Dole valve

The Dole Flow Control Valve is designed to deliver a constant volume of water flow over a wide pressure drop range. [ [http://www.eddington-ind.com/gallery4.htm Dole Valves ] ] The constant flow of water is maintained by the use of a flexible orifice.

The Dole flow control valve looks like a normal pipe coupling with a flexible orifice inside that restricts the gallons per minute that can flow through the Dole valve. [ [http://www.do-it-yourself-pumps.com/dole-flow-control-valves.htm Dole flow control valves are metering valves to control allowing only a specified amount of water per minute through the valve ] ] It is often used on the discharge of well water pumps. As the pressure increases, the orifice flexes to maintain the target flow rate.

Some Dole valves operate as a thermo-bleed valve. As the temperature gets colder, the valve opens wider to allow flow and to prevent freezing in the pipe. [ [http://www.backwoodshome.com/articles/hackleman64.html Radiant floor heating by Michael Hackleman Issue #64 ] ]

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