Pump Preload Valve for Axial Piston Pumps

Pump Preload Valve for Axial Piston Pumps  

Some variable displacement pumps, such as the Parker PV series axial piston pumps, require a minimum pressure of 20 bar for proper operation. This can be applied by a preload valve. The Wessel preload valve is available in connection sizes ¾” to 1 1/4″. It is mounted as an intermediate block directly onto the pump connection. In the valve, the flow is preloaded by a valve cone. The preload pressure is applied constantly and without loss by a pressure reducing valve. The valve is typically set to 20 bar. If the pump pressure exceeds the preload pressure, the valve opens completely and the volume flow is passed on with virtually no loss. Two connections P1 and MP are available upstream of the preload valve, from which a pilot pressure supply could be tapped, for example.