Plast-O-Matic Series CKM Self-Closing Thermoplastic Check Valves

1/2 in.
3/4 in.
1 in.
0.00 LBS
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Series CKM & CK Check Valves, normally closed in design, feature a patented diaphragm seal that will neither stick nor chatter and is automatic in action. The valves are not dependent upon gravity so they can be mounted in any position. Even in the absence of reverse flow or pressure, the diaphragm will automatically reposition itself to seal against the valve seat. This provides both design simplicity and maximum operating dependability.

Flow entering the valve inlet will open the valve by pushing the diaphragm off the valve seat until it comes to rest on the internal stop. This supports the diaphragm and eliminates force or stress under high flow condition. In this position both the diaphragm and valve seat are kept clean by the flushing action of the internal flow, keeping the entire sealing area free of particles which could cause leakage.


  • Patented Design: Self-sealing - they are not dependent on gravity, mounting position or reverse flow, a significant improvement over ball check valves.
  • Silent Operation: No internal sliding or loose parts to slam or vibrate, chattering is eliminated!
  • Dependability: Leak-free sealing protects against the potential hazards created by reverse flow of corrosive liquids such as acids, caustics and chlorine solutions.
  • Repetitive Long Term Sealing: Diaphragm automatically positions itself against seat in the identical location. Superior to ball check valves which often leak at lower pressures.
  • Convenience: Union nut on Series CKM simplifies valve inspection/removal with minimum piping breakdown.
  • Minimal Cracking Pressure: Diaphragm begins to open at approximately 1.0 to 1.5 PSI.
  • Cost Efficient: Designed to improve system performance and competitively priced.
  • Great Selection: Molded valves available in Geon® PVC, Kynar® PVDF, glass-filled Polypropylene, and now Corzan® CPVC. Series CK available in PTFE. Socket connection available instead of NPT threads.
  • EPDM seals available instead of Viton.