JPH028093Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a leak prevention device used to prevent leakage of fluid flowing inside a pipe, for example, at a flange portion of a pipe joint.

[Conventional technology]

When connecting pipes, flanges are formed on the end faces of the pipes, the flanges are butted against each other, and the flanges are fastened together with a plurality of bolts. A gasket is sandwiched between the flanges for the purpose of preventing leakage of fluid flowing inside the pipe.

[Problems to be Solved by the Invention] Generally speaking, the torque of the bolts used to tighten the flange portion is controlled in order to keep the tightening force as constant as possible. However, considering deformation of gaskets, deformation of bolts and nuts, and accuracy of tightening surfaces, controlling the bolt torque does not necessarily mean controlling the tightening force.

In addition, when tightening through a gasket, such as with a flange, when the gasket becomes flat due to expansion and contraction in the tube axis direction due to temperature changes, vibration, etc., the bolts may loosen and the seal may become incomplete. ,
This may cause leakage. For this reason, it is necessary to retighten the bolts after a certain period of time after installation, making maintenance time-consuming.

Furthermore, even if the tightening force is controlled at the time the bolt is tightened, over time, the bolt or tightening surface may become loose due to wear, and the tightening force may not be exerted correctly. It was hot.

[Means for solving problems]

The leak prevention device of the present invention is used, for example, in the flange portion of a pipe joint as described above, and includes a cylindrical case that is open at both ends. A movable spring seat is provided which is movable in the direction and has a hole in the center for passing a bolt through. The opening on the other end of the case is provided with a fixed spring seat that also has a hole for bolt insertion in the center, and a plurality of disc springs are installed between the fixed spring seat and the movable spring seat. are housed in series.

A viewing window for looking into the inside of the case is provided on the side wall of the case, and one or more types of colored display portions with a specific color are provided on the outer peripheral surface of the movable spring seat. This colored display section is
The spring is disposed at such a position that it appears in the viewing window when the disc spring is deflected by a predetermined amount, and disappears from the viewing window at other times.

[Effect]

In the leak prevention device configured as described above, a bolt is passed through the spring seat and the disc spring, and when the bolt is tightened with a nut or the like, each disc spring is compressed and bent. As the disk spring is bent, the movable spring seat moves relative to the case in the axial direction. When a predetermined load is applied to the disc spring, the specific color of the colored display section appears in the viewing window and becomes visible. Therefore, by looking through the viewing window, it is possible to easily judge whether or not the axial force acting on the bolt is appropriate.

〔Example〕

In the leak prevention device 1 shown in FIG. 1, the case 2 has a short cylindrical shape and is open at both ends.
The case 2 is preferably made of a corrosion-resistant metal such as stainless steel, but other materials may also be used.

Spring seats 3 and 4 are provided at both end openings of the case 2. Holes 6, 7 for bolt insertion are formed in the center of each spring seat 3, 4. The surfaces of the spring seats 3 and 4 are hardened by appropriate heat treatment so that they can fully exhibit the functions of the disc spring 12 described below.

One spring seat 3 is provided so as to be relatively movable in the axial direction of the case 2. This movable side spring seat 3
is a large diameter portion 3a located on the inside side of the case 2;
It consists of a small diameter part 3b located on the outside side. The other spring seat 4 is fixed to the case 2 by caulking the end 9 of the case 2 inward. This fixed side spring seat 4 may be fixed to the case 2 by welding or screwing.

Inside the case 2, a plurality of disc springs 12 are housed between spring seats 3 and 4 in an unloaded or compressed state. The disc springs 12 are stacked in series with alternate orientations. Between each disc spring 12,
Grease is applied between the disc spring 12 and the spring seats 3 and 4. The spring characteristics of the disc spring 12 are designed so that even if it becomes flat, it remains within an allowable stress range, and can be used repeatedly. The number of disc springs 12 is selected as required.

The case 2 is provided with a stopper portion 14 that prevents the movable spring seat 3 from coming off. The stopper portion 14 is formed by machining the opening edge of the case 2 into a stepped shape, or by bending the opening edge of the case 2 inward. Then, the large diameter part 3a of the spring seat hits this stopper part 14 from the inside, so that the movable spring seat 3 is moved to the case 2.
I'm trying not to jump out. Furthermore, as shown in FIG. 1, the large diameter portion 3a is the stopper portion 14.
In the state where the small diameter portion 3b of the spring seat 3
protrudes to the outside of case 2.

A plurality of slit-shaped viewing windows 16, 16' are provided on the side wall of the case 2, spaced apart from each other in the axial direction of the case 2. These viewing windows 1
6 and 16' are formed on a display plate 17 manufactured separately from the case 2. Display board 17 is case 2
It is fitted into a mounting hole (not shown) provided in the case 2, and is attached to the case 2 by screws or welding.
Fixed. The viewing windows 16, 16' may be through holes formed in the display panel 17, but in order to improve the sealing performance of the case 2, the holes may be covered with a transparent cover material.

On the other hand, a plurality of annular colored display portions 18 and 19 are provided on the outer surface of the movable spring seat 3 along the circumferential direction. The colored display parts 18 and 19 have different colors and are arranged alternately in the axial direction of the spring seat 3 at the same interval as the pitch between the viewing windows 16 and 16'.

More specifically, when the disk spring 12 reaches a predetermined amount of deflection, one of the colored display sections 18 first displays the viewing window 1.
6 and 16', this colored display section 18 can be seen through the viewing windows 16 and 16'. When the load increases and the deflection of the disc spring 12 increases, the other colored display section 19 is positioned in the viewing window 16, 16', and this colored display section 19 is moved to the viewing window 16, 16'. It can be seen from. At times other than the above-mentioned deflection, the colored display section 18,
19 are both hidden from the viewing windows 16, 16'.
The above-mentioned colored display parts 18 and 19 may be formed by fitting a color ring made of synthetic resin into the circumferential groove formed in the spring seat 3, or by applying paint to the groove. good. Moreover, the colored display parts 18 and 19 may be provided only in a part of the spring seat 3 in the circumferential direction. Each colored display section 18, 19
The color width and the groove width and pitch of the viewing windows 16, 16' are determined according to the load-deflection characteristics of the disc spring 12.

Note that by dividing the colored display parts 18 and 19 into three or more colors (for example, red, blue, yellow, etc.), three or more different colors are displayed one after another in the viewing window corresponding to the amount of deflection of the disc spring 12. 16, 16'.

An example of how the leak prevention device 1 is used is shown in FIG. Flange portions 23 and 2 are provided on each end surface of the tubes 21 and 22.
4 are provided, and the flange parts 23 and 24 are butted against each other, and the flange parts 23 and 24 are connected in the circumferential direction using a plurality of sets of bolts 26 and nuts 27 and the leak prevention device 1.
A gasket 30 is sandwiched between the flange portions 23 and 24 on their opposing surfaces.

When the bolt 26 or nut 27 is tightened, the disc spring 12 is compressed between the spring seats 3 and 4, and the gasket 30 is tightened by the reaction force. When the deflection of the disc spring 12 reaches a predetermined amount, the colored display portions 18 and 19 change to one of the colors in the viewing windows 16 and 1 according to the deflection.
Appears at 6'. That is, since the axial force of the bolt 26 is determined based on the amount of deflection of the disc spring 12, the tightening force can be determined more accurately than in the conventional torque management system. Moreover, no special tools are required.
Further, even if the gasket 30 becomes sag, the gasket 30 is held down by the repulsive force of the disc spring 12, so that additional tightening work can be omitted. Further, the variable load on the bolt 26 due to temperature changes etc. is also reduced.

Since the leak prevention device 1 described above is housed in a space surrounded by the case 2 with the disc spring 12 coated with grease or anti-corrosion paint, it cannot be used in a harsh atmosphere exposed to dust or rain. It also prevents sand from getting in, corrosion, deterioration of grease, and loss of grease, resulting in high reliability.

In this embodiment, two rows of viewing windows 16, 16' are provided, but the intended purpose of the present invention can be achieved as long as there is at least one viewing window. Further, the colored display section may be made easier to see by providing three or more rows of viewing windows and correspondingly providing three or more rows of the same type of colored display section. Furthermore, two or more leak prevention devices 1 may be stacked and used on one bolt. Furthermore, if it is combined with a bolt whose axial force is controlled, it will be even more effective in preventing leaks.

[Effect of idea]

According to the present invention, the tightening force of the bolt can be easily grasped, and the occurrence of loosening can be prevented, which is particularly effective in preventing leakage at the flange portion of the pipe joint.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, in which FIG. 1 is a partially sectional front view of the leak prevention device, FIG. 2 is a perspective view of the display board, and FIG. 3 is the movable side spring. It is a perspective view of a seat. FIG. 4 is a sectional view showing how the leak prevention device shown in FIG. 1 is used. 1... Leak prevention device, 2... Case, 3...
Movable side spring seat, 4... Fixed side spring seat, 6, 7...
Hole for bolt insertion, 12... disc spring, 14... stopper part, 16, 16'... viewing window, 18, 19
...Colored display section.

Claims (1)

[Scope of utility model registration request] A cylindrical case with both ends open; a movable spring seat provided at one end opening of the case so as to be movable in the axial direction of the case and having a bolt insertion hole in the center; a fixed side spring seat fixed to the other end side opening and having a bolt insertion hole in the center; a plurality of disc springs housed in series between the spring seats in the case; and a side surface of the case. A viewing window provided on the wall and a color arranged on the outer peripheral surface of the movable spring seat, which appears in the viewing window when the disc spring is bent by a predetermined amount, and disappears from the viewing window at other times. 1. A leak prevention device characterized by comprising more than one type of colored display section.