Bi-Directional Valves/Seals

How Do Bi-Directional Valves Work?

Dome shaped all-rubber valves open more easily in one direction than the other
Slit at top of dome opens more easily when pressure is applied on the dome inside
Opening in the reverse direction (pressure outside dome) requires buckling
Can be engineered with two specific opening pressures based on shape/thickness
Flow is always more restricted than with duckbill and umbrella valves
Valve is mounted by the flange the same way a duckbill is mounted
Often used not as a valve but rather as a catheter seal (seals around a probe / pipe)