Reserve System

System consists of a charging valve, accumulator valve, and a compressed gas accumulator. System is open to pressure port of booster unit. Charging valve has an orifice and ball check. Fluid from pump passes through orifice in valve, and if pressure exceeds pressure in accumulator, it unseats ball check valve and enters accumulator. Ball check valve prevents reverse flow when accumulator pressure is greater than pump pressure.

Accumulator valve is a poppet type valve held closed by pressure stored in accumulator. An actuator on spool valve sleeve opens accumulator valve when a stop with no pump pressure is made that requires use of reserve pressure.

Fluid pressure can also enter accumulator from boost chamber through accumulator valve, when boost camber pressure exceeds accumulator pressure. A pressure relief valve vents accumulator to the pump return port when pressure in accumulator exceeds 1600 psi.