Precision Preparation Before Assembly
Assembling a stainless steel ball valve is like preparing for a precision surgery; every component requires strict quality control:
Valve Body and Ball: Made of 316L stainless steel, surface polished to below Ra0.8μm to ensure zero resistance during fluid flow.
Sealing Components: PTFE or graphite sealing rings must be stored in a dust-free environment and wiped with an alcohol swab before assembly.
Fasteners: All bolts must be pre-coated with anti-seize grease; torque values are preset to the range of 25-30 N·m.
Four Core Assembly Steps
Ball Positioning: Place the polished ball into the valve cavity and calibrate it with a laser positioning instrument to a deviation of ±0.1mm from the pipe axis.
Sealing Assembly: Utilizing a heat-fitting process, the sealing ring is heated to 120℃ and quickly embedded into the valve seat groove.
Transmission Connection: The lower end of the valve stem's square tenon is aligned with the ball's groove, with the gap controlled within 0.05mm.
Bolt Pre-tightening: The flange bolts are tightened three times in a diagonal sequence, achieving a final pressure test rating of PN40.
Ideal Testing Before Shipment: The assembled ball valve undergoes three rigorous tests:
Air Tightness Test: Injected with 0.6MPa nitrogen and held at that pressure for 5 minutes, with zero leakage detected by bubble detection.
Torque Test: A handle operating torque ≤15N·m is considered合格 (qualified), ensuring easy operation for the elderly and children.
Life Test: After simulating 50,000 full-open and full-close cycles, the sealing performance degradation does not exceed 3%.
