A safety liquid seal device and method

Abstract

The application discloses a safe liquid seal device and method, relates to a liquid seal device, and is characterized in that an inner pipe and an outer pipe are fixed on a tank body and are communicated with each other, the inner pipe is located in the tank body, the outer pipe is located outside the tank body, a liquid outlet of the inner pipe, a liquid inlet of the outer pipe and a liquid level position in the tank body are located on the same horizontal plane in space, and a gas outlet end of the gas inlet pipe is located lower than the liquid level position in the tank body in space. The application can guarantee the sealing effect of the liquid seal, prevent gas channeling, automatically discharge and supply liquid medium dynamically, avoid the gas in the tank body from being in a high-pressure state or an under-pressure state, adjust the operating pressure of the gas inlet end equipment on the tank body, and guarantee the normal operation of the mechanical equipment connected with the gas outlet end of the tank body and the stable liquid seal pressure in the tank body.

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid seal device, in particular to a safe liquid seal device and method. BACKGROUND

[0002] The safe liquid seal device is widely used in chemical production, especially in the aspects of overpressure safety discharge, regulating gas outlet pressure, etc., and is also widely used in the sealing of toxic, harmful, flammable and explosive gas phase media, such as the liquid column sealing of flammable and explosive acetylene medium in the natural gas acetylene process. With the increasing requirements for the operation of chemical devices, especially the liquid seal device with outstanding effects in the aspects of environmental protection, intelligence, safety, etc.

[0003] The existing safe liquid seal can basically realize the liquid sealing function, but since the liquid inlet pipe and the liquid outlet pipe of the liquid phase are located in the same space, the gas phase medium often enters the liquid inlet pipe and enters the pump or other equipment through the pipe, which can cause cavitation and even damage to the running pump, and can affect the safety and process operation requirements of the equipment; the equipment cannot dynamically supply and discharge the liquid level, and the fluctuation of the inlet gas pressure during the operation of the liquid seal can cause the liquid level to change constantly, the change of the liquid level can affect the liquid seal pressure, and the gas in the tank body can also appear in the high pressure state or underpressure state, which can affect the normal operation of the equipment (such as the reactor, compressor) connected with the gas outlet of the tank body, and can cause accidents in serious cases; when the gas discharge pressure of the inlet pipe breaks through the liquid seal pressure, the gas discharge is uneven, the gas contains a high amount of liquid, and the equipment generates a large vibration, which affects the service life and safety of the equipment. SUMMARY

[0004] The purpose of the present application is to provide a safe liquid seal device and method, which can ensure the sealing effect of the liquid seal, prevent gas leakage, dynamically automatically discharge and supply the liquid medium, avoid the gas in the tank body appearing in the high pressure state or underpressure state, adjust the operating pressure of the equipment at the gas inlet end of the tank body, and ensure the normal operation of the mechanical equipment connected with the gas outlet end of the tank body and the stability of the liquid seal pressure in the tank body.

[0005] The technical scheme adopted by the present application is as follows: a safe liquid seal device, comprising a tank body with an inlet pipe, an inner pipe and an outer pipe which are in communication with each other are fixed on the tank body, the inner pipe is located in the tank body, the outer pipe is located outside the tank body, a liquid inlet for adding liquid is arranged on the outer pipe, the liquid outlet of the inner pipe and the liquid level position in the tank body are in the same horizontal plane in space, and the gas outlet end of the inlet pipe is lower than the liquid level position in the tank body in space.

[0006] Further, an outlet is formed on the tank body, the outlet is higher than the liquid outlet in space, and a breather valve is arranged at the outlet, which controls the balance of the internal and external gas pressures of the tank body.

[0007] Further, a filling pipe for adding liquid to the liquid inlet is fixed on the outer side wall of the tank body, and the liquid outlet end of the filling pipe is located above the liquid inlet with a gap between them.

[0008] Further, a buffer container is fixed on the outer side wall of the tank body, and the liquid inlet is located in the buffer container; the filling pipe is fixed on the buffer container.

[0009] Further, a liquid discharge pipe is arranged at the bottom of the buffer container for discharging the overflow liquid in the buffer container.

[0010] Further, the gas inlet pipe is arranged vertically, and the gas flow direction in the gas inlet pipe is from the top of the tank body to the bottom of the tank body.

[0011] Further, a diffuser is arranged at the gas outlet end of the gas inlet pipe, and a plurality of V-shaped tooth grooves are arranged on the diffuser.

[0012] Further, a discharge port pipe is arranged at the bottom of the tank body for discharging the liquid in the tank body.

[0013] A safe liquid sealing method using the safe liquid sealing device, comprising the following steps:

[0014] S1: When the gas pressure in the gas inlet pipe fluctuates, the liquid in the tank body has a tendency to enter the gas inlet pipe, and the liquid level in the tank body has a tendency to decrease;

[0015] S11: After S1, the liquid in the outer pipe gives the liquid level in the tank body to keep the liquid level in the tank body, and the gas pressure in the tank body remains unchanged to ensure the liquid sealing pressure.

[0016] S2: When the gas pressure in the gas inlet pipe fluctuates, the liquid in the gas inlet pipe has a tendency to enter the tank body, and the liquid level in the tank body has a tendency to rise;

[0017] S21: After S2, the liquid in the tank body flows through the inner pipe into the outer pipe to overflow, so that the liquid level in the tank body remains unchanged, and the gas pressure in the tank body remains unchanged to ensure the liquid sealing pressure.

[0018] S3: When the gas pressure in the gas inlet pipe exceeds the liquid sealing liquid level height in the tank body, the gas in the gas inlet pipe overflows into the tank body until the gas pressure in the tank body reaches the opening pressure of the breather valve, and the breather valve opens to discharge and relieve pressure, so that the gas pressure inside and outside the tank body is balanced.

[0019] Further, S4: In the normal liquid sealing state, the liquid level in the tank body is higher than the gas outlet end of the gas inlet pipe in the space position to realize liquid sealing.

[0020] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0021] 1. Under the premise of ensuring liquid sealing, the present invention can automatically replenish or overflow the liquid in the tank body when the gas pressure in the intake pipe fluctuates, so that the liquid level in the tank body remains stable, thereby maintaining a stable liquid sealing pressure in the tank body;

[0022] 2. When the tank is connected to other machinery, the present invention can maintain a stable liquid level in the tank and a stable gas phase pressure above the liquid level in the tank, thereby preventing the gas in the tank from being in a high-pressure or low-pressure state, regulating the pressure at the gas inlet end, and ensuring the normal operation of the mechanical equipment at the gas inlet connection end;

[0023] 3. The filling pipe on the liquid inlet pump is isolated from the air outlet pipe, and the liquid exists in the inner tube of the present invention, which can effectively prevent gas from entering the liquid inlet pump through the inner tube, prevent cavitation and gas leakage of the liquid inlet pump, and ensure the sealing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0025] Figure 1 A schematic structural diagram of a first embodiment of the present invention;

[0026] Figure 2 It is a structural schematic diagram of a second embodiment of the present invention;

[0027] Figure 3 It is a structural schematic diagram of a third embodiment of the present invention;

[0028] Figure 4 This is a liquid flow diagram of the present invention during low-pressure fluctuation state / ultra-low-pressure fluctuation;

[0029] Figure 5 This is a liquid flow diagram of the present invention during high pressure fluctuation state / ultra-high pressure fluctuation;

[0030] Markings in the figure: 1-tank body; 11-air outlet; 12-air inlet pipe; 121-diffuser, 122-V-shaped tooth groove; 13-drain pipe; 2-external pipe; 21-liquid inlet; 3-inner pipe; 31-liquid outlet; 4-buffer container; 4-drain pipe; 5-filling pipe; 6-breathing valve. DETAILED DESCRIPTION

[0031] All features disclosed in this specification, or all steps in the disclosed methods or processes, except mutually exclusive features and / or steps, can be combined in any manner.

[0032] Any feature disclosed in this specification, unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0033] like Figures 1-5 As shown, a safety liquid sealing device includes a tank body 1 with an air inlet pipe 12, the tank body 1 stores the liquid for liquid sealing, and an inner pipe 3 and an outer pipe 2 are fixed to the tank body 1 to communicate with each other. In this embodiment, the inner pipe 3 and the outer pipe 2 can be components of a U-shaped tube, the inner pipe 3 is located inside the tank body 1, and the outer pipe 2 is located outside the tank body 1. The outer pipe 2 is provided with a liquid inlet 21 for adding liquid, and the inner pipe 3 and the outer pipe 2 are both arranged vertically, and their axes are parallel to the axis of the tank body 1, because the hydraulic pressure is related to the vertical height; the liquid level position in the tank body 1 and the position of the liquid outlet 31 of the inner pipe 3 are spatially on the same horizontal plane, so that the air inlet pipe 12 No matter how the air pressure inside fluctuates, as long as it is within the normal fluctuation range (the air pressure in the air inlet pipe will not break the liquid seal), the liquid level height in the tank body 1 will not change, and thus the liquid seal pressure will not change, and the gas pressure in the tank body (the gas pressure above the liquid) will not change. Therefore, the purpose of liquid seal stability is achieved, and for other machinery connected to the tank body 1, the air pressure at the air outlet is stable, further ensuring the air pressure stability of other machinery; the air outlet end of the air inlet pipe 12 is spatially lower than the liquid level position in the tank body 1, and the liquid blocks the air inlet pipe 12, thereby achieving normal liquid seal for the air inlet pipe 12.

[0034] It should be noted that the liquid sealing pressure refers to the pressure generated by the liquid in the tank body 1.

[0035] Specifically, in this embodiment, in the first implementation mode, as Figure 1As shown, when the air pressure inside the tank body 1 is equal to the air pressure outside the tank body 1 or both are at normal pressure, for this embodiment, the normal pressure state is used for explanation below, and the liquid outlet 31 of the inner tube 3 is flush with the liquid inlet 21 of the outer tube 2 in the spatial position, that is, the liquid level position inside the inner tube 3 and the liquid level position of the outer tube 2 should be in the same plane in terms of spatial position, and the outer tube 2 can continuously add liquid, and the liquid level position of the outer tube 2 can be maintained at the position of the liquid inlet 21 of the outer tube 2, and the liquid of the inner tube 3 The outlet 31 and the liquid level position in the tank body 1 are spatially on the same horizontal plane. Therefore, the liquid level positions in the tank body 1, the liquid level positions in the inner pipe 3 and the liquid level positions in the outer pipe 2 are all consistent; and the pressure that produces the liquid seal is the liquid level height in the tank body 1. When an allowable (normal) air pressure fluctuation occurs in the air inlet pipe 12, the liquid in the tank body 1 is promptly replenished or overflowed through the liquid outlet 31, so that the liquid level position in the tank body 1 remains constant, thereby maintaining a constant liquid seal pressure and a constant gas pressure in the tank body 1.

[0036] Furthermore, in the second embodiment, if Figure 2 As shown, when the air pressure inside the tank body 1 is lower than the air pressure outside the tank body 1, the spatial position of the liquid outlet 31 of the inner tube 3 needs to be higher than the spatial position of the liquid inlet 21 of the outer tube 2. That is, the liquid level in the inner tube 3 is higher than the liquid level in the outer tube 2. The outer tube 2 can continuously add liquid, and the liquid level of the outer tube 2 can be maintained at the position of the liquid inlet 21 of the outer tube 2. In addition, the liquid outlet 31 of the inner tube 3 and the liquid level in the tank body 1 are spatially on the same horizontal plane. Therefore, the liquid level in the tank body 1 and the liquid level in the inner tube 3 are both stably higher than the liquid level in the outer tube 2. The pressure that creates a liquid seal is the liquid level height in the tank body 1. When allowable (normal) air pressure fluctuations occur in the air inlet pipe 12, the liquid in the tank body 1 is promptly replenished or overflowed through the liquid outlet 31, so that the liquid level in the tank body 1 remains constant, thereby maintaining a constant liquid seal pressure and a constant gas pressure in the tank body 1.

[0037] Furthermore, in the third embodiment, if Figure 3As shown, when the air pressure inside the tank 1 is higher than the air pressure outside the tank 1, the spatial position of the liquid outlet 31 of the inner pipe 3 needs to be lower than the spatial position of the liquid inlet 21 of the outer pipe 2, that is, the liquid level position inside the inner pipe 3 is lower than the liquid level position of the outer pipe 2, and the outer pipe 2 can continuously add liquid, and the liquid level position of the outer pipe 2 can be kept at the position of the liquid inlet 21 of the outer pipe 2, and the liquid outlet 31 of the inner pipe 3 and the liquid level position inside the tank 1 are at the same level in space, so the liquid level position inside the tank 1 and the liquid level position inside the inner pipe 3 are both stably lower than the liquid level position inside the outer pipe 2; and the pressure of the liquid seal is the liquid level height inside the tank 1. When the allowable (normal) air pressure fluctuation occurs in the air inlet pipe 12, the liquid inside the tank 1 is supplemented or overflowed in time through the liquid outlet 31, so that the liquid level position inside the tank 1 is kept constant, thereby keeping the liquid seal pressure constant, and the air pressure inside the tank 1 is constant.

[0038] In this embodiment, when the air pressure inside the tank 1 and the air pressure outside the tank 1 are both in a normal pressure state, that is, the liquid level position inside the tank 1, the liquid level position inside the inner pipe 3 and the liquid level position inside the outer pipe 2 are consistent, and the air pressure in the air inlet pipe 12 fluctuates, that is, high pressure fluctuation or low pressure fluctuation occurs; for normal high pressure fluctuation, such as Figure 1 and Figure 5 As shown, the air pressure in the air inlet pipe 12 pushes the liquid in the air inlet pipe 12 into the tank 1, resulting in a decrease in the gas space inside the tank 1 and an increase in the air pressure inside the tank 1 (greater than the normal pressure state), and the liquid inside the tank 1 enters the outer pipe 2 through the liquid outlet 31 of the inner pipe 3 and overflows through the liquid inlet 21 of the outer pipe 2; for the case of abnormal super-high pressure fluctuation, that is, the air pressure in the air inlet pipe 12 is greater than the liquid seal pressure inside the tank 1, the air pressure in the air inlet pipe 12 will break the liquid seal, and the gas will enter the tank 1, thereby causing the air pressure inside the tank 1 to be higher than the normal pressure state, and the liquid inside the tank 1 has no feasible flow (pressure relief) direction, so the gas inside the tank 1 can only compress and push the liquid inside the inner pipe 3, causing the liquid inside the inner pipe 3 to flow towards the outer pipe 2, and the outer pipe 2 overflows, until the air pressure inside the tank 1 is in a normal pressure state. Thereafter, the liquid inside the inner pipe 3 to the outer pipe 2 also forms a liquid seal for the gas inside the tank 1, which can avoid gas leakage caused by abnormal pressure fluctuation, and since the liquid level position inside the tank 1 does not change, the liquid seal pressure also remains relatively unchanged; on the other hand, the air pressure inside the tank is kept in a normal pressure state; for the case of normal low pressure fluctuation and abnormal super-low pressure fluctuation in the air inlet pipe 21, such as Figure 1 and Figure 4As shown, the liquid in the tank 1 increases the amount of air entering the inlet pipe 12, the liquid in the tank 1 decreases, resulting in the space above the liquid level in the tank 1 increasing, so that the air pressure in the tank 1 is lower than the normal pressure state, and then the liquid in the outer pipe 2 enters the inner pipe 3, so that the liquid in the tank 1 is replenished; the above process is a dynamic process, so the liquid level in the tank 1 is relatively unchanged, maintaining the liquid seal pressure; the air pressure in the tank 1 can also be dynamically maintained at normal pressure, and when other machinery is connected to the tank, the embodiment can maintain the liquid level in the tank stable, so that the air pressure at the air outlet 11 is stable, and further ensure the air pressure stability of other machinery connected to the air outlet 11.

[0039] In the embodiment, when the tank 1 is connected with other machinery, the tank 1 is provided with an air outlet 11, and the other machinery is connected to the air outlet 11. The outlet pipe is higher in space position than the liquid outlet 31 or / and the liquid level position in the tank 1, so as to avoid the liquid in the tank 1 blocking the outlet pipe. The air outlet 11 is provided with a breather valve 6, which controls the balance of the air pressure inside and outside the tank 1. In the case of the above-mentioned super-high pressure, the over-high air pressure will not break the liquid seal state in the inner pipe 3 and the outer pipe 2. This effect is due to the breather valve 6 provided at the air outlet 11. The breather valve 6 will open under a certain pressure. When the air pressure in the tank 1 reaches the pressure value at which the breather valve 6 opens, the breather valve 6 opens, so that the air pressure in the tank 1 is released, thereby balancing the air pressure inside and outside the tank 1.

[0040] Generally, in the embodiment, the liquid seal height in the tank 1 is usually required to reach the opening pressure of the breather valve 6, that is, to satisfy the condition that the air inlet pipe 12 can break the liquid seal and be timely relieved.

[0041] In the embodiment, the outer side wall of the tank 1 is fixed with a filling pipe 5 for adding liquid to the liquid inlet 21. The filling pipe 5 continuously adds liquid to the liquid inlet 21, maintaining the liquid seal ability. The liquid outlet end of the filling pipe 5 is located above the liquid inlet 21 and there is a gap between the liquid inlet 21 and the liquid outlet end of the filling pipe 5. The existence of the gap ensures that the air pressure state of the liquid inlet 21 is normal pressure state.

[0042] In the embodiment, the filling pipe 5 is usually connected with a liquid inlet pump, which provides energy for the liquid flow in the filling pipe 5.

[0043] In the embodiment, the outer side wall of the tank 1 is fixed with a buffer container 4, and the liquid inlet 21 is located in the buffer container 4. The buffer container 4 buffers the overflow liquid at the liquid inlet 21, and the liquid is automatically discharged through the buffer container 4. The filling pipe 5 is fixed to the buffer container 4.

[0044] In the embodiment, in order to realize automatic discharge of the liquid in the buffer container 4, the bottom of the buffer container 4 is provided with a liquid discharge pipe 41 for discharging the liquid in the buffer container 4.

[0045] Further, in the embodiment, according to the working condition, the liquid discharge pipe 41 and the filling pipe 5 can be communicated to form a liquid circuit, so as to achieve the purpose of circulating the liquid and reduce the waste of the liquid.

[0046] In the embodiment, the gas inlet pipe 12 is vertically arranged, and the gas flow direction in the gas inlet pipe 12 is from the top of the tank body 1 to the bottom of the tank body 1.

[0047] In the embodiment, the gas outlet end of the gas inlet pipe 12 is provided with a diffusion piece 121, and a plurality of V-shaped tooth grooves 122 are formed on the diffusion piece 121. When the gas pressure in the gas inlet pipe 12 appears abnormal pressure fluctuation, especially when the pressure is too high, the gas in the gas inlet pipe 12 is diffused and discharged through the diffusion piece 121, and then is uniformly released into the liquid in the tank body 1 through the V-shaped tooth grooves 122, so as to avoid that the liquid is oscillated due to the too large impact of the super-high pressure gas on the liquid, and when the pressure in the gas inlet pipe 12 instantaneously exceeds the static pressure of the liquid seal, the gas can be uniformly overflowed through the diffusion piece 121 and the V-shaped tooth grooves 122, and the excess pressure is released through the breather valve 6, so as to automatically adjust the pressure in the tank body to the initial sealing state.

[0048] In the embodiment, the bottom of the tank body 1 is provided with a discharge port pipe 13 for discharging the liquid in the tank body 1 when the liquid seal gas inlet pipe 12 is not needed.

[0049] A safe liquid sealing method using the safe liquid sealing device, comprising the following steps:

[0050] S0: initial state: the initial pressure of the buffer container 4 and the tank body 1 is equal, generally in a normal pressure state, the liquid enters the liquid inlet 21 through the filling pipe 5, the liquid enters the inner pipe 3 from the liquid inlet 21 and enters the tank body from the liquid outlet 31, when the liquid level reaches the upper edge of the liquid inlet 21 and the liquid level position in the tank body 1 is at the same position as the inner pipe 2, the liquid overflows from the upper edge of the liquid inlet 21 to the buffer container 4, and is discharged through the lower liquid discharge port of the buffer container 4;

[0051] S1: when the gas pressure in the gas inlet pipe 12 appears low pressure fluctuation, the liquid in the tank body 1 has a tendency to enter the gas inlet pipe 12, and the liquid level in the tank body 1 has a tendency to decrease;

[0052] S11: after S1, the liquid in the outer pipe 2 supplements the liquid level in the tank body 1, so that the liquid level in the tank body 1 is maintained, and the liquid seal pressure in the tank body 1 is ensured;

[0053] S2: When the air pressure in the inlet pipe 12 has a high pressure fluctuation, the liquid in the inlet pipe 12 has a tendency to enter the tank 1, and the liquid level in the tank 1 has a rising tendency;

[0054] S21: After S2, the liquid in the tank 1 flows through the inner pipe 3 into the outer pipe 2 overflow, so that the liquid level in the tank 1 is maintained, ensuring the liquid seal pressure in the tank 1.

[0055] It should be noted that the air pressure fluctuations described in S1, S11, S2, S21 are all normal working condition allowable air pressure fluctuations, that is, even if it is a high pressure fluctuation, it will not break the liquid seal pressure in the tank 1.

[0056] S3: When the air pressure in the inlet pipe 12 exceeds the liquid seal liquid level height in the tank 1, that is, a non-normal air pressure fluctuation under normal working conditions, the gas in the inlet pipe 12 breaks through the liquid seal of the liquid in the tank 1, and the gas in the inlet pipe 12 overflows into the tank 1, until the air pressure in the tank 1 reaches the opening pressure of the breather valve 6, the breather valve 6 opens to vent and relieve pressure, so that the air pressure inside and outside the tank 1 is balanced, that is, in this embodiment, the gas phase pressure in the tank 1 is balanced with the gas phase pressure in the buffer container 4.

[0057] S4: In the normal liquid seal state and without air pressure fluctuation, the liquid level in the tank 1 is higher than the outlet end of the inlet pipe 12 in the spatial position, realizing the liquid seal.

[0058] The present application is not limited to the foregoing specific embodiments. The present application extends to any novel feature or any new combination described in this specification, and any new method or process steps or any new combination disclosed.

Claims

1. A safety liquid seal device comprising a tank body (1) having an air inlet pipe (12), characterised in that: The tank body (1) is fixed with an inner pipe (3) and an outer pipe (2) which are in communication with each other, the inner pipe (3) is located in the tank body (1), the outer pipe (2) is located outside the tank body (1), the outer pipe (2) is provided with a liquid inlet (21) for adding liquid, the liquid outlet (31) of the inner pipe (3) and the liquid level position in the tank body (1) are in the same horizontal plane in space, and the gas outlet end of the air inlet pipe (12) is lower than the liquid level position in the tank body (1) in space; the tank body (1) is provided with a gas outlet (11), and the gas outlet (11) is higher than the liquid outlet (31) in space; The outer side wall of the tank body (1) is fixed with a filling pipe (5) for adding liquid to the liquid inlet (21) of the outer pipe (2), and the liquid outlet end of the filling pipe (5) is located above the liquid inlet (21) and has a gap with the liquid inlet (21); The gas outlet end of the air inlet pipe (12) is provided with a diffusion member (121), and the diffusion member (121) is processed with a plurality of V-shaped tooth grooves (122).

2. The safety fluid-filled device according to claim 1, characterized in that: The gas outlet (11) is provided with a breathing valve (6), when the high pressure fluctuation of the air inlet pipe (12) exceeds the liquid seal pressure of the tank body (1), the breathing valve (6) is opened to release pressure, and the breathing valve (6) balances the internal and external air pressure of the tank body (1).

3. The safety fluid-filled device according to claim 1, wherein: The outer side wall of the tank body (1) is fixed with a buffer container (4), and the liquid inlet (21) is located in the buffer container (4); the filling pipe (5) is fixed on the buffer container (4).

4. The safety fluid-filled device according to claim 3, wherein: The bottom of the buffer container (4) is provided with a drain pipe (41) for draining the liquid in the buffer container (4).

5. The safety fluid-filled device according to claim 1, wherein: The air inlet pipe (12) is vertically arranged, and the gas flow direction in the air inlet pipe (12) is from the top of the tank body (1) to the bottom of the tank body (1).

6. The safety fluid-filled device according to claim 1, wherein: The bottom of the tank body (1) is provided with a discharge port pipe (13) for discharging the liquid in the tank body (1).

7. A method of safety fluid sealing using the safety fluid sealing device according to any one of claims 2 to 6, characterized in that: The method comprises the following steps: S1: when the air pressure in the air inlet pipe (12) appears low pressure fluctuation, the liquid in the tank body (1) has the tendency to enter the air inlet pipe (12), and the liquid level in the tank body (1) has the tendency to decrease; S11: after S1, the liquid in the outer pipe (2) supplements the liquid level in the tank body (1), so that the liquid level in the tank body (1) is maintained, and the liquid seal pressure in the tank body (1) is ensured; S2: when the air pressure in the air inlet pipe (12) appears high pressure fluctuation, the liquid in the air inlet pipe (12) has the tendency to enter the tank body (1), and the liquid level in the tank body (1) has the tendency to rise; S21: after S2, the liquid in the tank body (1) enters the outer pipe (2) overflow through the inner pipe (3), so that the liquid level in the tank body (1) is maintained, and the liquid seal pressure in the tank body (1) is ensured; S3: When the air pressure in the inlet pipe (12) exceeds the liquid level height in the tank (1), the gas in the inlet pipe (12) overflows into the tank (1), until the air pressure in the tank (1) reaches the opening pressure of the breather valve (6), the breather valve (6) opens to exhaust and release pressure, so that the air pressure in the tank (1) is balanced.

8. The safety liquid seal method according to claim 7, wherein: S4: In the normal liquid seal state, the liquid level in the tank (1) is higher than the gas outlet end of the inlet pipe (12) in the spatial position, realizing liquid seal.

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