The closing parts are often scoured and eroded by the fluid, which accelerates the development of corrosion. Some valve discs, although using better materials, are still more severely corroded than the shell.
The upper and lower closing parts and the valve stem and valve seat are usually connected with threads, and the connection is less oxygen than the general part, which is easy to form an oxygen concentration battery, causing it to be corroded and damaged. Some closed files
The cover is in the form of press-fit. Due to the loose fit and slight gaps, oxygen concentration battery corrosion will also occur.
The general protection measures for closures are as follows:
① Use corrosion-resistant materials as much as possible. The closing part is generally smaller in size and lighter in weight, but plays a key role in the valve, as long as it can resist corrosion, even if a little
Precious materials are also fine.
②Improve the structure of the closing part to make it less eroded by the fluid.
③Improve the connection structure to avoid the generation of oxygen concentration difference batteries.
④ In the valve below 150°C, the junction of the closing part and the junction of the sealing surface should be sealed with polytetrafluoro-Zene raw material tape, which can reduce the corrosion of these parts.
⑤ While considering corrosion resistance, pay attention to the erosion resistance of the closing material. Use a material with strong erosion resistance for closing parts.
