PLASTIC CHECK VALVES

Series CKM:

Unsurpassed performance in a plastic check valve. Patented diaphragm design provides the ultimate normally-closed, zero reverse-flow valve. Available pipe sizes 1/2" 3/4" and 1". Body materials are GeonŽ PVC, CorzanŽ CPVC, Glass-filled polypropylene, and KynarŽ PVDF. Seal materials are EPDM and FKM.

• Self-sealing -- not dependent upon gravity, mounting position or reverse flow.
• Leak-free sealing protects against the hazards of reverse flow.
• Rapid closure helps to eliminate sudden back-flow water hammer.
• Union nuts simplify inspection/removal with minimal piping breakdown.
• Minimal Cracking Pressure: Valve begins to open for desired flow at approximately 1.0 to 1.5 PSI.
• Maximum working pressure is 150 PSI inlet, 100 PSI backpressure at 77° F, except Glass-filled polypro which is rated 100 PSI inlet.
• No metal parts internally or externally.

Series CK:

Unsurpassed performance in a plastic check valve. Patented diaphragm design provides the ultimate normally-closed, zero reverse-flow valve. Available pipe sizes 3/4" and 1". PTFE Body; seal materials are EPDM and FKM.

• Self-sealing -- not dependent upon gravity, mounting position or reverse flow.
• Leak-free sealing protects against the hazards of reverse flow.
• Rapid closure helps to eliminate sudden back-flow water hammer.
• Minimal Cracking Pressure: Valve begins to open for desired flow at approximately 1.0 to 1.5 PSI.
• Generally the same as Series CKM. Series CK is simply a PTFE bodied version with the same diaphragm design and performance of CKM, but it has no union nut feature (Body requires wrench for disassembly and seal replacement).
• Maximum working pressure is 40 PSI inlet, 40 PSI backpressure at temperatures to 185° F.
• No internal metal parts; external fasteners are stainless steel.

Please click here for complete specifications (a web page specific to Series CK & CKM)

Series CKS:

Unsurpassed performance in a plastic check valve. Unique poppet and PFA encapsulated spring design emulates the CKM diaphragm and provides the ultimate normally-closed, zero reverse-flow valve. Available pipe sizes 1-1/2" 2" and 3". Body materials are Geon PVC, Corzan CPVC, Natural polypropylene, and Kynar PVDF. Seal materials are EPDM and FKM (Viton).

• Self-sealing -- not dependent upon gravity, mounting position or reverse flow.
• Leak-free sealing protects against the hazards of reverse flow.
• Rapid closure helps to eliminate sudden back-flow water hammer.
• Union nuts simplify inspection/removal with minimal piping breakdown.
• Minimal Cracking Pressure: Valve begins to open for desired flow at approximately 1.0 to 1.5 PSI.
• Maximum working pressure is 100 PSI at 77° F.
• No exposed metal parts. Spring is PFA encapsulated steel...note that this is preferable to coating; encapsulation eliminates the possibility for "flaking" and exposure of the metal. No other metal parts are used.

Series CKD:

These 1/4" & 1/2" valves utilize a flexible elastomer disk as opposed to Plast-O-Matic's patented diaphragm. The advantage is that the CKD requires even less pressure than the CKM to open. The drawback, of course, is that it is dependent on some reverse pressure for sealing assistance, and in low flow applications requires gravity to seal (install with flow direction "up"). But please note that when used for liquids with a high specific gravity, the disk may "float," so it is therefore recommended to install with flow direction "down" with those types of liquids. Also note that in 1/2" piping systems where high flow is required, the 1/2" Series CKM check valve should be used, unless the super low cracking pressure of Series CKD is absolutely a requirement. Flow performance of 1/4" size exceeds the recommended flow rates for fractional size tubing.

• Very compact; slim design -- not much larger diameter than corresponding pipe size.
• Available in Geon PVC, Natural polypro, PTFE and Kynar PVDF;
• Sizes 1/4" & 1/2".
• Seals in EPDM or Viton.
• High performance, heavy-duty design.
• Maximum pressure is 140 PSI in PVC, 125 PSI in natural polypro, and 100 PSI in Kynar and PTFE.
• Minimal cracking pressure required.

Vacuum Breakers:

The operating principle of check valves and vacuum breakers is identical: both are one way valves that open only in the direction you desire, and remain closed under reverse pressure. But the specific use of a check valve in place of a properly capped vacuum breaker is not recommended -- unless it is used in combination with a pipe (in lieu of the dustcap) for drawing air or other desired fluid from a remote location, or in combination with a pipe to "vent" emissions in the event that a valve sticks open due to trapped debris.

Anti-Siphon Applications

Sometimes users will install a check valve after a pump, in a line with a significant altitude drop downstream of the check valve. Their intention is that when the pump is switched off, the absence of positive flow will cause the normally-closed check valve to close -- and it will indeed close. But because of the system design, a pressure drop is created, resulting in negative pressure: A vacuum. Because this type of check valve is the basis for an extremely effective vacuum breaker (see above) it naturally opens, and permits unwanted flow through the pump head and is now a fully open check valve.

In this type of application, an Anti-Siphon Valve is the correct product to use. The anti-siphon valve can be set to open at higher pumping pressures, and actually closes more tightly in the event of negative downstream pressure.
• Please click here if you need to know more about anti-siphon applications; please click here for a web page on Series RVDT Anti-Siphon Valves.

Pump Prime Applications

Plast-O-Matic normally-closed check valves are ideal for maintaining pump prime when the liquid source is below the elevation of the pump. Series CKS or CKM should be installed between the pump and the lower elevation source, permitting flow to the pump but not back to the tank. The valves thus provide a bubble tight seal to trap liquid in the pump, preventing loss of prime.

The check valve most suited to this application is Series CKS. As listed above, Series CKS uses a PFA encapsulated spring and poppet to provide a positive, repetitive seal. This enables the valve to close with less liquid loss, and provides greater versatility in system design.