Patent attributes
A valve arrangement for placing a supply of motive fluid in alternating communication with first and second motive fluid chambers. The valve arrangement includes a power valve including a supply chamber, a pilot chamber, and a shiftable member separating the supply chamber from the pilot chamber. The valve arrangement also includes a pilot valve actuable between an on condition in which the pilot valve generates a pilot signal that shifts the power valve, and an off condition in which the pilot valve does not generate the pilot signal. At least a portion of the pilot valve is exposed to motive fluid, and the portion of the pilot valve exposed to motive fluid includes surface areas giving rise to a net zero actuating force arising from pressure of the motive fluid. Because there is no biasing force on the pilot valve, the pilot valve is shifted between the on and off conditions without significant resistance.
