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Check Valves & Vacuum Breakers
All True Blue Check Valves feature rugged thermoplastic construction with no wetted metal parts. As your assurance of quality, each valve is individually tested under pressure by a Plast-O-Matic inspector prior to shipment.
The patented diaphragm in the Plast-O-Matic True Blue Check Valve is designed to re-seat with a bubble tight seal regardless of mounting position or reverse flow. Ball style check valves require two properties to seal properly: First, the ball check must be mounted with the flow direction pointed up, because gravity is required to pull the ball to the seat. Secondly, some reverse pressure and flow must be present, because pressure is required to seal the ball exactly on the seat.
If either of these conditions are not met, the ball check will leak! On the other hand, the Plast-O-Matic diaphragm check will seal in any position, whether or not flow is present.
Here's a Simple Test: Take a Plast-O-Matic diaphragm check valve and place it flow arrow up on a paper towel. Pour a small amount of water into the outlet, lift up the valve, and you will see that it has remained absolutely sealed -- no evidence of dampness on the paper towel. Now take any ball-style check valve and perform the exact same test -- just be sure to have extra paper towels on hand!
Series CKM provides unbeatable performance with absolute zero leakage
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 Geon® PVC, Corzan® CPVC, Glass-filled polypropylene, and Kynar® 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 0,07 to 0,1 bar.
• Maximum working pressure is 10 bar inlet, 7 bar backpressure at 25°C, except Glass-filled polypro which is
rated 7 bar inlet.
• No metal parts internally or externally.
Series CK is a self-sealing PTFE bodied check valve
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 0,07 - 0,1 bar.
• 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.
• Maximum working pressure is 2,7 bar inlet, 2,7 bar backpressure at temperatures to 85°C.
• No internal metal parts; external fasteners are stainless steel.
Series CKS Self Closing Check Valves
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 0,07 to 0,1 bar.
• Maximum working pressure is 0,5 bar at 25°C.
• 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 for check valves that perform well in very low flow applications
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 10 bar in PVC, 8,5 bar in natural polypro, and 7 bar in Kynar and PTFE.
• Minimal cracking pressure required.
Vacuum breakers protect storage tanks against implosion
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.
If, as in most applications, you are simply mounting the valve on top of a tank to use as a vacuum breaker, it is recommended to use a Plast-O-Matic Vacuum Breaker designed for that purpose. The specially fitted and tested dust cover prevents unwanted particles from entering the tank, and also prevents errant debris or tools from lodging in the valve and opening it.
Just as the check valve remains closed against reverse flow, the vacuum breaker diaphragm (Series VBM) or poppet (Series VBS) remains closed regardless of the pressure within the tank. As negative pressure is created, however, the vacuum pulls the valve open, and atmosphere is drawn in. As soon as the vacuum condition is eliminated by an appropriate amount of air drawn into the tank, the lack of negative pressure on the diaphragm causes it to close again.
• Available in Geon PVC, Corzan CPVC, Natural polypro, PTFE, Glass-filled polypro and Kynar PVDF;
• Series VBM is based on CKM, above, in sizes 1/2", 3/4" & 1".
• Series VB is a based on CK, above, PTFE only in sizes 3/4" & 1".
• Series VBS is a very high capacity vacuum breaker based on CKS, above, in sizes 1-1/2", 2" & 3".
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.
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