JPS6114538A - Inspecting method of airtightness of pipe - Google Patents

Abstract

PURPOSE:To perform economization by forming a sealed space while bringing a wall body into contact with a pipe and using part of the internal or external peripheral surface of the pipe in the pipe axis direction as part of the wall surface over the whole periphery, and reducing the size of the sealed space optionally. CONSTITUTION:Guide plates 8 and 9 which have holes 8a and 9a for air ventilation are fitted to both ends of the pipe 5 to be inspected, thereby guiding operation rod parts 6a and 7a of pistons 6 and 7. An O ring (not shown in the figure) for sealing is mounted on outer peripheral surfaces of the piston bodies 6b and 7b and a through hole 12 for pressing liquid 11 for inspection in the sealed space 10 is formed in one piston 6. Then, both pistons 6 and 7 are moved to the other terminal side of the pipe 5 while held at a specific interval after the airtightness of a specific section is inspected, thus performing inspection to the overall length of the pipe successively. Consequently, the liquid for inspection is saved and the cost of inspection is reduced.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method for testing the airtightness of a pipe.

Structure of conventional example and its problems Conventionally, when testing the airtightness of a pipe, as shown in Fig. 8, a suitable sealing means (not shown) is attached to both ends of the pipe (1) to be tested. The occlusion plates (2) and (3) are brought into contact with each other,
A test fluid was filled at a predetermined pressure through a through hole (4) formed in one of the closing plates (2) to check for leakage of fluid from the pipe (1).

However, such a conventional method requires a large amount of expensive pressure liquid or pressure gas for inspection when the pipe (1) is thick and long, which is uneconomical. Furthermore, when dangerous pressure liquid or pressure gas is used as a fluid for inspection, there is a problem in that the amount of leakage is large and the degree of danger is correspondingly high. There was also the problem that local inspection of the pipe (1) could not be performed.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and provides a pipe that uses a small amount of fluid, is economical, has low risk in the event of leakage, and can also be inspected locally. The purpose is to provide an airtightness inspection method.

Structure of the Invention In order to achieve the above-mentioned objects, (1) the airtightness testing method for a pipe according to the present invention includes a method for inspecting airtightness of a pipe by bringing a wall into close contact with the pipe, so that a part of the inner circumferential surface or the outer circumferential surface of the tube in the tube axis direction is covered with the wall surface over the entire circumferential length; A sealed space is formed as a part of the pipe, and a fluid is pressurized into this sealed space.

According to this configuration, the size of the sealed space can be made arbitrarily smaller than the volume inside the pipe, and the amount of fluid used for inspection can be reduced, making it extremely economical and suitable for use when using dangerous fluids. The risk of leakage can be reduced. In addition, the tube can be inspected locally, and by moving the wall in the direction of the axis of the tube, the entire tube can be inspected.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on the drawings.

FIGS. 1 to 8 are cross-sectional views showing the steps of a method for testing the airtightness of a pipe in an embodiment of the present invention, in which (5) shows the pipe to be tested;
(6'+ (7) is a piston that is slidably fitted into the inner peripheral surface of the pipe (5), (8) and (9) is the piston (6)
(7) is an annular guide plate that guides the operating rod part (6aM7a), and this guide plate ('8) (9) is attached to both ends of the tube (5), and also has an air vent hole (8aM7a). )(
9a) is formed. Said piston (6) (7
Although not shown, a sealing O-ring is attached to the outer circumferential surface t of the main body (6b) (7b) of the tube (5) to ensure a seal with the inner circumferential surface of the tube (5). ing. That is, a sealed space αO is formed by the pistons (6) (7) and the pipe (5), and one piston (6) has a through hole for pressurizing the test fluid (b) into the sealed space αO. A hole @ is formed.

Next, the airtightness inspection procedure will be explained. First, as shown in Figure 1, one piston (0) is aligned with one end of the pipe (5), and the other piston (7) is aligned with one end of the pipe (6)
Both pistons (6) (7) are positioned at a predetermined distance from
) is fixed, and the test fluid (2) is filled at a predetermined pressure into the airtight space αO from the through hole @ of one piston (6). At this time, the main body (6b) of one piston (6)
is in contact with one guide plate (8). Next, as shown in FIG. 2, both pistons (6) and (7) are moved to the other end of the tube (5) while maintaining a predetermined distance. At this time, the pressure of the fluid αD in the closed space QO is kept at a predetermined value. Then, as shown in Fig. 3, when the other piston (7) coincides with the other end of the tube (5), “
Stop the movement of the piston (s) (7). At this time,
The main body (7b) of the other piston (7) is in contact with the other guide plate (9). Thus, the closed space αO is a tube (
5), and by checking for leakage of the fluid (6) from the outer circumferential surface of the tube (5) during this period, an airtightness test can be performed over the entire length of the tube (5).

FIG. 4 shows another embodiment, in which the socket (
5a), one guide plate (8) and one end face of the tube (5) and one piston (6).

A sealing means such as an O-ring (not shown) may be provided between each of the operating rod portions (6a), and a through hole may be provided in one of the guide plates (8). In this case, through hole @
After filling the closed space αO with the fluid (b), first move one piston (6) to the other end of the pipe (5) so that the main body (6b) of the piston (6) is connected to the pipe (5). Both pistons (6) and (7) are moved together toward the other end of the tube (5) from the time when they fit into the inner circumferential surface of the tube (5). When inspecting only the socket part (5a), use only one piston (6) and one guide plate (8) as shown in Fig. 5, or use the other piston (6) and one guide plate (8) as shown in Fig. 6. Only the piston (7) and one disc-shaped guide plate 8) may be used.

FIG. 7 shows yet another embodiment, thus:
A tube (5) has a cylindrical body (end) having an annular collar protruding radially inward at both ends in the tube axis direction and a through hole (2).
The closed space αQ formed by the cylindrical body (to) and the outer peripheral surface of the tube (5) is filled with fluid α℃, and the cylindrical body (to) is fitted along the axial direction of the tube (5). It may also be moved by moving. In this case, the tube (5
) is fitted with an O-ring or the like to seal between the outer circumferential surface of the

DETAILED DESCRIPTION OF THE INVENTION As described in detail, according to the present invention, only a small amount of expensive testing fluid is required, which reduces testing costs, and the amount of leakage in the event of a leak is small, making it possible to avoid the use of dangerous fluids. Even if there is a problem, the risk is low, and inspections can be performed at higher pressures than conventional methods. In addition to being able to perform local inspections, it is also possible to inspect the entire length of the pipe by moving the wall. Furthermore, it is also possible to change the testing pressure for each testing location on a single pipe.

[Brief explanation of drawings]

FIGS. 1 to 3 are cross-sectional views showing the steps of a pipe airtightness inspection method in one embodiment of the present invention, FIGS. 4 to 7 are cross-sectional views showing different embodiments, and FIG. 8 is a conventional method. FIG. 3 is a cross-sectional view showing a method for testing the airtightness of a pipe.

Claims (1)

[Claims] 1. By bringing the wall into close contact with the tube, a sealed space is formed in which a portion of the inner circumferential surface or outer circumferential surface of the tube in the direction of the pipe axis becomes part of the wall surface over the entire circumferential length, and fluid is A method for testing the airtightness of a pipe, characterized by press-fitting the pipe.