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

SealedOpen

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

MotorsFixed 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

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