pressure port, pushing the diaphragm down and further compressing the air in the bottom chamber.
Under peak load, the air pressure in the lower chamber forces fluid back into the hydraulic system to
maintain operating pressure. Also, if the power pump fails, the compressed air forces a limited amount
of pressurized fluid into the system.
Bladder Accumulator. The bladder accumulator operates on the same principle and for the same
purpose as the diaphragm accumulator but varies in construction, as shown in Figure 1-11. The unit is a
one-piece metal sphere with a fluid pressure inlet at the top and an opening at the bottom for inserting
the bladder. A large screw-type plug at the bottom of the accumulator is a retainer for the bladder that
also seals the unit. A high-pressure air valve is also incorporated in the retainer plug. Fluid enters
through the system pressure port. As fluid pressure increases above the initial air charge of the
accumulator, it forces the bladder downward against the air
Figure 1-11. Bladder Accumulator.