SEPARATOR TYPE OF ACCUMULATOR. - In the separator type of air-operated accumulator, a means is provided to separate the gas from the liquid. The three styles of separators are bladder (bag), diaphragm, and piston (cylinder).

Figure 10-26 illustrates one version of an air- operated accumulator of the

bladder style. This accumulator derives its name from the shape of the synthetic rubber bladder or bag that separates the liquid and gas within the accumulator.

Although there are several different modifications of the

diaphragm style accumulator, it is usually spheri- cal in shape. Figure 10-27 illustrates an example of this type. The shell is constructed of two metal hemispheres, that are either screwed or bolted together. The fluid and gas chambers are separated by a synthetic rubber diaphragm.

A cylinder style accumulator is illustrated in figure 10-28. This accumulator contains a free-floating piston

Figure 10-26.-Air-operated bladder type of accumulator (separator type).

Figure 10-27.-Diaphragm type of accumulator.

that separates the gas and liquid chambers. The cylindrical accumulator consists of a barrel assembly, a piston assembly, and two end cap assemblies, The barrel assembly houses the piston and incorporates provisions for securing the end caps.

APPLICATION

Much of today's CESE is equipped with one or more hydraulic accumulators that serve several purposes in the hydraulic system, as described in the paragraphs below. Some of the hydraulic systems illustrated and described later in this chapter show the applications of accumulators and their relationship to other components in the system.

Shock Absorber

A liquid, flowing at a high velocity in a pipe, will create a backward surge when stopped suddenly. Even the closing of a valve will develop instantaneous pressures two to three times the operating pressure of the system. This shock will result in objectional noise and vibration, which can cause considerable damage to tubing, fittings, and components. The incorporation of an accumulator will enable such shocks and surges to be absorbed or cushioned by the entrapped gas, thereby reducing their effects. The accumulator will also dampen pressure surges caused by the pulsating delivery from the pump.