Accumulators are divided into types according to the means used to separate the air fluid chambers;
these are the diaphragm, bladder, and piston accumulators.
Diaphragm Accumulator. The diaphragm accumulator consists of two hollow, hemispherical metal
sections bolted together at the center. Notice in Figure 1-10 that one of the halves has a fitting to attach
the unit to the hydraulic system; the other half is equipped with an air valve for charging the unit with
compressed air or nitrogen. Mounted between the two halves is a synthetic rubber diaphragm that
divides the accumulator into two sections. The accumulator is initially charged with air through the air
valve to a pressure of approximately 50 percent of the hydraulic system pressure. This initial air charge
forces the diaphragm upward against the inner surface of the upper section of the accumulator.
Figure 1-10. Diaphragm Accumulator.
When fluid pressure increases above the initial air charge, fluid is forced into the upper chamber
through the system