JPH02195094A - Seal material for pipe joint - Google Patents

Abstract

PURPOSE:To obtain good sealing effect without deforming a circular-formed body by filling the circular-formed body of flexible rubber or plastic with a non-fluid rubber elastic body and semi-fluid seal material. CONSTITUTION:A seal material 5 to be mounted inside a pipe fitting A is constructed of a circular-formed body B composed of a flexible rubber or plastic material to be deformed by applying pressure. A substantially non-fluid rubber elastic body 8 is filled in the hollow portion of the circular-formed body B opening 7 and a semi-fluid seal material 6 is filled at the opening side. The type of the rubber elastic body 8 is, for example, urethane, acrylic, silicone, etc. with a compressive recovery rate of more than 50%. The type of the seal material 6 is, for example, butyl rubber, silicone rubber, etc. As a result, when the seal material 5 is used for a pipe joint, it is forced out and a clearance is blocked and sealed. Also, good sealing property can be obtained without deforming the circular-formed body B.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is applicable to a packing-type joint with a grease-absorbing lining, particularly for a pipe joint used in a sealing method between a mechanical pipe joint and a pipe connected thereto. This relates to sealing materials.

<Prior art> Waterproofing or corrosion protection of the connection between a pipe that transports fluids such as gas or liquid and a joint pipe that connects the pipes can be achieved by wrapping the outside of this part in a spiral shape with tape. Methods such as covering the connector with a heat-shrinkable tube and shrinking it by heating, or tightening a rubber backing or an O-ring with a nut screwed onto the connecting portion have been adopted.

<Problem to be solved by the invention> However, many recent pipes have a lining layer made of synthetic resin etc. formed on the surface of the steel pipe for the purpose of corrosion prevention.
Mechanical joints are often used for joints, and conventional methods of protecting against corrosion include wrapping them with tape or covering them with heat-shrinkable tubes, but these coverings have poor workability (and have not yielded satisfactory results). is the current situation.

On the other hand, as a watertight method for sealing resin-lined gasket-type joints and the pipe body, there is a method of sealing the pipe body with gaskets inside the pipe joint, but this method also has problems such as bending and insufficient watertightness during tension. there were.

On the other hand, in order to solve these problems, a semi-fluid sealing material that flows out under pressure is filled into a hollow annular molded body that deforms under pressure. Recently, a method has been proposed in which the molded body is deformed under pressure to extrude the sealing material, and the gap between the ring and the tube is closed and sealed by tightening. However, even with this method, it is difficult to uniformly flow the sealing material into the gap, and sealing failures often occur due to deformation of the annular molded body, so that it is not satisfactory.

<Means for Solving the Problems> The present invention has been made as a result of studies to solve the above problems. That is, the present invention provides a sealing material for a pipe joint, which is formed by filling a peripheral hollow portion of an annular molded body made of a flexible rubber or plastic material that deforms under pressure with a sealing material, the hollow portion on the closed side of the molded body being filled with a sealing material. The present invention provides a sealing material for a pipe fitting having a multi-layer structure in which a substantially non-flowing rubber elastic body is filled in the opening side of the rubber elastic body, and a semi-fluid sealing material is then filled in the opening side of the sealing material. By using a sealing material, tightening to screw into the pipe joint pressurizes and deforms the molded body with the ring to push out the sealing material, and tightening is performed by closing and sealing the gap between the ring and the pipe body. It has been discovered that a good sealing effect can be obtained without deformation of the molded body.

Function> The sealing material for a pipe joint of the present invention is used as a sealing material 5 to be filled in a hollow portion at the periphery of an annular molded body B, as shown in a cross-sectional view in FIG. It has a multilayer structure using a semi-fluid rubber elastic body 8 and a semi-fluid sealing material 6 in the hollow portion on the opening 7 side.

In this invention, the substantially non-fluid rubber elastic body 8 filled in the hollow part on the closed side of the annular molded body B has a compression recovery rate of 5.
Those exhibiting 0% or more, preferably 65% or more are good. This is because if it is less than this, the ability to repair the deformation of the circular molded product is not desirable.

Furthermore, the rubber elastic body 8 having adhesive properties has better sealing properties. The reason for this is thought to be that the adhesion between the molded body and the elastic body is excellent.

The filling ratio of the rubber elastic body 8 and the semi-fluid sealing material 6 into the hollow portion of the annular molded body B is preferably in the range of 1:4 to 4:1 in terms of volume ratio. Good sealing performance cannot be obtained outside this range.

As the non-fluid rubber elastic body 8 used in this invention, known materials such as urethane, acrylic, EPT (ethylene propylene terpolymer), NBR (tolyl-butadiene rubber), and silicone are used. However, urethane is most preferable in terms of compression recovery rate, adhesiveness, etc. However, the same effect can be obtained even if the surface of a non-tacky elastic body is coated with a sticky polymer, so most elastic bodies are used. In addition, in order to control the elastic modulus of the elastic body within an appropriate range, it is also an effective means to cause the polymer to foam independently.

Next, the semi-fluid sealing material 6 used in the present invention preferably has an apparent viscosity of 10'' to 106 voids at 20°C.Such sealing materials include butyl rubber, silicone rubber, and urethane rubber. Known materials such as polysulfide, polysulfide, and EPT are used.

<Example> Hereinafter, this invention will be explained in detail with reference to Examples.

Example 1 A urethane-based elastic body with adhesiveness and a compression recovery rate of 75% was inserted into the hollow part on the closed side of an annular molded body having the structure shown in FIG. Next, on the opening side above it, the apparent viscosity is 3
Inject a 10' voice butyl rubber semi-fluid sealant. The ratio of the elastic body to the sealing material was 1:1.

As shown in FIG. 2, the annular molded body whose hollow part is filled with the urethane elastic material and the butyl rubber semi-fluid sealing material is tightened so that the opening 7 of the filled sealing material in the molded body is tightened on the side of the ring. Extrapolate so that

Next, a lock ring 9 having a horseshoe shape and having a plurality of engagement protrusions on its inner peripheral surface, a holding ring 10 made of hard rubber or plastic, and an annular packing 11 made of rubber or the like and having a trapezoidal cross section are attached. Extrapolate to tube C, respectively.

On the other hand, the pipe joint A has an enlarged diameter portion 1 that holds the annular packing 11.
2, and the outer circumferential part is tightened with an internal thread 3 of the ring.
An external thread 13 is provided which is screwed into the external thread 13.

As described above, the pipe joint A configured in this manner includes a tightening ring D, an annular molded body B, a lock ring 9, a retaining ring 10, an annular backing 11, etc., which are inserted into the pipe body C and a second As shown in the figure (it is inserted into pipe joint A).

Next, as shown in FIG.
The horseshoe-shaped lock ring 9 is tightly fitted into the enlarged diameter portion 12 of the tube body C to obtain a sealing effect against the fluid flowing through the tube body C, and the horseshoe-shaped lock ring 9 is deformed into a substantially circular shape by tightening the ring to form an engaging protrusion. This is what bites into the lining layer of the tubular body C and securely fixes the tubular body C.

Furthermore, as the rings are sequentially tightened, the annular molded body B is uniformly pressed and deformed by the inclined surface 1 in the enlarged diameter part 2 of the ring, and as shown in FIG. Push out the required amount of sealing material 5 filled in the part from the opening part 7, and remove the ring and the pipe body C.
This fills the gap between the lock ring 9 and the lock ring 9 to close and seal the gap to prevent corrosion of the lock ring 9 and the like.

In this way, the pipe body and the pipe joint were sealed using the sealing material for pipe joints of the present invention, and good sealing performance was obtained, showing excellent watertightness.

Example 2 The same annular molded body as in Example 1 was filled with a sticky acrylic elastic material having a compression recovery rate of 80%, and then filled with an EPT semi-fluid sealing material. The ratio is l:3 and 3:
There are two types: 1. All pipe joints sealed with this sealing material in the same manner as in Example 1 exhibited good watertightness.

Comparative Example 1 A product similar to Example 1, but filled entirely with a semi-fluid sealing material without using an elastic body, could not provide sufficient sealing performance and water leaked.

Note that the non-flowable rubber elastic body used in this invention has a content of 50%
This compression recovery rate is as follows when compressing a 10 mm thick elastic sample by 50% at 50°C.
After leaving for 2 hours, take out the sample and remove the compressive force at 20°C.
After leaving it in an atmosphere of ×65% RH for 30 minutes, the thickness (mm) after the following formula compression test was 710 mm × 100 (
%)=calculation recovery rate.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the structure of the sealing material of the invention, and FIGS. 2 and 3 are longitudinal sectional views showing the sealed state of a pipe joint using the sealing material of the invention. B... Annular molded body 5... Sealing material 6... Semi-fluid sealing material 7... Opening 8
...Non-flowable rubber elastic body

Claims (4)

[Claims] (1) A sealing material for a pipe joint, which is formed by filling a peripheral hollow part of an annular molded body made of a flexible rubber or plastic material that deforms under pressure with a sealing material, the sealing material being filled in the hollow part on the closing side of the molded body. A sealing material for pipe fittings having a multi-layer structure made of a substantially non-fluid rubber elastic body and then filling the opening side with a semi-fluid sealing material. (2) The sealing material for pipe fittings according to claim (1), wherein the non-flowable rubber elastic body has a compression recovery rate of 50% or more. (3) Claim (1) in which the non-flowable rubber elastic body has adhesive properties.
) or the sealing material for pipe joints described in (2). (4) Claim (1) wherein the filling ratio of the non-fluid rubber elastic body and the semi-fluid sealing material is in the range of 1:4 to 4:1 by volume.
) Seal material for pipe fittings.