Wayne Parham Messages: 18786 Registered: January 2001
Illuminati (33rd Degree)
That's right, no moving parts. The pressure differential is low, but flow is more restrictive one way than the other, so it creates unidirectional flow. There are an assortment of flapper valves we could have used, and a variety of opening pressures. But the valves we chose don't seal, they work on a pressure differential instead.