JPS6143518A - Lining method of inside of tube - Google Patents

Abstract

PURPOSE:To improve working efficiency and workability of a core by obtaining a lining which possesses a necessary lining thickness, is favorable in joining with an existing lining layer and hard to peel off, by making use of an external cylinder of the core whose outside diameter does not exceed remarkably the inside diameter of a tubular lining part and a core body whose length exceeds both ends of the external cylinder of the core by combining them as the core. CONSTITUTION:An article made into one body by inserting a core body 12, which is provided on an air feed pipe and concurrently operating rod 13, into an external cylinder 11 of the core is inserted into a connecting part of a tube 21, the core body is inflated by blowing air into the same, the diameter of the external cylinder 11 is made to enlarge and the surface of the external cylinder 11 is made to adhere closely to an existing lining layer 22. In this instance, as the external cylinder does not expand remarkably by exceeding the inside diameter of a tubular lining even if necessary inner pressure is applied to the external cylinder, a space 3 into which a lining material is to pour is hardly narrowed and a necessary thickness of a lining layer is secured. Then the lining material 4A is poured into the space 3, which is made to cure, the core body 12 is made to shrink by releasing air pressure, the diameter of the external cylinder of the core is reduced also and the same is pulled off along with the core.

Description

[Detailed description of the invention]

1st to 11th

INDUSTRIAL APPLICATION FIELD OF THE INVENTION The present invention relates to a method for lining the inner surface of a pipe. 2. Description of the Related Art For example, when connecting rlI pipes whose inner surfaces are lined with rubber or synthetic resin by welding, the joint must be lined after welding. If the diameter of the pipe is too small to allow a person to enter and work on it, this lining is carried out by the leaf spring coil method or the expander method. The leaf spring coil method is a method in which a leaf spring is wound into a coil and placed inside a pipe, unwound to increase the diameter, and a lining material is injected into the space formed between the pipe and the connecting part and hardened. It is. This method uses overlapping ICs of leaf springs.
The problem of leakage of liquid lining material due to insufficient sealing in some areas is unavoidable. According to the expander method, insert the rubber core into the tube,
The method of blowing it up and applying it tightly to the lining surface prevents the lining material from leaking, but on the other hand, the inner pressure necessary to seal the contact surface between the existing lining surface and the core can be applied to the core. In addition, the surface of the core bulges out, narrowing the space into which the lining material is to be injected, resulting in an insufficient lining thickness. Another problem is that when the internal pressure of the core is released, if the saw that tries to return the core to its original shape is strong, it will act as a large peeling force against the lining layer. The core must remain blown and inflated until it develops its full strength, which results in poor core utilization and workability.A mold release agent is applied to the surface of the core to prevent peeling. However, the mold release agent may get caught up in the lining I and cause defects.If the seal between the existing lining surface and the core is incomplete, the lining The material penetrates into it, forming a thin layer at the edge of the lining layer. It is a common experience that the flakes that originate from this thin layer grow, often leading to larger flakes. (Problem that the invention seeks to solve) An object of the present invention is to solve the above-mentioned problems and provide a method for lining the inner surface of a tube, which uses the principle of the expander method and can form a lining layer of 1q which is superior to the conventional method. . 11.

[Means to solve the problem]

The method for lining the inner surface of a tube according to the present invention involves injecting a lining material into the gap formed between the inner surface of the tube and the outer surface of the core, and then hardening the material. A core outer cylinder that is normally slightly smaller than the inner diameter of the pipe lining, expands due to internal pressure but does not significantly exceed the inner diameter of the pipe lining, and a core outer cylinder that is inflatable and has a length that exceeds both ends of the core outer cylinder. It is characterized by the use of a combination of a core body and a core body.

[For use]

To explain with reference to the drawings, first, as shown in FIG.
Insert the core body 12 attached to 3 into one piece. If necessary, apply a mold release agent to the surface of the core outer cylinder. Subsequently, air is blown in to inflate the core body, increasing the diameter of the core outer cylinder 11 as shown in FIG. 2, and bringing its surface into close contact with the existing lining TA22. At this time, even if the necessary internal pressure is applied to ensure a sufficient seal on the contact surface, the outer cylinder will not expand beyond the inner diameter of the pipe lining, so the space 3 into which the lining material should be injected will not expand.
The required thickness of the lining wall is ensured with almost no narrowing. Therefore, the lining material 4A is injected into the gap 3 and hardened. Once the core has hardened, release the air pressure and remove the core body 12.
to contract. The diameter of the core outer cylinder also decreases as the internal pressure is released, and it is removed together with the core. When the adhesive force of the lining part is strong or when the effect of the mold release agent is low, the core outer cylinder 11 remains. Remaining core outer cylinder 1
1 is removed by using a key rod 5 or the like, for example, as shown in FIG. 3, after the lining material has completely cured and becomes a hardened lining material 4B. At this time, the peeling force acting on the lining surface is negligible. If there is no problem in using the tube, the outer cylinder may be left inside the tube as it is. .

[Embodiment]

The core outer cylinder is made from a material that expands slightly due to internal pressure. Rubber is usually sufficient, but a reinforcing layer of woven or non-woven fabric that can be expanded and contracted to some extent may be provided inside. The length of the core outer cylinder has an overlapping allowance of 5 to 7 with the existing lining surface.
It is best to select a value within the range of 5Il1m. Needless to say, if the overlap is too small, the necessary sealing effect will not be obtained, and if it is too large, the core will become unnecessarily large. In particular, 10 to 5 Qmm is preferable. The thickness is 0.5-5 mm, especially 1-b. Both ends of the core outer cylinder may be tapered to some extent so that the thickness becomes thinner toward the ends. This makes the adhesion to the existing lining even more reliable. The core body can be made of a material that can be inflated by blowing air into it, usually soft rubber. Injection and curing of the lining material may be performed according to known techniques. If it is desired to accelerate curing, the lining portion may be heated by an appropriate method, such as hot air or a band heater. 1 ri! ■UL According to the method of the present invention, the lining has the required thickness,
A lining that is well bonded to the existing lining layer and is difficult to peel off can be obtained. After the lining material is injected, the core can be removed once it has hardened, resulting in good core utilization and improved workability.

[Brief explanation of drawings]

The drawings are cross-sectional views illustrating the process of not lining the inner surface of the tube according to the present invention. Figure 3 shows the core outer cylinder being brought into close contact with the inner surface of the tube and the lining material being injected into the space formed by this, and Figure 3 showing the core outer cylinder being removed after the lining material has hardened. show. 1...Middle child

Claims (1)

[Claims] In a method of lining the inner surface of a tube, which consists of injecting a lining material into the gap formed between the inner surface of the tube and the outer surface of the core and curing it, the outer diameter of the core is normally slightly smaller than the inner diameter of the tube lining, and the inner pressure A core outer cylinder that expands due to the inner diameter of the tube lining but does not significantly exceed the inner diameter of the pipe lining, and a core body that is inflatable and has a length that exceeds both ends of the core outer cylinder. A method for lining the inner surface of a tube, characterized in that it is used.