JPH0457920B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a ring seal ring for a pipe joint that prevents poor sealing performance due to creep deformation or the like in a sealing part, especially in a resin seal ring.

[Conventional technology]

Among pipe joints, fluororesin joints used in particular for connecting fluororesin plastic pipes and tubes have various structures, but all of them generally have the drawback of poor sealing performance. Therefore, in order to improve this drawback, it is possible to use a seal ring such as a rubber O-ring.
Depending on the nature of the fluid flowing through the joint, elution may occur from the seal ring, so a rubber joint cannot be used. This also applies to fluororubber. Also, PTFE (polytetrafluoroethylene)
If the seal ring is made of a fluororesin such as PTFE, the problem of eluates can be solved, but this PTFE has a problem that it has poor elasticity and is prone to cleave deformation. Therefore, as a solution to this problem, a sealed joint structure is disclosed in Japanese Patent Application Laid-Open No. 62-237192.

[Problem to be solved by the invention]

However, the above structure forms a band-shaped seal part that tightly contacts the entire outer circumferential surface of the plastic pipe inserted into the inner wall surface of the joint body, and this band-shaped seal part thickens radially inward. Since it forms a fin-like shape that gradually becomes thinner, it initially adheres well to the outer periphery of the plastic tube inserted, but the tip of the fin-like wall is extremely thin and weak in strength, causing permanent deformation at an early stage. This results in deterioration of the seal quality, and in manufacturing, the band-shaped seal part is formed integrally with the joint body.
The problem was that it was difficult.

The present invention has been made in view of these conventional problems, and aims to solve the above problems by imparting elasticity and strength to a disc-shaped seal ring.

[Means to solve the problem]

The present invention is a seal ring for a pipe joint, which is a disc-shaped seal ring having a circular hole in the center, and has an elastic ring embedded in its outer circumferential side and an O-ring-shaped inner circumferential edge. be.

[Effect]

Since the present invention has the above-described structure, the disc-shaped portion formed from the outer periphery in the direction of the circular hole fits well and tightly against the outer periphery of the plastic tube etc. inserted into the circular hole, and the disc-shaped portion The inner peripheral edge is shaped like an O-ring, so it has great strength.
Therefore, permanent deformation is unlikely to occur in this portion. In addition, since an elastic ring is embedded in the outer circumferential side, it has elasticity similar to that of a rubber O-ring, and does not suffer from poor sealing performance as in the conventional example.

〔Example〕

The present invention will be explained below based on the drawings. 1 to 3 are diagrams showing an embodiment of the present invention.
FIG. 1a is a plan view of a seal ring 1 according to the present invention, and FIG. 1b is a sectional view taken along line A-A in FIG. 1a. 1a is a circular hole provided on the outer peripheral side, 1b is an inner peripheral edge, and 1c is a circular hole provided in the center of the seal ring 1,
Its diameter is sized to fit the plastic tube to be joined. An elastic ring 2 is embedded in the outer peripheral side 1a, and a spiral spring made of rubber or a thin metal wire is used as the elastic ring 2. The inner circumferential edge portion 1b is formed in the shape of an O-ring, and if a highly elastic monofilament is embedded therein, the elasticity and strength will be enhanced. The main body material of the seal ring 1 is made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) or the aforementioned PTFE.

2 and 3 are diagrams showing the state in which the seal ring 1 is attached to the pipe fitting 4, and FIG. 2 shows the state in which the outer peripheral side 1a of the seal ring 1 is fitted into the seal ring mounting groove 4a of the pipe fitting 4. Indicates the condition. At this time, the plastic tube 5 inserted into the inlet of the pipe joint 4 and the seal ring 1 are not yet engaged. FIG. 3 shows the state in which the plastic tube 5 has been completely inserted into the pipe fitting 4 and the nut 8 has been tightened. It passes through hole 1c. In this state, the inner peripheral edge 1b of the seal ring 1 is in close contact with the entire circumference of the plastic tube, but since the inner peripheral edge 1b is formed into an O-ring shape, it has sufficient strength. , hard to cause permanent deformation even after long-term use.

In addition, since the elastic ring 2 is embedded inside the outer circumferential side 1a of the seal ring 1, creep deformation of the outer circumferential side 1a is difficult to occur due to its elasticity.
The sealing performance of the pipe joint 4 with respect to the seal ring mounting groove 4b is also maintained well.

5a is an annular groove provided in the plastic tube 5, and when the tube 5 is inserted into the pipe joint 4 and the nut 8 is tightened, the diameter of the distal end of the pipe joint 4 is reduced by the threading of the tapered screws together. As a result, the rib 4b formed in the pipe joint 4 and the annular groove 5a of the tube 5 engage with each other. Thereby, the tube 5 is reliably locked to the pipe joint 4.

FIG. 4 is a diagram showing another embodiment.

This is done by sandwiching the elastic ring 2 and monofilament 7 in the above embodiment between two fluororesin films 6, 6 such as PFA or PTFA, as shown in FIG. A circular hole 6c is bored to fit into the plastic tube to be connected to the seal ring, and the seal ring shown in cross section in Figure b is formed.The only difference is the manufacturing method, and the shape and function are This is the same as in the previous embodiment. Although not shown in the drawings, if pressing is performed so that a void remains between the elastic ring 2 and the monofilament 7, the inner peripheral edge side will flexibly deform during use, improving adhesion to the tube. .

〔Effect of the invention〕

As explained above, according to the present invention, fluororesin such as PTFE, which conventionally could not be used as a seal ring, is given elasticity that it lacked and is configured to prevent creep deformation. It has become possible to provide a seal ring that is free of material and has good sealing performance at a low cost.

[Brief explanation of drawings]

FIG. 1a is a plan view of an embodiment according to the present invention, FIG. 1b is a sectional view taken along line A-A in FIG.
The figure shows this embodiment installed in a pipe joint, FIG. 2 is a half-sectional view in a state where it is not yet engaged with a plastic tube, and FIG. 3 is a diagram showing a state in which the embodiment and a plastic tube are engaged. Figure 4 shows another example of a seal ring formed by pressing an elastic ring between two fluororesin films; Figure a shows the seal ring before processing, and Figure b shows the seal ring before processing. It is a sectional view showing the rear. 1... Seal ring, 1a... Outer circumference side, 1b...
...Inner peripheral edge, 1c, 6c...Circular hole, 2...Elastic ring.

Claims (1)

[Claims] 1. A seal ring for a pipe joint, which is a disk-shaped seal ring having a circular hole in the center, having an elastic ring embedded in its outer circumferential side and an O-ring shaped inner circumferential edge.