Flow Coefficient Notes
A couple of times recently people have tried to apply flow coefficient (Cv) to low pressure flow. The flow coefficient is the amount of water that will flow through a device (or length of pipe, etc) in one minute with a one psi pressure drop.
[See the Airpinch website and open the Flow Capacity link on the left side of the opening page to find out more about Cv]
At low pressures, like gravity feed, Cv values are not accurate. In the extreme, if there is only one psi head pressure, then conceptually there will be no flow out of the valve ---- because 1 psi minus a 1 psi pressure drop = zero psi or no flow.
Image from www.rtlyrics.net ---- where they got it I have no idea.
