JPS5987074A - Plastic lining method for steel pipe - Google Patents

Abstract

PURPOSE:To line a steel pipe at a low cost with excellent work efficiency, by jointly using a resin powder spraying method and a fluidized immersion method of resin powder for the plastic lining of said steel pipe. CONSTITUTION:A steel pipe 1 after being pretreated and then preheated is supported with rolls 4, 4 and gently rotated about its horizontally longitudinal axis by a driving means 5. Resin powder is quantitatively sprayed from a sprayer 3 to the steel pipe 1, the lower surface of the steel pipe 1 is brought into contact with the fluidized dipping tank 2 of resin powder, and compressed air is sent therein through an air pipe 8. Hence, the resin powder floats up under a fluidized condition, comes in contact with the bottom of the preheated pipe 1 and adheres thereto by melting. Thus, the lining is performed with excellent work efficiency at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for finishing steel pipes using both a powder scattering method and a powder fluidized dipping method.

Blastic fining steel pipes are used industrially as alkali- and organic chemical-resistant pipes, and are also used for rust prevention and decorative purposes.

As a method of lining steel pipes using resin powder,
There is a spreading method in which a heated M-tube is lined with plastic powder, or a heated M-tube is immersed in a flowing Pufnutik powder layer to form a surface V? - It is known that there are powder fluidized dipping methods for lining resin, but these methods have advantages and disadvantages.

In other words, the scattering method wastes less powder, but on the other hand, it produces a uniform and smooth finish. Since the exposed area of the preheated steel pipe is large, the cooling rate is fast and there is a large loss.On the other hand, in the fluidized dipping method, the thickness of the coating can be adjusted freely by adjusting the heating temperature and dipping time, and it can be applied to complex shapes. Although it has advantages such as easy lining, good adhesion, and little deterioration of the resin, large-diameter steel pipes require thick H4V because the entire coated object is immersed in 't41if. It is expensive and requires a large amount of work, the amount of national fat powder required is several tens of times the amount deposited, and there is a disadvantage that there is a lot of waste.

The present invention aims to eliminate the drawbacks and promote the advantages of the above painting methods,
This provides a new lining method for plastic lining of WI pipes that utilizes both the resin powder scattering method and the resin powder fluidized dipping method. It is characterized by lining the steel pipe by spreading Pufnutsk powder almost uniformly over the entire length and fusing it, and at the same time immersing the lower surface of the steel pipe in a fluidized bed of Puchnutk powder. The size of the resin powder can be so large that the bottom surface of the steel pipe comes into contact with the resin powder, so it can be applied to lining steel pipes of various sizes without changing the thickness of the resin powder. The defects caused by the method are compensated for and a uniform and smooth lining can be achieved.

The present method will be explained below based on the drawings shown as examples.

Figure 1 is a longitudinal sectional front view showing the mechanism of an example of a device that is plastic lining a steel pipe with water droplets, and Figure 2 is a
It is an m cross section arrow direction view.

In the figure (1), resin powder is pretreated with a steel pipe lined with σ and then preheated.
It is supported by L/(4)<4) and is gently rotated about the horizontal long axis by the drive device (5). (3) is a spraying device that sprays all [1] above the steel pipe (1) to be lined.
) that opens at regular intervals over the length (-,
Resin powder is sprinkled over the surface of the rotating steel pipe (1) in stationary increments. (2) is a fluidized immersion tank for resin powder, which is provided so deep that the lower surface of the steel pipe comes into contact with the resin powder, as shown in the figure. The fluidized immersion tank is a box with a porous bottom (7). Powdered resin is placed in this box, and when compressed air is sent from the air pipe (8) to the bottom of the box, the resin powder floats to a fluid state and pre-P. Touch the bottom of the awned tube (1) and weld it to the surface. (6) is a lid plate that prevents (vd) fat powder from adhering to the inside of the tube, but fluid immersion of water droplets is only performed on the bottom surface of the tube.
Unlike the original fluidized dipping method, the entire surface is not immersed in V in j,'j+Ij, so it is not necessary to cover the entire cover plate, but only around the edges.

Plastic materials lined with water droplets include polyethylene, polyamide F, polystyrene, polyfluoroethylene,
Fluoroethish/Ambrovirenti? J fat '4 is 6, but in the case of polyethylene resin lining, diameter 1
A large-diameter steel pipe with a length of 1 m and a length of 1 m was pretreated with plasticizer, preheated to about 280°C, and put into the apparatus shown in Figs. Lined for a minute. The film thickness can be set to a predetermined value depending on the rotating Nuvede, the rotation time, and the amount of powder sprayed. At 300 kQ, it is possible to provide 1 g of uniform polyethylene resin lining of 5 to 1 υ.

The required amount of this resin powder is approximately 15 times the amount required when using only the conventional fluidized dipping method, and the finished surface (1) is very even and smooth compared to the case where only the conventional spreading method is used. It was comparable to the case where

As mentioned above, the method of the present invention satisfies various conditions such as being suitable for VC lining small quantities and various sizes of 44M with resin powder, easy to set up, low equipment cost, and low lining cost. Moreover, since the scattering method and the flowing method are used together, it combines the advantages of the scattering method, which saves powder, and the flowing method, which provides a uniform and smooth finish, and eliminates the drawbacks of the drawing method.

[Brief explanation of the drawing]

n (Figure 1 is a longitudinal sectional front view showing an example of a machine (1k) in which plastic lining is being applied to a steel pipe by water droplets. Figure 2 is a cross-sectional view taken in the direction of the If and -m arrows in Figure 1. l: steel pipe, 2: Resin fluid immersion (soda, 3: resin spraying device,
4: Steel pipe support is a roll, 5: Drive device, 6: Cover plate, 7: Porous bottom, 8: Air pipe, 9: Fluidized bed of resin powder Figure 1 Procedure amendment (method) % formula % ■ , Minor case indication 1982 Patent Application No. 194918 2 Name of the invention Branutik-Finink method for copper pipes 3 Relationship with the case of the person making the amendment Patent applicant Address 2 Dejima Nishimachi, Sakai City, Osaka Name Name Sumikin University Diameter Steel Pipe Co., Ltd. Representative Tadao Teramachi 4 Representative 6 Drawings to be amended 7 Contents of amendment drawings as attached 405-

Claims (1)

[Claims] (1) While holding the preheated steel pipe horizontally and rotating it around its long axis, sprinkle and fuse Poonuchik powder almost uniformly over the entire surface of the steel pipe, and at the same time pour the lower surface of the steel pipe into a fluidized bed of Pounuchik powder. A method for lining steel pipes by immersion.