JPH07181098A - Leak test coupler for pipe coupling assembly - Google Patents

Abstract

PURPOSE:To provide a leak test coupler for pipe coupling assembly in which stress is not generated in the axial direction at a nipple part at the time of leak test. CONSTITUTION:The leak test coupler is employed for feeding a test fluid to a nipple part 6 through a test fluid supply pipe 16 at the time of leak test of a pipe coupling assembly having the nipple part 6. The coupler comprises a housing 28, a cylindrical body 30 sliding in the housing 28, a cylindrical sealing body 32 being held at the front end in the cylindrical body 30, a piston 34 sliding toward the rear side of the sealing body 32 while being sealed, and means for driving the piston 34. The cylindrical sealing body 32 is made of an elastic polymer material having the intermediate part being compressed and swelled inward, and a piping 16 for feeding a test fluid is coupled between the piston 34 and the sealing body 32 at the front dead center of the piston 34.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coupler used for connecting a test fluid supply pipe to a nipple portion in a leak test of a pipe joint assembly having the nipple portion.

[0002]

2. Description of the Related Art For example, as a pipe joint assembly 2, as shown in FIG. 1, a bent pipe 4 has a nipple portion 6 having a retaining portion 6a at one end, and an eyelet 8 at the other end. There is a configuration in which the mounting brackets 10 are welded and fixed by brazing or the like.

Such a pipe joint assembly 2 has conventionally used a pipe joint assembly leak test coupler as shown in FIG. 2 in order to inspect for a leak in a brazing portion or the like.

It comprises a coupler body 12 and an air cylinder 14 for reciprocating the coupler body 12 in the front-rear direction.
The coupler body 12 is held at the tip of the body block 20 and a body block 20 having a fluid feeding nozzle 20a at the center of the tip to which a flexible test fluid supply pipe 16 is connected by a connection nut 18. It is composed of an annular seal body 22 and a fixed socket 24 for fixing the annular seal body 22 to the main body block 20.

The air leak test was conducted as follows.

With the eyelet 8 side closed with a seal member or the like, the joint assembly 2 is fixed by setting it on the test piece holding jig 26. In this state, the air cylinder 14 is driven on the tip of the nipple portion 6 to press the annular seal body 22 of the coupler body 12 by the cylinder rod 14a.
Subsequently, the main plug of the test air supply pipe (fluid supply pipe) 16 is opened, air is sent from the nozzle 20a of the coupler body 12 into the pipe joint assembly 2 through the nipple portion 6, and at the brazing site. Check for air leak by submerging it in water.

[0007]

However, in this leak test, since the coupler body 12 is pressed against the tip of the nipple portion 6, a stress is generated in the axial direction of the nipple portion 6, and as shown in FIG.
As indicated by the dotted line in FIG. 3, the nipple portion 6 of the pipe joint assembly 2 is
Also, one or both of the brackets 10 may be deformed. When it is deformed, the end surface of the nipple portion 6 is tilted, and it is difficult to ensure the sealing property with the annular seal body 22.

In view of the above, it is an object of the present invention to provide a pipe joint assembly leak test coupler in which stress is not generated in the axial direction of the nipple portion when performing a leak test of the pipe joint assembly.

[0009]

SUMMARY OF THE INVENTION A pipe joint assembly leak test coupler according to the present invention solves the above problems by the following constitution.

A coupler for use in feeding a test fluid from a test fluid supply pipe into the nipple portion when performing a leak test on a pipe joint assembly having a nipple portion, which is a cylindrical housing. A sliding cylinder that slides in the housing, a cylindrical seal body that is held at the front end of the sliding cylinder, and a piston that can seal and slide on the rear side of the cylindrical seal body. The cylindrical seal body is made of a polymer elastic material, and the intermediate portion bulges inward by a compression action of the piston so that it can be deformed. Then, a fluid supply pipe is connected between the piston and the cylindrical seal body so that the test fluid can be fed.

[0011]

Embodiments of the present invention will be described below mainly with reference to FIGS.
It will be described based on. The same parts as those of the conventional example are designated by the same reference numerals, and the whole or part of the description thereof will be omitted.

(1) The coupler for pipe joint assembly leak test of the present invention uses the test fluid supply pipe 16 from the test fluid supply pipe 16 to the nipple part 6 when performing the leak test of the pipe joint assembly 2 having the nipple part 6. It is a prerequisite that it be used to deliver the test fluid.

(2) A cylindrical housing 28, a sliding cylinder 30 that slides in the housing 28, a cylindrical seal member 32 held at the front end of the sliding cylinder 30, and a cylindrical shape. The seal 34 includes a piston 34 that is slidable on the rear side of the seal body 32, and a driving unit 14 that drives the piston 34.

Here, the housing 28 has a protrusion 28a for preventing the sliding cylinder 30 from slipping off at the tip. The sliding cylinder 30 is
It includes a cap portion 30a and a tubular portion 40. Housing 2
In the illustrated example, 8 is fixed to an air cylinder 14 described later.

The tubular seal body 32 has an engaging flange portion 32a on the tip side, and is sandwiched between the tip of the tubular portion 30a of the sliding tubular body 30 and the cap portion 30b so that the inside of the sliding tubular body 30 is held. Is held on the front end side of the.

The piston 34 is a flat bottomed cylindrical body, and an O-ring 38 is mounted on the outer periphery thereof, so that it can be slidably moved inside the sliding cylindrical body 30.

The drive means 14 is the air cylinder 14 in the illustrated example, but the drive means 14 is not limited to the air cylinder 14, and may be crank drive, screw drive, or the like.

The housing 28, the sliding cylinder 30, and the piston 34 are usually made of metal, but may be made of ceramic or plastic as long as they have a predetermined strength.

(3) The tubular seal member 32 is made of a polymeric elastic material and is deformable by being compressed by the piston 34 so that the intermediate portion bulges inward.

Here, examples of the polymer elastic material include natural rubber, synthetic rubber (NBR, CR, EPDM, etc.) or thermoplastic elastomer (ester, olefin, urethane, amide, etc.), It is desirable that the amount of swelling during compression is large, that is, that the Poisson's ratio is as large as possible.

(4) Fluid supply pipe 1 so that a test fluid can be fed between the front dead center position of the piston 34 and the cylindrical seal member 32.
6 is connected. Specifically, a joint (nipple) 36 connected to the fluid supply pipe 16 is screwed to the side wall of the intermediate portion of the sliding cylinder 30, and when the piston 34 is at the front dead center position on the circumferential wall. An air communication hole 38 corresponding to the hole of the nipple 36 is formed. The housing 28 has a nipple 36 at a position corresponding to the nipple 36.
A cutout portion 28b is formed in the axial direction so as not to buffer.

(5) Next, the manner of use of the above embodiment will be described.

First, as in the conventional case, the eyelet 8 side is closed with an elastic plug or the like and set on the test piece holding jig 28 to fix the joint assembly (see FIG. 1). At this time, as shown in FIG. 3, the nipple portion 6 of the pipe assembly is made to face the opening of the cap portion 30a of the sliding cylinder 30.

Then, the air cylinder 14 is driven to advance the piston 34. Then, the piston 34
First contacts the rear end of the tubular seal body 32 and advances the sliding tubular body 30 through the tubular seal body 32.

Then, the sliding cylinder 30 comes into contact with the retaining projection 28a of the housing 28 to reach the front dead center position. Further, when the piston 34 is moved forward, the cylindrical seal body 32 is compressed and bulges inward to compress and seal the outer circumference of the nipple portion 6.

In this state, when the main plug of the test air supply pipe (fluid supply pipe) 16 is opened, the through hole of the joint 36 and the air through hole 38 of the piston 34 correspond to each other. Air flows between the front dead center position and the cylindrical seal body, and air is sent into the pipe joint assembly through the nipple portion 6. Then, the presence or absence of air leakage at the brazing portion of the pipe joint assembly is checked by submerging it in water.

Although compressed air is used as the test fluid here, water or the like may be used.

[0028]

The pipe joint assembly leak test coupler of the present invention has the following actions and effects due to the above configuration.

When performing the leak test of the pipe joint assembly, the nipple portion is sealed by compressing the cylindrical seal body and bulging it inward. Therefore, the sealing direction of the nipple is changed from the end surface of the nipple to the peripheral part, and no stress is generated in the axial direction of the nipple. There is no fear of occurrence of the above, and further, the end face of the nipple portion is not inclined, and the sealing performance of the seal body can be secured.

[Brief description of drawings]

FIG. 1 is an overall schematic view of a pipe joint assembly leak test apparatus using a conventional coupler.

FIG. 2 is a sectional view of a conventional coupler.

FIG. 3 is a cross-sectional view showing a state before sealing the nipple portion in an example of the coupler of the present invention.

FIG. 4 is a sectional view showing a state when the nipple part is sealed.

[Explanation of symbols]

 2 Pipe Joint Assembly 6 Nipple Section 14 Air Cylinder (Drive Means) 16 Fluid Supply Pipe 28 Housing 30 Sliding Cylindrical Body 32 Cylindrical Seal Body 34 Piston 36 Joint (Nipple) 38 Air Conduction Hole

Claims (2)

[Claims] 1. A coupler for use in feeding a test fluid from a test fluid supply pipe into a nipple portion when performing a leak test on a pipe joint assembly having a nipple portion, the coupler having a cylindrical shape. Housing, a sliding cylinder body that slides in the housing, a cylindrical seal body held at the front end of the sliding cylinder body, and a piston capable of sealing sliding on the rear side of the cylindrical seal body. And a driving means for driving the piston, wherein the cylindrical seal body is made of a polymeric elastic material, and the intermediate portion bulges inward under a compressive action from the piston to be deformable. The pipe joint assembly leak test coupler, wherein the fluid supply pipe is connected between the piston and the cylindrical seal body so that the test fluid can be fed at the front dead center position. 2. The coupler for pipe joint assembly leak test according to claim 1, wherein the driving means for the piston is an air cylinder.