1. The valve must not be damaged, missing parts, corrosion, nameplate falling off, etc., and there must be no dirt in the valve body

2. Both ends of the valve should be protected. The handle or handwheel operation should be flexible and light, and there should be no jamming phenomenon

3. When the valve body is a casting, its surface should be smooth and free of defects such as cracks, keyholes, blisters, pores, burrs, etc.; when the valve body is forged, its surface should be free of defects such as cracks, interlayers, heavy skins, scars, etc.

4. The inner surface of the valve body of rubber lining, enamel lining and plastic lining should be flat and smooth, and the lining layer and the base body should be firmly combined without cracks, bubbling and other defects. Check the surface of the lining layer one by one with a high-frequency electric spark generator to ensure that no lining is found. The layer is broken down (white flash phenomenon) is qualified

5. The sealing surface of the valve flange should meet the requirements, and there should be no radial scratches