JPH10132167A - Packing type pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a problem of seal quality degradation due to the shortage of sealing surface pressure by forming recessed grooves on the inner periphery surface of a packing, and fitting a seal material having viscoelasticity into the recessed grooves in a device whose packing is fitted in a joint body involving a packing chamber and is pressed with a pressing body against the packing chamber. SOLUTION: In a packing 7 to be fitted in a packing chamber 21 in a joint body 2, recessed grooves 71, 72 are formed at the inner periphery surface 78, and a seal material 77 is fitted at the recessed grooves 71, 72. The inclined surface 76 of the packing 7, where the packing 7 is fitted in the packing chamber 21, is formed so as to have the same angle as a taper surface 22 of the packing chamber 21, and the inclined surface 76 compresses the whole inclined surface 76 uniformly by the taper surface 22. When a pressing body is tightened against the joint body 2, the packing 7 is compressed to the deep side in the axial direction of the packing chamber 21, the packing 7 is squeezed by the wedge effect of the taper surface 22, and surface pressure acts on the inclined surface 76 and the inner periphery surface 78. It is thus possible to bring the packing 7 into close contact with the outer periphery surface of a connection pipe 1 for a positive seal action.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint having good sealability used for connecting a pipe for supplying gas, water, etc., wherein the pipe has a corroded and uneven surface. The present invention relates to a packing type pipe joint which can surely seal even when a pipe in a poor condition is connected.

[0002]

2. Description of the Related Art FIG. 3 disclosed in Japanese Patent Publication No. 59-48911 discloses a conventional technique. This one is
A cylindrical joint body 2, an annular packing 3 attached to an end of the joint body 2, and the packing 3
, And a retainer 5 and a biting ring 6 are interposed between the pressing body 4 and the packing 3. The inner end of the bite ring 6 compresses the surface of the pipe 1 by tightening the pressing body 4 and the packing 3
Is compressed to the tapered surface of the joint body 2 so that the pipe 1 is prevented from coming off simultaneously with the sealing. This conventional pipe joint is characterized by the packing 3, in which the surface of the packing on the side in contact with the tapered surface of the joint body is formed as a two-step tapered surface, and the joint body 2 and the packing 3 come into contact with each other. The sealing surface pressure of the packing is increased to improve the sealing performance.

[0003]

In the above-mentioned conventional packing type pipe joint, the seal surface pressure is increased at the partial contact portion with the joint body 2 due to the two-stage tapered surface of the packing 3, so that
Although the sealing performance between the joint bodies is improved, the sealing surface pressure on the inner peripheral surface of the packing on the side in contact with the pipe surface extends to a portion where the relief of the partial deformation of the packing 3 is not in contact with the tapered surface. The surface pressure acting on the inner peripheral surface side of the packing 3 does not increase, so that the contact pressure of the packing 3 in contact with the pipe surface is low, and there is a problem that the sealing performance between the packing 3 and the pipe 1 is poor.

For this reason, as shown in FIG. 4, an annular projection is provided on the inner peripheral side in contact with the pipe surface in the same manner as the joint body side so as to increase the seal surface pressure, and the seal surface pressure in contact with the pipe is increased. A packing is disclosed in JP-A-7-286686. However, even in this case, if the surface condition of the tube was poor, a reliable sealing action could not be obtained. In particular, it has been difficult to obtain perfect sealing properties when the surface of the pipe to be connected is rusted and has irregularities or when the pipe surface is scratched, such as when connecting with an existing buried pipe. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems and to provide a packing type pipe joint capable of performing reliable sealing even when the surface condition of the connection pipe is poor.

[0005]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a joint body having a packing chamber having a tapered surface in which the inner peripheral surface at the end on the connection side with the pipe has a larger diameter toward the end. In a packing type pipe joint including a packing made of an annular elastic body to be mounted in a packing chamber of the joint main body and a pressing body for pressing the packing against the packing chamber of the joint main body, the packing is formed on a surface of the pipe. A packing type pipe joint characterized in that a concave groove is provided on an inner peripheral surface that comes into contact with the groove, and a viscoelastic sealing material is attached to the concave groove. In the above, the packing is formed such that the inner diameter of the inner peripheral surface of the packing is slightly smaller than the outer diameter of the pipe, and the inner peripheral surface is provided with a plurality of the concave grooves, and a viscoelastic sealing material is attached to the concave grooves. May be provided. In the above, as the viscoelastic sealing material, an uncured butyl rubber which is not elastically cured or a condensation reaction type silicone rubber which undergoes a hydrolysis reaction with moisture in the air to form a rubber elastic body from the surface sequentially is used. In the above,
The connection may be performed using a packing in which a viscoelastic sealing material is attached to the annular groove of the packing in advance, or the pipe may be attached by attaching a viscoelastic sealing material to the annular groove of the packing when connecting with the pipe. Connection construction may be performed.

[0006]

According to the present invention having the above construction, when the packing is compressed by the pressing body, the viscoelastic sealing material attached to the groove on the inner peripheral surface of the packing is pushed out to the outer peripheral surface of the pipe, and the inner peripheral surface of the packing is pressed. And the entire gap between the tube and the outer surface of the tube.
Therefore, even if the surface of the tube has irregularities due to scratches or corrosion, the space between the tube surface and the packing is securely filled and adhered, and a complete airtight state can be obtained. Even if the sealing material is, for example, a condensation reaction type rubber that reacts with the moisture in the air to gradually become a rubber elastic body from the surface, it is in a viscous state because it is completely sealed with the air in the connected state Even if the rubber elastic material is hardened for a long period of time, the airtight state is maintained because it is maintained in a state of keeping close contact with the tube surface.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. Since the present invention is particularly characterized in the packing portion, the joint body 2, the pressing body 4, the retainer 5, and the bite ring 6 are denoted by the same reference numerals as those described in the related art. Further, the pressing body 4 may be a pressing body 4 of a type in which the packing is pressed by being screwed into a screw on the outer surface or the inner surface of the end of the joint body 2. FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention, and shows a packing 7 in a free state mounted in a packing chamber 21 of a joint main body 2. The inner diameter of the packing 7 is formed smaller than the outer diameter of the connecting pipe 1, and two annular concave grooves 71, 72 are provided on the inner peripheral surface 71. Therefore, a total of three annular projections 73 and 74 are provided on both sides and the center of the inner peripheral surface.
The annular concave grooves 71 and 72 are provided with a sealing material 77 made of butyl rubber that has not been poured. Uncured rubber has viscoelastic properties for a long time.

The viscoelastic sealing material 77 may be a condensation reaction type silicone rubber or the like which undergoes a hydrolysis reaction with water in the air to become a rubber elastic body sequentially from the surface, and is mounted in an annular groove. It always has viscoelasticity in the state. In addition, the inner peripheral surface is covered with vinyl or the like in consideration of contact with air and workability in a state where the sealing material 77 is attached to the packing 7.
At the time of connection with the pipe, this vinyl is peeled off and attached to the pipe. At the time of connection with the pipe, a viscoelastic sealing material 77 may be attached to the annular groove of the packing 7 and assembled into the pipe to perform the connection. The inclined surface 76 of the packing on the side where the packing 7 is mounted in the packing chamber 21 is formed at the same angle as the angle of the tapered surface 22 of the joint main body packing chamber, and the packing inclined surface 76 is formed by the tapered surface 22 of the packing chamber 21. The entire packing inclined surface 76 is uniformly contacted and compressed.

When the pressing body 4 is tightened to the joint body 2, the packing 7 is compressed to the inner side in the axial direction of the packing chamber 21, and the packing 7 is narrowed by the wedge effect of the tapered surface 22 of the packing chamber 21. Surface pressure acts on the inner peripheral surface 78. At this time, since the viscoelastic sealing material 77 is attached to the annular concave grooves 71 and 72 of the inner peripheral surface 78, the sealing material 77 is pushed out from the concave grooves 71 and 72 while compressing the outer peripheral surface of the pipe 1. Then, it is compressed over the entire contact portion between the packing 7 and the surface of the tube 1. For this reason, unevenness due to surface flaws or corrosion of the pipe 1 is evenly filled, and the packing 7 and the outer peripheral surface of the pipe 1 are in close contact with each other, so that a reliable sealing action is performed. In addition, the inclined surface 76 of the packing 7 is the tapered surface 2 of the joint body packing chamber.
The tapered surface 22 may be provided at an angle different from that of the tapered surface 22 so that the surface pressure is partially increased with respect to 2.

FIG. 2 is a longitudinal sectional view showing a second embodiment of the present invention, in which an annular groove 81 is provided on the inner peripheral surface of the packing 8 so as to be wider by one line, and also on the inclined surface of the packing on the joint body 2 side. An annular concave groove 82 is provided, and viscoelastic sealing materials 83 and 84 are attached to the annular concave grooves 81 and 82. In this case, the inner surface of the packing chamber 21 of the joint body 2 is in close contact with the viscoelastic sealing material 83 via the viscoelastic sealing material 83, and the viscoelastic sealing material 84 having a large volume is mounted on the inner peripheral surface 85 side. The inner surface of the packing 8 should be filled enough to fill the uneven surface even with the uneven tube.
5 and can be sealed. Therefore, particularly in the case of a pipe having a poor surface condition, it is preferable to form the pipe in the annular groove 81 which allows a large capacity of the sealing material.

[0011]

As described above, the present invention solves the problem of sealing performance due to insufficient sealing pressure on the inner peripheral side of the packing, which has been a particular problem in the past, and reduces the existing pipes having poor surface condition. It is a packing type pipe joint that can reliably seal even when connected.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a joint main body and a packing showing one embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a joint body and a packing showing another embodiment of the present invention.

FIG. 3 is a partial sectional view of a packing type pipe joint showing a conventional technique.

FIG. 4 is a partial cross-sectional view of a packing type pipe joint showing another conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Pipe 2 Joint main body 4 Pressing body 7, 8 Packing 21 Packing chamber 22 Tapered surface 71, 72, 81, 82 Annular groove 77, 83, 84
Viscoelastic sealing material

Claims (2)

[Claims] 1. A joint body having a packing chamber in which an inner peripheral surface at an end on a connection side with a pipe has a tapered surface having a larger diameter toward the end, and a circle mounted in the packing chamber of the joint body. In a packing type pipe joint including a packing made of an annular elastic body and a pressing body that presses the packing against a packing chamber of the joint main body, the packing is provided with a concave groove on an inner peripheral surface in contact with a surface of the pipe. And a viscoelastic sealing material mounted in the groove. 2. The packing according to claim 1, wherein the inner diameter of the inner peripheral surface of the packing is slightly smaller than the outer diameter of the pipe, and the inner peripheral surface is provided with a plurality of the concave grooves. The packing type pipe joint according to claim 1, wherein a material is mounted.