Valve maintenance mechanism and valve maintenance device

Abstract

The utility model provides a valve maintenance mechanism which comprises a four-way pipe, a pressure gauge communicated with a first connector of the four-way pipe through a switching valve, an external valve communicated with a second connector of the four-way pipe, and a pressure release valve communicated with a third connector of the four-way pipe. A fourth connector of the four-way pipe can be communicated with a valve cavity of a tested valve. The external valve can selectively communicate with medium input equipment. According to the technical scheme, the valve maintenance mechanism and the valve maintenance device provided by the utility model have the advantages that the four-way pipe is connected with the external valve, the pressure release valve and the pressure gauge, so that a stable channel is established between the valve cavity of the tested valve and the outside in a state that the pressure of the high-pressure pipeline is not released, and the valve maintenance work is carried out. Meanwhile, the switching valve is used for opening or isolating the pressure gauge on the four-way pipe, the requirement that different types of media pass through the interior of the mechanism can be met, and the purpose of valve maintenance is achieved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of high-pressure pipeline valve maintenance, and in particular to a valve maintenance mechanism and a valve maintenance device. Background Art

[0002] The use of high-pressure pipelines to transport crude oil, refined oil and natural gas has the advantages of large transportation volume, long transportation distance, low transportation cost, safe and reliable transportation, etc. It is currently the main mode of transportation of natural gas and other energy sources. The maintenance of high-pressure pipeline valves is an important guarantee for pipeline transportation operations.

[0003] There are many situations in the daily maintenance of high-pressure pipeline valves, such as:

[0004] The high-pressure pipeline valve cavity is in a non-pressurized state for a long time. Under the influence of the high pressure difference between the upstream and downstream valve seats, the valve may be locked, resulting in an increase in the torque required to open the valve, or even the inability to open and close the valve. Forcibly opening and closing the valve will cause damage to the valve. At this time, it is necessary to reduce the pressure difference on both sides of the valve seat to achieve the purpose of opening the pipeline valve normally.

[0005] After a high-pressure pipeline valve has been used for a long time, scratches may appear between the valve seat and the valve body or the elastic seal of the valve may be damaged, which may cause internal leakage of the valve. It is necessary to check the internal leakage.

[0006] When a high-pressure pipeline valve has serious internal leakage and cannot be handled by conventional methods such as switching, adjusting the limit, cleaning the valve and injecting sealing grease, it is necessary to fill the valve cavity with sealing grease to achieve the purpose of complete blocking.

[0007] Currently, the pipeline valve repair tools used by professional valve maintenance engineers are low-pressure maintenance tools. The high-pressure pipeline needs to be depressurized before the operation. In addition, the tools currently used have single functions and cannot simultaneously meet the needs of valve pressurization, internal leakage inspection and full valve sealing. Utility Model Content

[0008] A technical problem to be solved by the present disclosure is: how to establish a stable passage between the valve cavity of the pipeline valve and the outside world when the high-pressure pipeline is not depressurized, and how to cope with different maintenance conditions of the high-pressure pipeline valve.

[0009] In order to solve the above technical problems, an embodiment of the present disclosure provides a valve maintenance mechanism, including a four-way pipe, a pressure gauge connected to the first interface of the four-way pipe through a switching valve, an external valve connected to the second interface of the four-way pipe, and a pressure relief valve connected to the third interface of the four-way pipe. The fourth interface of the four-way pipe can be connected to the valve cavity of the valve to be tested, and the external valve can be selectively connected to a medium input device.

[0010] In some embodiments, a cross-way pipe can be connected to a drain valve of the valve under test.

[0011] In some embodiments, the valve maintenance mechanism further includes a maintenance joint, which is used to connect the drain valve and the four-way pipe.

[0012] In some embodiments, the valve maintenance device includes a plurality of maintenance fittings of different sizes.

[0013] In some embodiments, the switching valve and the external valve are ball valves.

[0014] In some embodiments, two valve groups are provided at the root of the pressure gauge.

[0015] The present disclosure also provides a valve maintenance device, including the above-mentioned valve maintenance mechanism, and the valve maintenance device is also provided with a nitrogen container and a sealing grease container connected in parallel to the external valve.

[0016] In some embodiments, the valve maintenance device further comprises a three-way valve, the three-way valve comprises two inlets and one outlet, the nitrogen container and the sealing grease container are respectively connected to the two inlets, and the external valve is connected to the outlet.

[0017] In some embodiments, the nitrogen container is connected to one inlet port of the three-way valve via a high-pressure hose.

[0018] In some embodiments, the sealing grease container is connected to an inlet port of the three-way valve through a grease injection nozzle.

[0019] Through the above technical solution, the valve maintenance mechanism and valve maintenance device provided by the present disclosure, through the connection of the four-way pipe with the external valve, the pressure relief valve and the pressure gauge, establish a stable channel between the valve cavity of the valve under test and the outside world when the high-pressure pipeline is not depressurized, so as to perform valve maintenance work. At the same time, by using the switching valve to open or isolate the pressure gauge on the four-way pipe, the needs of different types of media passing through the interior of the mechanism can be met, thereby achieving the purpose of valve maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 It is a structural schematic diagram of the valve maintenance mechanism of the implementation scheme of this invention;

[0022] Figure 2 It is a structural schematic diagram of the valve maintenance device in the working state according to the implementation scheme of the present invention.

[0023] Description of reference numerals:

[0024] 1. Four-way pipe; 2. Switching valve; 3. External valve; 4. Pressure relief valve; 5. Drain valve; 6. Drain pipe; 7. Pressure gauge; 8. Maintenance joint; 9. Three-way valve; 10. Nitrogen container; 11. Sealing grease container. DETAILED DESCRIPTION

[0025] The following is a further detailed description of the embodiments of the present disclosure in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

[0026] The present disclosure provides these embodiments to make the present disclosure thorough and complete, and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary, and not as limiting.

[0027] It should be noted that, in the description of the present disclosure, unless otherwise specified, the meaning of "multiple" is greater than or equal to two; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating the orientation or positional relationship, are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present disclosure. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0028] In addition, the words "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. "Vertical" does not mean vertical in the strict sense, but is within the tolerance range. "Parallel" does not mean parallel in the strict sense, but is within the tolerance range. "Include" or "comprising" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements.

[0029] It should also be noted that in the description of the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances. When a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0030] All terms used in the present disclosure have the same meanings as those understood by those of ordinary skill in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, for example, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined as such herein.

[0031] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0032] like Figure 1 As shown, the present disclosure provides a valve maintenance mechanism, including a four-way pipe 1, a pressure gauge 7 connected to the first interface of the four-way pipe 1 through a switching valve 2, an external valve 3 connected to the second interface of the four-way pipe 1, and a pressure relief valve 4 connected to the third interface of the four-way pipe 1. The fourth interface of the four-way pipe 1 can be connected to the valve cavity of the valve to be tested, and the external valve 3 can be selectively connected to a medium input device.

[0033] Specifically, when in use, the fourth interface of the four-way pipe 1 is connected to the valve cavity of the valve to be tested, so that a stable channel is established between the valve cavity and the outside world, so that valve maintenance and inspection work can be carried out. The switching valve 2 is used to switch the connection state and isolation state between the four-way pipe 1 and the pressure gauge 7. The switching valve 2 is opened to make the four-way pipe 1 and the pressure gauge 7 in a connection state, and the external valve 3 and the pressure relief valve 4 are closed at the same time. By observing the reading change of the pressure gauge 7, it can be judged whether the valve to be tested has leakage; the other side of the external valve 3 is connected to the medium input device, and the medium required for maintenance, such as inert gas or sealing material, can be input into the valve cavity through the channel established by the valve maintenance mechanism; the pressure relief valve 4 can empty the pressure and impurities in the four-way pipe 1 after completing the medium input, and then remove the medium input device after confirming safety; when the medium passing through the four-way pipe 1 will penetrate into the pressure gauge 7 and damage it (such as when injecting sealing grease), the switching valve 2 is closed to make the four-way pipe 1 and the pressure gauge 7 in an isolation state, so that the valve maintenance mechanism can inject different types of media into the valve cavity to meet different maintenance conditions.

[0034] like Figure 2 As shown, in some embodiments, the cross-tube 1 can be connected to the drain valve 5 of the valve to be tested. Specifically, the valve cavity of the valve to be tested is connected with a drain pipe 6, and the drain pipe 6 is provided with a drain valve 5 at the end away from the valve cavity. The drain valve 5 is connected to the fourth interface of the cross-tube 1, and the drain valve 5 is opened, so that the valve cavity of the valve to be tested and the cross-tube 1 of the valve maintenance mechanism can form an integral space.

[0035] like Figure 2 As shown, in some embodiments, the valve maintenance mechanism further includes a maintenance joint 8, which is used to connect the drain valve 5 and the four-way pipe 1. Specifically, in order to reduce the wear of the fourth interface of the four-way pipe 1 due to repeated disassembly to extend the service life of the mechanism, a maintenance joint 8 is provided at the fourth interface of the four-way pipe 1.

[0036] In some embodiments, the valve maintenance mechanism includes a plurality of maintenance joints 8 of different sizes. Specifically, the plurality of maintenance joints 8 are connected to the fourth interface of the four-way pipe 1 by 1 / 2-14NPT standard threaded connection, and the side where the plurality of maintenance joints 8 are connected to the drain valve 5 has different sizes such as 1", 1 / 2", 3 / 8", etc., which is convenient for connecting drain valves 5 of different sizes, thereby improving the adaptability of the device.

[0037] like Figure 2 As shown, in some embodiments, the switching valve 2 and the external valve 3 are ball valves. The ball valve has the advantages of simple structure and operation principle, good sealing, and easy maintenance, which can enhance the stability of the device during use and reduce the maintenance cost of the device itself. Of course, in other embodiments, the switching valve 2 and the external valve 3 can also be other types of valves such as gate valves and stop valves, and the pressure relief valve 4 can be a conventional pressure relief plug, a ball valve, or other types of common valves.

[0038] In some embodiments, a two-valve group is provided at the root of the pressure gauge 7. The two-valve group serves as a supporting device for the pressure gauge 7 and is arranged between the pressure measuring part of the pressure gauge 7 and the switching valve 2 to play an auxiliary sealing role. When the switching valve 2 is opened, the two-valve group is in an open state, and when the switching valve 2 is closed, the two-valve group is in a closed state, which is used to enhance the sealing of the four-way pipe 1 and the pressure gauge 7 when they are in an isolated state.

[0039] In some embodiments, the valve maintenance mechanism completes the drainage and pressure relief of the valve chamber under test through the external valve 3, while the valve maintenance mechanism itself completes the drainage and pressure relief with the help of the pressure relief valve 4. The specific operation is as follows:

[0040] One end of the valve maintenance mechanism is connected to the valve under test through the maintenance joint 8, the switching valve 2 and the pressure relief valve 4 are closed, the drain valve 5 of the valve cavity under test is opened, and the pressure relief and sewage discharge of the valve cavity under test are completed by using the external valve 3, and then the external valve 3 is closed and the switching valve 2 is opened. After standing for a period of time, observe whether the reading of the pressure gauge 7 changes to determine whether there is leakage in the valve cavity under test. After the test is completed, the drain valve 5 of the valve cavity under test is closed, and then the pressure relief valve 4 is used to relieve the pressure of the valve maintenance mechanism;

[0041] One end of the valve maintenance mechanism is connected to the valve under test through the maintenance joint 8, the switching valve 2 and the pressure relief valve 4 are closed, and the other end of the external valve 3 is connected to the nitrogen-filled high-pressure hose to realize the pressurization operation of the valve cavity under test, and the switching valve 2 is opened at the same time to observe the pressure of the valve maintenance mechanism and the valve cavity under test in real time. As the pressurization process gradually proceeds, the pressure difference between the valve under test and the high-pressure pipeline gradually decreases. When the valve under test can rotate freely, it proves that the problem of the valve cavity being locked due to long-term lack of pressure has been solved through the pressurization operation. At this time, the drain valve 5 on the valve under test can be closed, and the pressure relief valve 4 can be used to relieve the pressure of the valve maintenance mechanism;

[0042] One end of the valve maintenance mechanism is connected to the valve under test through the maintenance joint 8, the switching valve 2 and the pressure relief valve 4 are closed, the drain valve 5 of the valve cavity under test is kept closed, the other end of the external valve 3 is connected to the grease injection nozzle for grease injection, and the drain valve 5 is opened at the same time. Sealing grease is poured into the valve cavity of the valve under test through the valve maintenance mechanism to fully seal the valve cavity under test. After the grease injection is completed, the drain valve 5 on the valve under test is closed, and the pressure relief valve 4 is used to relieve the pressure on the valve maintenance mechanism.

[0043] like Figure 2 As shown, the present disclosure also protects a valve maintenance device, including the above-mentioned valve maintenance mechanism, and the valve maintenance device is also provided with a nitrogen container 10 and a sealing grease container 11 connected in parallel to the external valve 3.

[0044] The valve maintenance device can complete various maintenance operations such as valve cavity pressurization, valve internal leakage detection and valve full plugging, as follows:

[0045] Valve maintenance device for valve cavity pressurization:

[0046] Connect the nitrogen container 10 with the external valve 3, connect the valve maintenance device with the valve cavity of the valve to be tested through the maintenance joint 8, open the external valve 3 to fill the valve cavity with nitrogen, and use the pressure gauge 7 to observe the pressure in the valve cavity. When the valve cavity pressure meets the requirements, close the external valve 3 to stop filling with nitrogen, close the drain valve 5 to cut off the valve cavity pressure, and then open the pressure relief valve 4 to drain the nitrogen in the valve maintenance device to restore the device to normal state.

[0047] In some embodiments, the valve cavity pressurization function of the device can solve the problem of valve locking caused by the pressure difference between the valve cavity and the pipeline. When the valve under test is in the fully closed position for a long time, the valve body is difficult to rotate relative to the valve seat due to the high pressure difference between the upstream and downstream valve seats. At this time, inert gas can be injected into the valve cavity to eliminate the pressure difference between the valve cavity and the pipeline. Before operation, confirm that each valve of the valve maintenance device is in the fully closed position to prevent leakage, open the drain valve 5 of the valve to be tested, and after draining the pressure and dirt, connect the maintenance joint 8 and the drain valve 5 to form an integral space between the valve cavity and the four-way pipe 1, connect the external valve 3 with the nitrogen container 10, slowly open the external valve 3, and open the switching valve 2 at the same time, and observe the pressure value in the valve cavity through the pressure gauge 7. As the pressure in the valve cavity gradually increases, the pressure difference between the valve cavity and the pipeline gradually decreases. Try to open the valve. When the valve can be opened normally, close the external valve 3, stop filling nitrogen into the valve cavity, and close the drain valve 5 at the same time to isolate the valve cavity from the four-way pipe 1, open the pressure relief valve 4, and drain the nitrogen in the valve maintenance device. Observe the reading of the pressure gauge 7, confirm that the pressure in the valve maintenance device is normal, and then close the pressure relief valve 4, disconnect the connection between the maintenance joint 8 and the drain valve 5, and close the switching valve 2 to ensure that each valve of the valve maintenance device is in the fully closed position for the next use;

[0048] Valve maintenance device is used for valve internal leakage detection:

[0049] Adjust the tested valve on the high-pressure pipeline to the fully closed position, confirm that all valves on the valve maintenance device are adjusted to the fully closed position to avoid pressure leakage after connection, open the drain valve 5 of the tested valve, and after draining the pressure and dirt, connect the maintenance joint 8 and the drain valve 5 to form an integral space between the valve cavity and the four-way pipe 1, open the switching valve 2, observe the pressure value in the valve cavity through the pressure gauge 7, slowly open the tested valve to allow the pressure in the high-pressure pipeline to enter the valve cavity and the four-way pipe 1, and after the reading of the pressure gauge 7 stabilizes, the pressure P0 in the valve cavity is the pipeline pressure, close the tested valve, isolate the pressure inside the valve cavity and the four-way pipe 1 from the pressure of the high-pressure pipeline, open the pressure relief valve 4 to release part of the pressure in the valve cavity and the four-way pipe 1, and then close the pressure relief valve 4 to allow a certain pressure difference between it and the pipeline pressure P0, record the reading P1 of the pressure gauge 7 at this time (the initial pressure of the valve cavity), start timing and observe the changes in the pressure gauge reading. If there is no internal leakage in the valve, the reading will rise slightly after closing the pressure relief valve 4, and then remain unchanged; if there is internal leakage in the valve, the pressure gauge reading will gradually rise, and after a period of time, record the pressure gauge reading P2 (valve cavity detection pressure).

[0050] At this time, the valve leakage V per unit time and unit nominal diameter can be calculated according to the following formula: x :

[0051] V x =(P2-P1)V0 / T·D

[0052] in:

[0053] P1: initial pressure of valve chamber (bar);

[0054] P2: Valve chamber detection pressure (bar);

[0055] V0: Valve chamber volume (m 3 ), the valve cavity volume can be obtained by consulting the valve manufacturer or from the equipment nameplate;

[0056] T: interval time (h);

[0057] D: Valve nominal diameter (in).

[0058] If we calculate V x More than 0.04m 3 / h·in, it is determined that the valve has internal leakage;

[0059] The valve maintenance device is used to fully block the valve:

[0060] Connect the sealing grease container 11 with the external valve 3, connect the valve maintenance device with the valve cavity of the valve to be tested through the maintenance joint 8, open the external valve 3 to inject sealing grease into the valve cavity, keep the switching valve 2 in the closed state during the grease injection process to prevent the sealing grease from penetrating into the pressure gauge 7 and causing damage to the pressure gauge 7, after the valve cavity is filled with sealing grease, close the external valve 3 to stop injecting sealing grease, close the drain valve 5 to prevent the sealing grease in the valve cavity from leaking, open the pressure relief valve 4, clean the sealing grease in the valve maintenance device, and after cleaning, close the pressure relief valve 4 to restore the device to normal state.

[0061] In some embodiments, the device's full valve sealing function can be used to perform emergency treatment when the leakage in the valve cavity is too large. When the valve leakage cannot be effectively handled by conventional methods such as switching, adjusting the limit, cleaning the valve and injecting sealing grease; or when the valve's external flange cannot be effectively handled by conventional tightening, especially during special hot work operations on long-distance pipeline trunk lines, sufficient sealing grease can be injected into the valve cavity to fully seal the valve. Before operation, confirm that all valves of the valve maintenance device are in full closed position to prevent leakage, open the drain valve 5 of the valve to be tested, and after draining the dirt (at this time, the valve is in a leaking state and the pressure cannot be drained, and pressure operation is required), connect the maintenance joint 8 and the drain valve 5 to form an integral space between the valve cavity and the four-way pipe 1, connect the external valve 3 with the sealing grease container 11, open the external valve 3, keep the switching valve 2 in a closed state, and use a manual or pneumatic grease injection tool to inject the sealing grease in the container into the valve cavity to achieve the purpose of full blocking. After the grease injection is completed, close the external valve 3, stop injecting sealing grease into the valve cavity, and at the same time close the drain valve 5 to isolate the valve cavity from the four-way pipe 1, open the pressure relief valve 4, drain the sealing grease in the valve maintenance device, disconnect the maintenance joint 8 and the drain valve 5, and after cleaning the sealing grease inside the device, close the pressure relief valve 4 to ensure that all valves of the valve maintenance device are in full closed position for the next use.

[0062] like Figure 2 As shown, in some embodiments, the valve maintenance device also includes a three-way valve 9, which includes two inlets and one outlet, a nitrogen container 10 and a sealing grease container 11 are respectively connected to the two inlets, and an external valve 3 is connected to the outlet.

[0063] Specifically, the nitrogen container 10 and the sealing grease container 11 are connected in parallel to the external valve 3 through the three-way valve 9. Valves are provided at the two inlets and one outlet of the three-way valve 9. By adjusting the valves of the three-way valve 9, the purpose of filling the valve cavity with high-pressure nitrogen or injecting sealing grease can be achieved.

[0064] like Figure 2 As shown, in some embodiments, the nitrogen container 10 is connected to an inlet of the three-way valve 9 through a high-pressure hose. The flexibility and high plasticity of the high-pressure hose have a good effect of eliminating vibrations of the high-pressure nitrogen passing through it, reducing the impact of the high-pressure nitrogen on the three-way valve 9, improving the stability of the device, and facilitating connection.

[0065] like Figure 2 As shown, in some embodiments, the sealing grease container 11 is connected to an inlet of the three-way valve 9 through a grease injection nozzle. One end of the grease injection nozzle is threadedly connected to an inlet of the three-way valve 9, and the other end is connected to the sealing grease container 11 through a snap buckle to ensure that the sealing grease does not leak out and can smoothly enter the interior of the four-way pipe 1.

[0066] So far, various embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0067] Although some specific embodiments of the present disclosure have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present disclosure. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict.

Claims

1. A valve maintenance mechanism, characterized in that: The invention comprises a four-way pipe (1), a pressure gauge (7) connected to a first interface of the four-way pipe (1) via a switching valve (2), an external valve (3) connected to a second interface of the four-way pipe (1), and a pressure relief valve (4) connected to a third interface of the four-way pipe (1); the fourth interface of the four-way pipe (1) can be connected to a valve cavity of a valve to be tested, and the external valve (3) can be selectively connected to a medium input device.

2. The valve maintenance mechanism according to claim 1, characterized in that: The four-way pipe (1) can be connected to the drain valve (5) of the valve to be tested.

3. The valve maintenance mechanism according to claim 2, characterized in that: The valve maintenance mechanism further comprises a maintenance joint (8), wherein the maintenance joint (8) is used to connect the sewage valve (5) and the four-way pipe (1).

4. The valve maintenance mechanism according to claim 3, characterized in that: The valve maintenance mechanism comprises a plurality of maintenance joints (8) of different sizes.

5. The valve maintenance mechanism according to claim 1, characterized in that: The switching valve (2) and the external valve (3) are ball valves.

6. The valve maintenance mechanism according to claim 1, characterized in that: The root of the pressure gauge (7) is provided with two valve groups.

7. A valve maintenance device, comprising the valve maintenance mechanism according to any one of claims 1 to 6, characterized in that: The valve maintenance device is also provided with a nitrogen container (10) and a sealing grease container (11) which are connected in parallel to the external valve (3).

8. The valve maintenance device according to claim 7, characterized in that: The valve maintenance device further comprises a three-way valve (9), wherein the three-way valve (9) comprises two inlets and one outlet, the nitrogen container (10) and the sealing grease container (11) are respectively connected to the two inlets, and the external valve (3) is connected to the outlet.

9. The valve maintenance device according to claim 8, characterized in that: The nitrogen container (10) is connected to an inlet of the three-way valve (9) via a high-pressure hose.

10. The valve maintenance device according to claim 8, characterized in that: The sealing grease container (11) is connected to an inlet of the three-way valve (9) via a grease injection nozzle.

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