A small check valve fitted to steam engines and hydraulic systems that automatically opens to release air or non-condensable gases. It operates by pressure differential, drawing in air to prevent a vacuum or expelling trapped air that would otherwise cause vapor lock or reduce the efficiency of the stroke. The name comes from the distinct sniffing sound it makes during operation.
The pump is cavitating because the snifting valve is stuck shut and air is building up in the chamber.
Also heard as
- snifter valve
Related terms
Pump valve
A mechanical barrier that directs or restricts fluid flow within a pumping system.
Poppet valve
A directional valve consisting of a flat disk on a stem that lifts away from its seat to permit flow.
Cylinder
The tubular chamber in which a piston travels to compress a fluid or convert fluid pressure into mechanical work.