JP2001018294A - Fusion method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the cleaning of a polyethylene pipe after scrape work by a method in which when a thermoplastic resin pipe is fused with a joint, during the scrape work of the pipe or after the end of the work, static electricity generated on the surface of the pipe is eliminated. SOLUTION: While a pipe of a thermoplastic resin such as polyethylene and polypropylene is scraped, air ionized by using a blower is sprayed to a scrape surface, and during scrape work or after the end of the work, static electricity generated on the surface of the pipe is eliminated. In this way, the pipe is inserted into a joint and fixed to a clamp. Next, after a fusion tool terminal is fitted to a joint terminal pin, they are fused, and after being allowed to stand, the terminal and the clamp are released so that the pipe and the joint are fused. In this way, the cleaning of the polyethylene pipe after the scrape work can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a fusing method.

[0002]

2. Description of the Related Art In recent years, a fusion method has been adopted as a method of connecting thermoplastic resin pipes used as water pipes and water pipes through joints made of thermoplastic resin.

[0003] This fusion method mainly comprises the following steps in the case of a polyethylene pipe EF fusion system for gas and for water and sewage, for example. (1) Scraping of pipe (2) Cleaning of scraped surface of pipe (3) Cleaning of inner surface of fitting (4) Inserting pipe into fitting and fixing to clamp (5) Attach fusion tool terminal to fitting terminal pin (6) ) Fusion (7) Stand still (8) Release terminal and clamp.

In the above method, first, the outer surface of the polyethylene pipe is thinly peeled in order to remove dirt and oxide film adhering to the surface of the polyethylene pipe. This is called scraping. Usually, a hand canner or an electric scraper is used for the scraping operation. However, it is inevitable that dust adheres to the tube surface during the scraping operation.

For this reason, after the scraping operation, it is necessary to clean the scraped surface of the polyethylene tube in order to remove dust adhering to the surface of the polyethylene tube. The cleaning operation is performed using a nonwoven fabric impregnated with alcohol.

However, (i) the cleaning operation is complicated, (i)
i) Non-woven fabric used for cleaning work is generated as garbage, (i
ii) The construction site is in a very dusty environment and the worker's own clothes are dirty, and the outer surface of the polyethylene pipe may be further stained during the cleaning process. Is not desirable.

[0007]

SUMMARY OF THE INVENTION In view of such circumstances, an object of the present invention is to develop a fusing method that does not require cleaning of a polyethylene pipe after a scraping operation.

[0008]

The inventor of the present invention has conducted various studies in order to solve the above-mentioned problems. As a result, static electricity was generated on the surface of the polyethylene pipe during the scraping operation, and the static electricity generated in the air was caused by the static electricity. Dust was sucked in and found to adhere to the tube surface. In order to fuse the thermoplastic resin tube and the joint while continuing research, the above problem was solved by removing static electricity generated on the tube surface during or after scraping the tube. I found what I could do. The present invention has been completed based on such findings.

The fusing method of the present invention includes a step of removing static electricity generated on the surface of the tube during or after scraping of the tube when the thermoplastic resin tube and the joint are fused. A method for fusing a pipe and a joint made of a thermoplastic resin, characterized in that:

Further, the fusion method of the present invention is a fusion method for removing static electricity generated on the tube surface by blowing ionized air onto the tube surface.

Further, the fusion method of the present invention is a fusion method in which air ionized by a blower or an air gun is blown onto the tube surface.

According to the present invention, there is provided a piping system in which a thermoplastic resin pipe and a joint are fused by the above-mentioned fusion method.

According to the welding method of the present invention, the thermoplastic resin pipe and the joint can be fused with sufficient strength without cleaning the thermoplastic resin pipe after the scraping operation. it can. Therefore, the reliability of the entire piping system can be greatly improved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, pipes and joints are
For example, conventionally known materials can be widely used as long as they are made of a thermoplastic resin such as polyolefin such as polyethylene or polypropylene.

In the method of the present invention, first, the outer surface of the pipe (the portion to be welded to the joint) is scraped. For the scraping operation, tools used in the conventional scraping operation, such as a hand canner and an electric scraper, can be widely used.

Since dust adheres to the tube surface during the scraping operation, the present invention removes static electricity generated on the tube surface next.

In removing static electricity generated on the tube surface, any of the conventionally known methods can be adopted. For example, ionized air may be blown onto the tube surface.

The means for blowing the ionized air onto the tube surface is not particularly limited, and a conventionally known method can be widely used. For example, the ionized air may be blown onto the tube surface by a blower or an air gun. Also, ionized air can be blown onto the tube surface using a bar or a nozzle. The amount of the blown ionized air is usually 1-3 m ³ /
The spraying speed is usually 1 to 5 m / min, and the spraying time is usually 5 to 20 seconds.

The removal of static electricity generated on the tube surface may be performed during the scraping operation or may be performed after the scraping operation is completed.

After the step of removing the static electricity generated on the tube surface, the cleaning operation of the scrape surface of the tube employed in the conventional fusion method becomes unnecessary.

In the present invention, the cleaning of the inner surface of the joint may or may not be performed. The pipe and the joint can be fused with sufficient strength without performing a cleaning operation on the inner surface of the joint.

In the present invention, a step after removing static electricity generated on the surface of the tube, that is, a step of inserting the tube into a joint and fixing it to a clamp, a step of attaching a fusion tool terminal to a joint terminal pin, The fusion step, the standing step, and the step of releasing the terminal and the clamp can be performed in the same manner as the conventional fusion method.

[0023]

According to the fusion method of the present invention, a thermoplastic resin tube and a joint can be fused with sufficient strength without cleaning the thermoplastic resin tube after the scraping operation. be able to. Therefore, the reliability of the entire piping system can be greatly improved.

[0024]

The present invention will be further clarified with reference to the following examples.

Example 1 While scraping a pipe (made of polyethylene), an ionized air was blown onto the scraped surface by using a blower (Aerostat XC type, manufactured by Simco Japan Co., Ltd.) to generate static electricity generated on the scraped surface. Was removed. on the other hand,
The inner surface of the joint (made of polyethylene) was not cleaned.
Thereafter, the pipe was inserted into the joint and fixed to the clamp according to the usual method, and then the welding terminal was attached to the joint terminal pin, and then the terminal was clamped and then the terminal and the clamp were released. Thus, the pipe and the joint were fused.

Example 2 While scraping a tube (made of polyethylene), an ionized air was sprayed on the scraped surface using an air gun (Air Gun HBA type manufactured by Simco Japan Co., Ltd.) to discharge static electricity generated on the scraped surface. Removed. on the other hand,
The inner surface of the joint (made of polyethylene) was not cleaned.
Thereafter, the pipe was inserted into the joint and fixed to the clamp according to the usual method, and then the welding terminal was attached to the joint terminal pin, and then the terminal was clamped and then the terminal and the clamp were released. Thus, the pipe and the joint were fused.

Comparative Example 1 A pipe (made of polyethylene) was scraped, and then the scraped surface was cleaned using a non-woven fabric impregnated with alcohol. The inner surface of the joint was also cleaned using a non-woven fabric impregnated with alcohol. Thereafter, in the same manner as in Example 1, the tube is inserted into the joint, fixed to the clamp, and then, after attaching the welding tool terminal to the joint terminal pin, fusion is performed, and after standing still, the terminal and the clamp are removed. Canceled. Thus, the pipe and the joint were fused.

Comparative Example 2 A pipe and a joint were fused in the same manner as in Example 1 except that air ionized using a blower was not blown onto the scraped surface.

Comparative Example 3 A pipe and a joint were fused in the same manner as in Example 1 except that the pipe (made of polyethylene) was not scraped, and the ionized air was not sprayed on the scraped surface using a blower.

Test Example 1 A peeling test was used as a technique for evaluating the fusion performance between a pipe and a joint. This peeling test is based on JIS K6
In accordance with the method defined in 765-3, the fused portion has a width of 1 cm.
This is a method in which the pipe is cut to a degree, the pipe is fixed to a jig of a tensile tester, and the joint is pulled. If the weld is tightly joined, the cut will occur across the tube. However, if the fusion joint is poor, the cut will occur at the pipe-to-joint interface, ie, at the interface, and will be bisected into the joint and the pipe.

In the pass / fail judgment of the fusion bonding in the peeling test, as specified in JIS K 6765-3, the fracture at the fusion interface is 1/3 or less of the fusion length of the joint. The case was regarded as passed.

The results are shown in Table 1.

[0033]

[Table 1]

When the ionized air is blown onto the scraped surface using a blower or an air gun (Examples 1 and 2), the amount of static electricity (20 kV; see Comparative Example 2) generated immediately after the scraping becomes almost 0 kV. Had become. This is the case when cleaning is performed like normal fusion (0k
V: see Comparative Example 1), and the static electricity was almost completely removed. Thus, the peel strengths of the fused products of Example 1 and Example 2 reached the passing points. From this, it can be seen that by blowing ionized air onto the scraped surface using a blower or an air gun after scraping the pipe, the fused portion can be joined firmly without performing cleaning work.

Claims (4)

[Claims] 1. A method for fusing a thermoplastic resin tube and a joint, the method comprising a step of removing static electricity generated on a surface of the tube during or after scraping of the tube. A method of fusing a pipe made of a plastic resin to a joint. 2. The method according to claim 1, wherein the ionized air is blown onto the tube surface to remove static electricity generated on the tube surface. 3. The fusion method according to claim 1, wherein air ionized by a blower or an air gun is blown to the surface of the tube. 4. A piping system in which a thermoplastic resin pipe and a joint are fused by the method according to claim 1.