JPS60257879A - Corrosion resistant pipe and its preparation - Google Patents

Abstract

PURPOSE:To efficiently form a thick coating layer having excellent capacity, by applying a liquid corrosion resistant paint having good adhesiveness to the surface of a matrix pipe and applying a corrosion resistant paint comprising hard particles onto the coated paint layer while gradually increasing the dispersing amount thereof. CONSTITUTION:The lower layer 2 formed onto the inner surface of a sewage concrete matrix pipe 1 comprises a paint having good adhesiveness, for example, a tar/epoxy paint and the upper layer 3 thereof comprises layers formed by dispersing inorg. particles having good corrosion resistance such as slica sand so as successively increase the ratio thereof and 70% or more of the surface comprises particles and is formed into a multiple layer with a thickness of 1mm. or more. The pipe having the above mentioned coating layers is obtained by a method wherein a liquid corrosion resistant adhesive is applied to the pipe at first by utilizing the centrifugal force of the rotary pipe and, thereafter, corrosion resistant particles are scattered on the adhesive layer to perform coating.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to concrete, cast iron, steel, or synthetic resin pipes with a corrosion-resistant layer formed on their inner surfaces for use in corrosive atmospheres such as sewer pipes. and its manufacturing method.

[Prior art and its problems]

Concrete pipes and steel pipes are excellent structural materials, but it is a well-known fact that they are vulnerable to chemical erosion. Especially when such pipe material is used as a sewer pipe, the sewer pipe is free from acid flowing into the pipe.

It is severely attacked by chemicals such as hydrochloric acid and various corrosive substances generated from decaying organic matter.

As a countermeasure, (1) improve the corrosion resistance by changing the composition of the material itself.

(2) The inner and outer surfaces, especially the inner surface, are coated with a corrosion-resistant material to isolate the constituent materials from the corrosion-resistant environment.

There are two methods.

Method (1) has limitations in terms of materials, and in particular, in the case of concrete, as long as cement is used as a hardening agent, there is a limit to the improvement of its properties.

In addition, as for method (2), ■ Painting with anti-corrosion paint ■ Lining with corrosion-resistant sheets, boards, etc. ■ Lining with anti-corrosion mortar or tiles ■ Is there an lining made of anti-corrosion bricks on top of the anti-corrosion lining, workability, and cost? 1. In view of the corrosion resistance and strength of the coating formed thereon, in (2), coating with a corrosion-resistant paint such as epoxy resin is generally performed.

However, when painting the surface with such corrosion-resistant paint, if a large amount is applied, the surface will sag, and a maximum of 0.2
Only one thickness of coating can be produced. With this degree of coating, pinpoles, uneven coating, etc. will occur, the corrosion resistance will be poor, and the coating will be mechanically weak (does not achieve the purpose. Therefore, in order to create the necessary and sufficient coating thickness, it is necessary to repeat the coating several times. Not only does it have to be applied, but it is also impossible to apply it to the same surface more than once a day, so it takes several days to apply it several times, which increases labor costs and is uneconomical. be.

In addition, these paints contain volatile organic substances, making it difficult to maintain worker safety due to thinner poisoning, and furthermore, they have the disadvantage of being difficult to apply in confined spaces.

In order to eliminate this drawback of paint application, for example,
As described in Japanese Patent No. 7-15874, a method has also been proposed in which a mixture of paint and inorganic particles is applied while rotating a tube.

In this method, the liquid and particles are mixed in advance and then coated, so the mixture contains a large amount of air, and the resulting coating layer has many air bubbles, making it impossible to obtain watertightness. ,
The disadvantage is that the adhesion between the coating layer and the pipe is significantly reduced by the inclusion of grit, making it impossible to obtain the desired effect.

[Problem that the invention seeks to solve]

Purpose of the invention! 4. The aim is to thicken the formation of aH in such a pipe, and provide a pipe that has resistance especially as an F water pipe in a complex corrosive atmosphere.

[Means and effects for solving the problem] The present invention has the following features:
Traditional sewage - concrete used as water pipes
1. Applicable to pipes, cast iron pipes, and steel pipes.

The material ff1P' formed on the inner surface of the corrosion-resistant tube of the present invention has a cross-sectional configuration shown in FIG. The upper layer 3 is composed of only a paint with good adhesion such as paint, and the upper layer 3 is formed of a layer in which inorganic powder and granule material with good corrosion resistance such as silica sand is dispersed, and more than 70% of the surface is made of a material with good corrosion resistance. It forms multiple layers with a thickness of 11" or more composed of inorganic powder particles.

Tubes with such a coating layer are first coated with a liquid corrosion-resistant adhesive using the centrifugal force of the rotating tube, and then the coating is applied by scattering erodible particles onto the adhesive using insect bodies. iM is done by. This layer of soil can be formed by not only spraying the corrosion-resistant particles on the car body alone (but also by spraying them mixed with a liquid adhesive, which is the forming agent for the lower layer).

The corrosion-resistant liquid paint that forms the lower layer is in liquid form at the time of coating, and if it has an extremely low viscosity, the powder or granules added later will mature into the laminate due to centrifugal force, so the viscosity should be at a temperature of 20°C. It is preferable that the temperature is about 3000 to 7000 CPS at °C. Of course, it is not necessary to have this viscosity at room temperature, and things that have this viscosity when heated,
It is also possible to use it in a heated state.

As the liquid paint of the present invention, a tar-epoxy resin paint is most suitable, but thermoplastic synthetic resins such as polyconalene and polypropylene can also be used as desired.

The corrosion-resistant particles in the upper layer include particles that are inert in an aqueous atmosphere, such as silica sand, natural sand, and glass powder.

There are recycled plastic particles, particle size 0.15~]
, 5 dragon diameters can be used in any combination.

The amount of corrosion-resistant particles to be added is preferably 1 to 1.3 times the volume of the liquid coating material to be sprinkled onto the liquid coating material layer.

〔Example〕 Examples of the present invention will be described below.

As shown in Figure 2, the inner diameter is 300 mm and the outer diameter is 360 mm.
mm.

A sewage concrete main pipe 1 having a length of 2000 mm is attached with a side link 4 on the end side surface to prevent the coating material from flowing out, and then placed on a horizontal rotary table 5 for coating treatment. .

Horizontal rotation: The concrete main pipe 1 was rotated at 24 Orpm (centrifugal force IC1, 5 G') by driving the stand 5. To this, a corrosion-resistant paint consisting of tar epoxy with a ratio of base: curing agent of j: 1 was applied from the computer 6 at room temperature for 2
．． +r (1,885cc) was an official at one time in 26.

After a uniform coating layer was formed on the inner surface of the tube in 0.5 minutes after charging, a 297 μm residue was added to the tube with a residual content of 1% or less.

6.37 kg (2450 cc) of Toyoura standard sand whose particle size had been adjusted to have a particle size of 95% or more with a residual content of 105, +1 m was introduced into the tube by inserting the dispersion injector 7 through the rotating forceps.

After 24 hours had passed after the coating treatment, the liquid paint was completely solidified. The thickness of the coating layer thus obtained is 2.
At No. 31, the lower layer showed a completely adhered state with partial penetration into the mother tube, and the upper layer gradually became a dog in powder distribution, with the distribution rate just below the surface reaching 80%.

The concrete pipe thus obtained was subjected to an impact test, 115
When a test was conducted based on J.

〔Effect of the invention〕

In the present invention, ■ Since the strong adhesive force of liquid corrosion-resistant paint such as tar epoxy paint is spread on the tube surface in its undiluted state, the granular anti-corrosion paint is In order to add and adsorb foodstuffs, the main tube and corrosion-resistant layer become completely integrated.

■ Conventionally, liquid paints can only form a thin film of about 0.2 yen per coating, but with this method, a layer of any thickness can be formed in one step.

■ Even if a liquid coating film is applied thickly, its own hardness and strength are insufficient. However, according to the present invention, by increasing the amount of hard particles such as silica sand dispersed in the surface layer. Strength is increased.

■Regardless of the thickness of the corrosion-resistant layer, the work is completed in one step, which is not only economical but also greatly reduces the chances of workers coming into contact with harmful substances such as thinner, which is advantageous in terms of preventing industrial accidents. .

Procedural amendment, 1930]
25 B], Incident indication Toge 159 Patent Application No. 116189 2 Name of the invention Corrosion-resistant pipe and its manufacturing method 3 Person making the amendment Relationship with Igyu Patent applicant address 4 Name of agent (8216 )Patent Attorney Handmade 1・-5, Subject of amendment ``-4',...: 1-2.1f Details of amendment 4 in the specification, brief explanation of the drawings Figure 1 shows the coating layer according to the present invention FIG. 2 shows an example of the coating layer forming method of the present invention.

1: Main pipe 2 Knee 4 1st layer 3: Upper layer 4: Side link 5; Horizontal rotating table 6: Shooter 7: Dispersion feeder Fig. 1 (1) 4 lines from the bottom of the first specification “-Water pipe, etc.” [Corrected to ``manholes, sewage pipes, etc.''

(2) ``The present invention...
Applicable to... ” to be deleted.

(3) Page 6 of the specification, lines 7-14 “Also...
··preferable. "In addition, the particles distributed in the coating layer include corrosion-resistant particles that are inert in the usage atmosphere, such as silica sand,
Natural sand, glass powder, fly ash.

Recycled plastic particles etc. can be used.

However, since these particles must first enter the coated liquid, it is preferable that they have wettability with this liquid paint, and the particle size is preferably 0.15 to 1.5 fl. used. From this point of view, since fly ash has no wettability with liquid paint and has a small particle size, it is used that has been granulated into fine particles.

The amount of these particles added varies depending on the material of the target pipe and the intended use, but the volume ratio is 0.7 to 2 times that of the liquid paint, preferably L;:f: ] to
It is better to sprinkle 13 times the amount on top of the paint layer.

The corrosion-resistant material of the present invention can be used for similar purposes such as conventionally used water pipes, water pipes, manholes, and other industrial wastewater treatment pipes. ” Correct δJ.

Claims (1)

[Claims] ], i@: A lower layer made of a corrosion-resistant adhesive is formed on the inner surface of the tube, and a two-layer structure in which the dispersion ratio of powder and granules is gradually increased is formed integrally with the lower layer. A corrosion-resistant pipe characterized by having a coating layer made of. 2. In the method of supplying a corrosion-resistant coating forming material to the inner surface of the tube while rotating the main tube to form the coating layer, after supplying only a liquid corrosion-resistant adhesive and coating the inner surface of the tube with the same liquid corrosion-resistant adhesive. A method for manufacturing a corrosion-resistant pipe, which comprises spraying and supplying corrosion-resistant powder particles onto a liquid corrosion-resistant adhesive layer.