Dispensing Valves, Head-pressure Valves

Dispensing valves and Head-pressure valves are in fact the same as pressure-relief valves except that they are used upside down. They stay shut until a certain pressure is reached and then open. This way they can keep a fluid head or pressure above the valve and start opening/metering when the fluid head or pressure gets higher. Examples are for instance non-dripping valves in a shampoo dispenser or an anti-bolus valve in an enteral nutrition delivery set. One should distinguish dispensing valves which are two-way allowing air to suck back, for instance in a plastic dispensing bottle and dispensing valves that are just one-way.

For this kind of applications one can use