Industrial Hydraulic Symbol Explanation

Last updated: February 9, 2020

The industrial hydraulic symbol or just the hydraulic symbol is the first step towards an understanding of the hydraulic system. Without a basic understanding of symbols, one cannot efficiently troubleshoot the hydraulic system completely. A hydraulic system consists of cylinders, motors, valves, and pumps connected via hydraulic hoses and pipes. Due to the complexity of showing these components in a diagram we use symbols instead of absolute components.

Industrial Hydraulic Symbol

Most hydraulic industries follow standard DIN ISO 1219 for the design of hydraulic circuits, however, one can find differences in individual drawings with the company.

The symbols in a hydraulic schematic give the following information about the system:

  1. Type of Prime mover (Engine or Electric Motor)
  2. General information about pump (CC/rev & RPM)
  3. The number of connections and joints for the representation of the hydraulic flow.
  4. Different types of valve and their functions.
  5. The number of switching positions of the valves.
  6. Actuation and return method of the valves.

Although we get all necessary information from schematic and symbols, it can define the following details:

  1. The exact location of the components.
  2. Dimensions of the component.
  3. Manufacturer of the components.

Now, by keeping the intention of a hydraulic schematic in mind, one can understand the basic symbol for the hydraulic system very easily.

Basic hydraulic symbols

Pressure Line
Pressure line or Return line.
quick release coupling
Quick release coupling.
Shuttle valve
Shuttle Valve.
Pressure Gauge
Pressure Gauge.
Multiport Swivel
Multiport Swivel.
Line Junction
Line Junction.
Connection for measuring port
Connection for measuring port.

Symbols for actuation type

Actuation by pneumatic
Actuation by pneumatic (compressed air).
Actuation by spring
Actuation by spring force.
Actuation by pilot-pressure
Actuation by Hydraulic pressure.
Actuation by plunger
Actuation by the plunger.
Actuation by roller
Actuation by the roller movement.
Actuation by solenoid
Actuation by solenoid (electrically)
Actuation by electro-hydraulic
Actuation by electro-hydraulically.
Actuation by lever
Actuation by foot paddle.
Actuation by lever
Actuation by a lever.

Symbols for filters and coolers


Symbols for Valves

Pressure relief valve
Pressure Relief Valve (non-adjustable)
adjustable pressure relief valve
Pressure relief Valve (adjustable)
Check valve
Check Valve
Pilot operated check valve
Pilot Operated Check Valve.
Pressure reducing Valve
3 Port Pressure Reducing Valve

Symbols for Pump and Motor

mono direction fix displacement pump
Mono direction fix displacement pump
Mono direction variable displacement pump
Mono direction variable displacement pump
mono direction fix displacement motor
Mono direction fix displacement motor
Mono direction variable displacement motor
Bi-directional fix displacement pump
Bi-direction variable displacement pump
Bi-direction fix displacement motor
Bi-direction fix displacement motor
Bi-direction variable displacement motor
Electric Motor
Electric Motor

Symbols for Cylinders

Single acting cylinder
Single Acting Cylinder
Double acting cylinder
Double Acting Cylinder
Telescopic cylinder
Telescopic Cylinder


(Que.1) What is the hydraulic symbol for concrete pumps?

Answer: The symbol will be the same for all pumps. Concrete pumps are designed differently because it has to handle dense liquid or semi-solid materials, but the symbol will be similar. See the Symbol

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