JPH0440071Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a connection structure suitable for connecting steel pipes, particularly relatively large-diameter thin-walled steel pipes, in an air-tight or liquid-tight manner.

[Conventional technology]

A conventionally known connection structure for steel pipes is shown in FIG. In this case, a flange 102 is joined to the end of one steel pipe 100 by welding 101, and a short pipe 120 having a flange 121 at the tip is butt welded to the end of the other steel pipe 110.
2, and with a gasket 130 interposed between the flange 102 and the flange 121, the flange 111 fitted into the short pipe 120 and the flange 102 are connected with bolts (not shown). ).

According to this connection structure, the gasket 130 is connected to the flange 102 and the collar portion 12 by the tightening force of the bolt.
1 and prevents fluid from leaking from the pipe to the outside and preventing fluid from entering the pipe from the outside.

[The problem that the idea aims to solve]

However, in order to adopt the conventional connection structure, it is necessary to weld the flange 102 and the steel pipe 100 or to
0 and the steel pipe 110 is not only required, but also the shielding gas (argon gas) sealed inside the steel pipe (stainless steel pipe, etc.) for corrosion prevention is expensive. This leads to increased costs.

Furthermore, when welding steel pipes, especially stainless steel pipes, the material tends to become sensitized, causing intergranular corrosion and stress corrosion cracking to occur after welding, thereby deteriorating corrosion resistance.

Furthermore, automatic welding machines are expensive and are not suitable for use at piping construction sites.
Further, manual welding has the disadvantage that it is susceptible to the above-mentioned intergranular corrosion and stress corrosion cracking.

In addition, it is difficult to remove the welded parts, so it is impossible to change the piping.

As mentioned above, conventional connection structures require a high degree of welding work and management, have poor workability, and are impossible to construct on-site.This problem becomes worse as the steel pipe becomes thinner. noticeable.

This idea was made in view of the above problems, and at the same time it eliminates the need for welding and improves work efficiency.
The purpose of the present invention is to provide a steel pipe connection structure that allows on-site construction and allows for the replacement of piping.

[Means to solve the problem]

In the steel pipe connection structure according to this invention, a steel pipe and a C-shaped ring fitted to the steel pipe are connected using fasteners inserted into through holes opened at multiple locations in the circumferential direction of both. In both cases, the space between the collar and the steel pipe is sealed by a first gasket interposed between the collar of the stop and the steel pipe, and a gasket is provided on the inner surface of the socket fitted to the steel pipe. A back-up spring and a second gasket, which are arranged in an overlapping manner on one side of the C-shaped ring, are accommodated in the recess formed therein, and a second gasket is formed on the inner surface of the holding member fitted to the steel pipe. A back-up spring and a third gasket, which are arranged in an overlapping manner on the other side of the C-shaped ring, are housed in the recess, and the flange provided on the socket and the flange provided on the presser member are connected to each other. The fourth gasket interposed between the socket and the holding member and the second and third gaskets are tightened by the tightening force of the fastened bolt.

[Effect]

According to this configuration, the second gasket disposed on one side of the C-shaped ring comes into close contact with the inner surface of the recess of the socket and the steel pipe due to the tightening force of the bolt, and seals that area, while the first gasket Since the gap between the collar of the stopper and the steel pipe is sealed, fluid leakage from the pipe to the outside is prevented by the first gasket and the second gasket. Further, the fourth gasket interposed between the socket and the holding member tightly contacts the socket and the holding member to seal the area, and the third gasket tightly contacts the inner surface of the recess of the holding member and the steel pipe. To seal that location, the third and fourth gaskets prevent fluid from entering the conduit from the outside.

Further, since the holding member engages with the C-shaped ring via the back-up spring and the third gasket, the C-shaped ring prevents the holding member and the socket fastened thereto from coming off.

〔Example〕

Fig. 1 is a partially exploded perspective view of a steel pipe connection structure according to an embodiment of the invention, Fig. 2 is a vertical sectional side view of the main part of the above connection structure, and Fig. 3 is a partially cutaway front view of the above connection structure. be.

Reference numeral 1 denotes a steel pipe such as a thin-walled stainless steel pipe, and through-holes 2 are formed at a plurality of positions at equiangular intervals at the end thereof. 3 is a C-shaped ring having a circular cutout 4, and through-holes 5 are also formed in a plurality of locations at equal angle intervals in this C-shaped ring 3. Then, the C-shaped ring 3 is fitted to the steel pipe 1 with each through-hole 2 of the steel pipe 1 and each through-hole 5 of the C-shaped ring 3 aligned, and a rivet is inserted into these through-holes 2 and 5 from inside the steel pipe 1. 6 is inserted, and a countersunk bolt 9 is screwed into the screw hole 7 of the rivet 6 via a washer 8. As a result, the C-shaped ring 3 is connected to the steel pipe 1. Further, a first gasket 11 is fitted into an annular groove formed in the flange 10 of the rivet 6, and this first gasket 11 is inserted into the countersunk head bolt 9.
It is tightly attached to the inner surface of the steel pipe 1 by the tightening force of.
Therefore, the relationship between the flange 10 and the inner surface of the steel pipe 1 is
The space between the two is sealed by a first gasket 11. The flange 10 of the rivet 6 has a shape that allows it to come into close contact with the inner surface of the steel pipe 1, and the washer 8 has a C
It has a shape that can be closely attached to the outer surface of the shaped ring 3.

The C-shaped ring 3 can be used to increase or decrease the inner circumferential diameter by using its cutout, and can be used with various steel pipes 1 having different outer circumferential diameters. Further, the through hole 5 of the C-shaped ring 3 is a long hole that is long in the circumferential direction. Therefore, even if the inner circumferential diameter of the C-shaped ring 3 is increased or decreased, its through hole 5 can be matched with the through hole 2 of the steel pipe 1. Further, the rivet 6 and countersunk bolt 9 are examples of fasteners, and other known fastening means such as bolts and nuts may be used instead of the rivet 6 and countersunk bolt 9. be.

On one side of the C-shaped ring 3, a metal back-up spring 13 fitted to the steel pipe 1 and a second gasket 14 are arranged in an overlapping manner.
Also on the other side of the ring 3 are a metal back-up spring 15 and a third gasket 16 fitted to the steel pipe 1.
are arranged in an overlapping manner. A socket 17 provided in a joint or another steel pipe is fitted into the steel pipe 1, and one back of the C-shaped ring 3 is inserted into a recess 18 formed on the inner surface of the socket 17. Spring 13 and second gasket 14
is accommodated. On the other hand, a back-up ring 15 on the other side of the C-shaped ring 3 and a third gasket 16 are accommodated in a recess 20 formed on the inner surface of the presser member 19 fitted to the steel pipe 1. Further, a flange 21 provided integrally with the socket 17 and a flange 22 provided integrally with the holding member 19 are fastened together with bolts 23 . The fourth gasket 25 fitted into the annular groove 24 formed in the socket 17, the second gasket 14 and the third gasket 16 are connected to the bolt 23.
It is tightened with a tightening force of .

With the above configuration, the second gasket 14 arranged on one side of the C-ring 3 is brought into close contact with the inner surface of the recess 18 of the socket 17 and the steel pipe 1 by the tightening force of the bolt 23, sealing that area, while the first gasket 11 seals the gap between the flange 10 of the rivet 6 and the steel pipe 1, preventing fluid leakage from the pipeline to the outside. Therefore, even if the fluid is corrosive, the corrosive fluid will not leak and come into contact with the bolt 9 and corrode it.
Further, the fourth gasket 25 interposed between the socket 17 and the pressing member 19 is in close contact with the wall surface of the annular groove of the socket 17 and the pressing member 19 to seal that portion, and the third gasket 16 is in contact with the recess 2 of the pressing member 19.
The inner surface of the pipe 0 is tightly fitted to the steel pipe 1 to seal that area, preventing fluid from entering the pipe from the outside.
In addition, since the pressing member 19 is engaged with the C-ring 3 via the backup ring 15 and the third gasket 16, the C-ring 3 prevents the pressing member 19 and the socket 17 fastened thereto by the bolt 23 from coming off.

Further, the overlapping surfaces of the back-up spring 13 and the second gasket 14 and the overlapping surfaces of the second gasket 14 and the inner surface of the recess 18 of the socket 17 are formed into inclined surfaces 26 and 27 as shown in FIG. Alternatively, if the overlapping surfaces of the back-up spring 15 and the third gasket 16 and the overlapping surfaces of the third gasket 16 and the inner surface of the recess 20 of the holding member 19 are made into inclined surfaces 28 and 29 as shown in the figure. , those inclined surfaces 26, 27, 28, 2 due to the fastening force of the bolt 23.
A wedge action occurs at 9, and the second gasket 14 and third gasket 16 are pushed out to the steel pipe 1 side.
This improves adhesion with the material and provides high sealing performance.

Further, a recess 18 of the socket 17 is formed in the stepped portions 13a and 15a formed on the back-up springs 13 and 15.
The stepped portion 18a formed in the recess 2 of the holding member 19
If the stepped portion 20a formed at 0 is engaged, the second gasket 13 and the third gasket 1
Since the compressive force applied to 6 is regulated, they can be compressed with an appropriate force, and they can be prevented from being compressed too much due to piping stress, etc., resulting in deterioration or shortening of their useful life. .

[Effect of idea]

As described above, according to this invention, it is possible to connect steel pipes with simple operations such as drilling holes in the steel pipes and tightening bolts, and since welding is not required, advanced welding techniques are no longer required. There is no need to use expensive shielding gas or automatic welding machines, and there is no need to worry about intergranular corrosion or stress corrosion cracking even if the steel pipe is a thin-walled stainless steel pipe. Furthermore, it has the effect of making it possible to easily change the piping by simply removing bolts and the like.

As described above, according to the steel pipe connection structure according to the present invention, piping construction is facilitated, workability is improved, and on-site construction is also possible.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing a part of a steel pipe connection structure according to an embodiment of the invention, Fig. 2 is a vertical sectional side view of the main part of the above connection structure, and Fig. 3 is a partially cutaway front view of the above connection structure. , FIG. 4 is a cross-sectional explanatory diagram of the prior art. 1... Steel pipe, 3... C-shaped ring, 2... Through-hole of steel pipe, 5... Through-hole of C-shaped ring, 6... Rivet (stop), 10... Flange of rivet (stop of flange), 11...first gasket, 13...backup spring on one side of the C-shaped ring, 14...second gasket, 15...backup spring on the other side of the C-shaped ring, 16...third gasket, 17
... Socket, 18 ... Recess of socket, 19 ... Holding member, 20 ... Recess of holding member, 21 ... Flange of socket, 22 ... Flange of holding member, 23 ...
Bolt, 25...Fourth gasket.

Claims (1)

[Scope of utility model registration request] A steel pipe and a C-shaped ring fitted to the steel pipe are connected using a stopper inserted into a plurality of through holes opened in the circumferential direction of both of them, and the flange of the stopper and A gap between the flange and the steel pipe is sealed by a first gasket interposed between the steel pipe and the above C A back-up spring and a second gasket are accommodated on one side of the shaped ring in an overlapping manner, and
A back-up spring and a third gasket, which are arranged to overlap with the other side of the C-shaped ring, are housed in a recess formed on the inner surface of the holding member fitted to the steel pipe, and the third gasket is inserted into the socket. The fourth gasket interposed between the socket and the holding member and the second and third gaskets are connected to each other by the tightening force of the bolts that fasten the provided flange and the flange provided on the holding member. A steel pipe connection structure characterized by being tightened.