The sequence valve is used to ensure that a certain pressure level is achieved in one branch of the circuit before a second branch is…
Month: December 2009
There is a type of unloading valve identified as a differential unloading valve. This valve is designed to allow the accumulator to partially discharge before…
In the circuit in Fig. 3.15, the pump builds pressure in the accumulator until the setting of the unloading valve is reached. At this point,…
The symbol for an unloading valve is similar to the symbol for a relief valve except that the pilot line is not connected to sense…
A pilot-operated relief valve can be used to unload the pump at low pressure during periods between work cycles. The schematic in Fig. 3.10 shows…
A pilot-operated relief valve has the same function as a direct-acting relief valve; however, it has a different pressure vs. flow curve. The performance curves…
A schematic of a direct-acting relief valve is shown in Fig. 3.4. Pressure acts on the annular area of the valve spool. The hydraulic force…
ANSI symbols are introduced here as they are needed. The directional control valve symbol is the most intuitive and selfexplanatory of the symbols. Some experience…
Pressure control is a key element in the design of any circuit. Not only is it the key to achieving a given functional objective, it…