Pre-fill - exhaust valve/ Sandwich (FPV)
Pre-fill valves are check valves with hydraulic (pilot) release function. They are also referred to as exhaust valves and are generally installed between a cylinder and oil reservoir in hydraulic presses and injection moulding machines where high speed operation is required. The use of these valves enables the manufacturer to use a smaller capacity pump and motor and at the same time achieve the expected cycle time of the equipment.
During the high speed forward stroke of cylinder, the pre-fill valves pulls a large amount of oil from the reservoir needed to fill the cylinder and the main pump-motor now sized optimally is used to achieve the required pressure. During pressurisation, the valve closes completely and prevents reverse oil flow. For the return stroke, the valve is opened by supplying a pilot pressure that opens the path back to reservoir and retract the cylinder. The decompression feature is built-in to the valve to enable controlled pressure release.
FPV valves have a unique sandwich design that enables the valve to be mounted between sandwich flanges and comes with decompression feature as standard across the range up to NG 200.
