Pressure Unloading Valve series DWPB-4N

Series DWPB-4N… cartridges are size 4, two stage, high performance pressure-unloading valves with an 3/4-16 UNF mounting thread. They consist of a spool-type main stage and a leak-free, ball-type pilot stage. Unloading valves are used wherever a pump has to be disconnected from and re-connected to a pressure circuit. For this purpose, either the ‘Off’ pressure or the ‘On’ pressure of the cartridge can be set. When the ‘Off’ pressure is set, the ‘On’ point will depend on the selected percentage on-off differential, or the other way round. To disconnect the pump, the cartridge responds to rising pressures at ports 4 and 1 by opening the connection from 4→3. This connection is then kept open until the selected percentage on-off differential is reached (falling pressure at port 1) and the connection 4→3 closes again (the ‘On’ point).