JPS6222672B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for cleaning the inner wall of a pipe.

Conventionally, a cleaning tool called a pig made of soft or semi-hard polyurethane foam molded into a cylindrical or bullet shape is passed through the pipe to remove scale, mayonnaise, ketchup, chiyocolate, and other fluid deposits that have adhered to the inner wall of the pipe. There are methods being used to remove it.

This pig is a foamed elastic body whose surface is coated with a wear-resistant elastomer if necessary. Because this pig is molded using a mold, a skin layer is formed on the surface, and the skin is smooth, and the inner wall of the pipe can be cleaned only by "rubbing" with the inner wall of the pipe using its abrasion resistance. This utilizes the cleaning effect. Even when the elastomer is applied to the surface of the pig, the applied surface is smooth, and from the perspective of removing scale from the inner wall of the pipe, the cleaning effect is simply that of "rubbing" that takes advantage of its abrasion resistance. In both cases, surface contact with the inner wall of the pipe is the main one, so fine particles and sticky deposits adhering to the inner wall of the pipe cannot be removed by polishing.

Furthermore, these pigs cannot sufficiently grind away scale and deposits that adhere to the bends of the pipe.

In order to eliminate such drawbacks, the present inventors
We have previously proposed a cleaning tool (plug for moving inside a pipeline) that is based on a polymer consisting of a three-dimensional skeleton network structure, and this cleaning tool also absorbs and discharges mayonnaise and other fluids with low viscosity. However, if a highly viscous rubbery substance adheres to the inner wall of the pipe, it is difficult to remove it.

The present invention aims to solve these problems, and its gist is as follows:
In this method, two or more pigs are used to clean the inner wall of a pipe by passing through a pig made of foamed polyurethane resin. This is a method for wiping the inner wall of a pipe, which is characterized by pumping the inside wall of a pipe.

Embodiments of the present invention will be described below with reference to the drawings.
In this explanation, an example will be explained in which two pigs are used.

1 to 3 are explanatory diagrams of the present invention, with FIG. 1 showing the situation immediately before the start of wiping, and FIGS. 2 and 3 showing the situation where the product is being fed under pressure through a straight pipe section and a curved pipe section, respectively. FIG. 4 shows a conventional situation in which one pig passes through a bent pipe section.

Reference numeral 1 indicates a pipe to be cleaned, and it may be any water supply pipe, city water main, industrial water pipe, cooling water pipe, jet fuel pipe, food transportation pipeline, gas pipe, or the like. In addition, there may be a straight pipe, a bent pipe, a T-shaped pipe, or a reused pipe.

A pig 4 made of foamed polyurethane resin, a polymer 5 made of only a three-dimensional skeletal network structure, and a pig 4 are inserted into the opening/closing opening 3 of the launcher 2 in this order. Next, close the opening/closing port 3 and turn on the compressor or pump 6.
By applying air pressure or water pressure, the pig 4 and the polymer body 5 consisting only of a three-dimensional skeleton network structure are pumped.

In the conventional pipe cleaning method using a pig, only one pig 4 is pumped as shown in FIG.
In the present invention, two or more pigs are used, and the polymer body 5 consisting of only a three-dimensional skeleton network structure is interposed between them, and the two or more pigs are simultaneously pumped.

The pig 4 may be made of foamed polyurethane resin, which is commercially available for cleaning the inner walls of pipes. The pig 4 and the polymer body 5 consisting only of a three-dimensional skeleton network structure may be bonded to one or both of the pigs in advance with a suitable polymer or rubber adhesive.

The polymer body 5 having a three-dimensional skeleton network structure is
For example, a foam with open cells is manufactured by completely destroying the cell membrane of a foam made from polyurethane, polyethylene, silicone, vinyl chloride, etc., leaving only the three-dimensional mesh cell skeleton. It has excellent shrinkage and expansion properties, elasticity or restoring force, occlusion properties, and abrasion resistance. One example is Everlight Scotto (trade name, manufactured by Bridgestone Tire Co., Ltd.).

Polymer body 5 consisting only of a three-dimensional skeleton network structure
The shape of the pipe may normally be cylindrical or bullet-shaped with a length/diameter ratio of approximately 1.8 to 1.5, but for pipelines with many curved parts, a cylindrical or spherical shape is appropriate. . The diameter should be slightly larger than the inner diameter of the pipe.

Polymer body 5 consisting only of a three-dimensional skeleton network structure
is interposed between the pigs 4, 4, and during pumping,
As shown in Figs. 2 and 3, the pigs are compressed between the pigs, and are in close contact with the inner wall of the pipe with a large surface pressure, and even if there is a recess in the inner wall of the pipe, it can penetrate into the inside and clean it. Completely wipe away scale and high viscosity inside the pipe. Since this polymer material 5 has the property of occluding fine particles and sticky deposits, the inner wall of the pipe can be completely cleaned. Even in the curved pipe section, as shown in Fig. 3, the deformation of the polymer body 5 is large, and it comes into close contact with the corner parts, and unlike the conventional method shown in Fig. 4, it is completely wiped. I can do it.

According to the present invention, in the method of wiping the inner wall of a pipe using a pig made of foamed polyurethane resin, fine particles and viscous deposits, such as tar-like substances and high molecular polymers, which were conventionally difficult to wipe, can be removed. Even if there is a recess on the inner wall of the pipe, it can be completely wiped off, and the inner wall of the corner of the bent pipe can also be completely wiped off. Therefore, the scope of application of the pipe inner wall cleaning method using a pig has been significantly expanded, and the method has greatly contributed to the industrial world.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams of embodiments of the present invention, and the first
The figure shows the situation immediately before pressure feeding, and Figures 2 and 3 show the situation during pressure feeding. FIG. 4 shows a conventional method in which a pig passes through a bent pipe section. 1... Pipe to be cleaned, 2... Launcher, 3...
... Launcher opening/closing opening, 4... Pig, 5... Polymer body consisting only of a three-dimensional skeleton network structure, 6... Compressor or pump.

Claims (1)

[Claims] 1. A method of wiping the inner wall of a pipe by passing through a pig made of foamed polyurethane resin, in which two or more pigs are used, and a polymer consisting only of a three-dimensional skeleton network structure is interposed between the pigs. , a method for cleaning the inner wall of a pipe, which is characterized by pressure-feeding the inside of the pipe.