JPS58174273A - Method for painting inside surface of laid piping - Google Patents

Abstract

PURPOSE:To paint the curved part of a pipe irrespectively of its diametral size uniformly, by containing paint between a pair of plug bodies which are inserted into the pipe and have annular pressing fins, and advancing the plug bodies while regulating the pressure before and behind the same. CONSTITUTION:Prior to painting, auxiliary cylinders 2, 2 are connected hermetically to both ends of a laid piping 1, and a pair of plug bodies 7 having an annular fin 8 are inserted into one end thereof. Paint 11 is injceted between the bodies 7 by means of a pipe 5 for supplying and discharging the paint and a pump 10. The pressure before and behind the bodies 7 is regulated with the air fed forcibly through the air supply and discharge pipes 4 at both ends so as to leak the paint 11 by the amt. necessary for painting from the outside circumference of the body 7 on the rear side. The pressure on the rear side of the body 7 on the rear side is made higher to advance the bodies 7, whereby a paint layer 13 is formed successively.

Description

[Detailed description of the invention] The present invention is directed to a method for painting the inner surface of installed piping.

In general, in order to prevent corrosion in oil transport pipelines or drug transport pipelines in chemical plants, etc., or to maintain the airtightness of joints in new fabric Jt9WII, repairs are made before and after new installation and use. In,
I am planning to paint it.

Conventionally, a method has been developed for such painting by supplying the paint into the pipe together with air, but with this method, when the pipe is winding, the paint is applied by the curved and straight parts. As the pipe diameter becomes larger and the diameter of the pipe becomes larger, the number of droop increases.
In the circular cross-section of the pipe, paint accumulates in the lower parts, and conversely, the paint on the upper part becomes thinner, making it impossible to obtain a uniform coating. III, and sealing the pipe joints with paint is 1! There are cases where it is desired! ! i! Although the degree achieved its purpose, it did not guarantee completeness.

In consideration of #lta as mentioned above, the present invention can paint the inner surface of the pipe regardless of whether it is new painting or repainting, and the degree of curvature of the pipe! ! The objective is to provide a method for painting the inner surface of installed pipes that can provide uniform coating regardless of the diameter, completely fill the spaces between joints, and achieve a high degree of sealing. In this case, a pair of plugs each having a plurality of annular fins made of a soft elastic material curved toward the rear end protruding from the outer peripheral surface are inserted from the end of the installed piping at intervals in the longitudinal direction, and both plugs are The special feature is to store paint in the can, adjust the air pressure in the tube between the front side of the front side plug and the rear side of the rear side plug, and use the difference in pressure to move both plugs and the intermediate paint forward. Among the installed piping, there is a WJ painting method.

Next, one aspect of an embodiment of the present invention will be described.

In the figure, 1 is a laid pipe whose inner surface is coated. Prior to painting, auxiliary pipes 2.2 for painting work are airtightly connected to both ends of the installed pipe 1. Each of these auxiliaries 112.2 is airtightly closed with a tip 13 that can be opened and closed, and an inlet/exhaust pipe 4 is connected to the end and a paint inlet/exhaust pipe 5 is connected to the center. A pressure regulating valve 6 is provided to exhaust the air when the internal pressure exceeds a certain level.

In this way, the auxiliary cylinders 2.2 are connected, and a pair of plug bodies 7.7 are inserted from the starting end side in a front-back arrangement.

The plug body 7 is made of a soft elastic material such as rubber or synthetic rubber, and has annular fins 8,8, 8, 8, 8, 8, 8, 8, 8, 8, 10, 10, 10, 10, 10, 2, 3, 4 annular fins on the outer periphery of which the periphery is curved rearward.
... are cut in multiple stages, and holes 9 are formed from the rear end to the front end.
is formed and distributed! ! The inner surface of 1 is shaped like a ring.

Then, the paint 11 is injected into the spaces between the two plug bodies 7, 7 through the paint injection/discharge pipe 5 on the starting end side using the pump 10.

Then, with the ends of both auxiliary units 1i2.2 closed, air is forcedly fed through the inlet and exhaust pipes 4 at both ends to adjust the internal pressure horns. This pressure adjustment allows the paint to be applied to the rear plugs 7, 7.
Both plugs 7.
At the same time, while adjusting the pressure before and after the rear plug 7, the rear side of the rear plug 7 is made to move forward both plugs 7.7 and the paint 11 to form a coating layer 13 in sequence, and reach the auxiliary 112 on the terminal side. let

When the stopper 7 on the forward side reaches the tip of the auxiliary cylinder 2 on the terminal side, the valve 14 of the auxiliary 112 of the paint inlet and outlet pipe 5 is opened to pour paint into the paint tank 15. After that, the lid 3 is removed and the stopper 7.7 is taken out.

The method for painting the inner surface of installed piping according to the present invention is configured as described above, in which a pair of movable plugs are inserted into the pipe by pressing the inner surface with an annular fin, and the paint is stored in the plug. By moving the plug and paint forward while adjusting the front and rear pressures, there is no uneven coating thickness even on curved parts, and relatively high viscosity paint can be used, making it easier to use when the pipe diameter becomes larger. Also, it was possible to coat both the upper and lower parts with a uniform thickness without causing any "sagging".

In addition, since the paint is moved while being pressurized from the front and rear plugs, if there is a gap in the joint of the pipe, the paint will be press-fitted to the negative part, and the paint will not be able to maintain a high degree of sealing. This is what became.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional view showing the state before the start of painting, and FIG. 2 is a partial sectional view showing the state during painting. 1... Laying piping, 4... Inlet/exhaust pipe, 5... Paint inlet/outlet pipe, 7... Plug body, 8... Annular fin. 388

Claims (1)

[Claims] 1.1 Insert a pair of plugs with annular fins made of soft elastic material curved on the end side and protruding from the outer circumferential surface at a distance from each other in the longitudinal direction from the end of the installed pipe, and inspect both plugs. It is characterized by storing paint in the tube, adjusting the air pressure in the tube between the front side of the front side plug and the rear side of the rear side plug, and moving both the plugs and the intermediate paint forward by the pressure difference. Method for installing inner surface of installed piping.