JPH0996387A - Pipe connecting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe connecting structure in which the peripheral direction is fastened by an even fastening force, and a seal leaking, a damage owing to a deflecting load, and the like are not generated. SOLUTION: On the outer periphery of a pipe 10 to be connected, a taper part 11 expanded to the front end side; a flange 13 projecting from the front end of the taper part 11 to the outer side; are provided, and furthermore, on the outer periphery of the taper part 11, a circular form of loose flange 12 is fitted by abutting its abutting part 12 provided on the inner periphery. And in the condition of forming a clearance 16 between the pipe side end face 13a of the flange 13 and the end face 12b of the opposite loose flange 12, the opposite flanges 13 and 13 are fastened to each other, with a bolt 14 and a nut 15 penetrating the loose flange 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flange structure of a connecting portion of piping for transporting various fluids.

[0002]

2. Description of the Related Art Conventionally, as a flange structure of a connecting portion of a pipe, for example, there are JP-A-55-139585 and JP-A-59-37392. In the former pipe connection structure, the flanges provided at the pipe ends are inserted into the through holes provided in one of the flanges, and the pressure bolt is inserted, and the other flange is screwed and fastened. It is a structure. Further, the latter flange joint has a structure in which a joint plate through which a bolt is penetrated is used on the outside of the flange, and an O-ring is interposed between the joint plate and the flange to fasten the flange. .

[0003]

However, in the pipe connecting structure described in the former Japanese Patent Laid-Open No. 59-37392, when the pressure bolt is screwed,
The contact surface at the pipe end is a mechanism that tightens the flange, but in this case there is no shape effect of the rib, and there is a problem that the shearing force acts more on the cross section of the flange than the bending moment and the rib is damaged from the root. is there. Further, in the latter case, in the flange joint described in JP-A-55-139585, the flange is fastened with one bolt using a seam plate, and since it is a one-sided tightening, this one-sided tightening causes damage to the O-ring. There is a problem of uneven flatness in the circumferential direction, and it is not possible to evenly fasten the flange. Also, the flare around one end of the pipe is deformed by pressure in one-side tightening, resulting in an incomplete seal. There's a problem.

In the conventional pipe connecting method, when the pipe is installed, some deviations such as so-called misalignment, step difference, and angular displacement are performed by flange connection of the existing pipe (pipe / connection according to site alignment). However, in many cases, the problems described above, such as damage to the pipe or the connection flange itself due to over-tightening of the flange or handedness, have been encountered.

The present invention has been made in view of the above problems, and an object of the present invention is to solve these problems and to perform fastening with a uniform tightening force in the circumferential direction. (EN) Provided is a pipe connection structure which does not cause seal leakage or damage due to an unbalanced load.

[0006]

In the pipe connecting structure of the present invention, a taper portion whose diameter is expanded toward the tip side is provided on the outer periphery of the pipe end to be connected, and the taper portion is projected outward from the tip end. And an annular loose flange is fitted to the outer periphery of the tapered portion by abutting an abutment portion provided on the inner periphery thereof, and the end face of the loose flange facing the pipe side end face of the flange. It is characterized in that the flanges facing each other are fastened together by bolts and nuts penetrating the loose flanges in a state where a clearance is formed between them.

[0007]

In the pipe connecting structure of the present invention, the abutting portion provided on the inner periphery of the loose flange is brought into contact with the taper portion provided on the outer periphery of the pipe end, and is opposed to the pipe side end surface of the flange. Since a clearance is formed between the loose flange and the end face of the loose flange, the fastening force due to the tightening of the bolt is transmitted from the contact portion of the loose flange to the taper portion of the flange. Due to the taper effect (component force effect) of the taper portion, most of it is transmitted in the pipe axial direction through the flange taper portion. Therefore, effective pipe connection is possible.

Further, the bolt can be tightened to a position where the above clearance is eliminated by an excessive tightening force, but the tightening is completed at the time of contact, and damage to the flange adapter part and loose flange and partial tightening are prevented. As a result, it is possible to secure more effective water stopping in which the packing is tightened with a uniform force over the entire circumference.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an essential part showing an example of the pipe connection structure of the present invention. In FIG. 1, the tubes 10, 10
Is a pipe connecting structure in which the pipe end faces are butted and connected via packing 10a, and a tapered portion 11 having a diameter increased toward the tip side is formed on the outer circumference of the pipe end to be connected. The taper portion 11 is provided with a flange 13 protruding outward from the tip end, and further, the outer periphery of the taper portion 11 is fitted with an abutment portion 12a provided on the inner periphery of the annular loose flange 12 so as to abut. In a state in which a clearance 16 is formed between the end surface 13a of the flange 13 and the end surface 12b of the loose flange that faces the flange 13,
Facing flanges 10 and 10 are loose flanges 1.
The structure is such that bolts and nuts 14 and 15 penetrating 2 and 12 are fastened together.

The connecting portion provided with the tapered portion 11 is made of a material having chemical resistance to various fluids such as water, sewage, seawater, and acid / alkaline fluids of chemical plants. The loose flange 12 is preferably made of steel (eg SS41) or glass fiber reinforced polypropylene resin.

A taper portion 11 whose diameter is enlarged toward the tip side is provided on the outer circumference of each pipe end of the pipes to be connected, and a flange 13 having an end face 13a is provided from the end of the taper portion 11. It is provided so as to project outward.
On the other hand, an abutting portion 12a that abuts the tapered portion 11a is provided on the inner periphery of the loose flange 12 on the flange 13 side.

The abutting portion 12a is the taper portion 11 described above.
It has the same slope as that of a and has a diameter that increases toward the end so that the tapered portion 11a is held in contact with each other.

Further, the end face 1 is formed on the inner peripheral side of the loose flange 12 of the fastening bolt 14 penetrating the loose flange 12.
2b is provided, and a clearance 16 is formed between the flange adapter portion 11 and the end surface 13a.

In this clearance 16, the tubes 10, 10
In order to connect with each other, the bolts 14 are penetrated through the loose flanges 12 provided so as to face each other and tightened by the nuts 15, so that some gaps still remain.

That is, if the tightening force required to maintain the watertightness is exceeded, the clearance 16 is temporarily eliminated due to one-side tightening or over-tightening.
Even when the 2b and the end surface 13a are in contact with each other, further tightening is prevented, so that it is possible to prevent the flange adapter portion 11 and the flange 13 from being damaged by an excessive offset load. Is.

[0016]

In the pipe connecting structure of the present invention, the abutting portion provided on the inner circumference of the loose flange is brought into contact with the tapered portion provided on the outer circumference of the pipe end, and the end surface of the flange on the pipe side is provided. Since a clearance is formed between the end face of the loose flange and the end face of the loose flange, the fastening force due to tightening the bolt is transmitted from the abutting part of the loose flange to the taper part of the flange. Most of the force is transmitted in the pipe axis direction through the flange taper portion due to the taper effect (component force effect) of the taper portion. Therefore, effective pipe connection is possible.

Further, the bolt can be tightened to a position where the above clearance is eliminated by an excessive tightening force, but the tightening is completed at the time of contact, and damage to the flange adapter part and loose flange and partial tightening are prevented. As a result, it is possible to secure more effective water stopping in which the packing is tightened with a uniform force over the entire circumference. Therefore, it is preferably used as a pipe connection structure.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part showing an example of a pipe connection structure of the present invention.

[Explanation of symbols]

 10 Pipe 10a Packing 11a Tapered Part 12 Loose Flange 12a Abutting Part 12b, 13a End Face 13 Flange 14 Fastening Bolt 15 Nut 16 Clearance

Claims (1)

[Claims] 1. A taper portion whose diameter is expanded toward the tip side and a flange protruding outward from the tip of this taper portion are provided on the outer circumference of the pipe end to be connected, and further, the taper portion of the taper portion is provided. An annular loose flange is fitted to the outer circumference by abutting a contact portion provided on the inner circumference, and a clearance is formed between the pipe-side end surface of the flange and the opposite end surface of the loose flange. A pipe connection structure in which the flanges are fastened together by bolts and nuts that pass through the loose flanges.