Hydrate plugging device for gas pipeline

Abstract

The present invention relates to the field of pipeline repair facilities, and in particular to a hydrate plugging device for a gas transmission pipeline, comprising a cylindrical shell, an upper baffle being fitted and installed at the inner upper edge of the cylindrical shell, a convex ring extending coaxially from the inner upper edge of the cylindrical shell, a groove being formed on the outer surface of the upper baffle, the convex ring being fitted inside the groove, a lower baffle being fitted and installed near the inner lower edge of the cylindrical shell, a hole-opening device and an injection device being installed between the upper and lower baffles, and a flange being fixedly installed at the outer lower edge of the cylindrical shell. The present invention saves manpower and time during plugging, and can adjust the spray direction of the nozzle, effectively meeting the spraying requirements, and can save more effort when opening holes.

Description

Technical Field

[0001] The present invention relates to the field of pipeline repair facilities, and in particular to a hydrate plugging device for a gas pipeline. Background Art

[0002] With the rapid development of my country's economy, the demand for energy has become increasingly important, so it is necessary to strengthen research in areas such as long-distance oil and gas pipeline equipment to meet energy needs.

[0003] The most mature and widely used method for emergency repairs on long-distance natural gas pipelines in China is to stop transmission and replace pipes. This involves venting the natural gas in the pipeline between the combustion valves while the pipeline is shut down. Nitrogen is then used to dilute the natural gas concentration before the pipe replacement operation is performed. However, this method results in the loss of a significant amount of natural gas within the pipeline's valves and consumes significant amounts of nitrogen resources. This operation is time-consuming and costly.

[0004] The natural gas hydrate plugging and pipe replacement device for gas pipelines is mainly used when there is a problem with the gas pipeline. When the long-distance natural gas pipeline is shut down and the pipe is replaced, there is no need to empty the large amount of natural gas in the combustion valve spacing, and there is no need to use a large amount of nitrogen to dilute the natural gas concentration in the pipeline between the valves. This can save a lot of time and resources, and can also reduce costs and safety risks. However, when the existing hydrate plugging device is plugging, it is necessary to open the hole and then take time and effort to switch to the injection system for plugging. The process is quite labor-intensive and time-consuming. Summary of the Invention

[0005] The purpose of the present invention is to solve the shortcomings of the background technology and to propose a hydrate plugging device for a gas pipeline.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is: a hydrate plugging device for a gas pipeline, comprising a cylindrical shell, an upper baffle is fittedly installed at the inner upper edge of the cylindrical shell, a convex ring extends coaxially at the inner upper edge of the cylindrical shell, a groove is provided on the outer surface of the upper baffle, the convex ring fits inside the groove, a lower baffle is fittedly installed near the lower edge of the cylindrical shell, an open-hole injection component is installed between the upper baffle and the lower baffle, and a flange is fixedly installed at the lower edge of the outer surface of the cylindrical shell.

[0007] Preferably, a positioning block extends from the side edge of the upper end surface of the upper partition, and two limit blocks are symmetrically fixedly installed on the upper end surface of the cylinder shell, and the positioning block is attached to one of the limit blocks.

[0008] Preferably, the open-hole injection component includes a No. 2 threaded rod that is rotatably embedded in the edge of the other side of the upper end face of the upper partition, a No. 2 threaded sleeve is screwed on the outer surface of the No. 2 threaded rod, and the lower end of the No. 2 threaded sleeve is fixedly connected to the lower partition, and a No. 1 threaded sleeve is fitted and installed through the rear edge of the upper end face of the upper partition, and a sleeve is fitted and installed through the rear edge of the upper end face of the upper partition and on the side of the No. 1 threaded sleeve, the lower end of the No. 1 threaded sleeve and the lower end of the sleeve are both fixedly connected to the lower partition, and the lower end of the No. 1 threaded sleeve and the lower end of the sleeve both pass through the lower end face of the lower partition.

[0009] Preferably, a No. 1 threaded rod is screwed inside the No. 1 threaded sleeve, a drill bit is coaxially fixedly installed on the lower end of the No. 1 threaded rod, a tool is coaxially inlaid on the outer surface of the No. 1 threaded rod near the lower edge for coaxial rotation, a large gear is coaxially fixedly installed on the outer surface of the tool, a rotating shaft is fitted inside the sleeve, a small gear is coaxially inlaid on the lower end of the rotating shaft, the small gear is meshed with the large gear, and the drill bit is lower than the tool.

[0010] Preferably, the outer covers of the small gear and the large gear are provided with a gear housing, the No. 1 threaded rod and the rotating shaft are rotated through the upper end of the gear housing, and the tool is rotated through the lower end of the gear housing.

[0011] Preferably, a shell is embedded through the front edge of the upper end face of the upper partition, and the shell is fitted through the lower end face of the lower partition. The shell is symmetrical with the center line of the partition above the No. 1 threaded sleeve as the center of symmetry. A guide seat is provided on the inner side of the shell, and guide wheels are installed in a circular array on the upper and lower end faces of the guide seat, and the guide wheels are fitted on the inner wall of the shell.

[0012] Preferably, a spray pipe is installed passing through the interior of the guide seat, the lower end of the spray pipe is connected to a nozzle through a hose, an adjusting ball is coaxially fixedly installed on the outer surface of the nozzle, a ball seat is fitly installed in the middle of the outer surface of the adjusting ball, the ball seat is fixed to the guide seat, a push rod is fixedly installed on the upper end of the guide seat, the push rod extends from the upper end of the outer shell, a limiting sleeve is fixedly installed on the upper end of the outer shell, and the push rod fits and passes through the interior of the limiting sleeve.

[0013] Preferably, rubber pads are provided inside the limiting sleeve and inside the ball seat, a wireless monitor is fixedly installed on the side of the ball seat, two connecting seats are installed on the upper part of the outer surface of the adjusting ball at a ninety-degree offset, a push rod is rotatably installed inside the connecting seat, the push rod passes through the interior of the guide seat and extends from the upper end of the outer shell, a connecting frame is fixedly installed on the lower end of the guide seat, the lower end of the connecting frame is fixedly connected to the ball seat, a fixing frame is extended from the inner wall of the guide seat, and the end of the fixing frame is fixedly connected to the injection pipe.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. Through the hole-opening ejection part, the No. 2 threaded rod can be rotated to make the No. 2 threaded sleeve move downward, thereby driving the lower partition to move downward, and the drill bit and the cutter on the lower partition to move downward together. When the drill bit fits on the pipe, the No. 1 threaded rod is rotated to make the No. 1 threaded rod drive the drill bit to rotate and move downward to drive the drill bit into the pipe. At this time, the cutter penetrates the pipe under the push of the No. 1 threaded rod, and then the shaft is rotated to use the small gear and the large gear to drive the cutter to rotate to cut the pipe wall. After completion, rotate the No. 2 threaded rod in the opposite direction to raise and reset the drill bit and the tool, and at the same time rotate the upper partition to move the drill bit and the tool away from the hole. At the same time, turn the shell to the opening, and then push the push rod to drive the nozzle to move down from the opening into the pipeline for jet sealing. At this time, the guide wheel on the guide seat will roll against the inner wall of the shell to assist the movement of the nozzle, thereby completing the sealing operation. The process does not require time-consuming and labor-intensive switching to the jet system for sealing after the hole is opened, which effectively saves manpower and time.

[0016] 2. During the spraying process, the two push rods that are offset by 90 degrees can be pulled or pressed respectively to drive the adjustment ball to rotate in the ball seat, thereby driving the nozzle to move and adjust the spraying direction of the nozzle to meet the spraying requirements.

[0017] 3. When the device is drilling a hole, the small gear drives the large gear to rotate and drill the hole, which can reduce the force and make the hole drilling more labor-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of a hydrate plugging device for a gas pipeline according to the present invention;

[0019] Figure 2 This is an internal view of a hydrate plugging device for a gas pipeline according to the present invention;

[0020] Figure 3 This is a bottom view of a hydrate plugging device for a gas pipeline according to the present invention;

[0021] Figure 4 This is an internal view of a gear housing of a hydrate plugging device for a gas pipeline according to the present invention;

[0022] Figure 5 This is a schematic diagram of a guide seat of a hydrate plugging device for a gas pipeline according to the present invention;

[0023] Figure 6 This is a schematic diagram of a restriction sleeve of a hydrate plugging device for a gas pipeline according to the present invention;

[0024] Figure 7This is a schematic diagram of an adjusting ball of a hydrate plugging device for a gas pipeline according to the present invention;

[0025] Figure 8 This is a schematic diagram of the actual working of a hydrate plugging device for a gas pipeline according to the present invention.

[0026] In the figure: 1. Cylinder shell; 2. Flange; 3. Upper partition; 4. Limit block; 5. Positioning block; 6. Sleeve shell; 7. Rotating shaft; 8. No. 1 threaded sleeve; 9. No. 1 threaded rod; 10. No. 2 threaded rod; 11. Outer shell; 12. Limiting sleeve; 13. No. 2 threaded sleeve; 14. Lower partition; 15. Adjusting ball; 16. Guide seat; 17. Convex ring; 18. Groove; 19. Ball seat; 20. Connecting frame; 21. Wireless monitor; 22. Push rod; 23. Connecting seat; 24. Nozzle; 25. Guide wheel; 26. Jet pipe; 27. Propelling rod; 28. Fixed frame; 29. ​​Gear shell; 30. Large gear; 31. Small gear; 32. Tool; 33. Drill bit. DETAILED DESCRIPTION

[0027] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations.

[0028] like Figure 1-Figure 7 The hydrate plugging device for a gas transmission pipeline shown in the figure includes a cylindrical shell 1, an upper baffle 3 is fitted and installed at the inner upper edge of the cylindrical shell 1, a convex ring 17 is coaxially extended at the inner upper edge of the cylindrical shell 1, and a groove 18 is provided on the outer surface of the upper baffle 3. The convex ring 17 and the groove 18 prevent the upper baffle 3 from separating from the cylindrical shell 1. The convex ring 17 fits inside the groove 18. A lower baffle 14 is fitted and installed near the lower edge of the cylindrical shell 1. An open-hole injection member is installed between the upper baffle 3 and the lower baffle 14. A flange 2 is fixedly installed at the lower edge of the outer surface of the cylindrical shell 1, and the flange 2 serves to connect to the gate valve.

[0029] A positioning block 5 extends from the side edge of the upper end surface of the upper partition 3, and two limit blocks 4 are symmetrically fixedly installed on the upper end surface of the cylinder shell 1. The positioning block 5 is attached to one of the limit blocks 4. The cooperation between the limit block 4 and the positioning block 5 serves to limit the rotation angle of the upper partition 3, so that after rotation and repositioning, the injection pipe 26 in the outer shell 11 can be located at the opening.

[0030] The open-hole injection component includes a No. 2 threaded rod 10 that is rotatably embedded in the edge of the other side of the upper end face of the upper partition 3. The outer surface of the No. 2 threaded rod 10 is screwed with a No. 2 threaded sleeve 13. The lower end of the No. 2 threaded sleeve 13 is fixedly connected to the lower partition 14. The No. 2 threaded rod 10 and the No. 2 threaded sleeve 13 play a role in driving the lower partition 14 to move up and down. The No. 1 threaded sleeve 8 is fitted and installed at the rear edge of the upper end face of the upper partition 3. The shell 6 is fitted and installed at the rear edge of the upper end face of the upper partition 3 and on the side of the No. 1 threaded sleeve 8. The lower end of the No. 1 threaded sleeve 8 and the lower end of the shell 6 are both fixedly connected to the lower partition 14, and the lower end of the No. 1 threaded sleeve 8 and the lower end of the shell 6 both pass through the lower end face of the lower partition 14.

[0031] A No. 1 threaded rod 9 is screwed inside the No. 1 threaded sleeve 8, and a drill bit 33 is coaxially fixedly installed at the lower end of the No. 1 threaded rod 9. A tool 32 is coaxially inlaid on the outer surface of the No. 1 threaded rod 9 near the lower edge. The No. 1 threaded rod 9 and the No. 1 threaded sleeve 8 drive the drill bit 33 and the tool 32 to move downward, and also drive the drill bit 33 to rotate. The drill bit 33 plays a centering role, and the tool 32 plays a hole-opening role. A large gear 30 is coaxially fixedly installed on the outer surface of the tool 32, and a rotating shaft 7 is fitted inside the sleeve 6. A small gear 31 is coaxially inlaid on the lower end of the rotating shaft 7. The sleeve 6 connects the rotating shaft 7, and the small gear 31 meshes with the large gear 30. The drill bit 33 is lower than the tool 32.

[0032] A gear housing 29 is provided on the outer side of the small gear 31 and the large gear 30. The No. 1 threaded rod 9 and the rotating shaft 7 are rotated and passed through the upper end of the gear housing 29. The gear housing 29 serves to cover and protect the small gear 31 and the large gear 30, and also serves to connect the No. 1 threaded rod 9 and the rotating shaft 7 together. The tool 32 is rotated and passed through the lower end of the gear housing 29.

[0033] The outer shell 11 is embedded in the front edge of the upper end face of the upper partition 3, and the outer shell 11 is fitted through the lower end face of the lower partition 14. The outer shell 11 is symmetrical with the center line of the partition 3 above the No. 1 threaded sleeve 8 as the center of symmetry, so that the outer shell 11 and the No. 1 threaded sleeve 8 can interchange positions after rotation. A guide seat 16 is provided on the inner side of the outer shell 11, and guide wheels 25 are installed in a circular array on the upper and lower end faces of the guide seat 16. The guide seat 16 serves to support the guide wheel 25, and the guide wheel 25 is fitted on the inner wall of the outer shell 11.

[0034] The guide seat 16 is provided with a spray pipe 26 running through the interior of the guide seat 16, and the lower end of the spray pipe 26 is connected to the nozzle 24 through a hose. The hose plays a role in not being hindered when adjusting the direction of the nozzle 24. The outer surface of the nozzle 24 is coaxially fixed with an adjusting ball 15, and the middle part of the outer surface of the adjusting ball 15 is fitted with a ball seat 19. The adjusting ball 15 and the ball seat 19 can be fixed by the friction between each other, so that the adjusting ball 15 will not rotate. The ball seat 19 is fixed to the guide seat 16, and the upper end of the guide seat 16 is fixed with a propulsion rod 27. The propulsion rod 27 extends from the upper end of the shell 11, and the propulsion rod 27 plays the role of pushing the guide seat 16 to drive the spray pipe 26 and the nozzle 24 to move up and down. The upper end of the shell 11 is fixed with a limiting sleeve 12, and the propulsion rod 27 fits and runs through the interior of the limiting sleeve 12. The limiting sleeve 12 plays the role of limiting and fixing the propulsion rod 27 by friction, so that the propulsion rod 27 will not slide down on its own.

[0035] The interior of the limiting sleeve 12 and the interior of the ball seat 19 are both provided with rubber pads, and a wireless monitor 21 is fixedly installed on the side of the ball seat 19. The rubber pad serves to increase friction. Two connecting seats 23 are installed on the upper portion of the outer surface of the adjusting ball 15 at a ninety-degree offset. The wireless monitor 21 is of night vision type, so that when the injection system is spraying, the internal situation can be clearly seen in the dark inside and real-time monitoring can be carried out. A push rod 22 is rotatably installed inside the connecting seat 23. The push rod 22 passes through the interior of the guide seat 16 and extends from the upper end of the shell 11. A connecting frame 20 is fixedly installed at the lower end of the guide seat 16. The lower end of the connecting frame 20 is fixedly connected to the ball seat 19. The connecting frame 20 serves to fix the guide seat 16 and the ball seat 19 together. A fixing frame 28 is extended from the inner wall of the guide seat 16. The end of the fixing frame 28 is fixedly connected to the injection pipe 26. The fixing frame 28 serves to fix the guide seat 16 and the injection pipe 26.

[0036] Before replacing a problem area in a gas pipeline, preparatory work is required. This includes determining the location of the problem pipeline through on-site survey, shutting down the problem pipeline, excavating, and determining the location to seal the perforation in the problem pipeline. Once these preparatory steps are complete, the sealing locations at both ends of the problem pipeline are simultaneously sealed. Since the sealing steps for both ends are the same, the following describes only one end.

[0037] 1. Install or weld a saddle pipe fitting with a flange at the location where the problem pipe needs to be opened and sealed.

[0038] 2. Install a flanged gate valve on the saddle fitting.

[0039] 3. Fix the shell 1 to the gate valve through the flange 2.

[0040] 4. Then open the gate valve and rotate the No. 2 threaded rod 10 to move the No. 2 threaded sleeve 13 downward, thereby driving the lower partition 14 downward, and allowing the drill bit 33 and the tool 32 on the lower partition 14 to move downward together.

[0041] 5. After the drill bit 33 is attached to the pipe, the No. 1 threaded rod 9 is rotated so that the No. 1 threaded rod 9 drives the drill bit 33 to rotate and move downward to drive the drill bit 33 into the pipe. At this time, the tool 32 is pushed into the pipe by the No. 1 threaded rod 9.

[0042] 6. Rotate the shaft 7 to use the small gear 31 and the large gear 30 to drive the cutter 32 to rotate, so as to cut a hole in the pipe wall.

[0043] 7. After the hole is opened, reversely rotate the second threaded rod 10 to drill the drill bit 33 and the tool 32

[0044] Raise to reset.

[0045] 8. Close the gate valve and rotate the upper partition 3 to move the drill bit 33 and the cutter 32 away from the hole, and at the same time rotate the housing 11 to the hole.

[0046] 9. Open the gate valve, then push the push rod 27 to move the nozzle 24 downward and into the pipeline through the opening.

[0047] 10. Connect the injection pipe 26 to the injection device, so that liquid nitrogen, water and promoting liquid are injected into the injection pipe 26 under the action of the injection device, and are sprayed into the interior of the pipeline through the nozzle 24 at the end of the injection pipe 26 to form ice and hydrate inside the pipeline for blocking.

[0048] 11. Use ultrasonic detectors and other detection equipment to determine the sealing length. After both sides are completely sealed and the safe sealing distance is reached, the pipe replacement operation is carried out. After the pipe replacement is completed, the pipeline is heated and unsealed.

[0049] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions merely illustrate the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydrate plugging device for a gas pipeline, comprising a shell (1), characterized in that: An upper baffle (3) is fitted on the inner upper edge of the cylinder shell (1), a convex ring (17) extends coaxially on the inner upper edge of the cylinder shell (1), a groove (18) is provided on the outer surface of the upper baffle (3), the convex ring (17) fits inside the groove (18), a lower baffle (14) is fitted on the inner side of the cylinder shell (1) near the lower edge, an open hole injection member is installed between the upper baffle (3) and the lower baffle (14), and a flange (2) is fixedly installed on the outer lower edge of the cylinder shell (1); The hole-opening injection member can rotate the No. 2 threaded rod (10) to move the No. 2 threaded sleeve (13) downward and then drive the lower partition (14) downward, so that the drill bit (33) and the tool (32) on the lower partition (14) move downward together. When the drill bit is attached to the pipe, the No. 1 threaded rod (9) is rotated to drive the drill bit (33) to rotate and move downward, so that the drill bit (33) is driven into the pipe. At this time, the tool (32) is inserted into the pipe under the push of the No. 1 threaded rod (9), and then the rotating shaft is rotated to use the small gear (31) and the large gear ( 30) drives the cutter (32) to rotate to cut and open a hole in the pipe wall. After the hole is opened, the second threaded rod (10) is rotated in the opposite direction to raise and reset the drill bit (33) and the cutter (32). At the same time, the upper partition (3) is rotated to move the drill bit and the cutter away from the hole. At the same time, the housing is rotated to the hole. Then, the push rod (27) is pushed to drive the nozzle (24) to move downward from the hole into the pipe to perform jet sealing. At this time, the guide wheel (25) on the guide seat will roll against the inner wall of the housing to assist the nozzle (24) to move, thereby completing the sealing operation.

2. The hydrate plugging device for a gas pipeline according to claim 1, characterized in that: A positioning block (5) extends from the side edge of the upper end surface of the upper partition (3), and two limit blocks (4) are symmetrically fixedly installed on the upper end surface of the cylinder shell (1), and the positioning block (5) is attached to one of the limit blocks (4).

3. The hydrate plugging device for a gas pipeline according to claim 1, characterized in that: The hole injection member includes a No. 2 threaded rod (10) that is rotatably embedded in the edge of the other side of the upper end face of the upper partition (3), the outer surface of the No. 2 threaded rod (10) is screwed with a No. 2 threaded sleeve (13), the lower end of the No. 2 threaded sleeve (13) is fixedly connected to the lower partition (14), the rear edge of the upper end face of the upper partition (3) is fitted with a No. 1 threaded sleeve (8), the rear edge of the upper end face of the upper partition (3) and the front side of the No. 1 threaded sleeve (8) are fitted with a sleeve (6), the lower end of the No. 1 threaded sleeve (8) and the lower end of the sleeve (6) are both fixedly connected to the lower partition (14), and the lower end of the No. 1 threaded sleeve (8) and the lower end of the sleeve (6) are both passed through the lower end face of the lower partition (14).

4. The hydrate plugging device for a gas pipeline according to claim 3, characterized in that: The No. 1 threaded sleeve (8) is screwed with a No. 1 threaded rod (9) inside, a drill bit (33) is coaxially fixedly mounted on the lower end of the No. 1 threaded rod (9), a tool (32) is coaxially mounted on the outer surface of the No. 1 threaded rod (9) near the lower edge, and a large gear (30) is coaxially fixedly mounted on the outer surface of the tool (32), a rotating shaft (7) is fitted inside the sleeve (6), a small gear (31) is coaxially mounted on the lower end of the rotating shaft (7), the small gear (31) is meshed with the large gear (30), and the drill bit (33) is lower than the tool (32).

5. The hydrate plugging device for a gas pipeline according to claim 4, characterized in that: The outer covers of the small gear (31) and the large gear (30) are provided with a gear housing (29), the No. 1 threaded rod (9) and the rotating shaft (7) are both rotated through the upper end of the gear housing (29), and the tool (32) is rotated through the lower end of the gear housing (29).

6. The hydrate plugging device for a gas pipeline according to claim 5, characterized in that: The front edge of the upper end face of the upper partition (3) is penetrated by a shell (11), and the shell (11) is fitted through the lower end face of the lower partition (14). The shell (11) is symmetrical with the center line of the partition (3) above the No. 1 threaded sleeve (8). A guide seat (16) is provided on the inner side of the shell (11), and the upper and lower end faces of the guide seat (16) are both annularly arrayed with guide wheels (25), and the guide wheels (25) are fitted on the inner wall of the shell (11).

7. The hydrate plugging device for a gas pipeline according to claim 6, characterized in that: The guide seat (16) is provided with a spray pipe (26) passing through the interior thereof, the lower end of the spray pipe (26) is connected to a nozzle (24) via a hose, an adjusting ball (15) is coaxially fixedly installed on the outer surface of the nozzle (24), a ball seat (19) is fitted on the middle portion of the outer surface of the adjusting ball (15), the ball seat (19) is fixed to the guide seat (16), a propulsion rod (27) is fixedly installed on the upper end of the guide seat (16), the propulsion rod (27) extends from the upper end of the outer shell (11), a limiting sleeve (12) is fixedly installed on the upper end of the outer shell (11), and the propulsion rod (27) fits and passes through the interior of the limiting sleeve (12).

8. The hydrate plugging device for a gas pipeline according to claim 7, characterized in that: The interior of the limiting sleeve (12) and the interior of the ball seat (19) are both provided with rubber pads, a wireless monitor (21) is fixedly installed on the side of the ball seat (19), and two connecting seats (23) are installed on the upper part of the outer surface of the adjusting ball (15) at a ninety-degree offset, and a push rod (22) is rotatably installed inside the connecting seat (23), and the push rod (22) passes through the interior of the guide seat (16) and extends from the upper end of the shell (11), and a connecting frame (20) is fixedly installed on the lower end of the guide seat (16), and the lower end of the connecting frame (20) is fixedly connected to the ball seat (19), and a fixing frame (28) is extended from the inner wall of the guide seat (16), and the end of the fixing frame (28) is fixedly connected to the injection pipe (26).

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