JPS6210708B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method of applying a liquid adhesive or paint to the inner surface of a pipe.

[Background of the Invention] For example, when water pipes or gas pipes become obsolete, construction methods are used in which the inner surface is lined with epoxy paint, or an adhesive is applied and a tube is attached. It is also common practice to apply a viscous liquid to the inner surface of a tube for purposes other than those mentioned above. If these pipes are short, various coating methods can be considered, but in the case of long pipes, for example, 100 m, the coating jig must be operated 50 m from the entrance of the pipe, so special methods are required. A method is needed.

Generally, in order to apply these viscous substances to the inner surface of a long pipe, a hose with a spraying jig attached to the tip is inserted into the pipe, is run, and the viscous substance is delivered by a pump, and the viscous substance is sequentially sprayed onto the pipe wall. A method is being used to attach it. Another method is to form a coating of a certain thickness by pouring paint or the like from one end of a tube and pressing it with a packing made of an elastic material or the like.

The former method allows for uniform coating by adjusting the discharge pressure of the pump, the running speed of the injection jig, the viscosity of the viscous material, etc.
In order to coat the inside of a pipe of this length, a hose of 100 m or more is required, and in order to spray at the tip of this hose, there is a pressure loss due to the length of the hose, so the feeding pressure of the viscous material must be increased accordingly. Must. Therefore, it is necessary to use a high-pressure hose, which has the drawback of requiring considerably high equipment costs including the pump.

On the other hand, when applying paint or the like by pushing it with packing, if a single pig is used, the viscous material in front of the packing will flow due to its own weight, so that the coating on the upper inner surface of the pipe will be incomplete.

For this reason, for example, a method is used in which paint or the like is placed between two packings and the paint is compressed by the packings so that it can be applied to the entire inner surface of the tube.

By the way, pipes such as water and gas pipes generally have branch sections, and if the above method is used, viscous substances such as paint will flow into the branch pipes through the openings in the branch sections, causing the problem of blockage of the branch sections. be.

The above conventional method will be explained with reference to the drawings.

As shown in Fig. 1, when a pipe 1 is filled with a fluid material 2 such as an adhesive or an anticorrosive paint (adhesive is used as a typical example below), and the material is pushed with a packing 3, due to its fluidity, the adhesive 2 tends to flow forward, resulting in insufficient application to the upper inner surface of the tube 1, especially when the amount of adhesive decreases as the packing 3 moves forward. In order to prevent this, it is possible to place packing in front of the adhesive 2, but if the front and rear packings are simply connected at a fixed interval, the same phenomenon will occur when the adhesive decreases as when pressing with a single packing. can be seen. Therefore, as shown in FIG. 2, by leaving the front second packing 32 free from the rear first packing 31 and the rope 4 connected to it, the rear first packing 31 is bonded. In contrast to pushing the adhesive 2, the second packing 32 at the front prevents the adhesive 2 from flowing, which in turn generates pressure within the adhesive and allows it to be applied to the entire inner surface of the tube. However, since a certain pressure is generated in the adhesive, the adhesive 2 is ejected into the branch pipe at the branch part 5 existing in the middle of the pipe, and the branch part 5 is blocked.

[Summary of the invention]

The present invention was developed to solve this problem.When pressure is applied from the outside to a bag made of a material with fine holes, such as cloth, filled with a viscous substance, the viscous substance inside oozes out. In this method, packing is arranged at the front and rear of this bag, and both packings are connected with a rope or a rod-shaped object and pulled into the pipe, and the front and rear packings are
This is a method in which the bags are pressed relatively close to each other so that the viscous material oozes out and is applied to the inner surface of the tube.

[Specific description of the invention]

As shown in FIG. 3, one example of the present invention is to place the adhesive 2 in a bag 6 made of cloth or the like and place it in the front and rear first and second bags.
When the rear first packing 31 is pulled forward by the towing rope 42, the rope 41 passes through the front second packing 32 and is connected to the towing rope 42, thereby creating an integrated structure. Since it is a rope, the second packing 32 and packing 31 come relatively close to each other, compressing the bag 6, which causes the adhesive 2 to ooze out from the micropores of the bag 6 and apply it to the inner surface of the tube. It is. Further, the portion of the rope 41 through which the second packing 32 is inserted may be a rod-shaped object. By adjusting the pulling speed of the jig to utilize the seepage of the adhesive, a constant amount can be applied, and there is no risk of clogging the branch as there is no sudden ejection at the branch. It is.

The packing is generally disc-shaped or spherical, but is not limited to this. The material may be flexible and elastic, such as soft rubber or foamed plastic, and the size may fit the inner diameter of the pipe. In addition, the force that presses the bag and causes the adhesive to ooze out takes advantage of the fact that the second packing 32 does not easily move forward due to the frictional force acting between the packing 32 and the inner wall of the tube 1. It is generally desirable that the diameter of the first packing 32 is larger than that of the first packing 31. However, this also results in too much pressure depending on the size of the micropores present in the bag, so it is necessary to adjust the size of the second packing 32 as appropriate.

Good results were obtained when the bag was made of cloth made of cotton, nylon, tetron, etc., or a plastic sheet made of polyethylene, soft PVC, nylon, etc. with micropores provided therein.
As the coating progresses, the distance between the first packing 31 and the second packing 32 becomes narrower and the bag is compressed, so a flexible one is preferable.

Any number of bags may be used, but it is said that it is better to have multiple bags rather than one, because when the spacing between the packings becomes narrower, the bags will shrink more smoothly and will fit better into the tube wall where they are sandwiched between the packings. There are advantages.
In the case of one bag, a rope or rod-like object is inserted through the inside of the bag, or a long bag is arranged so as to be wound around the rope or rod-like object.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a conventional method for coating the inside of a pipe, FIG. 2 is a longitudinal sectional view showing a method for coating the inside of a pipe that is an improved method of the method shown in FIG. 1, and FIG. FIG. 3 is a vertical cross-sectional view showing a surface coating method. DESCRIPTION OF SYMBOLS 1...Pipe, 2...Adhesive, 31...First packing, 32...Second packing, 41...Rope, 4
2... Towing rope, 5... Branch pipe, 6... Bag.

Claims (1)

[Claims] 1. A bag made of a porous membrane that can permeate the fluid material is filled with a fluid material, and the bag is connected to first and second layers made of an elastic body connected by a rope or a rod-like object. The inner surface of the tube is characterized in that by drawing the bag into the tube with a traction rope connected to the rope or the rod-shaped object while the bag is placed between packings, a fluid material exuding from the bag is applied to the inner surface of the tube. Application method. 2. The method for coating an inner surface of a pipe according to claim 1, wherein the porous membrane is a cloth or a mesh-like material. 3. Claims 1 or 2, wherein the distance between the first and second packings is narrowed by pulling the tow rope, thereby compressing the bag placed between the first and second packings. The method of coating the inner surface of the pipe as described. 4 Claims in which the rope connecting the first and second packings and the towing rope are an integral rope, and the integrated rope is inserted through the center of the second packing on the towing rope side. The method for coating the inner surface of a tube as described in item 3.