Fluorine-lined valve quality control and inspection

It is stipulated in the technical conditions that the lining must be derusted and textured according to the requirements of the standard, and the manual derusting is in accordance with the St3 level specified in the GB/T11373 standard; the mechanical device derusting is in accordance with the St2 level. In specific operations, the interval between rust removal and lining should be as short as possible. In terms of quality control and inspection, requirements are put forward for the qualifications of inspectors and measurement and test equipment. This is primarily dictated by the properties of fluoroplastic lined valves. If the quality of the testing personnel does not meet the requirements or the testing equipment is faulty, it will cause misjudgment, so that the unqualified products will be left out of the factory, which will cause catastrophic consequences. In the inspection items, in addition to the conventional valve inspection and pressure test items. Also increase the thickness of the lining layer, the lining layer EDM detection. Rework can be performed for unqualified lining layers, but must be carried out in accordance with the prescribed procedures. Generally speaking, fluorine-lined valves cannot be used as vacuum valves. If users have special requirements, they should be satisfied. In the design and manufacturing process, special treatment should be done, and a vacuum test should be carried out, and the requirements in Table 7 should be met. The technical conditions stipulate the ex-factory inspection items and type inspection items of fluorine-lined valves respectively, and they are inspected and tested according to the requirements of relevant standards. Regulations 6.1.4, 9.2.5 and 9.2.2 in the technical conditions make special provisions for the parts involving safety and health. For sanitary fluorine-lined valves, the use of recycled, recycled and unbranded materials is strictly prohibited. The medium can use pure water. After lining, if it is found that the shell has pinholes and pores and leaks, it shall not be repaired and welded and shipped directly from the factory. In practice, we found that if the welding is directly repaired, although there is no leakage on the surface, the medium will penetrate between the lining layer and the shell along the pinholes and pores under the action of pressure. If it is a highly corrosive medium, It will quickly corrode the steel valve housing and leak, and the consequences will be serious.