ABSTRACT
A hydraulic reservoir can be pressurized at some low pressure (≈3 bar), but most often is designed to operate at atmospheric pressure. In addition to holding the supply of fluid needed to fill all lines and components, it separates entrained air, dissipates pressure pulses, provides cooling, and traps contaminants.
Three types of conductors are used to route the fluid in hydraulic circuits: pipe, tubing, and hose. For normal service, the working pressure is one-fourth of the burst pressure; thus, the design ratio is 4:1. Severe applications require a 6:1 ratio, and severe applications in a hazardous environment require an 8:1 ratio.
It is recommended that the lines be sized such that the velocity in pressure lines does not exceed 4.5 m/s. Recommendations for the return line and suction line are 3 and 1.2 m/s, respectively.
Manifolds can be used to simplify the assembly of a circuit. Cartridge valves for all types of pressure control are available for installation in machined cavities in a manifold. Also, manifolds can be stacked to assemble a complex circuit in a confined space.
