JP2007225005A - Expansion pipe joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expansion pipe joint having improved working efficiency allowing easy connecting work for a pipe with reduced sliding resistance during expanding operation and further having improved durability maintaining good sealing performance for a long period without giving wear or damage to a sealing member due to abrasion on the sealing surface or the biting of powder and grain. <P>SOLUTION: The expansion pipe joint comprises an outer pipe 1, and an inner pipe 2 to be inserted into the outer pipe along the pipe axis, the inner pipe and the outer pipe being relatively moved along the pipe axis to adjust the length. Between the outer pipe and the inner pipe, the sealing member 4 is provided which is pressed against the outer peripheral face of the inner pipe when supplying compressed air to develop sealing function between the inner pipe and the outer pipe and prohibit relative movement therebetween at the same time and which is separated from the outer peripheral face of the inner pipe when stopping/releasing the compressed air to cancel the sealing function between the inner pipe and the outer pipe and permit relative movement therebetween at the same time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a double-pipe type expansion joint that is frequently used for pipe connection, and more specifically, for example, when a granular material stored in a granular material tank is transported in a pipe by compressed air, the granular material The present invention relates to a double pipe type expansion joint that can be suitably used to effectively connect an outlet pipe of a tank and a transport pipe.

  In general, in double pipe type expansion joints frequently used for pipe connection, a gland packing or rubber ring is used between the outer pipe and the inner pipe as a seal member for preventing leakage of fluid transported in the pipe. A method is employed (see, for example, Patent Documents 1 and 2).

  However, the sealing method using a gland packing or rubber ring requires that the sealing surface is always firmly pressed against the inner peripheral surface of the outer tube and the outer peripheral surface of the inner tube. There is a problem that the sliding resistance during the expansion / contraction operation of the joint to be performed is large and it is difficult to expand and contract easily.

In addition, expansion pipe joints using a seal method using a gland packing or rubber ring, especially pipes for receiving granular materials stored in a tank for transportation such as a tank truck using an in-pipe transportation method using compressed air When used for connection, the connection work with the expansion joints is repeated every time the tanker truck arrives. As a result, there is a problem that the sealing member is scratched, deteriorates in a short period of time, and is likely to leak.
Japanese Patent Laid-Open No. 9-112772 JP-A-6-114359

  An object of the present invention is to solve the above-described problems of the conventional ones, and has a low sliding resistance during an expansion and contraction operation, and can easily connect pipes. In addition, it is possible to provide an expansion joint having excellent durability that can maintain good sealing performance in the long term without causing abrasion or damage to the sealing member due to scratching of the sealing surface or biting of the granular material. It is in.

  The object of the present invention described above can be achieved by adopting the configuration of the expansion joint according to the present invention described in the following (1).

  (1) It has an outer tube and an inner tube inserted into the outer tube along the tube axis, and the length can be adjusted by the relative movement of the inner tube and the outer tube along the tube axis. In the expansion joint, when compressed air is supplied between the outer tube and the inner tube, the outer tube is brought into contact with the outer peripheral surface of the inner tube, exerting a sealing function between the inner tube and the outer tube, and at the same time fixing the relative movement between the two. When the compressed air is stopped / released, it is separated from the outer peripheral surface of the inner tube, and the sealing function is provided so that the sealing function of the inner tube and the outer tube is released and at the same time the relative movement of both is possible. Expansion tube fittings.

  Such an expansion joint of the present invention further has a preferable aspect described in the following (2).

  (2) Aside from the seal member, a cylindrical slide ring that contacts the outer peripheral surface of the inner tube is attached to the outer peripheral surface of the inner tube even when the seal member is separated from the outer peripheral surface of the inner tube. The expansion joint according to (1) above, which is characterized.

  According to the present invention, as a seal member between the outer tube and the inner tube of the double-pipe expansion / contraction pipe joint, a seal mechanism capable of expanding and contracting by supplying, stopping and releasing compressed air is provided. This is an expansion pipe joint with excellent workability that can reduce the sliding resistance during operation and simplify pipe connection work. It was possible to provide an expansion joint having excellent durability that can maintain and exhibit good sealing performance over the long term without being damaged by abrasion or biting of the granular material.

  Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 1 is an overall schematic cross-sectional view showing an example of an expansion joint according to the present invention, and shows a state in which a seal member of a seal unit is in contact with an outer peripheral surface of an inner pipe by supplying compressed air. FIG. 2 is an enlarged schematic cross-sectional view of the seal unit portion showing a state in which the seal member of the expansion joint according to the present invention is contracted by the stop / release of compressed air and is separated from the outer peripheral surface of the inner tube. FIG. 3 shows one embodiment of the expansion joint, and shows a standby state before connection with the tank truck by the expansion joint. FIG. 4 shows a state where the connection work with the tank lorry vehicle by the expansion pipe joint is completed from the standby state of FIG. 3.

  In FIG. 1, a seal unit 3 storing a seal member 4 and a slide ring 10 is fixed to another end flange portion of a cylindrical outer tube 1 having a flange 13 at one end by bolts 7 and nuts 8. The inner tube 2 is inserted along the tube axis of the outer tube 1 to form a double tube type expansion joint according to the present invention.

  The seal member 4 stored in the seal unit 3 employs a hollow expansion / contraction seal material.

  The seal unit 3 includes a compressed air supply pipe 9 having a compressed air supply pipe 9 </ b> A, a seal member 4 built in a position communicating with the supply pipe 9 </ b> A of the compressed air supply pipe 9, and the compressed air supply pipe 9. A cylindrical slide ring 10 is provided between the lower end portion and the inner tube 2.

  The compressed air supply pipe 9 is fixedly attached to the flange portion of the outer pipe 1 with bolts 7 and nuts 8.

  Further, the seal member 4 is installed at a position between the compressed air supply pipe 9 and the inner pipe 2 communicating with the supply pipe 9 </ b> A, and is fitted into the outer peripheral surface of the inner pipe 2 to form an annular shape. One side of the seal member 4 is in contact with the inner wall of the compressed air supply pipe 9, and the other side is pressed by a seal member presser plate 5 so as not to slide along the pipe axis. The seal member presser plate 5 is attached to the compressed air supply pipe 9 by a bolt 6.

  The seal member 4 has a concave annular groove, and a compressed air introduction member 18 having a compressed air introduction hole having a diameter smaller than that of the supply pipe line 9A is installed in the concave annular groove on the compressed air supply pipe 9 side. A space for introducing compressed air is formed between the compressed air introduction member 18 and the concave annular groove 4 of the seal member 4. The compressed air introduction member 18 is a cylindrical metal material such as stainless steel, and is fitted into the concave annular groove of the compressed air supply pipe 9 with the seal member 4, and the compressed air is supplied to the seal member 4. It has the function to hold | maintain this sealing member 4 simultaneously with the function to introduce | transduce.

  The slide ring 10 is fitted to the outer periphery of the inner tube 2 at a position between the lower end of the compressed air supply tube 9 and the inner tube 2, and one side of the slide ring 10 is the inner wall of the compressed air supply tube 9. The other side is pressed by the slide ring presser plate 11 so as not to slide along the tube axis. The slide ring 10 is made of, for example, a plastic such as a cylindrical fluororesin (for example, “Teflon (registered trademark)”), and at the same time as a guide guide during the expansion and contraction operation of the expansion tube joint, It also has a function of preventing the inner surface and the outer surface of the inner tube 2 from contacting each other and protecting the mutual surfaces from being wrinkled. The slide ring presser plate 11 is attached to the compressed air supply pipe 9 by a bolt 12.

  In such a structure, when the compressed air P is supplied from the compressed air supply line 9A, the compressed air is introduced into the space of the seal member through the compressed air introduction hole 18A of the compressed air introduction member 18, and the seal member 4 expands and protrudes to uniformly contact the outer peripheral surface on the inner tube 2 side to exert a sealing function between the outer tube 1 and the inner tube 2 and at the same time fix the relative movement of both.

  On the other hand, as shown in FIG. 2, when the compressed air P from the compressed air supply line 9 is stopped / released, the seal member 4 contracts from the overhanging state and is separated from the outer peripheral surface of the inner tube 2, and The seal function with the inner tube 2 is canceled, and at the same time, the relative movement between the two becomes possible.

  Further, as shown in FIGS. 1 and 2, a cylindrical slide ring 10 fitted to the outer peripheral surface of the inner tube 2 is attached to the seal unit 3 that houses the seal member 4, and the outer tube 1 and the inner tube 2. Even when the seal member 4 is contracted and separated from the outer peripheral surface of the inner tube 2 so that the alignment property can be maintained, the outer tube 1 and the inner tube 2 do not cause rattling or galling, A guide guide function is provided so that relative movement can be easily performed along the guide.

  The seal member 4 housed in the seal unit 3 is a seal member that expands and contracts by the supply, stop, and release of compressed air. As materials, ethylene propylene rubber, chloroprene rubber, nitrile rubber, fluorine rubber, silicon rubber It is preferable to use synthetic rubbers such as, but not limited to these, as long as they can exhibit the same function.

  Next, an example of how the expansion joint of the present invention is used will be described with reference to the drawings.

  In order to discharge the terephthalic acid powder from the bulk lorry tank tank by in-pipe transportation using compressed air, the double pipe type expansion pipe joint according to the present invention was used for the connection part between the tank outlet and the in-pipe transportation piping. An embodiment is shown in FIGS.

  FIG. 3 shows a state in which the inner pipe of the expansion joint is housed in the outer pipe and the tank outlet 16 and the expansion joint are separated from each other in a standby state before the connection work. In FIG. 3, the outer pipe end flange 13 of the expansion joint is always connected and fixed to the in-pipe transport pipe 15 side. In addition, the inner pipe end flange 14 on the opposite side of the expansion joint is provided with a one-touch coupling 17 combined with the tank outlet 16 in order to facilitate the connection with the tank outlet 16. . From the standby state in FIG. 3 to the completion of the pipe connection operation, as shown in FIG. 2, the seal member 4 is in a contracted state and the expansion joint can be freely moved relative to the tube axis.

  FIG. 4 shows a state in which the expansion pipe joint is extended and the tank discharge port 16 and the one-touch coupling 17 provided at the inner pipe side end of the expansion pipe joint are connected. In this state, as shown in FIG. As described above, when compressed air P is supplied to the seal member 4 from the compressed air supply line 9A of the seal unit 3, the seal member 4 is expanded and inflated to uniformly contact the outer peripheral surface of the inner tube 2 and to At the same time that the sealing function between the pipe 1 and the inner pipe 2 is exhibited, the relative movement between the two is fixed, and the pipe connecting operation is completed.

  According to the expansion tube joint according to the present invention, as described above, the expansion and contraction type seal member is used as the seal member, so that the seal member is contracted at the time of relative movement accompanying expansion and contraction of the outer tube and the inner tube, The sliding resistance applied to the members can be reduced, and the connecting operation can be performed very easily. In addition, even if the relative displacement between the outer tube and the inner tube fluctuates slightly due to vibration or misalignment of the tank truck or the in-pipe transport device during use, the contact surface of the seal member is pressed by compressed air, Since the fluctuation can be immediately followed, excellent sealing performance is exhibited. Furthermore, the sliding surface of the seal member is separated from the outer peripheral surface of the inner tube during the expansion / contraction operation, and the seal surface of the outer tube and the inner tube is worn by rubbing or the granular material is caught in the seal surface. Therefore, the problem that occurs in the sealing method using a gland packing or a rubber ring, such as a scratch on the sealing member, is avoided, and good sealing performance can be exhibited in the long term.

  In this embodiment, the transport pressure of the compressed air used for the transport in the pipe inside the expansion joint is 0.07 MPa, and the compressed air pressure for the expansion operation to the seal member 4 is 0.2 MPa. If the transport pressure of compressed air used for in-pipe transport is 0.5 MPa or less and the compressed air pressure for expansion operation of the seal member 4 is twice or more of the transport pressure, the same seal Function can be obtained. In addition, applicable transport particles are not limited to the terephthalic acid powder shown in this example. It should be noted that the expansion joint according to the present invention is repeatedly used for about 4000 times of connection work for one year in the embodiment shown in FIGS. 3 and 4, and the workability of the pipe joint is greatly improved. It was confirmed that good stretchability and sealing functionality were maintained.

BRIEF DESCRIPTION OF THE DRAWINGS It is the whole cross-sectional schematic which shows the structure of the expansion-contraction pipe joint by this invention, and has shown the state which the sealing member contacted to the inner pipe outer peripheral surface. It is an expanded section schematic diagram of a seal unit part of an expansion pipe joint by the present invention, and shows a state where a seal member was separated from an inner pipe peripheral surface. It is a state figure which shows the example of 1 embodiment of the pipe connection using the expansion-contraction pipe joint by this invention, Comprising: The standby state before pipe connection with a tank lorry vehicle. FIG. 4 is a state diagram showing a state in which the connection operation with the tank lorry vehicle by the expansion pipe joint is completed from the standby state of FIG. 3.

Explanation of symbols

A: Flow of granular material P: Compressed air 1: Outer tube 2: Inner tube 3: Seal unit 4: Seal member 5: Seal member presser plate 6: Seal member presser plate mounting bolt 7: Bolt 8: Nut 9: Compression Air supply pipe 9A: Compressed air supply pipe 10: Slide ring 11: Slide ring holding plate 12: Slide ring holding plate mounting bolt 13: Outer pipe end flange 14: Inner pipe end flange 15: In-pipe transport piping 16 : Tank outlet 17: One-touch coupling 18: Compressed air introduction member 18A: Compressed air introduction hole

Claims (2)

  An expansion tube joint having an outer tube and an inner tube inserted into the outer tube along the tube axis, the length of which can be adjusted by the relative movement of the inner tube and the outer tube along the tube axis In this case, when compressed air is supplied between the outer tube and the inner tube, the outer surface of the inner tube is brought into contact pressure, and the sealing function of the inner tube and the outer tube is exhibited. An expansion and contraction tube provided with a seal member configured to move away from the outer peripheral surface of the inner tube when the tube is stopped / released, thereby releasing the sealing function of the inner tube and the outer tube and simultaneously allowing relative movement between the two Fittings.   Aside from the seal member, a cylindrical slide ring that contacts the outer peripheral surface of the inner tube is attached to the outer peripheral surface of the inner tube even when the seal member is separated from the outer peripheral surface of the inner tube. The expansion joint according to claim 1.

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