Anti-Siphon Valve, 1/2" NPT, PVDF

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ASV50 Anti-Siphon Valve, 1/2" NPT

The ASV Anti Siphon Valve is an anti suction device for pump dispense and injection applications for chemical or other liquids. In the forward flow direction, the ASV behaves similarly to a check valve with a cracking pressure of 5 PSI. Unlike a check valve, fluid flow is blocked when suction is applied to the outlet regardless of how strong the suction is. The ASV does not prevent backflow of fluid and should be used in conjunction with a check valve in most cases for this reason. The ASV will prevent siphoning due to gravity, or in situations where suction is present at the chemical injection point such as the suction side of a pump in a CIP loop.

Constructed of injection molded PVDF polymer, its durable construction ensures durability and a broad range of chemical compatibility. A non-wetted 316 stainless steel spring controls the opening and closing of the diaphragm which is available as EPDM, Silicone, or Viton. The diaphragm and spring are easily serviceable by simply unscrewing the top cap by hand. No small metallic fasteners to deal with!

Review our chemical compatibility chart for best use cases or contact your chemical manufacturer.

Available as single valve or kit with hose barbs (3/8" and 1/2") and hose clamps



  • Prevents tank siphoning and suction
  • 1/2” NPT inlet and outlet with flow indicator
  • Larger inlet than traditional anti-siphon or suction valves (pancake valves)
  • Flows more than other anti-siphon or suction valves
  • Easy to remove diaphragm (no hardware or metallic fasteners)
  • Integrated splash guard
  • Durable constructions (PVDF and 316 SS)
  • Able to be serviced while installed in-line



Material of Construction PVDF and 316SS
Diaphragm Materials  Viton, EPDM, or Silicone
Opening (cracking) Pressure 5 PSI
Inlet Size 1/2" NPT



Install hose fittings/pipe adapters as necessary and place in-line, after pump, above the fluid level and/or the highest point in the hose/pipe run. Not recommended for bulk containers.



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