 3. It is used to detect the pressure in the electrical and signal isolation chamber 3. The control system 2 is communicatively connected to the two-position three-way solenoid valve V5, the two-position two-way solenoid valve V6, and the pressure transmitter P1. The control system 2 controls the opening and closing of the two-position three-way solenoid valve and the two-position two-way solenoid valve according to the pressure detected by the pressure transmitter P1.
[0048] 1. When the pressure transmitter detects a pressure lower than the set value (0.5MPa), the control system outputs a signal to open the two-position three-way solenoid valve (ports A and B are open, ports B and C are closed; when ports A and B are connected, the nitrogen source is connected to the isolation chamber, and the electrical and signal isolation chambers are pressurized).
[0049] 2. When the pressure detected by the pressure transmitter is higher than the required value of the isolation chamber (0.8MPa), the control system outputs a signal to close the two-position three-way solenoid valve. Ports A and B are closed, while ports B and C are open, thus connecting the isolation chamber to the exhaust port and stopping the gas supply.
[0050] 3. When the pressure detected by the pressure transmitter is higher than the maximum allowable pressure of the isolation chamber (1.0MPa), the control system outputs a signal to close the two-position three-way solenoid valve, with ports A and B closed and ports B and C open. At the same time, the two-position two-way solenoid valve is opened to discharge the overpressure gas from the isolation chamber, so as to avoid the system overpressure affecting the safety of the isolation chamber.
[0051] 4. In the event of a gas leak or excessive nitrogen filling in the isolation chamber, in order to avoid danger due to overpressure in the system, the overpressure medium in the isolation chamber needs to be actively released. When the isolation chamber is actively released, the control system will issue an alarm signal (when the discharge solenoid valve is opened) to remind the operator to pay attention and take timely measures to conduct on-site investigation and check whether a gas leak has occurred in the isolation chamber. If so, the cryogenic pump needs to be stopped immediately and the isolation chamber with the gas leak should be replaced in time.
[0052] Example 1 achieves automated control, reduces the workload of operators, and reduces interlock tripping caused by human error; through automated detection and control, it improves the safety of equipment operation, saves energy and reduces consumption, and ensures a safe and stable control process. Comparative Example 1
[0053] use Figure 1The commonly used nitrogen replenishment device for the isolation chamber consists of a pressure regulator 1, a one-way valve V1, a No. 1 switch valve V2, and a pressure transmitter P1 installed sequentially on the nitrogen main pipe. It is then connected to the inlet of the electrical and signal isolation chamber 3. The pressure transmitter P1 is connected to the control system 2, and nitrogen is replenished to the isolation chamber through the opening of the No. 1 switch valve V2. There are two operating conditions: In one condition, the No. 1 switch valve V2 is fully open, and the No. 2 switch valve V3 is slightly open (ensuring a constant flow of nitrogen), ensuring stable nitrogen pressure within the isolation chamber. The operating status of the isolation chamber is monitored in real-time by monitoring the pressure of the pressure transmitter P1. In the other condition, both the No. 1 switch valve V2 and the No. 2 switch valve V3 are fully closed. Operators periodically inspect the nitrogen pressure within the isolation chamber and manually open the No. 1 switch valve V2 to replenish nitrogen when the pressure is low. This process requires extreme caution; excessive pressurization can easily lead to the interlocking shutdown of the cryogenic pump.
[0054] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.
Claims
1. An automatic nitrogen filling device for a cryogenic electrical and signal isolation chamber, characterized in that, It includes an electrical and signal isolation chamber (3), and a pressure regulator (1), a needle valve (V4), a check valve (V1), a two-position three-way solenoid valve (V5), and a pressure transmitter (P1) are sequentially installed on the nitrogen main pipe (L1) connecting the electrical and signal isolation chamber. The two-position three-way solenoid valve (V5) includes a first port A, a second port B and a third port C. The first port A and the second port B are respectively connected to the nitrogen main pipe (L1). The third port C of the two-position three-way solenoid valve is connected to the vent pipe. The two-position two-way solenoid valve (V6) is installed on the vent pipe. The pressure transmitter (P1) is installed on the nitrogen replenishment line between the two-position three-way solenoid valve (V5) and the electrical and signal isolation chamber (3) to detect the pressure in the electrical and signal isolation chamber. The control system (2) is connected to the two-position three-way solenoid valve (V5), the two-position two-way solenoid valve (V6) and the pressure transmitter (P1) and controls the opening and closing of the two-position three-way solenoid valve (V5) and the two-position two-way solenoid valve (V6) according to the detected pressure.
2. The automatic nitrogen filling device for the cryogenic electrical and signal isolation chamber according to claim 1, characterized in that, The electrical and signal isolation chamber is equipped with an air inlet and an exhaust outlet. The air inlet is connected to a nitrogen replenishment pipeline to replenish the isolation chamber with nitrogen. The exhaust outlet is sealed with a sealing flange or a plug.
3. The automatic nitrogen filling device for the cryogenic electrical and signal isolation chamber according to claim 1 or 2, characterized in that, The electrical and signal isolation compartment (3) includes an electrical isolation compartment (31) and a signal isolation compartment (32).
4. The automatic nitrogen filling device for the cryogenic electrical and signal isolation chamber according to claim 1 or 2, characterized in that, When the pressure transmitter detects that the pressure is lower than the set value, the control system outputs a signal to open the two-position three-way solenoid valve. Ports A and B are open, while ports B and C are closed. When ports A and B are connected, the nitrogen source is connected to the isolation chamber, thus pressurizing the electrical and signal isolation chambers.
5. The automatic nitrogen filling device for the cryogenic electrical and signal isolation chamber according to claim 1 or 2, characterized in that, When the pressure detected by the pressure transmitter is higher than the required value of the isolation chamber, the control system outputs a signal to close the two-position three-way solenoid valve. Ports A and B are closed, while ports B and C are open, connecting the isolation chamber to the exhaust port and stopping the gas supply.
6. The automatic nitrogen filling device for the cryogenic electrical and signal isolation chamber according to claim 1 or 2, characterized in that, When the pressure detected by the pressure transmitter is higher than the maximum allowable pressure of the isolation chamber, the control system outputs a signal to close the two-position three-way solenoid valve, closing ports A and B and opening ports B and C, connecting the isolation chamber to the exhaust port. At the same time, the two-position two-way solenoid valve is opened to discharge the overpressure gas from the isolation chamber, preventing the system overpressure from affecting the safety of the isolation chamber.
7. The automatic nitrogen filling device for the cryogenic electrical and signal isolation chamber according to claim 1 or 2, characterized in that, When the solenoid valve of the isolation chamber is opened under active venting, the control system issues an alarm signal to alert the operator and prompt them to conduct an on-site inspection to check for gas leaks in the electrical and signal isolation chambers. If a gas leak is detected, the cryogenic pump must be stopped immediately and the isolation chamber with the gas leak must be replaced promptly.
8. The automatic nitrogen filling device for the cryogenic electrical and signal isolation chamber according to claim 1 or 2, characterized in that, The automatic nitrogen filling device for the cryogenic electrical and signal isolation chamber is used in the cryogenic storage tank (10). The cryogenic storage tank (10) is equipped with a cryogenic pump barrel (13). The cryogenic pump barrel (13) extends to near the bottom of the cryogenic storage tank. The cryogenic pump (11) inside the tank is lowered to the bottom of the cryogenic pump barrel (13) via the cryogenic pump hoisting cable (14). The power cable (16) of the cryogenic pump is connected to the electrical isolation chamber (31) and the electrical control cabinet (40). The vibration signal cable (17) is connected to the signal isolation chamber (32) and the vibration signal junction box (50). The electrical isolation chamber (31) and the signal isolation chamber (32) are respectively connected to the dry nitrogen source.