How to Choose a PVC 2-Piece Ball Valve?
Seal material directly affects service life and leakage resistance. PTFE seats handle many corrosive chemicals and maintain smooth operation. EPDM performs well with water, mild acids, and alkaline solutions. FKM can suit oils and higher-temperature applications, but compatibility must be verified.
Do not select a seal by temperature alone. Check concentration, pressure, cycling frequency, and cleaning chemicals. In field evaluations, mismatched seals often fail before the PVC body. That result is frustrating, but preventable.
Tips: Request a chemical compatibility chart. Confirm the actual operating temperature. Inspect the seat after pressure testing. A soft seat may reduce torque, yet it can deform under excessive heat or pressure.
Flow performance deserves equal attention.
A full-port ball valve usually creates less pressure loss than a reduced-port design. This difference matters in long pipelines, small pumps, and systems with limited pressure. Compare the valve’s flow coefficient, or Cv, with the required flow rate.
A higher Cv can reduce turbulence and pumping demand. However, published values may use ideal test conditions. Real installations include elbows, filters, and partially open valves.
Measure the complete system when accuracy matters. Avoid oversizing, because poor control and unstable flow can follow.
Small details count.