Fuel gas steel-plastic conversion pipe fitting with double-sealing structure

Abstract

The invention relates to the technical field of pipe fittings, in particular to a fuel gas steel-plastic conversion pipe fitting with a double-sealing structure, which comprises a metal inner pipe, steel-plastic pipes are inserted into the two ends of the metal inner pipe, each steel-plastic pipe comprises a steel pipe and a plastic pipe fixedly sleeved on the outer side of the steel pipe, and the two ends of the steel pipe are exposed out of the plastic pipe. Inserting blocks are inserted into the two ends of the metal inner pipe, the outer side of the metal inner pipe is sleeved with a plastic outer pipe, the plastic outer pipe pushes the inserting blocks to be inserted into a steel pipe of the steel-plastic pipe, the outer wall of the plastic outer pipe is in threaded connection with a connecting screw rod, the connecting screw rod penetrates through the plastic outer pipe and then is in threaded connection with the surface of the metal inner pipe, and sealing gaskets are fixed to the two ends of the metal inner pipe. The double-sealing structure is adopted, on one hand, the sealing gasket is clamped between the metal inner pipe and the steel-plastic pipe, the preliminary sealing effect is achieved, and gas leakage can be effectively prevented; and on the other hand, the two ends of the plastic outer pipe are welded on the plastic pipe of the two steel-plastic pipes to form a welding joint ring, so that the sealing performance is further enhanced.

Description

Technical Field

[0001] This invention relates to the field of pipe fittings, specifically a gas steel-plastic conversion pipe fitting with a double sealing structure. Background Technology

[0002] In gas transmission systems, steel-plastic conversion fittings play a crucial role in connecting steel and plastic pipes. Their sealing performance and connection stability directly affect the safety and reliability of gas transmission. Traditional gas steel-plastic conversion fittings have certain limitations in structural design, typically employing only a single sealing method, such as relying solely on a gasket. However, in actual use, this single sealing structure is susceptible to various factors, such as temperature changes, pressure fluctuations, and pipe vibration, leading to decreased sealing performance and potential safety hazards such as gas leaks, seriously threatening the safe operation of the gas transmission system.

[0003] Furthermore, traditional pipe fittings lack effective pre-positioning and fixing measures when connecting steel-plastic composite pipes. During installation, the connection between the steel-plastic composite pipe and the inner metal pipe is prone to loosening and detachment, which not only increases installation difficulty and construction time, but also may lead to safety accidents due to insecure connections during subsequent use. At the same time, the fixing of the plastic outer pipe to the metal inner pipe is often not secure enough, and it is prone to detachment during use, further affecting the overall performance and service life of the pipe fittings.

[0004] Therefore, developing a gas steel-plastic conversion pipe fitting with a dual-sealing structure and stable and reliable connection is of great practical significance. It can effectively solve the problems of poor sealing performance and unstable connection of traditional pipe fittings, and improve the safety and reliability of gas transmission systems. Summary of the Invention

[0005] The purpose of this invention is to provide a gas steel-plastic conversion pipe fitting with a double sealing structure to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a gas steel-plastic conversion pipe fitting with a double sealing structure, comprising a metal inner pipe, with steel-plastic pipes inserted at both ends of the metal inner pipe. The steel-plastic pipe includes a steel pipe and a plastic pipe sleeved and fixed on the outside of the steel pipe, with the plastic pipe protruding from both ends of the steel pipe. Insert blocks are inserted at both ends of the metal inner pipe, and a plastic outer pipe is sleeved on the outside of the metal inner pipe. The plastic outer pipe pushes the insert blocks into the steel pipe of the steel-plastic pipe. A connecting screw is screwed to the outer wall of the plastic outer pipe. The connecting screw passes through the plastic outer pipe and is screwed onto the surface of the metal inner pipe. Sealing gaskets are fixed at both ends of the metal inner pipe, and the sealing gaskets are sandwiched between the metal inner pipe and the steel-plastic pipe.

[0007] Preferably, the inner metal tube is a round tube with a "T" shaped cross-section, the sealing gasket is a circular annular plate with a "Z" shaped cross-section, the steel tube of the steel-plastic pipe is inserted into the end opening of the inner metal tube, one end of the sealing gasket is clamped between the steel tube of the steel-plastic pipe and the inner metal tube, the middle part of the sealing gasket is sleeved on the part of the steel tube of the steel-plastic pipe that protrudes from the plastic tube, and the other end of the sealing gasket is clamped between the plastic tube of the steel-plastic pipe and the inner metal tube.

[0008] Preferably, the steel pipe of the steel-plastic pipe has a groove on its outer wall, the groove being an annular groove, and the groove matching the insert block.

[0009] Preferably, the surface of the metal inner tube is provided with two sets of insertion holes, each set of insertion holes has multiple insertion holes, the multiple insertion holes are distributed in a circle with the metal inner tube as the central axis, the insertion block and the insertion hole correspond one to one, the height of the insertion block is greater than the depth of the insertion hole, one end of the insertion block passes through the insertion hole and is fixed to the outer ring surface of the sealing gasket, and the other end of the insertion block has bevels on both sides.

[0010] Preferably, after the plastic outer tube pushes the insert block through the insertion hole, it stretches the sealing gasket to produce elastic deformation, and one end of the insert block and the deformed sealing gasket are both inserted into the slot.

[0011] Preferably, the inner wall of the plastic outer tube is fitted with a metal inner core tube, and the inner circumferential surface of the metal inner core tube is provided with a second groove, which is an annular groove. The outer wall of the metal inner tube is fitted with a rubber limiting ring that matches the second groove. After the plastic outer tube is fitted onto the metal inner tube, the rubber limiting ring is inserted into the second groove.

[0012] Preferably, the outer wall of the plastic outer tube has a reserved hole, which is a "T"-shaped round hole. The reserved hole passes through the metal inner core tube. The outer wall of the metal inner tube has a screw groove that corresponds to the reserved hole. The connecting screw passes through the reserved hole and is screwed into the screw groove.

[0013] Preferably, both ends of the plastic outer tube are welded to the plastic tubes of the two steel-plastic pipes to form welded joint rings.

[0014] Compared with the prior art, the beneficial effects of the present invention are: The gas-steel-plastic conversion pipe fitting proposed in this invention features a dual-sealing structure. Firstly, a sealing gasket clamps between the inner metal pipe and the steel-plastic pipe, providing an initial seal and effectively preventing gas leakage. Secondly, the two ends of the outer plastic pipe are welded to the plastic sections of the two steel-plastic pipes to form welded joint rings, further enhancing the sealing performance. This dual-sealing structure significantly improves the sealing reliability of the fitting. Even if one seal fails partially, the other seal can still function, effectively preventing gas leakage and ensuring the safe operation of the gas transmission system.

[0015] By installing a plug on the inner metal tube and creating a groove on the outer wall of the steel-plastic composite pipe, once the steel tube of the steel-plastic composite pipe is inserted into the inner metal tube, the outer plastic tube is moved. The outer plastic tube pushes the plug into the insertion hole along the inclined surface at the end of the plug, ensuring that one end of the plug and the deformed sealing gasket are both inserted into the groove, thus forming a limiting clamp between the inner metal tube and the steel-plastic composite pipe. This design effectively prevents the steel-plastic composite pipe from detaching from the end of the inner metal tube, improves the stability and reliability of the pipe connection, reduces safety hazards during installation, and facilitates subsequent maintenance and disassembly.

[0016] The installation process is simple and convenient. The outer plastic tube is pre-installed on top of the inner steel-plastic composite tube. After the inner metal tube connects the two steel-plastic composite tubes, the outer plastic tube is moved to cover the inner metal tube and then welded and secured to complete the installation. When it's necessary to remove the steel-plastic composite tube, simply move the outer plastic tube away from the inner metal tube. The sealing gasket springs back, pulling the insert back. Once the end of the insert is pulled out of the slot, the steel-plastic composite tube can be removed from the inner metal tube. This greatly improves the efficiency of installation and disassembly, and reduces construction costs and maintenance difficulty. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 for Figure 1 Sectional view of the structure at point AA; Figure 3 for Figure 2 Enlarged schematic diagram of the structure at point B; Figure 4 This is a schematic diagram of the connection structure between the metal inner tube and the plastic outer tube of the present invention; Figure 5 This is a schematic diagram of the metal inner tube structure of the present invention; Figure 6 This is a schematic diagram of the plastic outer tube structure of the present invention.

[0018] In the diagram: 1. Metal inner tube, 101. Insertion hole, 102. Rubber limiting ring, 103. Screw groove, 2. Steel-plastic tube, 201. Slot 1, 3. Sealing gasket, 4. Insert block, 5. Plastic outer tube, 501. Metal inner core tube, 502. Slot 2, 503. Reserved hole, 6. Connecting screw, 7. Welded node ring. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the present invention clear and complete, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some, not all, embodiments of the present invention, and are merely illustrative of the embodiments of the present invention. They are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see Figures 1-6 The present invention provides a technical solution: a gas steel-plastic conversion pipe fitting with a double sealing structure, including a metal inner pipe 1, a plastic outer pipe 5 sleeved on the outside of the metal inner pipe 1, and steel-plastic pipes 2 inserted at both ends of the metal inner pipe 1. The steel-plastic pipe 2 includes a steel pipe and a plastic pipe sleeved and fixed on the outside of the steel pipe. The plastic pipes protrude from both ends of the steel pipe. The two ends of the plastic outer pipe 5 are welded to the plastic pipes of the two steel-plastic pipes 2 to form welding node rings 7. Sealing gaskets 3 are fixed at both ends of the metal inner pipe 1 and are sandwiched between the metal inner pipe 1 and the steel-plastic pipe 2.

[0021] Two steel-plastic pipes 2 are connected by a metal inner pipe 1. A plastic outer pipe 5 is pre-installed on the plastic tube of one of the steel-plastic pipes 2. After the metal inner pipe 1 is connected to the two steel-plastic pipes 2, the plastic outer pipe 5 is moved to cover the metal inner pipe 1. The two ends of the plastic outer pipe 5 are respectively installed on the plastic tubes of the two steel-plastic pipes 2. The plastic outer pipe 5 is welded to the plastic tube of the steel-plastic pipe 2 using adhesive welding technology. At this time, the sealing gasket 3 is clamped between the metal inner pipe 1 and the steel-plastic pipe 2 to play a sealing role, and the welded node ring 7 also plays a sealing role.

[0022] To achieve the pre-limiting positioning of the metal inner tube 1 fitted onto the steel-plastic pipe 2, the following was proposed: Both ends of the inner metal tube 1 are fitted with insert blocks 4. A plastic outer tube 5 is fitted over the outer side of the inner metal tube 1. The plastic outer tube 5 pushes the insert blocks 4 into the steel tube of the steel-plastic pipe 2. The inner metal tube 1 is a round tube with a "T"-shaped cross-section. The sealing gasket 3 is a circular plate with a "Z"-shaped cross-section. The steel tube of the steel-plastic pipe 2 is inserted into the end opening of the inner metal tube 1. One end of the sealing gasket 3 is clamped between the steel tube of the steel-plastic pipe 2 and the inner metal tube 1. The middle part of the sealing gasket 3 is fitted over the part of the steel tube of the steel-plastic pipe 2 that protrudes from the plastic tube. The other end of the sealing gasket 3 is clamped between the plastic tube of the steel-plastic pipe 2 and the inner metal tube 1. The outer wall of the steel tube of the steel-plastic pipe 2 has a groove. 1201, the slot 1201 is an annular groove, the slot 1201 matches the insert 4; the surface of the metal inner tube 1 is provided with two sets of insertion holes 101, each set of insertion holes 101 has multiple holes, the multiple insertion holes 101 are distributed in a circle with the metal inner tube 1 as the central axis, the insert 4 corresponds to the insertion hole 101 one by one, the height of the insert 4 is greater than the depth of the insertion hole 101, one end of the insert 4 passes through the insertion hole 101 and is fixed to the outer ring surface of the sealing gasket 3, the other end of the insert 4 has a bevel on both sides; the plastic outer tube 5 pushes the insert 4 through the insertion hole 101 and then stretches the sealing gasket 3 to produce elastic deformation, one end of the insert 4 and the deformed sealing gasket 3 are inserted into the slot 201.

[0023] When the steel pipe of the steel-plastic composite pipe 2 is inserted into the groove of the inner metal pipe 1, the sealing gasket 3 is clamped between the inner metal pipe 1 and the steel-plastic composite pipe 2, providing a seal while increasing the friction between the steel pipe of the steel-plastic composite pipe 2 and the inner metal pipe 1. At this time, the sealing gasket 3 blocks the groove of the insertion hole 101, moves the outer plastic pipe 5, and pushes the outer plastic pipe 5 onto the inner metal pipe 1. During this process, the outer plastic pipe 5 pushes the insertion block 4 into the insertion hole 101 along the inclined surface at the end of the insertion block 4. After the insertion hole 101 is compressed, the sealing gasket 3 is stretched and deformed. The deformed part is pushed into the slot 201 by the insert block 4, thus forming a limiting clip between the metal inner tube 1 and the steel-plastic tube 2, preventing the steel-plastic tube 2 from falling off the end of the metal inner tube 1; when the steel-plastic tube 2 needs to be removed, the plastic outer tube 5 is pulled away from the metal inner tube 1, that is, at this time the plastic outer tube 5 no longer covers the metal inner tube 1, the sealing gasket 3 rebounds and pulls the insert block 4 back, the end of the insert block 4 is pulled away from the slot 201, at this time the clip between the metal inner tube 1 and the steel-plastic tube 2 is removed, and the steel-plastic tube 2 can be pulled away from the metal inner tube 1.

[0024] To prevent the plastic outer tube 5 from detaching from the metal inner tube 1, the following measures were proposed: A connecting screw 6 is screwed onto the outer wall of the plastic outer tube 5. The connecting screw 6 passes through the plastic outer tube 5 and is screwed onto the surface of the metal inner tube 1. A metal inner core tube 501 is embedded in the inner wall of the plastic outer tube 5. A second groove 502 is opened on the inner annular surface of the metal inner core tube 501. The second groove 502 is an annular groove. A rubber limiting ring 102 matching the second groove 502 is fixedly fitted onto the outer wall of the metal inner tube 1. After the plastic outer tube 5 is fitted onto the metal inner tube 1, the rubber limiting ring 102 is inserted into the second groove 502. A reserved hole 503 is opened on the outer wall of the plastic outer tube 5. The reserved hole 503 is a "T"-shaped round hole. The reserved hole 503 passes through the metal inner core tube 501. A screw groove 103 corresponding to the reserved hole 503 is opened on the outer wall of the metal inner tube 1. The connecting screw 6 passes through the reserved hole 503 and is screwed into the screw groove 103.

[0025] After the plastic outer tube 5 is fitted onto the metal inner tube 1, the rubber limiting ring 102 is inserted into the slot 502 to increase the friction between the plastic outer tube 5 and the metal inner tube 1. At this time, the reserved hole 503 corresponds to the screw groove 103. After the connecting screw 6 is inserted into the reserved hole 503, it is screwed into the screw groove 103. It should be noted that a gasket is pre-fitted before the connecting screw 6 is inserted into the reserved hole 503.

[0026] The usage method of gas steel-plastic conversion pipe fittings with a double sealing structure is as follows: The outer plastic tube 5 is pre-fitted onto the plastic tube of the steel-plastic pipe 2. The inner metal tube 1 is a circular tube with a "T"-shaped cross-section, and its surface has two sets of insertion holes 101. Each set of insertion holes 101 has multiple holes, which are distributed circumferentially around the inner metal tube 1. Insert blocks 4 are inserted into both ends of the inner metal tube 1. The insertion blocks 4 correspond one-to-one with the insertion holes 101. The height of the insertion block 4 is greater than the depth of the insertion hole 101. One end of the insertion block 4 passes through the insertion hole 101 and is fixed to the outer ring surface of the sealing gasket 3. The other end of the insertion block 4 has bevels on both sides. The sealing gasket 3 is a circular annular plate with a "Z"-shaped cross-section. Insert the steel pipe of the steel-plastic composite pipe 2 into the end opening of the metal inner pipe 1. At this time, one end of the sealing gasket 3 is clamped between the steel pipe of the steel-plastic composite pipe 2 and the metal inner pipe 1, the middle part of the sealing gasket 3 is sleeved on the part of the steel pipe of the steel-plastic composite pipe 2 that protrudes from the plastic pipe, and the other end of the sealing gasket 3 is clamped between the plastic pipe of the steel-plastic composite pipe 2 and the metal inner pipe 1. The steel pipe of the steel-plastic composite pipe 2 has a groove 201 on its outer wall. The groove 201 is an annular groove and matches the insert block 4. The sealing gasket 3 is clamped between the metal inner pipe 1 and the steel-plastic composite pipe 2, which not only provides a seal but also increases the friction between the steel pipe of the steel-plastic composite pipe 2 and the metal inner pipe 1. At this time, the sealing gasket 3 blocks the groove of the insertion hole 101. Move the plastic outer pipe 5 and push it onto the metal inner pipe 1. During this process, the plastic outer tube 5 pushes the insert 4 into the insertion hole 101 along the inclined surface at the end of the insert 4. The insertion hole 101, under pressure, stretches and deforms the sealing gasket 3. The deformed portion of the sealing gasket 3 is pushed into the slot 201 by the insert 4, thus forming a limiting clip between the metal inner tube 1 and the steel-plastic tube 2, preventing the steel-plastic tube 2 from falling off the end of the metal inner tube 1. A metal inner core tube 501 is embedded in the outer wall of the plastic outer tube 5. A slot 502, which is annular, is formed on the inner circumferential surface of the metal inner core tube 501. A rubber limiting ring 102, matching the slot 502, is fitted and fixed to the outer wall of the metal inner tube 1. After the plastic outer tube 5 is fitted onto the metal inner tube 1, the rubber limiting ring 102 is inserted into the slot 502, increasing the friction between the plastic outer tube 5 and the metal inner tube 1. The outer wall of the plastic outer tube 5 has a pre-drilled hole 503, which is a T-shaped circular hole that penetrates the metal inner core tube 501. The outer wall of the metal inner tube 1 has a threaded groove 103 that corresponds one-to-one with the pre-drilled hole 503. Before inserting the connecting screw 6 into the pre-drilled hole 503, a washer is pre-fitted. Then, the connecting screw 6 is threaded into the pre-drilled hole 503 and screwed into the threaded groove 103, thus fixing the plastic outer tube 5 onto the metal inner tube 1. The two ends of the plastic outer tube 5 are respectively fitted onto the plastic tubes of the two steel-plastic tubes 2. The plastic outer tube 5 is welded to the plastic tubes of the steel-plastic tubes 2 using adhesive welding technology to form a welded joint ring 7. At this time, the sealing effect of the sealing gasket 3 and the sealing effect of the welded joint ring 7 together constitute a double sealing structure. Loosen the connecting screw 6 and pull it out of the screw groove 103 and the reserved hole 503 to release the screw connection between the plastic outer tube 5 and the metal inner tube 1.Pull the outer plastic tube 5 away from the inner metal tube 1. At this point, the outer plastic tube 5 no longer covers the inner metal tube 1. The sealing gasket 3 springs back, pulling the insert 4 back. The end of the insert 4 is pulled out of the slot 201, and the locking between the inner metal tube 1 and the steel-plastic tube 2 is released. Pull the steel-plastic tube 2 away from the inner metal tube 1 to complete the entire removal process.

[0027] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A gas steel-plastic conversion pipe fitting with a double-sealed structure, comprising a metal inner pipe (1), both ends of which are connected to steel-plastic pipes (2), the steel-plastic pipes (2) comprising a steel pipe and a plastic pipe sleeved and fixed on the outside of the steel pipe, with the plastic pipes protruding from both ends of the steel pipe, characterized in that: Both ends of the metal inner tube (1) are connected to insert blocks (4), and a plastic outer tube (5) is sleeved on the outside of the metal inner tube (1). The plastic outer tube (5) pushes the insert blocks (4) into the steel pipe of the steel-plastic pipe (2). A connecting screw (6) is screwed to the outer wall of the plastic outer tube (5). The connecting screw (6) passes through the plastic outer tube (5) and is screwed to the surface of the metal inner tube (1). Both ends of the metal inner tube (1) are fixed with sealing gaskets (3). The sealing gaskets (3) are sandwiched between the metal inner tube (1) and the steel-plastic pipe (2).

2. A gas-steel-plastic conversion pipe fitting with a double-sealing structure according to claim 1, characterized in that: The inner metal tube (1) is a round tube with a "T" shaped cross section, and the sealing gasket (3) is a circular ring plate with a "Z" shaped cross section. The steel tube of the steel-plastic pipe (2) is inserted into the end of the inner metal tube (1). One end of the sealing gasket (3) is clamped between the steel tube of the steel-plastic pipe (2) and the inner metal tube (1). The middle part of the sealing gasket (3) is sleeved on the part of the steel tube of the steel-plastic pipe (2) that is exposed to the plastic tube. The other end of the sealing gasket (3) is clamped between the plastic tube of the steel-plastic pipe (2) and the inner metal tube (1).

3. A gas-steel-plastic conversion pipe fitting with a double-sealing structure according to claim 1, characterized in that: The steel pipe of the steel-plastic pipe (2) has a groove (201) on its outer wall. The groove (201) is an annular groove and matches the insert (4).

4. A gas-steel-plastic conversion pipe fitting with a double-sealing structure according to claim 3, characterized in that: The surface of the metal inner tube (1) is provided with two sets of insertion holes (101), each set of insertion holes (101) is provided with multiple holes, and the multiple insertion holes (101) are distributed in a circle around the metal inner tube (1) as the central axis. The insertion block (4) corresponds to the insertion hole (101) one by one. The height of the insertion block (4) is greater than the depth of the insertion hole (101). One end of the insertion block (4) passes through the insertion hole (101) and is fixed to the outer ring surface of the sealing gasket (3). The other end of the insertion block (4) is provided with inclined surfaces on both sides.

5. A gas-steel-plastic conversion pipe fitting with a double-sealing structure according to claim 4, characterized in that: The plastic outer tube (5) pushes the insert (4) through the insertion hole (101) and then tensions the sealing gasket (3) to produce elastic deformation. One end of the insert (4) and the deformed sealing gasket (3) are inserted into the slot (201).

6. A gas-steel-plastic conversion pipe fitting with a double-sealing structure according to claim 1, characterized in that: The inner wall of the plastic outer tube (5) is fitted with a metal inner core tube (501). The inner ring surface of the metal inner core tube (501) is provided with a second groove (502). The second groove (502) is an annular groove. The outer wall of the metal inner tube (1) is fitted with a rubber limiting ring (102) that matches the second groove (502). After the plastic outer tube (5) is fitted onto the metal inner tube (1), the rubber limiting ring (102) is inserted into the second groove (502).

7. A gas-steel-plastic conversion pipe fitting with a double-sealing structure according to claim 6, characterized in that: The outer wall of the plastic outer tube (5) is provided with a reserved hole (503). The reserved hole (503) is a "T"-shaped round hole. The reserved hole (503) passes through the metal inner tube (501). The outer wall of the metal inner tube (1) is provided with a screw groove (103) that corresponds one-to-one with the reserved hole (503). The connecting screw (6) passes through the reserved hole (503) and is screwed into the screw groove (103).

8. A gas-steel-plastic conversion pipe fitting with a double-sealing structure according to claim 1, characterized in that: The two ends of the plastic outer tube (5) are welded to the plastic tubes of the two steel-plastic tubes (2) to form a welding node ring (7).

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