A grease injection valve for gas wellheads and its usage method

Abstract

This invention discloses a grease injection valve for gas wellheads and its usage method, belonging to the technical field of grease injection valves. The valve body includes a receiving groove at one end of its inner wall and a valve passage at the other end. A connecting groove is formed inside the valve body and outside the receiving groove near the valve passage. The valve passage is connected to both the receiving groove and the connecting groove. A plug ball is movably installed inside the receiving groove near the valve passage. An injection unit is installed inside the other end of the receiving groove. The plug ball is connected to the injection unit via a support unit, and a guide unit is installed inside the support unit and connected to the plug ball. A valve cap is fixedly attached to the outside of the valve body near the valve passage. When the sealing grease pushes the plug ball through the guide unit, the plug ball rotates on the inner wall of the receiving groove. This rotation reduces the adhesion of the sealing grease and allows for the switching of the sealing surface during rotation, thus avoiding corrosion and wear on only one sealing surface during the sealing process, thereby achieving a better sealing effect.

Description

Technical Field

[0001] This invention belongs to the field of grease injection valve technology, specifically relating to a grease injection valve for gas wellheads and its usage method. Background Technology

[0002] Natural gas is a combustible gas stored deep underground. It is a clean, convenient, and efficient fuel, as well as an important chemical raw material with high economic value. Natural gas is usually extracted through gas wells. The extracted natural gas cannot be used directly and requires certain processing before it can be used as fuel, chemical raw material, or for other purposes. Depending on the different uses, the extracted natural gas is transported to different locations for processing via different routes. The flat gate valves and ball valves used in oil and gas field extraction and transportation processes are all equipped with grease injection valves. During routine maintenance of these valves, sealing grease needs to be added to the grease injection valves to protect the internal sealing mechanism and prevent leakage. Currently, most grease injection valves produced domestically are single-seal grease injection valves. This single-seal method is prone to grease leakage, failing to provide the lubrication function of the grease for the entire valve, which has a significant negative impact on the overall operation of the valve. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the present invention aims to provide a grease injection valve for gas wellheads and a method of use, so as to solve the technical problems that the single-seal grease injection valve in the prior art is prone to "running and leaking" grease, which affects the injection of sealing grease, and the leakage of the grease injection valve also leaves a safety hazard.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] This invention discloses a grease injection valve for gas wellheads, comprising: a valve body, a receiving groove at one end of the inner wall of the valve body, a valve passage at the other end, a connecting groove at the inside of the valve body and the outside of the receiving groove near the valve passage, the valve passage being connected to the inside of the receiving groove and the connecting groove, a plug ball being movably disposed inside the receiving groove near the valve passage, an injection unit being disposed inside the other end of the receiving groove, the plug ball being connected to the injection unit through a support unit, and a guide unit being disposed inside the support unit and connected to the plug ball, and a valve cap being fixedly connected to the outside of the valve body near the valve passage.

[0006] Preferably, the support unit includes a support ring, which is connected to the ball stopper. The support ring is fixed to a support tube via a connecting rod. One end of the support tube is connected to a damping spring via a fixing ring. The other end of the damping spring is connected to the filling unit. A support frame is provided inside the damping spring, with one end connected to the filling unit and the other end connected to the guide unit.

[0007] Preferably, the guiding unit includes a guide post, one end of which is fixedly connected to a ball stopper, and the other end is movably connected to a guide tube, which is fixed to the support unit.

[0008] Preferably, a fixing block is fixedly installed at one end of the guide tube away from the support tube. The fixing block is fixedly connected to the support frame of the support unit. A guide ring is fixedly connected to the surface of the support frame, and the guide ring is sleeved on the surface of the guide tube. A first limiting piece is fixedly connected to the surface of the guide ring, and a second limiting piece is fixedly connected to the surface of the guide tube. The first limiting piece and the second limiting piece are in contact with each other.

[0009] Preferably, the guide post has a spiral structure, and the inner wall of the guide tube matches the surface of the guide post.

[0010] Preferably, the filling unit includes a fixing pin, which is movably disposed at the end of the receiving groove away from the valve passage. The fixing pin has a filling hole inside, which penetrates the fixing pin and communicates with the inside of the receiving groove. A support unit is connected to the outside of the fixing pin.

[0011] Preferably, a fixed column is rotatably connected to the center of the valve cap at the position corresponding to the valve body, a plug is fixedly connected to the fixed column, a rubber gasket is provided outside the plug, and a sealing ring is fixedly connected to the surface of the rubber gasket.

[0012] Preferably, the cross-section of the plug is trapezoidal.

[0013] Preferably, the valve cap has an air vent inside, and the air vent passes through and connects both ends of the valve cap.

[0014] This invention also discloses a method for using a grease injection valve at the gas wellhead, comprising the following steps:

[0015] Inject sealing grease into the valve passage;

[0016] The sealing grease pushes the ball plug to move, and the guide unit drives the ball plug to rotate, so that the sealing grease enters the filling unit through the receiving groove to complete the filling;

[0017] The support unit pushes the ball to move in the opposite direction without rotating, returning it to its original position for sealing.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The grease injection valve for gas wellheads disclosed in this invention uses a guide unit to make the sealing grease push the plug ball, which rotates on the inner wall of the receiving groove. This rotation can reduce the adhesion of the sealing grease and change the sealing surface during the rotation process, thereby avoiding corrosion and wear on only one sealing surface during the sealing process, thus achieving a better sealing effect.

[0020] Furthermore, in the support unit, when the sealing grease no longer pushes the ball, the damping spring, in conjunction with the fixing ring, support tube, connecting rod, and support ring, drives the ball to move towards one end of the valve passage. At the same time, the guide column moves towards one end of the valve passage, and the guide tube rotates counterclockwise. This prevents the ball from rotating when it moves towards one end of the valve passage to seal. This reduces the adhesion of the sealing grease and allows the sealing surface to change during rotation, thus avoiding corrosion and wear on only one sealing surface during the sealing process, which would affect the sealing effect.

[0021] Furthermore, the inner wall of the guide tube inside the guide unit matches the surface of the guide column, so that when the sealing grease pushes the plug ball, the plug ball rotates on the inner wall of the receiving groove.

[0022] Furthermore, a fixed post is rotatably connected to the center of the valve cap at the position corresponding to the valve body. A plug is fixedly attached to the fixed post. When the valve cap is threadedly connected to the surface of the valve body, the valve cap will cause the plug to block the valve passage. When the valve cap rotates, the plug will not rotate under the action of the fixed post, thus pressing the plug tightly against the inner wall of the valve passage. In addition, through the rubber gasket and sealing ring, the rubber gasket is tightly attached to the inner wall of the valve passage, and the sealing ring is tightly attached to the end of the valve body corresponding to the valve cap position, thus making the sealing effect better. Attached Figure Description

[0023] Figure 1 This is a front sectional view of the overall structure of a grease injection valve for gas wellheads according to the present invention;

[0024] Figure 2 This is a front sectional view of the valve body structure of a grease injection valve for gas wellheads according to the present invention;

[0025] Figure 3 This is a partial orthogonal sectional view of the guide pipe structure for a grease injection valve at the gas wellhead according to the present invention;

[0026] Figure 4 This is a partial side sectional view of the guide pipe structure for a grease injection valve at the gas wellhead according to the present invention;

[0027] Figure 5 This is a flowchart illustrating the method of using a grease injection valve at a gas wellhead according to the present invention.

[0028] Wherein: 1-valve body; 2-receiving groove; 3-fixing pin; 4-filling hole; 5-valve passage; 6-connecting groove; 7-plug ball; 8-support ring; 9-connecting rod; 10-support tube; 11-fixing ring; 12-damping spring; 13-support frame; 14-fixing block; 15-guide tube; 16-guide post; 17-valve cap; 18-vent hole; 19-fixing post; 20-plug; 21-rubber pad; 22-sealing ring; 23-guide ring; 24-first limiting piece; 25-second limiting piece. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] The present invention will now be described in further detail with reference to the accompanying drawings:

[0032] In practical use, existing technologies often encounter problems because the medium being transported is generally corrosive, which can corrode the sealing structure inside the grease injection valve, causing leakage. This results in the grease being squeezed out of the valve by gas, affecting the grease injection process. Furthermore, the leakage of the grease injection valve poses a safety hazard. This invention provides a grease injection valve for gas wellheads to solve the above problems.

[0033] See Figure 1 The present invention discloses a grease injection valve for gas wellheads, comprising: a valve body 1, a receiving groove 2 at one end of the inner wall of the valve body 1, and a valve passage 5 at the other end; a connecting groove 6 at the inside of the valve body 1 and at the outside of the receiving groove 2 near the valve passage 5; the valve passage 5 is connected to the inside of both the receiving groove 2 and the connecting groove 6; a plug ball 7 is movably disposed inside the receiving groove 2 at the end near the valve passage 5; an injection unit is disposed inside the other end of the receiving groove 2; the plug ball 7 is connected to the injection unit through a support unit; and a guide unit is disposed inside the support unit and connected to the plug ball 7; and a valve cap 17 is fixedly connected to the outside of the valve body 1 at the end near the valve passage 5.

[0034] When the sealing grease is pushed by the guide unit, the ball rotates on the inner wall of the receiving groove. This rotation can reduce the adhesion of the sealing grease and change the sealing surface during the rotation process, thereby avoiding corrosion and wear on only one sealing surface during the sealing process, thus achieving a better sealing effect.

[0035] Working principle:

[0036] Inject sealing grease into the valve passage 5; the sealing grease pushes the ball plug 7 to move, and the guide unit drives the ball plug 7 to rotate, so that the sealing grease enters the filling unit through the receiving groove 2 to complete the filling; when the sealing grease no longer pushes the ball plug, the support unit pushes the ball plug 7 to move in the opposite direction without rotating, returning it to its original position for sealing.

[0037] In some embodiments, the support unit includes a support ring 8, which is connected to a ball stopper 7. The support ring 8 is fixed to a support tube 10 via a connecting rod 9. One end of a damping spring 12 is connected to the support tube 10 via a fixing ring 11. The other end of the damping spring 12 is connected to a filling unit. A support frame 13 is provided inside the damping spring 12, with one end connected to the filling unit and the other end connected to a guide unit.

[0038] Working principle:

[0039] Inject sealing grease into the valve passage 5; the sealing grease pushes the ball plug 7 to move, and the guide unit drives the ball plug 7 to rotate, so that the sealing grease enters the filling unit through the receiving groove 2 to complete the filling; when the sealing grease no longer pushes the ball plug, the damping spring 12, together with the fixing ring 11, the support tube 10, the connecting rod 9 and the support ring 8, drives the ball plug 7 to move towards one end of the valve passage 5, and at the same time the guide post 16 moves towards one end of the valve passage 5, and at this time the guide tube 15 rotates counterclockwise, so that the ball plug 7 does not rotate when it moves towards one end of the valve passage 5 to seal.

[0040] In some embodiments, the guide unit includes a guide post 16, one end of which is fixedly connected to a ball stopper 7, and the other end is movably connected to a guide tube 15, which is fixed to the support unit.

[0041] In some embodiments, a fixing block 14 is fixedly installed at one end of the guide tube 15 away from the support tube 10. The fixing block 14 is fixedly connected to the support frame 13 of the support unit. A guide ring 23 is fixedly connected to the surface of the support frame 13, and the guide ring 23 is sleeved on the surface of the guide tube 15. A first limiting piece 24 is fixedly connected to the surface of the guide ring 23, and a second limiting piece 25 is fixedly connected to the surface of the guide tube 15. The first limiting piece 24 and the second limiting piece 25 are in contact with each other.

[0042] In some embodiments, the guide post 16 has a spiral structure, and the inner wall of the guide tube 15 matches the surface of the guide post 16.

[0043] Working principle

[0044] Inject sealing grease into the valve passage 5. The sealing grease pushes the plug ball 7 to move until the sealing grease enters the receiving groove 2 at the corresponding position of valve passage 5, and enters the receiving groove 2 at the corresponding position of fixing pin 3 through the connecting groove 6. At this time, under the action of pressure, the sealing grease can enter the filling hole 4 through the receiving groove 2 and complete the grease injection operation. When the sealing grease pushes the plug ball 7 to move, it will cause the plug ball 7 to drive the guide post 16 to move towards the inner wall of the guide tube 15. Since the guide post 16 has a spiral structure and the inner wall of the guide tube 15 matches the surface of the guide post 16, the guide post 16... While moving and rotating towards the inner wall of the guide tube 15, the guide tube 15 can only rotate counterclockwise due to the cooperation between the guide ring 23, the first limiting piece 24, and the second limiting piece 25. When the guide post 16 moves towards the inner wall of the guide tube 15, the guide tube 15 cannot rotate clockwise, thus causing the guide post 16 to drive the ball plug 7 to rotate. As a result, when the sealing grease pushes the ball plug 7, the ball plug 7 rotates on the inner wall of the receiving groove 2, allowing the sealing grease to enter the filling unit through the receiving groove 2 and complete the filling. When the sealing grease no longer pushes the ball plug, the support unit pushes the ball plug 7 to move in the opposite direction without rotating, returning it to its original position for sealing.

[0045] In some embodiments, the filling unit includes a fixing pin 3, which is movably disposed at one end of the receiving groove 2 away from the valve passage 5. The fixing pin 3 has a filling hole 4 inside, which passes through the fixing pin 3 and communicates with the inside of the receiving groove 2. A support unit is connected to the outside of the fixing pin 3.

[0046] In some embodiments, a fixing post 19 is rotatably connected to the center of the valve cap 17 at the position corresponding to the valve body 1. A plug 20 is fixedly connected to the fixing post 19. A rubber pad 21 is provided outside the plug 20. A sealing ring 22 is fixedly connected to the surface of the rubber pad 21.

[0047] In some embodiments, the cross-section of the plug 20 is trapezoidal.

[0048] In some embodiments, the valve cap 17 has an air vent 18 inside, and the air vent 18 passes through and connects the two ends of the valve cap 17.

[0049] See Figure 5 The present invention also discloses a method for using a grease injection valve at a gas wellhead, comprising the following steps:

[0050] S1: Inject sealing grease into position 5 of valve passage;

[0051] S2: The sealing grease pushes the ball plug 7 to move, and the guide unit drives the ball plug 7 to rotate, so that the sealing grease enters the filling unit through the receiving groove 2 to complete the filling;

[0052] S3: The support unit pushes the ball stopper 7 to move in the opposite direction without rotating, returning it to its original position for sealing.

[0053] See Figure 1 , Figure 2 The present invention provides a technical solution comprising: a valve body 1, an inner wall of which is provided with a receiving groove 2, a valve passage 5 at one end of the valve body 1, and a connecting groove 6 in the valve body 1 corresponding to the receiving groove 2. The interior of the valve passage 5 is connected to both the receiving groove 2 and the connecting groove 6. A ball stop 7 is movably connected to the inner wall of the receiving groove 2. A support ring 8 is rotatably connected to the end of the ball stop 7 away from the valve passage 5. A connecting rod 9 is fixedly installed at the end of the support ring 8 away from the ball stop 7. A support tube 10 is fixedly installed at the end of the connecting rod 9 away from the support ring 8. A fixing ring 11 is fixedly installed on the surface of the support tube 10. A damping spring 12 is fixedly installed at the end of the fixing ring 11 away from the valve passage 5. A guide post 16 is fixedly installed at the end of the ball stop 7 away from the valve passage 5. A guide tube 15 is movably connected to the surface of the guide post 16.

[0054] As a preferred embodiment, a fixing pin 3 is movably connected to one end of the receiving groove 2 away from the valve passage 5. The fixing pin 3 has a filling hole 4 inside, which passes through and connects to both ends of the fixing pin 3. The inside of the filling hole 4 is connected to the inside of the receiving groove 2.

[0055] As a preferred embodiment, the end of the damping spring 12 away from the support tube 10 is fixedly installed at the end of the fixing pin 3 corresponding to the position of the support tube 10.

[0056] As a preferred option, see Figure 4 A fixing block 14 is fixedly installed at one end of the guide tube 15 away from the support tube 10, and a support frame 13 is fixedly installed at the other end of the fixing block 14 away from the guide tube 15. The support frame 13 is fixedly installed at one end of the fixing pin 3 corresponding to the support tube 10. A guide ring 23 is fixedly connected to the surface of the support frame 13, and the guide ring 23 is sleeved on the surface of the guide tube 15. A first limiting piece 24 is fixedly connected to the surface of the guide ring 23, and a second limiting piece 25 is fixedly connected to the surface of the guide tube 15 corresponding to the position of the first limiting piece 24. The first limiting piece 24 and the second limiting piece 25 fit together. Both the first limiting piece 24 and the second limiting piece 25 are made of rubber. The guide post 16 has a spiral structure. See [reference needed]. Figure 3 Furthermore, the inner wall of the guide tube 15 matches the surface of the guide post 16.

[0057] As a preferred embodiment, a valve cap 17 is threadedly connected to the end of the valve body 1 away from the fixed pin 3. An air vent 18 is provided inside the valve cap 17, and the air vent 18 passes through and connects both ends of the valve cap 17. A fixed post 19 is rotatably connected to the end of the valve cap 17 corresponding to the position on the valve body 1 via a bearing. A plug 20 is fixedly installed at the end of the fixed post 19 away from the valve cap 17. The plug 20 has a trapezoidal cross-section.

[0058] More preferably, a rubber pad 21 is fixedly installed on the surface of the plug 20, and a sealing ring 22 is fixedly installed on the surface of the rubber pad 21. The end of the valve passage 5 away from the plug ball 7 has a flared structure, and the inner wall of the valve passage 5 is movably connected to the surface of the rubber pad 21. When the valve cap 17 is threadedly connected to the surface of the valve body 1, the valve cap 17 will drive the plug 20 to block the valve passage 5. When the valve cap 17 rotates, the plug 20 will not rotate under the action of the fixing column 19, so that the plug 20 is pressed against the inner wall of the valve passage 5. And through the cooperation of the rubber pad 21 and the sealing ring 22, the rubber pad 21 is tightly attached to the inner wall of the valve passage 5, and the sealing ring 22 is tightly attached to the end of the valve body 1 corresponding to the valve cap 17, so as to achieve a better sealing effect.

[0059] Working principle: In use, when sealing grease is injected into the valve passage 5, the grease pushes the plug ball 7 to move away from the valve passage 5 along the inner wall of the receiving groove 2 until the sealing grease enters the receiving groove 2 at the corresponding position of the valve passage 5 and enters the receiving groove 2 at the corresponding position of the fixing pin 3 through the connecting groove 6. At this time, under the action of pressure, the sealing grease can enter the filling hole 4 through the receiving groove 2 and complete the grease injection operation. When the sealing grease pushes the plug ball 7 to move, it will cause the plug ball 7 to drive the guide post 16 to move towards the inner wall of the guide tube 15. Since the guide post 16 has a spiral structure and the inner wall of the guide tube 15 matches the surface of the guide post 16, the guide post 16 rotates while moving towards the inner wall of the guide tube 15. This is achieved through the cooperation between the guide ring 23, the first limiting piece 24, and the second limiting piece 25. This allows the guide tube 15 to rotate only counterclockwise. When the guide post 16 moves towards the inner wall of the guide tube 15, the guide tube 15 cannot rotate clockwise. This causes the guide post 16 to drive the ball plug 7 to rotate. As the sealing grease pushes the ball plug 7, the ball plug 7 rotates on the inner wall of the receiving groove 2. When the sealing grease stops pushing the ball plug 7, the damping spring 12, together with the fixing ring 11, support tube 10, connecting rod 9 and support ring 8, drives the ball plug 7 to move towards one end of the valve passage 5. At the same time, the guide post 16 moves towards one end of the valve passage 5, and the guide tube 15 rotates counterclockwise. This prevents the ball plug 7 from rotating when it moves towards one end of the valve passage 5 to seal. This reduces the adhesion of the sealing grease and allows the sealing surface to change during the rotation, thus avoiding corrosion and wear on only one sealing surface during the sealing process, which would affect the sealing effect.

[0060] The present invention has the following advantages:

[0061] 1. The present invention uses the inner wall of the guide tube to cooperate with the surface of the guide column, so that when the sealing grease pushes the plug ball, the plug ball rotates on the inner wall of the receiving groove. This rotation can reduce the adhesion of the sealing grease and change the sealing surface during the rotation process, thereby avoiding corrosion and wear on only one sealing surface during the sealing process, thus achieving the purpose of better sealing effect.

[0062] 2. The present invention also achieves better sealing by the following: when the valve cap is threadedly connected to the valve body, the valve cap will drive the plug to block the valve passage. When the valve cap rotates, the plug will not rotate under the action of the fixing column, so that the plug is pressed against the inner wall of the valve passage. In addition, the rubber gasket and the sealing ring work together to make the rubber gasket fit tightly against the inner wall of the valve passage, and the sealing ring fits tightly against the end of the valve body corresponding to the valve cap position, thereby achieving better sealing effect.

[0063] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A grease injection valve for gas wellheads, characterized in that, include: The valve body (1) has a receiving groove (2) at one end of its inner wall and a valve passage (5) at the other end. A connecting groove (6) is provided inside the valve body (1) and outside the receiving groove (2) near the valve passage (5). The valve passage (5) is connected to the inside of the receiving groove (2) and the connecting groove (6). A plug ball (7) is movably installed inside the receiving groove (2) near the valve passage (5). A filling unit is installed inside the other end of the receiving groove (2). The plug ball (7) is connected to the filling unit through a support unit. A guide unit is installed inside the support unit and connected to the plug ball (7). A valve cap (17) is fixedly connected to the outside of the valve body (1) near the valve passage (5). The support unit includes a support ring (8), which is connected to the ball stopper (7). The support ring (8) is fixed to a support tube (10) via a connecting rod (9). The support tube (10) is connected to one end of a damping spring (12) via a fixing ring (11). The other end of the damping spring (12) is connected to the filling unit. A support frame (13) is provided inside the damping spring (12), with one end connected to the filling unit and the other end connected to the guide unit. The guiding unit includes a guide post (16), one end of which is fixedly connected to a ball stopper (7), and the other end is movably connected to a guide tube (15), which is fixed on the support unit; The guide post (16) has a spiral structure, and the inner wall of the guide tube (15) matches the surface of the guide post (16), so that the guide post (16) moves towards the inner wall of the guide tube (15) and rotates at the same time.

2. The grease injection valve for gas wellheads according to claim 1, characterized in that, A fixing block (14) is fixedly installed at one end of the guide tube (15) away from the support tube (10). The fixing block (14) is fixedly connected to the support frame (13) of the support unit. A guide ring (23) is fixedly connected to the surface of the support frame (13), and the guide ring (23) is sleeved on the surface of the guide tube (15). A first limiting piece (24) is fixedly connected to the surface of the guide ring (23), and a second limiting piece (25) is fixedly connected to the surface of the guide tube (15). The first limiting piece (24) and the second limiting piece (25) fit together, so that the guide tube 15 can only rotate counterclockwise.

3. A grease injection valve for gas wellheads according to claim 1, characterized in that, The filling unit includes a fixing pin (3), which is movably disposed at one end of the receiving groove (2) away from the valve passage (5). The fixing pin (3) has a filling hole (4) inside, and the filling hole (4) passes through the fixing pin (3) and is connected to the inside of the receiving groove (2). A support unit is connected to the outside of the fixing pin (3).

4. A grease injection valve for gas wellheads according to claim 1, characterized in that, The valve cap (17) is rotatably connected to a fixed column (19) at the position corresponding to the valve body (1). A plug (20) is fixedly connected to the fixed column (19). A rubber pad (21) is provided outside the plug (20). A sealing ring (22) is fixedly connected to the surface of the rubber pad (21).

5. A grease injection valve for gas wellheads according to claim 4, characterized in that, The cross-section of the plug (20) is trapezoidal.

6. A grease injection valve for gas wellheads according to claim 1, characterized in that, The valve cap (17) has an air vent (18) inside, and the air vent (18) passes through and connects the two ends of the valve cap (17).

7. A method of using a grease injection valve for a gas wellhead as described in any one of claims 1 to 6, characterized in that, Includes the following steps: Inject sealing grease into the valve passage (5); The sealing grease pushes the plug ball (7) to move, and the guide unit drives the plug ball (7) to rotate, so that the sealing grease enters the filling unit through the receiving groove (2) to complete the filling; The support unit pushes the ball (7) to move in the opposite direction without rotating, and returns to its original position to seal.

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