The stainless steel Shuttle Valve is a two inlet, one outlet device utilizing a free moving shuttle which blocks one of two inlet ports while allowing the unblocked inlet port to flow to the outlet.
When a pressure signal is applied to one of the inlet ports, the shuttle shifts blocking off the opposite inlet port and flow exits through the outlet. The shuttle stays in this condition until the original signal is removed or a higher pressure signal is applied to the opposite inlet port. In logic terms, a shuttle valve is an “OR” function.