Cold box ventilation structure for LNG (Liquefied Natural Gas) supply system
By installing auxiliary contact feedback systems and one-way valve structures for the No. 1 and No. 2 blowers in the LNG fuel tank, the problem of the main valve of the fuel tank being mistakenly closed due to the disappearance of negative pressure when the cold box door is opened was solved, thus achieving stable operation and safety of the LNG supply system.
Patent Information
- Application Number
- CN202520001067.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-02
- Publication Date
- 2025-11-21
- Estimated Expiration
- 2035-01-02
AI Technical Summary
The existing LNG fuel tank main valve has a problem of accidentally closing when the cold box door is opened, causing the engine to stop suddenly. The existing system is unable to effectively maintain negative pressure ventilation.
The system uses No. 1 and No. 2 fans to send feedback signals to the monitoring and alarm system via auxiliary contacts. Combined with the wind pressure sensor, it ensures that the backup fan is started in time when the fan fails, preventing the fuel tank main valve from closing accidentally. The system also ensures the one-way and safety of ventilation through one-way valves and fireproof dampers.
This effectively prevents the fuel tank main valve from closing accidentally due to the loss of negative pressure inside the cold box, reduces the probability of blower failure, and ensures the normal operation and safety of the LNG supply system.
Smart Images
Figure CN223578063U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of LNG supply system, in particular to a cold box ventilation structure for LNG supply system. BACKGROUND
[0002] The LNG supply system is a fuel supply system for providing suitable temperature and pressure for the equipment or ship using natural gas as fuel, which includes a fuel tank, a low-temperature pump, a gasification heating system, a filling system and a safety control system; in the prior art, according to the regulation requirements, when the fuel tank joint requires an effective mechanical ventilation system, the ventilation capacity is ≥ 30 times / hour; when the ventilation capacity in it is reduced, an alarm needs to be sent to remind the crew to repair, and at the same time the standby fan is automatically started. When both the two fans fail, the fuel supply valve needs to be closed, the fuel pump is stopped, the engine is stopped, the ventilation capacity is realized by monitoring the negative pressure of the fan inlet through the air pressure sensor, but when the personnel need to enter the cold box and open the door of the cold box, since the door is communicated with the outside world, at this time the negative pressure in the cold box will disappear, the sensor will misreport an alarm, even if the standby fan starts, it is still difficult to establish a negative pressure, resulting in the situation that the supply system is mistakenly closed and the engine is suddenly stopped, therefore, the present application provides a cold box ventilation structure for LNG supply system to improve the problem of LNG fuel tank main valve mis-closing. CONTENT OF THE UTILITY MODEL
[0003] In order to improve the problem of LNG fuel tank main valve mis-closing, the present application provides a cold box ventilation structure for LNG supply system.
[0004] The cold box ventilation structure for LNG supply system provided by the present application adopts the following technical scheme:
[0005] A cold box ventilation structure for LNG supply system, comprising a cold box arranged at a fuel tank joint, wherein an LNG storage tank is arranged in the cold box, a ventilation inlet and a ventilation outlet are formed in the cold box, the ventilation outlet is communicated with an air pressure sensor, and a first fan and a second fan are connected in parallel at the ventilation outlet; further comprising a monitoring and alarm system, wherein the air pressure sensor, the first fan and the second fan are in communication connection with the monitoring and alarm system.
[0006] By adopting the technical scheme, the first fan and the second fan transmit feedback signals to the monitoring alarm system through auxiliary contact, the air pressure sensor is always open, when the air pressure sensor detects that the air pressure inside the cold box is greater than a threshold value, the monitoring alarm system judges that the ventilation capacity inside the cold box is low, thereby the second fan can be controlled to start; if the detection value of the air pressure sensor is still greater than the threshold value after the second fan is started, and the operation feedback of the first fan and the second fan are both lost, the monitoring alarm system judges that the ventilation fails, thereby the fuel tank main valve is closed and the engine is stopped. The ventilation structure can prevent the problem that the fuel tank main valve is mistakenly closed when the cold box is opened and the internal negative pressure disappears, and ensure the normal operation of the LNG supply system.
[0007] Optionally, the ventilation inlet and the ventilation outlet are both provided with a fire damper.
[0008] By adopting the technical scheme, the fire damper can block the spread of fire when the cold box catches fire, thereby ensuring the safety of other devices.
[0009] Optionally, the air inlets of the first fan and the second fan are both provided with a check damper.
[0010] By adopting the technical scheme, the check damper can prevent the airflow at the first fan and the second fan from flowing backward, thereby improving the working safety of the first fan and the second fan.
[0011] Optionally, the ventilation inlet and the ventilation outlet located at one end of the cold box are both provided with a check valve.
[0012] By adopting the technical scheme, the check valve can prevent the gas from flowing backward from the ventilation inlet or the ventilation outlet, thereby ensuring the one-way flow of the ventilation structure, and ensuring the sealing and safety during the working process of the ventilation structure.
[0013] Optionally, the one-way valve comprises an air inlet pipe, an abutment plate, a sealing plate, a movable plug and an elastic member, the air inlet pipe is arranged on the inner wall of the cold box, the abutment plate and the sealing plate are arranged on the inner wall of the air inlet pipe, the movable plug is arranged through the abutment plate and the sealing plate, one end of the movable plug extending out of the abutment plate, the one end of the movable plug extending out of the abutment plate is formed with a limiting piece, the elastic member is sleeved on the peripheral wall of the movable plug extending out of the abutment plate, the elastic member abuts between the abutment plate and the limiting piece, the elastic member makes the movable plug keep a movement trend of moving away from the sealing plate, the other end of the movable plug passes through the sealing plate, the other end of the movable plug passing through the sealing plate is provided with a limiting block, the abutment plate is provided with an air inlet along the thickness direction, the part of the movable plug between the abutment plate and the sealing plate is internally provided with a ventilation channel, the peripheral wall of the movable plug between the abutment plate and the sealing plate is provided with a one-way inlet, the peripheral wall of the movable plug passing through the sealing plate is provided with a one-way outlet, and the one-way inlet and the one-way outlet are communicated with the ventilation channel.
[0014] By adopting the above technical scheme, when the gas is about to pass through the one-way valve, the gas will push the movable plug to slide, the gas enters between the abutment plate and the sealing plate through the air inlet, and further enters the one-way inlet, passes through the ventilation channel and leaves from the one-way outlet. Since the movable plug slides, the one-way outlet is dislocated from the sealing plate, so that the circulation of the gas can be realized, the non-return function is realized, and the sealing performance of the cold box as a whole is improved.
[0015] Optionally, a plug column is arranged in the air inlet, and an abutting rod is arranged at the end of the plug column away from the sealing plate, and the abutting rod is connected with the limiting piece at the end away from the plug column.
[0016] By adopting the above technical scheme, when the movable plug does not slide, the plug column is arranged in the air inlet, thereby plugging the air inlet, which can further prevent the gas on the other side of the abutment plate from leaking, improve the working effect of the one-way valve of the application, and improve the overall sealing performance.
[0017] Optionally, one end of the air inlet pipe extends out of the cold box, and a connecting flange is arranged at the end of the air inlet pipe extending out of the cold box.
[0018] By adopting the above technical scheme, the connecting flange is arranged to facilitate quick installation or disassembly of the one-way valve, thereby improving the assembly convenience.
[0019] Optionally, airtight doors are arranged on the side walls of the cold box.
[0020] By adopting the above technical scheme, the airtight doors are arranged to effectively improve the sealing performance of the cold box, reduce the probability of internal leakage, and thereby improve the use safety.
[0021] In summary, the application has at least one of the following beneficial technical effects:
[0022] 1. The first and second fans transmit feedback signals to the monitoring alarm system through auxiliary contacts, and the air pressure sensor is always open. When the air pressure sensor detects that the internal air pressure of the cold box is greater than the threshold value, the monitoring alarm system determines that the internal ventilation capacity of the cold box is low, thereby controlling the second fan to start. If the detection value of the air pressure sensor is still greater than the threshold value after the second fan is started, and the operation feedback of the first and second fans is lost, the monitoring alarm system determines that the ventilation fails, thereby closing the fuel tank main valve and stopping the engine. The ventilation structure of the application can prevent the internal negative pressure of the cold box from disappearing when the cold box is opened, causing the fuel tank main valve to be closed by mistake. The probability of simultaneous failure of the two fans is smaller, ensuring the normal operation of the LNG supply system.
[0023] 2. The one-way valve can prevent gas from flowing backward from the ventilation inlet or the ventilation outlet, thereby ensuring the one-way flow of the ventilation structure and the sealing and safety during the operation of the ventilation structure. BRIEF DESCRIPTION OF DRAWINGS
[0024] Figure 1 FIG. 1 is a structural schematic diagram of a cold box ventilation structure for an LNG supply system in an embodiment of the application.
[0025] Figure 2 FIG. 2 is an enlarged view of position A in FIG. 1. Figure 1
[0026] BRIEF DESCRIPTION OF DRAWINGS1. cold box; 11, ventilation inlet; 12, ventilation outlet; 2, LNG storage tank; 3, air pressure sensor; 4, first fan; 5, second fan; 6, fireproof air brake; 7, check air brake; 8, one-way valve; 81, air inlet pipe; 811, connecting flange; 82, abutment plate; 821, air inlet; 822, plug column; 823, connecting rod; 83, sealing plate; 84, movable plug; 841, limiting sheet; 842, limiting block; 843, ventilation channel; 844, one-way inlet; 845, one-way outlet; 85, elastic member; 9, air-tight door. DETAILED DESCRIPTION
[0027] The application will be described in further detail below with reference to the accompanying drawings. Figures 1-2 The application will be described in further detail below with reference to the accompanying drawings.
[0028] The embodiment of the application discloses a cold box ventilation structure for an LNG supply system. Referring to FIG. 1, Figure 1 which comprises a cold box 1 arranged at a fuel tank joint, an LNG storage tank 2 arranged in the cold box 1, and an air-tight door 9 arranged on one side of the cold box 1, thereby ensuring the sealing of the cold box 1. A ventilation inlet 11 and a ventilation outlet 12 are arranged on the side wall of the cold box 1, and a fireproof air brake 6 is arranged at each of the ventilation inlet 11 and the ventilation outlet 12, thereby improving the safety during the operation of the cold box 1.
[0029] Referring to FIG. 1,Figure 1 The wind pressure sensor 3 is arranged at the ventilation outlet 12 to detect the air pressure inside the cold box 1 in real time, and the first fan 4 and the second fan 5 are arranged in parallel at the ventilation outlet 12. The ventilation structure further comprises a monitoring alarm system, and the wind pressure sensor 3, the first fan 4 and the second fan 5 are in communication connection with the monitoring alarm system. The first fan 4 and the second fan 5 send running feedback signals to the monitoring alarm system through auxiliary contacts, so that the monitoring alarm system obtains the running states of the two fans. In the embodiment, the air inlet of the first fan 4 and the air inlet of the second fan 5 are provided with check air gates 7 to ensure the one-way flow of air.
[0030] With reference to Figure 1 and Figure 2 The inner walls of the ventilation inlet 11 and the ventilation outlet 12 are provided with one-way valves 8, and the installation directions of the one-way valves 8 on both sides are opposite. The one-way valve 8 comprises an air inlet pipe, an abutment plate 82, a sealing plate 83, a movable plug 84 and an elastic member 85. The air inlet pipe is connected to the ventilation inlet 11 or the ventilation outlet 12, one end of the air inlet pipe penetrates through the cold box 1, and a connecting flange 811 is arranged on the peripheral wall of the cold box 1 to facilitate quick assembly or disassembly of the one-way valve 8.
[0031] With reference to Figure 1 and Figure 2 The abutment plate 82 and the sealing plate 83 are arranged in the air inlet pipe in sequence along the flow direction of the airflow in the air inlet pipe, and the movable plug 84 penetrates through the abutment plate 82 and the sealing plate 83. The movable plug 84 penetrates through the abutment plate 82 at one end and penetrates through the sealing plate 83 at the other end. The one end of the movable plug 84 penetrating through the abutment plate 82 is provided with a limiting piece 841, and the other end penetrating through the sealing plate 83 is provided with a limiting block 842. The elastic member 85 is sleeved on the peripheral wall of the movable plug 84 penetrating through the abutment plate 82 and abuts between the limiting piece 841 and the abutment plate 82. In the embodiment, the elastic member 85 is a spring. Under the action of the elastic member 85, the movable plug 84 maintains a movement tendency away from the sealing plate 83.
[0032] With reference to Figure 1 and Figure 2 The abutment plate 82 is provided with a plurality of air inlets 821 penetrating through along the thickness direction, and the air inlets 821 are provided with plug columns 822. The one end of the plug column 822 away from the sealing plate 83 is provided with a connecting rod 823, and the diameter of the connecting rod 823 is smaller than that of the plug column 822. The other end of the connecting rod 823 is connected with the limiting piece 841. When the airflow enters the air inlet pipe, the airflow will push the limiting piece 841 to move, so that the elastic member 85 is compressed, and the plug column 822 will be separated from the air inlet 821. The airflow can enter between the abutment plate 82 and the sealing plate 83 through the air inlet 821.
[0033] With reference to Figure 1 and Figure 2The part of the movable plug 84 between the abutting plate 82 and the sealing plate 83 is internally provided with a ventilation channel 843, the peripheral wall of the movable plug 84 between the abutting plate 82 and the sealing plate 83 is provided with a one-way inlet 844, the peripheral wall of the movable plug 84 penetrating the sealing plate 83 is provided with a one-way outlet 845, and the one-way inlet 844 and the one-way outlet 845 are in communication with the ventilation channel 843. When the movable plug 84 moves, the one-way outlet 845 will be dislocated from the sealing plate 83, so as to facilitate the gas circulation.
[0034] The implementation principle of the cold box ventilation structure of the LNG supply system in the embodiment of the application is as follows: the first fan 4 and the second fan 5 transmit feedback signals to the monitoring alarm system through the auxiliary contact mode, the wind pressure sensor 3 is always open, when the wind pressure sensor 3 detects that the internal air pressure of the cold box 1 is greater than a threshold value, the monitoring alarm system judges that the internal ventilation capacity of the cold box 1 is low, so as to control the second fan 5 to start; if the detection value of the wind pressure sensor 3 is still greater than the threshold value after the second fan 5 is started, and the operation feedback of the first fan 4 and the second fan 5 is lost, the monitoring alarm system judges that the ventilation fails, so that the fuel tank main valve is closed and the engine is stopped. The ventilation structure of the application can prevent the problem that the internal negative pressure of the cold box 1 disappears when the cold box 1 is opened, and the fuel tank main valve is mistakenly closed. The probability of simultaneous failure of the two fans is smaller, and the normal operation of the LNG supply system is ensured.
[0035] The above are preferred embodiments of the application, and do not limit the protection scope of the application, so that: any equivalent changes made according to the structure, shape, principle of the application should be covered in the protection scope of the application.
Claims
1. A cold box ventilation structure for an LNG supply system, comprising a cold box (1) arranged at a fuel tank joint, wherein an LNG storage tank (2) is arranged in the cold box (1), a ventilation inlet (11) and a ventilation outlet (12) are arranged on the cold box (1), and characterized in that: The ventilation outlet (12) is communicated with a wind pressure sensor (3), and the ventilation outlet (12) is also connected with a first fan (4) and a second fan (5) in parallel; a monitoring alarm system is further included, and the wind pressure sensor (3), the first fan (4) and the second fan (5) are in communication connection with the monitoring alarm system.
2. The vent structure for a cold box of an LNG supply system according to claim 1, characterized by: The ventilation inlet (11) and the ventilation outlet (12) are provided with fireproof air brakes (6).
3. The vent structure for a cold box of an LNG supply system according to claim 1, characterized by: The air inlets (821) of the first fan (4) and the second fan (5) are provided with check air brakes (7).
4. The cold box vent structure for an LNG supply system according to claim 1, characterized by: The ventilation inlet (11) and the ventilation outlet (12) located at one end in the cold box (1) are provided with one-way valves (8).
5. The cold box vent structure for an LNG supply system according to claim 4, characterized by: The one-way valve (8) comprises an air inlet pipe (81), an abutment plate (82), a sealing plate (83), a movable plug (84) and an elastic element (85), the air inlet pipe (81) is arranged on the inner wall of the cold box (1), the abutment plate (82) and the sealing plate (83) are arranged on the inner wall of the air inlet pipe (81), the movable plug (84) penetrates through the abutment plate (82) and the sealing plate (83) and is arranged, one end of the movable plug (84) close to the air inlet pipe (81) extends out of the abutment plate (82), a limiting sheet (841) is formed on the end of the movable plug (84) extending out of the abutment plate (82), the elastic element (85) is sleeved on the peripheral wall of the movable plug (84) extending out of the abutment plate (82), the elastic element (85) abuts between the abutment plate (82) and the limiting sheet (841), the elastic element (85) makes the movable plug (84) keep a movement trend in a direction away from the sealing plate (83), the other end of the movable plug (84) penetrates through the sealing plate (83), a limiting block (842) is arranged on the end of the movable plug (84) penetrating through the sealing plate (83), the abutment plate (82) is provided with an air inlet (821) penetratingly arranged along the thickness direction, a ventilation channel (843) is arranged inside the part of the movable plug (84) between the abutment plate (82) and the sealing plate (83), a one-way inlet (844) is arranged on the peripheral wall of the movable plug (84) between the abutment plate (82) and the sealing plate (83), a one-way outlet (845) is arranged on the peripheral wall of the movable plug (84) penetrating through the sealing plate (83), and the one-way inlet (844) and the one-way outlet (845) are in communication with the ventilation channel (843).
6. The cold box vent structure for an LNG supply system according to claim 5, characterized by: A plug column (822) is arranged in the air inlet (821), one end of the plug column (822) away from the sealing plate (83) is provided with a connecting rod (823), and the other end of the connecting rod (823) away from the plug column (822) is connected with the limiting sheet (841).
7. The cold box vent structure for an LNG supply system according to claim 5, characterized by: One end of the air inlet pipe (81) extends out of the cold box (1), and the end of the air inlet pipe (81) extending out of the cold box (1) is provided with a connecting flange (811).
8. The vent structure for a cold box of an LNG supply system according to claim 1, characterized by: An airtight door (9) is arranged on the side wall of the cold box (1).