JP2007093421A - Method for using packing, sealing structure and pipe quality testing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for using a packing, a sealing structure and a pipe quality testing machine which can suppress breakage of the packing. <P>SOLUTION: The packing 3 is disposed in an annular groove 13 formed on the inner circumferential surface of a pipe inserting hole 12, and the packing 3 is shrunk radially by a pressure applied to its outer circumferential surface, thereby sealing the outer circumferential surface side of both ends of a pipe 2, and preventing fluid from leaking out of the both ends of the pipe 2 toward the outer circumferential surface side. A bias member 4 which biases the packing 3 to the center axis of the pipe inserting hole 12 so that the center axis of the packing 3 coincides with the center axis of the pipe inserting hole 12, is interposed between the outer circumferential surface of the packing 3 and the bottom surface of the annular groove 13. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a packing usage method and a sealing structure used in a testing machine (pipe quality testing machine) for confirming pipe quality (leakage), and a pipe quality testing machine.

  As a testing machine for confirming the quality (leakage) of a pipe, there is a conventional testing machine as shown in FIG. FIG. 8 is a schematic cross-sectional view of a pipe quality testing machine according to the prior art. The pipe quality tester 101 applies fluid pressure in the pipe 102 and checks whether or not there is a fluid leak from the inner peripheral surface side to the outer peripheral surface side of the pipe 102 or the leak amount. The pipe quality testing machine 101 has an annular groove 113 on the inner peripheral surface of the pipe insertion hole 112 of the pipe 102, and a packing 103 is attached to the annular groove 113. Then, pressure is applied to the outer peripheral surface of the packing 103 to reduce the diameter of the packing 103, and the inner peripheral surface of the packing 103 is brought into close contact with the outer peripheral surfaces of both ends of the pipe 102. It prevents leakage from both ends to the outer peripheral surface. After the leakage is confirmed, the packing 103 is released from the pressure and returns to the initial dimension (the dimension indicated by the dotted line in the figure).

  Related techniques include those shown in the following documents.

Japanese Utility Model Publication No. 61-44 Japanese Utility Model Publication No. 61-45 JP-A-5-296898 JP-A-10-148607 JP 2001-183274 A

  Since the packing 103 is contracted and expanded for each test, when the expansion and contraction deformation is repeated, the initial diameter dimension is obtained even when the pressure is released as shown in FIG. It will not recover until the diameter becomes smaller. If it does so, a clearance gap will arise between the groove bottoms of the annular groove 113, and it will be in the state eccentric with respect to the annular groove by the fall by self-weight. As a result, as shown in FIG. 10, in the next use, when the pipe is inserted into the pipe insertion hole, the pipe interferes with the packing, and the packing is damaged (FIG. 10B). In the market, such packing breakage may occur with a probability of about once every three days, which increases the cost.

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a packing usage method, a sealing structure, and a pipe quality tester in which damage to the packing is suppressed. is there.

In order to achieve the above object, the method of using the packing in the present invention is as follows.
A pipe insertion hole into which a pipe to be tested is inserted is provided. With the pipe inserted into the pipe insertion hole, fluid pressure is applied to the pipe from the end side of the pipe, and the pipe outer peripheral surface from the pipe inner peripheral surface side. In a pipe quality tester that collects fluid leaked to the side and confirms the leakage of the pipe, in the usage method of the packing used for sealing between the pipe outer periphery and the pipe insertion hole at both ends of the pipe ,
The packing is mounted in an annular groove provided on the inner peripheral surface of the pipe insertion hole, and the outer peripheral surface side at both ends of the pipe is sealed by reducing the diameter by applying pressure to the outer peripheral surface of the packing. And used to prevent fluid from leaking from both ends of the pipe to the outer peripheral surface side, and between the outer peripheral surface of the packing and the groove bottom surface of the annular groove, the central axis of the packing and the pipe An urging member for urging the packing toward the central axis of the pipe insertion hole is interposed so as to coincide with the central axis of the insertion hole.

  In this way, the packing is urged toward the central axis of the pipe insertion hole by the urging member so that the central axis of the packing and the central axis of the pipe insertion hole coincide with each other. To suppress eccentricity. Therefore, even if the packing is reduced in diameter due to settling or the like and a gap is formed between the outer peripheral surface of the packing and the groove bottom surface of the annular groove, eccentricity due to the weight of the packing is suppressed, and a part of the packing is inserted into the pipe insertion hole. It is possible to prevent the pipe and the packing from interfering when the pipe is inserted by protruding inward from the inner peripheral surface of the pipe.

In order to achieve the above object, the sealing structure in the present invention is:
It is equipped with a pipe quality tester that applies fluid pressure into the pipe from the end side of the pipe, collects the fluid leaking from the pipe inner peripheral surface side to the pipe outer peripheral surface side, and confirms pipe leakage,
In the sealing structure used for sealing between the pipe insertion hole into which the pipe to be tested is inserted and the outer periphery of the pipe at both ends of the pipe,
The pipe is inserted into an annular groove provided on the inner peripheral surface of the pipe insertion hole, and the outer peripheral surface side at both ends of the pipe is sealed by reducing the diameter by pressure applied to the outer peripheral surface, so that the fluid flows at both ends of the pipe. Packing to prevent leakage from the side to the outer peripheral surface side,
The packing is disposed between the outer peripheral surface of the packing and the groove bottom surface of the annular groove, and the packing is connected to the central axis of the pipe insertion hole so that the central axis of the packing and the central axis of the pipe insertion hole are aligned with each other. And an urging member that urges toward.

In order to achieve the above object, the pipe quality tester in the present invention is:
A pipe insertion hole into which a pipe to be tested is inserted is provided, the pipe is inserted into the pipe insertion hole, and the pipe is sealed between the pipe outer periphery and the pipe insertion hole at both ends of the pipe with packing. A pipe quality tester that applies fluid pressure into the pipe from the end side of the pipe and collects fluid leaking from the pipe inner peripheral surface side to the pipe outer peripheral surface side,
The packing is attached to an annular groove provided on the inner peripheral surface of the pipe insertion hole, and the outer peripheral surface side at both ends of the pipe is sealed by reducing the diameter by the pressure received on the outer peripheral surface of the packing, In a pipe quality tester configured to prevent fluid from leaking from both ends of the pipe to the outer peripheral surface side,
The packing is directed toward the central axis of the pipe insertion hole so that the central axis of the packing and the central axis of the pipe insertion hole are aligned between the outer peripheral surface of the packing and the groove bottom surface of the annular groove. An urging member for urging is provided.

  As described above, according to the present invention, it is possible to suppress the packing from being damaged by the interference between the pipe and the packing.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

  With reference to FIGS. 1-4, the usage method, sealing structure, and pipe quality testing machine which concern on the Example of this invention are demonstrated. FIG. 1 is a schematic cross-sectional view of a pipe quality tester when a pipe is inserted. FIG. 2 is a schematic cross-sectional view of a pipe quality tester when pressure is applied to the outer peripheral surface of the packing to bring it into close contact with the pipe. FIG. 3 is a schematic cross-sectional view of a pipe quality tester when a test pressure is applied to the pipe. FIG. 4 is a schematic cross-sectional view of a pipe quality testing machine when the pressure is released and the pipe is pulled out. FIG. 5 is a schematic cross-sectional view of a rubber ring, (a) is a schematic cross-sectional view of an O-ring, and (b) is a schematic cross-sectional view of a square ring. FIG. 6 is a schematic cross-sectional view showing a state where the packing and the rubber ring are attached in the initial state. FIG. 7 is a schematic cross-sectional view showing a state in which the packing and the rubber ring are attached when the packing is set.

  The pipe quality testing machine 1 according to the present embodiment is a device for applying a fluid pressure in the pipe 2 and confirming fluid leakage from the inner peripheral surface side to the outer peripheral surface side of the pipe 2. The pipe quality testing machine 1 includes a pipe insertion hole 12 into which the pipe 2 is inserted, a packing 3 mounted in an annular groove 13 provided on the inner peripheral surface of the pipe insertion hole 12, and an outer peripheral surface of the packing 3. And a rubber ring 4 fitted between the groove bottom surface of the annular groove 13.

  The sealing structure according to the present embodiment is composed of the packing 3 and the rubber ring 4, and hereinafter, the elements constituting the pipe quality tester 1 are combined with the method of using the packing according to the present embodiment. I will explain.

  The pipe insertion hole 12 is a hole with a circular cross section having an inner diameter larger than the outer diameter of the pipe 2, and annular grooves 13 for mounting the packing 3 are provided on the bottom side and the inlet side, respectively.

  The packing 3 includes an inner peripheral surface that is in close contact with the outer peripheral surface of the pipe 2, both end surfaces that are in close contact with both side surfaces of the annular groove 13, and an outer peripheral surface for receiving pressure. Further, lip portions protruding in the radial direction are provided at both end edges of the outer peripheral surface.

  As shown in FIGS. 1 and 4, in the initial state, the diameter of the inner peripheral surface of the packing 3 (the inner diameter of the packing 3) is the inner diameter of the pipe insertion hole 12 (the inner diameter of the portion where there is no annular groove 13). Is set larger than. Further, the width dimension between both end faces of the packing 3 is set smaller than the width dimension between both side faces of the annular groove 13, and both end faces of the packing 3 are not in close contact with both side faces of the annular groove 13.

  When pressure is applied to the outer peripheral surface of the packing 3, as shown in FIGS. 2 and 3, the packing 3 is reduced in diameter by the force received by the outer peripheral surface, and the inner peripheral surface of the packing 3 is the outer peripheral surface of both ends of the pipe 2. And both ends of the packing 3 are in close contact with both side surfaces of the annular groove 13.

  The pipe quality testing machine 1 according to the present embodiment prevents the fluid from leaking from the both end sides of the pipe 2 to the outer peripheral surface during pressurization by causing the packing 3 to be in close contact in this way. .

  As shown in FIG. 5, the rubber ring 4 is set such that the outer diameter D1 is larger than the diameter D2 of the groove bottom surface of the annular groove 13 in a state before mounting. That is, the rubber ring 4 has a crushing allowance (D1-D2) with respect to the groove bottom of the annular groove 13, and when mounted, as shown in FIG. It will be inserted in a state of being crushed between the bottom of the groove.

Therefore, the packing 3 is urged toward the central axis of the pipe insertion hole 12 so that the central axis of the packing 3 and the central axis of the pipe insertion hole 12 are aligned by receiving the elastic force of the rubber ring 4. Will be installed.

<Quality test process>
Next, a test process for confirming the quality (leakage) of the pipe will be described with reference to FIGS. First, as shown in FIG. 1, the pipe 2 to be tested is inserted into the pipe insertion hole 12 of the pipe quality tester 1. The packing 3 is in a state where no pressure is applied yet, and the diameter is in an initial state.

  Next, as shown in FIG. 2, a pressure of about 2.5 MPa is applied to the outer peripheral surface of the packing 3 to bring the packing 3 into close contact with the outer peripheral surface of the pipe 2 (this pressure is hereinafter referred to as pre-seal pressure). The packing 3 is reduced in diameter by the force received at the outer peripheral surface so that the inner peripheral surface of the packing 3 is in close contact with the outer peripheral surface of both ends of the pipe 2 and is expanded in the axial direction so that both end surfaces of the packing 3 are on both sides of the annular groove 13. Adhere to the surface.

  Next, as shown in FIG. 3, a test pressure of about 20 MPa is applied to the pipe 2. And the fluid which leaked from the inner peripheral surface side of the pipe 2 to the outer peripheral surface side is collected, and the quality (leakage) of a pipe is confirmed.

  In the present embodiment, the fluid leaking from the inner peripheral surface side to the outer peripheral surface side of the pipe 2 is collected in the container 5 via the drain port 11, and the collected fluid is detected by a sensor or the like. By doing so, the presence or absence of fluid leakage and the amount of leakage can be confirmed. Note that detection means may be provided in a path through which the leaked fluid is collected so that the presence or absence of fluid leakage can be confirmed.

  In the present embodiment, the test pressure is also applied to the side surfaces of the packing 3 at both ends of the pipe 2, so that a pressure equivalent to the test pressure is also applied to the outer peripheral surface of the packing 3.

  Here, as a pressurizing method for applying the pre-seal pressure or the test pressure to the pipe 2 and the packing 3, for example, a method of introducing high-pressure water or high-pressure air set to the pre-seal pressure or the test pressure into each part is used. Can do. Also, a method for checking leakage can be appropriately selected according to the pressurizing method.

  When the leak check is completed, as shown in FIG. 4, the pressurization is stopped and the packing 3 returns to the initial diameter dimension. And the pipe 2 is pulled out from the pipe insertion hole 12, and a pipe quality test process is complete | finished.

  As described above, the packing 3 is reduced in diameter and increased in diameter for each test, and therefore, when the test is repeated, settling occurs due to repeated expansion / contraction deformation. If it does so, even if it cancels | releases pressurization, it will not return to the diameter dimension of an initial state, and as shown in FIG. 7, a diameter dimension will become small with respect to an initial state.

  However, since the packing 3 is urged toward the central axis of the pipe insertion hole 12 by the rubber ring 4, it may be eccentric and a part of the packing 3 may protrude inward from the inner peripheral surface of the pipe insertion hole 12. It is suppressed. Therefore, interference between the pipe 2 and the packing 3 when the pipe 2 is inserted is suppressed, and damage to the packing 3 can be suppressed.

  Here, the outer diameter of the pipe 2, the inner diameter of the pipe insertion hole 12 (where the annular groove 13 is not provided), the inner diameter of the groove bottom of the annular groove 13, the inner diameter and the outer diameter of the packing 3 are made constant, and the rubber ring 4 When the outer diameter dimension is set larger than the inner diameter dimension of the groove bottom surface of the annular groove 13, the inner diameter dimension of the rubber ring 4 is appropriately set as follows.

  For example, when the pipe 2 is inserted coaxially into the pipe insertion hole 12 by an automatic machine or the like, the total thickness in the radial direction of the packing 3 and the rubber ring 4 is annular from the outer peripheral surface of the pipe 2 in the mounted state. The width is set to be smaller than the width of the groove 13 up to the groove bottom surface.

  When the pipe 2 is inserted into the pipe insertion hole 12 by manual work or the like, the total thickness in the radial direction of the packing 3 and the rubber ring 4 in the mounted state is annular from the inner peripheral surface of the pipe insertion hole 12. The width is set to be smaller than the width of the groove 13 up to the groove bottom surface.

  Furthermore, it is necessary to appropriately set the inner diameter dimension of the rubber ring 4 in consideration of the following points.

  That is, if the inner diameter dimension of the rubber ring 4 is too small (the wall thickness is too thick), the urging force acting in the inner diameter direction on the outer peripheral surface of the packing 3 is increased, and the packing 3 is reduced in diameter by the urging force. 3 protrudes inward from the inner peripheral surface of the pipe insertion hole 12.

  Further, if the inner diameter of the rubber ring 4 is too large (the wall thickness is too thin), the amount of crushing with respect to the packing 3 when no pressure is applied will be reduced or eliminated. It becomes impossible to energize, and the function of suppressing eccentricity becomes insufficient.

  The rubber ring 4 can be applied to an existing pipe quality test apparatus if the diameter of the rubber ring 4 is appropriately set in consideration of the above points.

  1 to 4, 6, and 7, the state in which the inlet for applying pressure to the outer peripheral side of the packing 3 is blocked by the rubber ring 4 is shown, but this is adopted in this embodiment. The rubber ring 4 does not need to be sealed and does not hinder pressurization on the outer peripheral side of the packing 3.

  In this embodiment, an O-ring having a circular cross section and a square ring having a rectangular cross section are used as the rubber ring 4. However, as long as the packing 3 can be urged toward the central axis of the pipe insertion hole 12. Since sealability is not required, it is of course possible to use other shapes of rubber rings.

  In this embodiment, an annular rubber ring 4 is used as a means for biasing the packing 3 to generate a biasing force over the entire circumference of the outer peripheral surface of the packing 3. However, if the packing 3 is urged toward the central axis of the pipe insertion hole 12 so that the central axis of the packing 3 and the central axis of the pipe insertion hole 12 coincide, There is no need to generate a biasing force around the circumference.

  Therefore, urging members for urging the packing 3 toward the central axis of the pipe insertion hole 12 are provided at several locations on the entire circumference of the bottom of the annular groove 13 to generate urging forces at several locations on the outer peripheral surface of the packing 3. The center axis of the packing 3 and the center axis of the pipe insertion hole 12 may be made to coincide with each other by balancing each urging force. That is, the urging member is not limited to the rubber ring 4, and other urging members can be appropriately employed.

  Although it is desirable that the center axis of the packing 3 and the center axis of the pipe insertion hole 12 are completely coincident with each other, it is not necessary to completely coincide with the packing 3 so long as the protrusion of the packing 3 is prevented. Be acceptable.

FIG. 1 is a schematic cross-sectional view of a pipe quality testing machine according to the present embodiment. FIG. 2 is a schematic cross-sectional view of the pipe quality testing machine according to the present embodiment. FIG. 3 is a schematic cross-sectional view of the pipe quality testing machine according to the present embodiment. FIG. 4 is a schematic cross-sectional view of the pipe quality testing machine according to the present embodiment. FIG. 5 is a schematic cross-sectional view of a rubber ring. FIG. 6 is a schematic cross-sectional view of a pipe quality testing machine according to the present embodiment. FIG. 7 is a schematic cross-sectional view of a pipe quality testing machine according to the present embodiment. FIG. 8 is a schematic cross-sectional view of a pipe quality testing machine according to the prior art. FIG. 9 is a schematic cross-sectional view of a pipe quality testing machine according to the prior art. FIG. 10 is a schematic cross-sectional view of a pipe quality testing machine according to the prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pipe quality tester 11 Drain port 12 Pipe insertion hole 13 Annular groove 2 Pipe 3 Packing 4 Rubber ring 5 Container

Claims (3)

A pipe insertion hole into which a pipe to be tested is inserted is provided. With the pipe inserted into the pipe insertion hole, fluid pressure is applied to the pipe from the end side of the pipe, and the pipe outer peripheral surface from the pipe inner peripheral surface side. In a pipe quality tester that collects fluid leaked to the side and confirms the leakage of the pipe, in the usage method of the packing used for sealing between the pipe outer periphery and the pipe insertion hole at both ends of the pipe ,
The packing is mounted in an annular groove provided on the inner peripheral surface of the pipe insertion hole, and the outer peripheral surface side at both ends of the pipe is sealed by reducing the diameter by applying pressure to the outer peripheral surface of the packing. And used to prevent fluid from leaking from both ends of the pipe to the outer peripheral surface side, and between the outer peripheral surface of the packing and the groove bottom surface of the annular groove, the central axis of the packing and the pipe A method of using a packing, characterized in that a biasing member for biasing the packing toward the central axis of the pipe insertion hole is interposed so as to be aligned with the central axis of the insertion hole. It is equipped with a pipe quality tester that applies fluid pressure into the pipe from the end side of the pipe, collects the fluid leaking from the pipe inner peripheral surface side to the pipe outer peripheral surface side, and confirms pipe leakage,
In the sealing structure used for sealing between the pipe insertion hole into which the pipe to be tested is inserted and the outer periphery of the pipe at both ends of the pipe,
The pipe is inserted into an annular groove provided on the inner peripheral surface of the pipe insertion hole, and the outer peripheral surface side at both ends of the pipe is sealed by reducing the diameter by pressure applied to the outer peripheral surface, so that the fluid flows at both ends of the pipe. Packing to prevent leakage from the side to the outer peripheral surface side,
The packing is disposed between the outer peripheral surface of the packing and the groove bottom surface of the annular groove, and the packing is connected to the central axis of the pipe insertion hole so that the central axis of the packing and the central axis of the pipe insertion hole are aligned with each other. And a biasing member that biases toward the sealing member. A pipe insertion hole into which a pipe to be tested is inserted is provided, the pipe is inserted into the pipe insertion hole, and the pipe is sealed between the pipe outer periphery and the pipe insertion hole at both ends of the pipe with packing. A pipe quality tester that applies fluid pressure into the pipe from the end side of the pipe and collects fluid leaking from the pipe inner peripheral surface side to the pipe outer peripheral surface side,
The packing is attached to an annular groove provided on the inner peripheral surface of the pipe insertion hole, and the outer peripheral surface side at both ends of the pipe is sealed by reducing the diameter by the pressure received on the outer peripheral surface of the packing, In a pipe quality tester configured to prevent fluid from leaking from both ends of the pipe to the outer peripheral surface side,
The packing is directed toward the central axis of the pipe insertion hole so that the central axis of the packing and the central axis of the pipe insertion hole are aligned between the outer peripheral surface of the packing and the groove bottom surface of the annular groove. A pipe quality testing machine comprising a biasing member for biasing.

Images