1. On the one hand, immersion in water will not rust, and there will be no electrochemical corrosion between the two metals; on the other hand, the smooth surface will reduce the water resistance.

2. The inside and outside of the valve body (including the transmission box) shall be shot blasting, sand removal and rust removal, and the powder non-toxic epoxy resin shall be sprayed with the thickness of more than 0.3mm. When it is difficult to spray non-toxic epoxy resin for extra large valve, similar non-toxic epoxy paint should be applied and sprayed.

3. The sanitary requirements of epoxy resin or paint for anticorrosion inside the valve body shall be provided with the test report of corresponding authority. The chemical and physical properties should also meet the relevant requirements.