from the reservoir, through the system, and back to the reservoir.

An air vent allows the air to be drawn in and pushed out of the reservoir by the ever-changing fluid level. An air filter is attached to the air vent to prevent drawing atmospheric dust into the system by the ever-changing fluid level. A securely fastened filling strainer of fine mesh wire is always placed below the system filler cap.

The sight gauge is provided so the normal fluid level can always be seen, as it is essential that the fluid in the reservoir be at the correct level. The baffle plate segregates the outlet fluid from the inlet fluid. Although not a total segregation, it does allow time to dissipate the air bubbles, lessen the fluid turbulence (contaminants settle out of nonturbulent fluid), and cool the return fluid somewhat before it is picked up by the pump.

Reservoirs used on CESE may vary considerably from that shown in figure 10-23; however, manu- facturers retain as many of the noted features as possible, depending on design limits and use.

ACCUMULATORS

Hydraulic accumulators are incorporated in some hydraulic systems to store a volume of liquid under pressure for subsequent conversion into useful work or to absorb rapid fluid pulsations when valves are operated repeatedly. Two types of accumulators are the spring operated and the air operated.

Spring-Operated Accumulator

In this type of accumulator, the compression resulting from the maximum installed length of the spring or springs should provide the minimum pressure required of the liquid in the cylinder assembly. As liquid is forced into the cylinder (fig. 10-24), the piston is forced upward and the spring or springs are further compressed, thus providing a reservoir of potential energy for later use.

Air-Operated Accumulators

The air-operated accumulator is often referred to as a pneumatic or hydropneumatic accumulator. This type of accumulator uses compressed gas (usually air or nitrogen) to apply force to the stored liquid. Air-operated accumulators are classified as either nonseparator or separator types.

Figure 10-24.-Spring-operated accumulator.

NONSEPARATOR TYPE OF ACCUMULATOR. - In the nonseparator type of accumulator (fig. 10-25), no means are provided for separating the gas from the liquid. It consists of a fully closed cylinder, mounted in a vertical position, containing a liquid port on the bottom and a pneumatic charging port (Schrader valve) at the top.

Figure 10-25.-Air-operated accumulator (nonseparator type).