Positive and negative pressure protector

Abstract

The utility model relates to the technical field of biogas fermentation engineering, and provides a positive and negative pressure protector. The positive and negative pressure protector comprises an outer cylinder, an inner cylinder, a first water retaining component, an exhaust pipe and a connecting pipe, the outer cylinder is provided with a water seal medium; the inner cylinder is connected to the top of the outer cylinder, part of the inner cylinder is located below the liquid level of the water seal medium, the inner cylinder and the outer cylinder form a liquid seal structure, and a water level rising channel is formed in the inner cylinder; the first water retaining component is arranged on the water level rising channel, and the water retaining surface of the first water retaining component faces the liquid level of the water seal medium; the exhaust pipe is connected to the inner cylinder and is communicated with the inner cylinder and the outside; and the connecting pipe is connected to the outer cylinder and communicates with the outer cylinder and the to-be-connected piece. According to the positive and negative pressure protector provided by the utility model, under the condition of high pressure, the first water retaining component can effectively prevent the water level from rising too fast and prevent a water seal medium from rushing to the outside of equipment, and can play a role in retaining, so that the positive and negative pressure protector is ensured to move stably, the water replenishing frequency is reduced, and the use experience of a user is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of biogas fermentation engineering, in particular to a positive and negative pressure protector. Background Art

[0002] During the process of biogas production, a certain amount of pressure will inevitably be generated on the gas storage membrane or fermentation tank. There is an upper limit to the pressure that the gas storage membrane or fermentation tank can withstand. If the pressure inside the tank or membrane exceeds this value, it may cause the tank or membrane to burst and cause serious safety accidents. When the tank is fed and stirred, the gas production will increase suddenly, and a large amount of biogas will quickly gather in the tank, generating very high pressure. If the biogas cannot be removed in time, it is easy to cause safety accidents. In addition, if the tank pressure is too low, the external atmospheric pressure will be greater than the internal pressure of the tank, and the tank will be subjected to an extrusion force from the atmospheric pressure. If the internal and external pressure difference reaches a certain value, the tank will be flattened by the atmospheric pressure, which is also a very serious safety accident. Positive and negative pressure protectors are currently used to protect biogas fermentation equipment, but the water seal medium inside the positive and negative pressure protectors on the market is easy to lose, causing users to need to replenish water on site multiple times; and, when the positive pressure is positive, the gas enters the water seal medium, and the positive and negative pressure protectors are prone to vibration during operation. The above problems cause troubles in use and poor user experience. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the related art. To this end, the utility model provides a positive and negative pressure protector to solve the defect that the positive and negative pressure protectors in the prior art cannot play a normal protective role, ensure the stable movement of the positive and negative pressure protectors, reduce the number of water replenishment, and improve the user experience.

[0004] The utility model provides a positive and negative pressure protector, comprising:

[0005] The outer cylinder is provided with a water sealing medium;

[0006] An inner cylinder is connected to the top of the outer cylinder, the inner cylinder is partially located below the liquid level of the water seal medium, and forms a liquid seal structure with the outer cylinder, and a water level rising channel is formed inside the inner cylinder;

[0007] A first water retaining component is arranged in the water level rising channel, and a water retaining surface of the first water retaining component faces the liquid surface of the water sealing medium;

[0008] An exhaust pipe connected to the inner cylinder and communicating with the inner cylinder and the outside;

[0009] The connecting pipe is connected to the outer cylinder and communicates with the outer cylinder and the part to be connected.

[0010] According to the positive and negative pressure protector provided by the utility model, under high pressure, the first water retaining component can effectively prevent the water level from rising too quickly and the water sealing medium from rushing to the outside of the equipment. The first water retaining component can play a blocking effect, thereby ensuring the stable movement of the positive and negative pressure protector, reducing the number of water replenishment times, and improving the user experience.

[0011] According to one embodiment of the utility model, the inner tube includes a pipe mouth portion and an expanded diameter portion, the pipe mouth portion is partially located below the liquid level of the water seal medium, the expanded diameter portion is connected to the pipe mouth portion, the inner diameter of the expanded diameter portion is larger than the inner diameter of the pipe mouth portion, the expanded diameter portion is arranged above the pipe mouth portion and connected to the outer tube, and the first water retaining component is arranged on the expanded diameter portion.

[0012] According to an embodiment of the present utility model, the first water retaining component includes a connecting portion and a water retaining portion, the connecting portion is fixedly connected to the diameter-enlarging portion, and the water retaining portion is connected to the connecting portion.

[0013] According to an embodiment of the present utility model, the gap area between the water retaining portion and the expanded diameter portion is not less than the cross-sectional area of ​​the pipe mouth portion.

[0014] According to an embodiment of the utility model, a protrusion is provided at the bottom of the inner cylinder, and the protrusion is provided around the liquid inlet of the inner cylinder.

[0015] According to an embodiment of the present invention, a second water-blocking component is further included. The second water-blocking component is arranged inside the outer cylinder, and a water-blocking surface of the second water-blocking component faces away from the opening position of the connecting pipe.

[0016] According to an embodiment of the present utility model, the distance between the connecting pipe and the liquid surface of the water sealing medium is 3 mm-5 mm.

[0017] According to an embodiment of the utility model, it also includes a fluid replenishment bucket, which is connected to the inner cylinder, a fluid replenishment channel is formed inside the fluid replenishment bucket, a valve is provided on the fluid replenishment channel, and a fluid replenishment bucket cover is provided on the top of the fluid replenishment channel.

[0018] According to an embodiment of the utility model, it also includes a liquid level gauge, the bottom of the liquid level gauge is connected to the outer cylinder and the water sealing medium, the upper part of the liquid level gauge is connected to the outer cylinder, and the top of the liquid level gauge is provided with a pipe cap, and the pipe cap can close the liquid level gauge.

[0019] According to an embodiment of the utility model, a pressure gauge is further included, and the pressure gauge is connected to the gas medium in the outer cylinder.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 It is a structural schematic diagram of a positive and negative pressure protector provided by an embodiment of the utility model.

[0023] Reference numerals:

[0024] 1. outer cylinder; 11. second water retaining member;

[0025] 2. Inner tube; 21. Water level rising channel; 22. Orifice; 23. Expanded diameter portion; 24. Protruding portion;

[0026] 3. first water retaining member; 31. connecting portion; 32. water retaining portion;

[0027] 4. Water seal medium; 41. Liquid level;

[0028] 5. Exhaust pipe;

[0029] 6. Connecting pipe; 61. Flange interface;

[0030] 7. Fluid filling hopper; 71. Fluid filling channel; 72. Valve; 73. Fluid filling hopper cover;

[0031] 8. Liquid level gauge; 81. Pipe cap;

[0032] 9. Pressure gauge. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be described clearly and completely in conjunction with the drawings in the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0034] The utility model provides a positive and negative pressure protector, please refer to Figure 1The positive and negative pressure protector comprises an outer tube 1, an inner tube 2, a first water retaining component 3, an exhaust pipe 5 and a connecting pipe 6. The outer tube 1 is provided with a water seal medium 4; the inner tube 2 is connected to the top of the outer tube 1, and a part of the inner tube 2 is located below the liquid level 41 of the water seal medium 4, forming a liquid seal structure with the outer tube 1, and a water level rising channel 21 is formed inside the inner tube 2; the first water retaining component 3 is arranged in the water level rising channel 21, and the water retaining surface of the first water retaining component 3 faces the liquid level 41 of the water seal medium 4; the exhaust pipe 5 is connected to the inner tube 2 and connects the inner tube 2 with the outside; the connecting pipe 6 is connected to the outer tube 1 and connects the outer tube 1 with the part to be connected.

[0035] According to the positive and negative pressure protector provided by the utility model, under high pressure, the first water retaining component 3 can effectively prevent the water level from rising too quickly and the water sealing medium 4 from rushing to the outside of the equipment. The first water retaining component 3 can play a blocking effect, thereby ensuring the stable movement of the positive and negative pressure protector, reducing the number of water replenishment times, and improving the user experience.

[0036] It can be understood that the outer cylinder 1 and the inner cylinder 2 constitute the main structure of the positive and negative pressure protector, which plays a supporting and fixing role. The outer cylinder 1 is filled with a water seal medium 4, and the inner cylinder 2 is located inside the water seal medium 4, forming a liquid seal structure, which together ensures the normal operation of the positive and negative pressure protector.

[0037] The exhaust pipe 5 is connected to the inner cylinder 2, and is used to discharge the biogas accumulated inside or to replenish air into the tank, so as to keep the pressure inside the tank within a safe range. The utility model does not limit the shape and location of the exhaust pipe 5, as long as it ensures that the biogas can be released in a timely and effective manner or the air can be replenished in a timely manner. In one embodiment, the inner cylinder 2 and the exhaust pipe 5 are on the same axis and the structure of the inner cylinder 2 is symmetrical about the axis.

[0038] The connecting pipe 6 is connected to the outer cylinder 1, and is used to connect the positive and negative pressure protector with the part to be connected, and the part to be connected can be other equipment or a pipeline system. For ease of understanding, the part to be connected hereinafter refers to the fermentation tank. Of course, the part to be connected is not limited to the fermentation tank, but can also be other equipment. When the fermentation tank generates negative pressure, the external air can be replenished into the fermentation tank in time through the connecting pipe 6 to maintain the pressure balance inside and outside the tank.

[0039] The water seal medium 4 forms a closed liquid seal structure between the outer cylinder 1 and the inner cylinder 2 to maintain the pressure balance of the system. Water is one of the most common water seal media 4, but other liquids can also be used, such as antifreeze, saturated salt water, oil, etc.

[0040] It should be noted that the water retaining surface of the first water retaining member 3 faces the liquid surface 41 of the water sealing medium 4, and can be used to positively block the splashing from the water sealing medium 4. The splashing of the water sealing medium 4 here can be caused by various reasons, such as bubbles, or a sudden increase in pressure, etc. The water retaining surface can be a plane (for example Figure 1 It can be a structure in , or a surface.

[0041] According to one embodiment of the utility model, the inner tube 2 includes a pipe mouth portion 22 and an expanded diameter portion 23, the pipe mouth portion 22 is partially located below the liquid level 41 of the water seal medium 4, the expanded diameter portion 23 is connected to the pipe mouth portion 22, the inner diameter of the expanded diameter portion 23 is larger than the inner diameter of the pipe mouth portion 22, the expanded diameter portion 23 is arranged above the pipe mouth portion 22 and connected to the outer tube 1, and the first water retaining component 3 is arranged on the expanded diameter portion 23.

[0042] It is understandable that the nozzle 22 is located below the liquid level 41 of the water seal medium 4, which can ensure that under normal operation, gas cannot enter the water seal medium 4 through the inner tube 2, thereby enhancing the water seal effect. In addition, when the water level of the inner tube 2 rises, the expanded diameter portion 23 has a buffer space with a cross-section change compared to the nozzle 22, which is conducive to water falling back and ensuring the stability of the positive and negative pressure protector.

[0043] The first water retaining member 3 is disposed at the enlarged diameter portion 23 , which can more effectively prevent the liquid in the water sealing medium 4 from rushing out of the exhaust pipe 5 , thereby reducing the loss of the water sealing medium 4 .

[0044] In one embodiment, the height of the enlarged diameter portion 23 is greater than or equal to the height of the water level drop of the outer cylinder 1 when the biogas flow rate is at a maximum.

[0045] It can be understood that the height of the expanded diameter portion 23 is greater than or equal to the height of the water level drop in the outer cylinder 1 when the biogas flow rate is maximum, which can ensure that there is enough space for the water level to rise in the expanded diameter portion 23 under high flow conditions.

[0046] According to an embodiment of the utility model, the first water retaining component 3 includes a connecting portion 31 and a water retaining portion 32, wherein the connecting portion 31 is fixedly connected to the diameter expansion portion 23, and the water retaining portion 32 is connected to the connecting portion 31. It can be understood that by fixing the connecting portion 31 to the diameter expansion portion 23, a firm connection is formed between the first water retaining component 3 and the inner tube 2. The first water retaining component 3 is connected to the connecting portion 31 and is appropriately positioned above the diameter expansion portion 23, effectively preventing the liquid in the water seal medium 4 from rushing out of the exhaust pipe 5.

[0047] In one embodiment, the water retaining portion 32 is a plate-shaped structure, and its plate surface is parallel to the liquid surface 41 of the water sealing medium 4, so as to achieve the best water retaining effect.

[0048] Of course, the water retaining portion 32 may also be other structures, and this embodiment is only used as an example rather than a limitation to the water retaining portion 32 .

[0049] In one embodiment, the connecting portion 31 is disposed at the position where the cross-section of the expanded diameter portion 23 and the nozzle portion 22 changes. It can be understood that the position where the cross-section of the expanded diameter portion 23 and the nozzle portion 22 changes has strong stability, and the connecting portion is fixed at the position where the cross-section of the expanded diameter portion 23 and the nozzle portion 22 changes, and the overall structure is more stable.

[0050] According to an embodiment of the utility model, the water retaining area of ​​the water retaining surface is not less than the cross-sectional area of ​​the nozzle portion 22. It is understandable that the gap area between the water retaining portion 32 and the expanded diameter portion 23 is greater than or equal to the cross-sectional area of ​​the nozzle portion 22 to ensure that the gas is discharged or replenished into the tank in time to maintain the pressure balance inside and outside the tank.

[0051] According to an embodiment of the utility model, a protrusion 24 is provided at the bottom of the inner cylinder 2, and the protrusion 24 is provided around the liquid inlet of the inner cylinder 2. When the pressure of the part to be connected to the connecting pipe 6 is too high, the protrusion 24 can break the bubbles in the equipment, prevent the positive and negative pressure protectors from vibrating, and thus ensure the stable operation of the equipment.

[0052] In one embodiment, the protrusion 24 is sawtooth-shaped.

[0053] Of course, the raised portion 24 is not limited to the sawtooth structure shown in the current figure, and may also adopt other structures, such as a triangle or other irregular structures, as long as the bubbles in the device can be broken.

[0054] According to an embodiment of the present invention, the positive and negative pressure protector further comprises a second water retaining component 11 , which is disposed inside the outer tube 1 , and a water retaining surface of the second water retaining component 11 faces away from the opening position of the connecting pipe 6 .

[0055] It can be understood that when the fermentation tank is subjected to negative pressure protection, air in the atmosphere is replenished into the tank body through the connecting pipe 6, and the water seal medium 4 will be driven by the impact of the airflow and then splashed into the fermentation tank body. The second water retaining component 11 can effectively prevent the water seal medium 4 from rushing into the connecting pipe 6 and causing the water seal medium 4 to be reduced.

[0056] It should be noted that the water retaining surface of the second water retaining member 11 is facing away from the opening of the connecting pipe 6, and can be used to block the splashing droplets of the water sealing medium 4. The splashing of the water sealing medium 4 here can be caused by various reasons, such as bubbles, or air flow impact from the exhaust pipe 5. The water surface of the second water retaining member 11 can be a plane (for example, Figure 1 It can be a structure in , or a surface.

[0057] It is understandable that during the positive pressure protection process, the first water retaining component 3 can effectively reduce the possibility of the water seal medium 4 overflowing and rushing out of the exhaust pipe 5, and during the negative pressure protection process, the second water retaining component 11 can effectively reduce the possibility of the water seal medium 4 overflowing and splashing into the fermentation tank body. The first water retaining component 3 and the second water retaining component 11 work together to greatly reduce the frequency of water seal medium maintenance of the positive and negative pressure protectors. The water seal medium 4 of the positive and negative pressure protectors is not easy to overflow, and the user does not need to frequently replenish the water seal medium 4, which reduces the use cost and maintenance cost and improves the reliability and economy of the equipment.

[0058] According to an embodiment of the present invention, the distance between the connecting pipe 6 and the liquid level 41 of the water sealing medium 4 is 3mm-5mm. It is understandable that the connecting pipe 6 and the liquid level 41 of the water sealing medium 4 are relatively close, which can avoid excessive water addition, resulting in changes in the protection pressure and affecting the structural safety of the protected equipment.

[0059] According to one embodiment of the utility model, the positive and negative pressure protector also includes a liquid replenishing bucket 7, which is connected to the inner tube 2. A liquid replenishing channel 71 is formed inside the liquid replenishing bucket 7. The liquid replenishing channel 71 is provided with a valve 72, and a liquid replenishing bucket cover 73 is provided on the top of the liquid replenishing channel 71.

[0060] It is understandable that the liquid replenishing hopper 7 can replenish the consumed water sealing medium 4, ensure that the water sealing medium 4 is always at an appropriate liquid level, and ensure the protective effect of the positive and negative pressure protector. The valve 72 can prevent the water sealing medium 4 from being flushed to the outside of the device through the liquid replenishing hopper 7 under high pressure.

[0061] It is understandable that the liquid infusion funnel cover 73 can protect the liquid infusion channel 71 and prevent external environmental factors (such as dust, water vapor, etc.) from affecting the liquid infusion channel.

[0062] According to one embodiment of the utility model, the positive and negative pressure protector also includes a liquid level gauge 8, the bottom of the liquid level gauge 8 is connected to the outer tube 1 and the water sealing medium 4, the upper part of the liquid level gauge 8 is connected to the outer tube 1, and a pipe cap 81 is provided on the top of the liquid level gauge 8, which can close the liquid level gauge 8.

[0063] It is understandable that the level meter 8 can accurately monitor the liquid level in the biogas fermentation device to ensure that the liquid level of the water seal medium 4 is within a normal range. A pipe cap 81 is provided on the top of the level meter 8 to prevent the water seal medium 4 from being flushed to the outside of the device under high pressure.

[0064] According to an embodiment of the present invention, the positive and negative pressure protector further includes a pressure gauge 9, which is connected to the gas in the outer tube 1. It can be understood that the pressure gauge 9 can monitor the gas pressure in the outer tube 1 in real time, accurately reflect the balance of the gas pressure inside and outside the system, and help to find pressure abnormalities in time.

[0065] According to an embodiment of the utility model, the connecting pipe 6 is provided with a flange interface 61. It is understandable that the flange interface 61 makes the connecting pipe 6 easy to install and disassemble, which is convenient for daily maintenance and equipment replacement. Quick assembly and disassembly can be achieved through simple bolt connection, reducing the time and cost of the maintenance process.

[0066] According to an embodiment of the present invention, the exhaust pipe 6 is connected to the outer tube 1 , and the exhaust pipe 6 and the connecting pipe 3 have the same diameter.

[0067] It is understandable that the exhaust pipe 6 and the connecting pipe 3 having the same diameter can reduce the resistance and turbulence of the fluid during the connection process, help optimize the fluid dynamics performance of the system, improve the exhaust efficiency, and thus reduce the possibility of splashing of the water sealing medium 4.

[0068] In the description of the embodiments of the present utility model, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present utility model and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present utility model. In addition, the terms "first", "second", and "third" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0069] In the description of the embodiments of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, wherein the fixed connection can include an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present utility model can be understood according to specific circumstances.

[0070] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0071] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model embodiment. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A positive and negative pressure protector, characterized in that: include: The outer cylinder is provided with a water sealing medium; An inner cylinder is connected to the top of the outer cylinder, the inner cylinder is partially located below the liquid level of the water seal medium, and forms a liquid seal structure with the outer cylinder, and a water level rising channel is formed inside the inner cylinder; A first water retaining component is arranged in the water level rising channel, and a water retaining surface of the first water retaining component faces the liquid surface of the water sealing medium; An exhaust pipe connected to the inner cylinder and communicating with the inner cylinder and the outside; The connecting pipe is connected to the outer cylinder and communicates with the outer cylinder and the part to be connected.

2. The positive and negative pressure protector according to claim 1, characterized in that: The inner tube includes a pipe mouth portion and an expanded diameter portion, the pipe mouth portion is partially located below the liquid level of the water seal medium, the expanded diameter portion is connected to the pipe mouth portion, the inner diameter of the expanded diameter portion is larger than the inner diameter of the pipe mouth portion, the expanded diameter portion is arranged above the pipe mouth portion and connected to the outer tube, and the first water retaining component is arranged on the expanded diameter portion.

3. The positive and negative pressure protector according to claim 2, characterized in that: The first water-blocking component includes a connecting portion and a water-blocking portion, the connecting portion is fixedly connected to the diameter-enlarging portion, and the water-blocking portion is connected to the connecting portion.

4. The positive and negative pressure protector according to claim 2, characterized in that: The gap area between the water retaining portion and the expanded diameter portion is not less than the cross-sectional area of ​​the pipe mouth portion.

5. The positive and negative pressure protector according to any one of claims 1 to 4, characterized in that: A convex portion is arranged at the bottom of the inner cylinder, and the convex portion is arranged around the liquid inlet of the inner cylinder.

6. The positive and negative pressure protector according to any one of claims 1 to 4, characterized in that: It also includes a second water-blocking component, which is arranged inside the outer tube, and a water-blocking surface of the second water-blocking component faces away from the opening position of the connecting pipe.

7. The positive and negative pressure protector according to any one of claims 1 to 4, characterized in that: The distance between the connecting pipe and the liquid surface of the water sealing medium is 3 mm-5 mm.

8. The positive and negative pressure protector according to any one of claims 1 to 4, characterized in that: It also includes a fluid replenishment bucket, which is connected to the inner cylinder, a fluid replenishment channel is formed inside the fluid replenishment bucket, a valve is provided on the fluid replenishment channel, and a fluid replenishment bucket cover is provided on the top of the fluid replenishment channel.

9. The positive and negative pressure protector according to any one of claims 1 to 4, characterized in that: It also includes a liquid level gauge, the bottom of which is connected to the outer cylinder and the water sealing medium, the upper part of which is connected to the outer cylinder, and the top of which is provided with a pipe cap, which can close the liquid level gauge.

10. The positive and negative pressure protector according to any one of claims 1 to 4, characterized in that: It also includes a pressure gauge, which is connected to the gas medium in the outer cylinder.

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