Hydraulic Symbols

Piping and Tubing Symbols Normal working line Flexible working line Pilot line Drain line Enclosure outline Direction of flow

Crossing lines Joining lines

Reservoirs Reservoir Connecting lines above fluid level Connecting lines below fluid level Sealed Open

Basic filter/strainer Separator Filter-separator Manual Automatic Fluid conditioning symbols are a diamond shape

Cooler Liquid Gaseous Heater Temperature controlled

Pressure Temperature Flow meter, rate Flow meter, totalizing Float switch Nozzle Pressure Switch

Pumps Fixed displacement Unidirectional Bidirectional Variable displacement, non-compensated, unidirectional Variable displacement, non-compensated, bidirectional

Pumps Variable displacement, pressure-compensated, unidirectional Variable displacement, pressure-compensated, bidirectional M Electric Motor Internal combustion

Motors Fixed displacement, unidirectional Fixed displacement, bidirectional Variable displacement, unidirectional Variable displacement, bidirectional

Valves Normally closed, two-way, two port Normally closed, two-way, two position, two port Normally closed, four way, three position, four port

Valves Normally open, two-way, two position, two port Normally open, two-way, three position, three port Normally open, four way, three position, four port Normally open, four way, infinite position, four port

Relief Valve Represents the pilot line Pressure Side Valve normally closed Spring loaded Variable When open, goes to tank Valve is regulated by the feed pressure

Pressure Reducing Valve Pressure Side Represents the pilot line Valve normally open Spring loaded Variable Discharge side goes to line Valve is regulated by the discharge pressure

Valves Relief Valve Sequencing Valve Pressure Reducing/Regulating Valve

Valves Orifice V Timing logic Check valve

Valves Flow control with bypass, pressure compensated Flow control with bypass, pressure and temperature compensated

Valves Counterbalance Valve Unloading Valve

Controls Push Button Lever Pedal Cam Solenoid Liquid pilot Gas pilot Servo Pilot or solenoid Pilot and solenoid activated, spring return

Cylinders Single acting Single acting, spring return Double acting Double acting, double rod Double acting, single cushion Double acting, Double cushion Double acting, double adjustable cushion Telescoping Ram Pressure intensifier