JPH0240390Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] In order to minimize the contact between the inner surface of the expansion joint bellows and the internal fluid, the present invention ensures that the inner cylinder is provided centripetally with respect to the bellows. This relates to expansion pipe joints.

[Conventional technology]

Established in 1974 as an expansion pipe joint to connect two pipes.
There are No.-68227 and No. 55-36790. Although this pipe fitting achieves its purpose in connecting both pipes,
In order to reduce fluid resistance within the conduit, an inner cylinder is used that minimizes contact between the inner surface of the expansion joint bellows and the internal fluid. However, in order to easily bend the telescopic bellows, it is necessary that the telescopic bellows and the inner cylinder inserted therein be fitted concentrically. In order to achieve this purpose, the idea of Japanese Utility Model Application Publication No. 55-36790 is to provide a tapered surface in the middle of the arcuate part of the inner tube, and when connecting to a piping system, the tip of the other tube is brought into contact with this tapered surface. I am trying to move towards the center of the world.

[The problem that the idea attempts to solve]

Even if the tip of the inner cylinder is tapered, there is a gap between it and the inner peripheral surface of the telescopic bellows. Therefore, if the tip of the pipe of the piping system is accurately and uniformly abutted against the tip surface of the inner cylinder, it will be centripetal as designed, and the bellows and the inner tube will be concentrically connected. However, the tip of the pipe in the piping system does not necessarily come into uniform contact with the inner pipe. Furthermore, the inner cylinder easily deforms when external pressure is applied to it, making it difficult to install the inner cylinder completely concentrically with the telescopic bellows.In practice, the inner cylinder is fixed in an eccentric state as described above. , which affects the bending and stretching of the telescopic bellows. Furthermore, it is difficult to form a tapered surface on the arcuate portion of the inner cylinder.

The object of the present invention is to simply arrange the inner cylinder and the telescopic bellows centripetally.

[Means to solve the problem]

The present invention has been made to achieve the above object, and includes an inner cylinder inserted into a retractable bellows that is integrally provided by being engaged between opposing end plates, and one end of the straight inner cylinder is moved in the outer circumferential direction. A flange is formed by bending the flange, and a ring-shaped protrusion that protrudes toward the outer circumference of the inner cylinder is formed near the inner side of the flange, and the outer diameter of the ring-shaped protrusion is set to the inner diameter of the straight tube part of the telescopic bellows. The gist is to make the outer circumferential surface of the protrusion substantially equal to the inner circumferential surface of the telescopic bellows inside the hole of the end plate, so that the telescopic bellows and the inner cylinder are fitted and supported concentrically. do.

[Effect]

When the inner cylinder is inserted into the telescopic bellows, a part of the inner cylinder is formed with a ring-shaped protrusion that is equal to the inner diameter of the straight pipe part of the bellows and protrudes toward the outer circumference at a position located in the straight pipe part of the telescopic bellows. Therefore, by simply inserting the inner cylinder into the telescopic bellows, the outer circumferential surface of this protrusion comes into contact with the inner peripheral surface of the straight tube part of the telescopic bellows, and the inner cylinder is easily inserted concentrically into the telescopic bellows. Even when connected to a piping system, the inner cylinder is held tightly by the ring-shaped protrusion on the inner circumferential surface of the straight pipe part of the telescopic bellows, so that misalignment will not occur.

〔Example〕

The present invention will be explained below based on embodiments shown in the drawings.

In the figure, 1 is the end plate of the expansion joint; the end plate 1,
1 are arranged oppositely at a required interval, and holes 3, 3 are drilled in the center to attach the telescopic bellows 2, and bolt holes 4, 4 are provided near the outer periphery to engage with a plurality of piping system flanges. is perforated. In order to maintain a constant distance between the two opposing end plates 1, 1, a connecting bolt 5 is installed between the end plates.

The telescopic bellows is constructed by forming a multi-striped ring of metal tubes made of the required material, and both ends of the telescopic bellows 2 are left as straight pipes 21, and the straight pipe portions 21 are inserted from the inner surface of the end plate. After inserting it into the hole 3, bend the tip of the straight tube along the outer surface of the end plate in the direction of the outer circumference of the hole, and fold back the straight tube at a position equal to the diameter of the ring portion 22 or the size before and after the diameter of the ring portion 22 to form a straight tube. The tip is double type. Therefore, the straight tube part 21 of the telescopic bellows is inserted into the hole 3 of the end plate, the end plate is held between the outermost ring 22 and the double folded part 23, and the telescopic bellows and the end plate are integrated. Ru. This telescopic bellows is made in the same way on both ends of the end plate 1,
1 is provided.

Then, an inner cylinder (internal sleeve) 6 is fitted into the telescopic bellows 2. One end of this inner cylinder 6 remains a straight pipe, but the other end is bent in the outer circumferential direction to form a flange 61. When this inner cylinder 6 is inserted into a telescopic bellows, the flange 61 becomes a double portion of the bellows. It is made to overlap the outside of the folded portion 23. A protruding ridge 62 protruding outward from the flange 61 in a ring shape is integrally formed.
At this time, the protrusion 62 and the straight pipe part of the inner cylinder are made concentric, and the outer diameter of the protrusion 62 is made approximately equal to the inner diameter of the straight pipe part of the telescopic bellows inserted into the hole 3 of the end plate. be.

By forming the protrusion 62 in this manner, the inner cylinder is disposed within the telescopic bellows and concentrically therewith.

[Effect of idea]

According to the present invention, a protrusion is formed on the inner side of the brim-like flange formed at one end of the inner cylinder inserted into the telescopic bellows, and has an outer diameter approximately equal to the inner diameter of the straight pipe portion of the telescopic bellows. By simply inserting the inner cylinder into the telescopic bellows, the outer circumferential surface of this protrusion comes into contact with the entire inner peripheral surface of the straight pipe part of the telescopic bellows, and the inner cylinder is held evenly. It is ensured that they are inserted concentrically. Furthermore, the inner cylinder is held in contact with the inner circumferential surface of the straight pipe part of the telescopic bellows via the ring-shaped protrusion without creating a gap, so even if external force is applied during piping, both It is possible to provide an expansion pipe joint with high precision at low cost and without affecting the concentricity of the pipe, which is easy to manufacture and assemble.

[Brief explanation of drawings]

FIG. 1 is an overall sectional view, and FIG. 2 is an enlarged sectional view of important parts. 1 is an end plate, 2 is an extensible bellows, 21 is a straight pipe part,
22 is a ring part, 23 is a double folded part, 3 is a hole, 4
5 is a bolt hole, 5 is a connecting bolt, 6 is an inner cylinder, 61 is a flange, and 62 is a protrusion.

Claims (1)

[Scope of utility model registration request] In a telescopic pipe joint in which an inner cylinder is fitted into a telescoping bellows with end plates attached to both ends, a flange is formed at one end of the inner cylinder, and a flange is formed on the inner side of the flange on the outer circumference of the inner cylinder. A telescopic pipe joint characterized in that a protruding ring-shaped protrusion is integrally formed, and the outer diameter of the protrusion is approximately equal to the inner diameter of a straight pipe portion of the bellows fitted into the end plate hole of the telescopic bellows.