A method for manufacturing glass-lined workpieces by spraying fluorine plastic on the outside

Abstract

The invention provides a manufacturing method for fluorine plastic injection outside a glass lining workpiece. The manufacturing method is characterized by comprising the following steps: step one, carrying out thorough clearing sand blasting on the surface of a metal blank body, and then enameling a ceramic glaze coating with uniform thickness on the surface; step two, uniformly spraying a fluorine plastic layer on the surface of the glass lining workpiece, and spraying on the surface of the glass lining workpiece in sequence, wherein the fluorine plastic layer is divided into a base material, a middle material and a surface material; step three, clearing the surface, and carrying out 20kv high-voltage discharge test to complete the preparation of the workpiece. The method for preparing the workpiece is wider in applicable medium, the surging range of temperature difference is improved, and the method has the obvious advantages of good medium permeability resistance, long service life, lower cost and the like; a PFA (Perfluoroalkoxy alkane) coating sprayed on the surface can compensate the defects of dark bubbles, pinholes and the like which are undetected by glass lining equipment; the temperature difference surging resistance of the equipment is further increased, and the risk of glass lining explosion caused by temperature difference surging is reduced.

Description

technical field [0001] The invention belongs to the technical field of chemical anticorrosion, and in particular relates to a manufacturing method of spraying fluorine plastic on a glass-lined workpiece. Background technique [0002] Commonly used equipment in chemical production, such as reaction kettles, storage tanks, metering tanks, etc., and most of them are corrosive reaction media, the required production equipment should also have good corrosion resistance, generally adopt fluorine-lined, plastic-lined, enamel Glass, rare alloys and other materials are used to solve the problem of corrosion resistance, and glass-lined equipment is one of the most commonly used chemical anti-corrosion equipment because of its low cost and wide application. The shape is relatively complex, especially for tower internals and similar parts, and the method of spraying fluorine materials (such as PFA) is often used to solve the problem of corrosion resistance. [0003] However, chemical e...

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Problems solved by technology

[0005] 1) The resistance to sudden changes in temperature difference between cold and heat is relatively poor. According to GB25025 "Technical Conditions for Glass-lined Equipment", thermal shock ≤ 120 ℃, cold shock ≤ 110 ℃;

[0006] 2) Not resistant to alkaline media, hydrofluoric acid, etc. and SiO 2 The chemical materials that react, such as high-temperature hydrochloric acid and high-temperature concentrated phosphoric acid, are also highly corrosive to them;

[0007] 3) The glass-lined layer is prone to defects such as dark bubbles and pinholes that are not easy to detect. After a period of use, due to the material corroding the surface of the glass-lined layer, the defects are exposed and directly contact the medium, causing the equipment to be corroded and invalid

[0008] 2. The equipment sprayed with fluorine materials (such as PFA, etc.) has good anti-corrosion performance, anti-peeling performance and compactness, but because the thickness of the spray coating is relatively thin, generally about 0.8-1.2mm, the agitator is in long-term operation. The medium continuously scours and infiltrates the coating, and the service life is short. In addition, the medium also continuously infiltrates the sprayed coating. If the coating is too thin, as time goes by, the material will penetrate to the surface. Equipment billets, causing coating bubbling, peeling and other phenomena

Therefore, the spraying equipment needs to consider the reasons of wear resistance and anti-penetration. The coating must be about 1mm. The fluoroplastic raw materials used for spraying are imported from abroad, which are expensive, and the thickness of each spraying is within 0.1mm. , to achieve the specified thickness, it must be sprayed and sintered many times, which consumes a lot of labor and electricity. Therefore, the cost of spraying fluoroplastics is also very high, which limits its scope of use.

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