These unloader valves are used to divert pump flow to a secondary circuit when pressure in the priority line reaches a pre-set level. The valves will close, causing the circuit to reload, when the pressure drops to approximately 85% of the unload pressure. The most common application is to maintain a pressure in an accumulator which may be used in an emergency to operate an essential hydraulic function (eg, a brake circuit). This valve has a drain port to ensure correct valve function while allowing the bypassed oil to be used for a secondary circuit requirement. eaton engine valves eaton valves 1PUL250 eaton valves india 1PUL200 PRIORITY UNLOADING VALVE PILOT OPERATED - SLIDING SPOOL TYPE vickers unloading valve eaton flow control valve eaton hydraulics eaton vickers eaton ball valve