JPH0515429Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to a welding jig used when seal-welding the outer periphery in order to improve the sealing performance of DO clamp-type pipe joints used to connect pipes together. It is something.

[Conventional technology]

Various types of pipe joints are used to connect pipes, depending on the type of pipe and the type of fluid flowing inside.

For example, vacuum insulated piping is used to connect a liquid hydrogen storage tank and a place where this liquid hydrogen is used because the temperature of liquid hydrogen is extremely low.
We try to prevent heat from entering from the outside as much as possible.

One of the pipe fittings for vacuum insulated piping
DO clamp type fittings may be used.

As shown in FIG. 4, for example, this DO clamp type pipe joint has inner circumferential meshing parts 3, 3a formed on the inner peripheries of flanges 2, 2a that are welded to the ends of pipes 1, 1a. O-ring 4 between the meshing parts 3 and 3a
are interposed, and the flanges 2, 2
Slanted surfaces 5, 5a whose thickness increases toward the center are formed on the back of the outer periphery of the flanges 2, 5a.
By tightening the fastening part 7 of the clamp 6, which is divided into two halves into the upper and lower parts, with the bolt 8 while the end contact surfaces of the clamps 2a and 2a are brought into contact with each other, the flanges 2 and 2a can be tightened using the tapered surface on the inner circumference of the clamp 6. It is designed to maintain the attached state.

[Problem that the invention attempts to solve]

Such DO clamp type pipe fittings provide sufficient sealing performance when used for piping normal temperature fluids, etc.
Although this is a highly reliable pipe fitting, when used as a pipe fitting for piping of extremely low temperature fluids such as liquid hydrogen, there is a risk that the sealing performance will deteriorate due to thermal shrinkage, etc., resulting in leakage of the liquid hydrogen inside.

Therefore, it has been considered to seal-weld the outer periphery of the flanges 2, 2a in order to further improve the sealing performance of the DO clamp type pipe joint.

In particular, when using this DO clamp type pipe joint for fuel piping in combustion test equipment for rocket engines, it is important not only to improve the sealing performance by seal welding, but also to eliminate the presence of a small amount of dust in the pipes 1 and 1a during welding. There is a problem in that it is necessary to prevent contamination with the like.

This idea was made in view of the problems of the conventional technology, and aims to improve the sealing performance by seal welding the outer circumference of the flange of the DO clamp type pipe fitting, which was completely unthinkable in the conventional usage. To provide a seal welding jig for a pipe joint, which can be welded without contaminating the inside of the pipe joint when the flange is in close contact with the flange.

[Means for solving problems]

In order to solve the above-mentioned problems, this invention has a sloped surface for tight tightening formed on the back of the outer periphery of a pair of flanges, a meshing part for centering formed on the inner periphery, and an O-ring attached to this inner periphery meshing part. In a jig for seal-welding the outer periphery of the flange of the DO clamp, which is sealed with A pair of semicircular abutting members having slopes in opposite directions that can be applied by sandwiching the flange are connected in the circumferential direction with a gap for seal welding, and the The present invention is characterized in that a fastening portion is formed that holds the flanges vertically and fastens them to obtain an axial adhesion force between the slope of the flange and the reverse slope of these abutting members to maintain a sealed state.

[Effect]

The slopes on the back of the outer periphery of the flange of the DO clamp type pipe joint are connected from both sides with contact members at intervals in the circumferential direction, and the contact members that form a pair above and below are tightened at the fastening part. This provides a close contact condition equivalent to tightening with a clamp, and also allows seal welding to be performed without any hindrance by utilizing the spacing between the abutting members.

〔Example〕

Hereinafter, one embodiment of this invention will be described in detail based on the drawings.

Figures 1 to 3 show an embodiment of the pipe joint seal welding jig of this invention, and Figure 1 is a front view;
FIG. 2 is a side view, and FIG. 3 is a plan view.

This seal welding jig 10 is used in place of the clamp 6 of a DO clamp type pipe joint to seal the outer periphery of the flanges 2, 2a. Member 11,1
1a are connected by connecting members 12 at two locations in the circumferential direction. Abutting member 1 connected by this connecting member 12
1, 11a are formed with slopes 13, 13a corresponding to the slopes 5, 5a at the back of the outer periphery of the flanges 2, 2a of the DO clamp type pipe joint, and the interval between these slopes 13, 13a is equal to the distance between the slopes 13, 13a. The size of the connecting member 12 is selected so as to be approximately equal to the interval between the slopes 6. In addition, fastening parts 14 that also serve as a connecting member are attached to both ends of the contact members 11 and 11a connected by the connecting member 12 so as to protrude outward in the horizontal direction, and bolt holes for tightening are formed. has been done.

Such two contact members 11, 11a and 2
A connecting member 12 and a fastening portion 14 at both ends are arranged on the outer periphery of the flanges 2, 2a of the DO clamp type pipe joint so as to be sandwiched from above and below,
In use, the bolt 15 is inserted into the bolt hole of the fastening part 14 and tightened.

Then, flange 2 of the DO clamp type pipe joint,
A contact member 11 is attached to the slope 5, 5a on the back of the outer periphery of 2a.
The contact surfaces of the flanges 2, 2a are arranged so that the slopes 13, 13a on the inner periphery of the flanges 11a abut, and the slopes 13, 13a tighten the pair of upper and lower contact members 11, 11a to reduce the inner diameter. At the same time, a space 16 is formed on the outer periphery of the flanges 2, 2a in a portion other than where the connecting member 12 and the tightening portion 14 are located. Therefore, seal welding can be performed by Teig welding or the like using this space 16.

After performing seal welding from all spaces 16, this seal welding jig 10 is removed, and seal welding is performed on the portion covered by the connecting member 12 and fastening portion 14, and the flanges 2, 2a are sealed.
Completed seal welding around the entire circumference.

After the seal welding is completed in this way, the clamp 6 of the DO clamp type pipe joint is tightened to complete the connection of the pipes 1 and 1a.

In this way, using the seal welding jig 10, DO
By seal-welding the outer peripheries of the flanges 2, 2a of the clamp-type pipe joint, together with the O-ring 4 between the inner circumferential meshing parts 3, 3a, leakage of the internal fluid within the pipes 1, 1a can be completely prevented.

Furthermore, even if dirt or the like attempts to enter from the outside during seal welding, it is sealed by the O-ring 4 and will not contaminate the inside of the pipes 1, 1a.

Therefore, it is suitable as a pipe joint for cases where high cleanliness is required, such as piping for liquid hydrogen for fuel in combustion test equipment for rocket engines, and has high reliability.

In addition, in the above embodiment, the connecting members are arranged in two semicircular shapes.
Although we have arranged them one by one, depending on the size of the DO clamp type pipe joint, it is possible to have more or fewer. Good.

Further, the two semicircular abutting members and the connecting member are not limited to being welded separately, but may be integrally formed.

[Effect of idea]

As explained above in detail with one embodiment, according to this invention, the seal welding jig for a pipe joint is held between the contact members on both sides of the slope on the back of the outer periphery of the flange of the D0 clamp type pipe joint. Since the contact members are connected at intervals in the circumferential direction, and the contact members that form a pair above and below are tightened at the fastening portion,
It is possible to achieve a close contact state equivalent to the tightening by the clamp of the DO clamp type pipe joint itself, and also seal welding can be performed using the spacing between the abutting members.

Therefore, it is easy to further improve the sealing performance of DO clamp type pipe joints, for which seal welding has not been considered at all in the past, and it is widely applicable and effective for rocket engine fuel piping, etc. be.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the pipe joint seal welding jig of this invention, and Figure 1 is a front view;
Figure 2 is a side view, Figure 3 is a plan view, Figure 4 is DO
It is a sectional view of a clamp type pipe joint. 1, 1a... Piping, 2, 2a... Flange,
3, 3a...Inner peripheral meshing part, 4...O ring, 5,
5a... Slope, 6... Clamp, 7... Fastening part,
8... Bolt, 10... Seal welding jig, 1
1, 11a...Abutment member, 12...Connection member, 1
3, 13a... Slope, 14... Fastening part, 15...
Bolt, 16...Space for seal welding.

Claims (1)

[Scope of utility model registration request] A slope for tight tightening is formed on the back of the outer periphery of the pair of flanges, and a meshing part for centering is formed on the inner periphery, and an O-ring is attached to this inner periphery meshing part to seal the outer periphery of the flange of the DO clamp. In a jig for seal welding, an inclined surface in the opposite direction that is applied by sandwiching the flange to the inclined surface for tightly tightening the outer circumferential back of the flange, which is aligned and sealed by mounting an O-ring on the inner circumferential meshing part. The pair of semicircular abutting members thus formed are connected in the circumferential direction with a gap for seal welding, and the flanges are vertically sandwiched and fastened to both ends of the pair of abutting members to form a flange. 1. A seal welding jig for a pipe joint, characterized in that a fastening portion is formed that maintains a sealed state by obtaining axial adhesion force between a slope and a reverse slope of these abutting members.