Body Internal/External Surfaces: Check for defects like sand holes or cracks.
Seat-Body Connection: Verify secure bonding; ensure disc and seat align properly with defect-free sealing surfaces.
Stem-Disc Linkage: Confirm flexible and reliable connection; inspect stem for bending, thread damage, or corrosion.
Sealing Components: Examine packing/gaskets for aging/damage; test valve opening flexibility.
Identification Markings:
Body and nameplate must display: Manufacturer's name, valve type, nominal pressure, and nominal diameter.
Transport Position Requirements:
(a) Closed position: Gate valves, globe valves, throttle valves, butterfly valves, foot valves, control valves.
(b) Open position: Plug valves, ball valves3.
(c) Gently closed: Diaphragm valves (never overtighten).
(d) Secured closure: Check valve discs fixed in closed state.
Safety Valves:
Spring type: Must have lead seals; lever type: Require hammer positioning devices.
Check Valve Discs: Ensure discs move flexibly and accurately without eccentricity or skewing.
Lined Valves (rubber/plastic/glass):
Internal surfaces: Smooth and even; lining-base adhesion must be firm, free from cracks or bubbles.
Flange Sealing Faces: Must meet standards with no radial scratches.
Overall Integrity:
No damage, missing parts, corrosion, or missing nameplates; body must be clean.
Protective Measures:
Protective covers on both ends; handwheel/handle operation must be smooth without jamming.
Quality Certificate Contents:
(a) Manufacturer name and production date.
(b) Product name, model, and specifications.
(c) Nominal pressure/diameter, applicable media/temperature.
(d) Applied standards, inspection conclusion, and date.
(e) Serial number, inspector, and responsible examiner signatures