neoperl - flow, stop and go
Working principles
Check valves static conditions (no flow)
Check valves dynamic conditions (flow)
Check valves backflow conditions (reversed flow)

Working Principles

In static conditions (no flow)
The check valve is normally closed. The spring tension forces the plunger into its seat keeping the check valve closed.

In dynamic conditions (flow)
The water pressure exceeds the spring tension. The plunger
is lifted off its seat allowing water to flow through the valve.

In backflow conditions (reversed flow)
If the pressure downstream of the valve increases (back pressure conditions) or if the system pressure upstream of the valve decreases (backsiphonage conditions) causing the flow to reverse direction, the spring-loaded plunger closes and prevents backflow.