Differential Unloading Relief Valve
When the accumulator is activated, the piston is made to go toward the pilot dart and makes the pilot dart go off its seat. When this happens it lets go of the main spool spring chamber of the pilot pressure. Then the valve is vented. This makes the spool move up and gives way to the flow that goes into the tank at a low pressure. And simultaneously the check valve closes so that the accumulator can’t release thru the relief valve.
At this time only one pressure has been had at maximum pressure. The differential piston goes in a bore that is on the other side of the pilot valve dart. The ends of the pistons that are unprotected by the pressure are the same. And it is the same pressure when the accumulator is being activated.
If you need more info on this subject, call 800-361-0068