It is well known that metal corrosion damage has a considerable impact on valve life, reliability and service life. The action of mechanical and corrosive factors on the metal greatly increases the total wear of the contact surface. The total amount of wear on the frictional surface of the valve during operation. During valve operation, the frictional surfaces are worn and damaged due to simultaneous mechanical and chemical or electrochemical interactions between the metal and the environment. For valves, the weather conditions for their pipeline operation are complex, and the presence of hydrogen sulfide, carbon dioxide and some organic acids in the media such as oil, natural gas and reservoir water increases the destructive power of the metal surface and quickly lose the ability to work.
The chemical corrosion of metals depends on the temperature, the mechanical load of the friction parts, the sulfides contained in the lubricating materials, the stability of the acid resistance, the contact duration of the medium, the catalysis of the metals to the nitriding process, the speed of the molecule-to-metal conversion of the corrosive materials, and so on. Therefore, the metal valve anti-corrosion methods (or measures) and the application of synthetic materials valves, will become one of the current valve industry research topics.
1. Anti-corrosion of Metal Valve
Metal Valves are protected from corrosion by coating them with a protective coating (paint, pigment, lubricating material, etc.) that protects the valve from corrosion during manufacture, storage, transportation, and use.
The anticorrosion method of Metal Valve depends on the required protection period, transportation and preservation conditions, valve construction characteristics and materials, of course, to consider the economic effect of lifting the anticorrosion.
There are four main methods of corrosion protection for Metal Valves and their components:
1.1 Release the volatile corrosion inhibitor into the vapor atmosphere (coated with blotting paper, blown through the product chamber, etc.).
1.2 Use blocked water and alcohol solutions.
1.3 Apply a thin coating of anticorrosive material to the surface of the valve and its parts.
1.4 Apply the blocked film or polymer film to the surface of the valve and its parts.
2. Application Of Material Valve
Synthetic valves are superior to metal valves in many corrosive conditions, first in corrosion resistance, second in net weight, and their strength depends on the shape, arrangement, and number of reinforcing fibers. (in general, the greater the percentage of fiber, the greater the strength of the composite.)
In Valve applications, the basic weight content of the fiber is in the range of 30%-40%, and its chemical stability is mainly determined by the resin noumenon characteristics of the encapsulated fiber in the final product. In synthetic valves, the solid polymer body may be either a Thermoplastic (such as PVC-polyvinylidene fluoride, PPS-poly(p-phenylene sulfide), etc.) or a thermosetting resin (such as polyester, ethylene and epoxy, etc.).
The thermosetting resin maintains its strength at a higher temperature than the Thermoplastic resin (i. e. the thermosetting resin has a higher thermal deformation temperature).
Post time: Dec-15-2021