In most cases, the gas is separated from the oil by a piston (fig. 3-31), a bladder (fig. 3-32), or a diaphragm (fig. 3-33). This prevents mixing of gas and oil, keeping gas out of the hydraulic system.

WEIGHT-LOADED ACCUMULATORS.- The weight-loaded accumulator uses a piston and cylinder along with heavy weights on the piston for loading or charging the oil. It is loaded by gravity and operation is very basic. The pressure oil in the hydraulic circuit is pushed into the lower section of the cylinder, raising the piston and weights. The accumulator is now charged and ready for work. When oil is needed, pressure drops in the system and gravity

Figure 3-31 .- Floating piston-type accumulator.

Figure 3-32.- Bladder-type accumulator.

Figure 3-33.- Diaphragm accumulator.

disadvantage is its bulky size and heavy weight which renders it not practical for mobile equipment.