-Operates hydraulically independent from any external power sources and controls high and low levels in a storage tank by utilizing the line static and dynamic pressure. -The incorporation of a control shaft in the valve bonnet allows the rate of flow through the valve to be set a pre-determined flow and also acts as a mechanical shut off feature. -Closing speed of the valve can be controlled by an integral needle valve on the valve bonnet. -The valve is easy to maintain and install due to its simple design.
