The Preset Valve is of a pilot operated, hydraulically actuated design, which ensures an easy opening and two stage cushioned closure. It consists of a main valve and a pilot valve. The pilot valve is connected to the preset register through an adjustable linkage.
To commence operation, the required delivery quantity is set on the preset register by the help of push buttons. The flow meter counter is reset to zero. Liquid delivery is initiated by pulling the preset handle. This actuates the linkage to move the pilot valve, which drains the pressurised liquid in the main valve causing a pressure drop across the main valve to open it.
At the end of the delivery the preset register knock-off plate gets released in two stage moving the linkage connected to it and allowing the main valve to gradually close in two stages. The rubber bonded seal fitted on the main valve ensures a bubble tight shut-off. The cushioning action of the valve is adjustable with the help of a needle valve fitted on the pilot valve cover