JPH0221094A - Heat insulation hose for painting inside pipes - Google Patents

Abstract

PURPOSE:To minimize the number of scratches by forming a lot of unevenness extending in the longitudinal direction of the external periphery of a protective coat made of high rigidity polyurethane. CONSTITUTION:An outer protective coat 3 is made of high rigidity and relatively low friction coefficient polyurethane. A lot of unevenness are formed in the longitudinal direction of the external periphery of the protective coat. The head section of a height 3a is formed into a circular arc of curvature R, which allows the protective coat to smoothly slide even if it is brought into contact with the internal wall surface of a pipe. Combined with the reduction of the contact area of the whole, the protective coat is enough slidable even in a bent pipe to be dragged smoothly leaving itself being brought into contact with the internal wall surface of the pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a painting hose used for painting inside a pipe.

[Prior Art] For example, for painting the inner surfaces of long pipes such as water pipes, a heat-retaining hose for painting the inside of pipes as shown in FIG. 3 has conventionally been used.

In other words, the heat insulating hose is made of a long piece with approximately loom, and a paint sprayer is attached to the tip, and the heat insulating hose is pulled into the pipe by a pull wire.
．． 1, a cable 2 that supplies power to a heater (not shown) provided in the heating tube 1, and a cable 2 that supplies power to the coating machine, and a cable made of plastic such as polyethylene or rubber that covers these all together. It is constituted by a protective coating 3. After this is drawn into the tube as described above, the paint is supplied through the heating tube 1.1 while being heated to prevent it from hardening, and the paint is applied to the inner surface of the tube by a coating machine at the tip.

[Problems to be Solved by the Invention] For example, when the water pipe to be painted with the pipe interior painting hose described above has a relatively narrow inner diameter of about 30 to 100 pipes, and is laid in a curved manner. There are many
In particular, when trying to pull a heat-retaining hose like the one shown in Figure 3 above into a curved pipe, the frictional resistance against the inner wall of the pipe is unexpectedly large, causing the hose to get caught inside the pipe, causing the hose to be pulled together abnormally. There is a risk that the cables and the like built into the ports and hoses may be broken, and the function as a heat insulating hose may be lost.

If you simply want to reduce the frictional resistance on the hose surface,
High-density polyethylene, which has a low coefficient of friction t'M, can be used as a protective coating, but this material suffers from environmental stress cracking and is not suitable for use under applied conditions such as tension or heat. be.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a heat-retaining hose for painting inside pipes that can minimize the chance of getting caught due to friction even when the hose is drawn into a pipe, especially a pipe with many curves. This is what I am trying to do.

Means for Solving the Problems] The present invention comprises a protective coating which is the outermost layer and is made of polyurethane which is rigid and has a relatively small coefficient of friction, and has a large number of irregularities formed in the longitudinal direction on its outer circumferential surface. be.

[Function] Polyurethane is relatively slippery, and since the irregularities extending in the longitudinal direction are formed on its outer periphery, the irregularities increase the flexibility of the coating itself, while the tips of the convex portions are shaped like an arc to improve sliding properties. is further increased, and the occurrence of abnormal tension during retraction is eliminated.

[Example 1 The present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing the true structure of a heat retaining port for painting inside a pipe according to the present invention, and the same reference numerals as in FIG. 3 indicate the same structure.

In the present invention, polyurethane is used as the material constituting the protective coating 3, and the outer surface is formed with a large number of irregularities extending in the longitudinal direction.

FIG. 2 is an enlarged explanatory diagram of the uneven portion, and shows the convex portion 3a.
, 3a is formed into an arc shape with a curvature R. Having an arcuate head like this makes it extremely easy to slip even when it comes into contact with the inner wall of the pipe, and combined with the reduction of the overall contact area, it is also very easy to slide inside a curved pipe. It can be drawn in smoothly while remaining in contact with the inner wall, and there is no risk of abnormal tension occurring due to catching as in the conventional example.

Note that it is preferable that the convex portions 3a, 3a having this curvature rt be formed over the entire circumference of the outer peripheral surface of the hose so that the convex portions 3a, 3a have the curvature rt and do not lie across the tube no matter where they come into contact.

A product of the present invention shown in FIG. 1 and a conventional product shown in FIG. 3 were prepared, two bends were set, and a dynamic load test was conducted in the pipe. The product of the present invention as a test material uses polyurethane (JIS Shore A hardness 90) as a coating material and has many irregularities formed on the surface, whereas the conventional product is coated with polyurethane (JIS Shore A hardness 85). Although it is used as a material, it does not have surface irregularities.

Table 1 shows the results of the Himame experiment.

This shows that the product of the present invention has a reduced dynamic load ratio and friction.Moreover, polyurethane with low hardness can be used, and as a result, flexibility is significantly improved.

Table 1 [Effects of the Invention] As described above, according to the present invention, the insulating hose for painting can be drawn into a pipe extremely smoothly, and painting can be performed without trouble even in a curved pipe. , its effectiveness should be highly evaluated.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment according to the present invention, FIG. 2 is an enlarged explanatory diagram of the vicinity of the outer surface, and FIG. 3 is an explanatory diagram showing the configuration of a conventional example. 1: Paint supply heating tube, 2: Cable, 3: @protective coating, 3a: Convex part. Agent Patent Attorney Fujio Sato

Claims (1)

[Claims] (1) In a hose formed by covering a heating tube for supplying paint and a cable together with a protective coating, the protective coating is made of rigid polyurethane, and a large number of irregularities extending in the longitudinal direction are formed on the outer peripheral surface of the hose. Insulating hose for painting inside pipes.