Fluid Power System Types and their Components

Fluid Power System

Fluid Power System: A fluid is a substance, It capable of flowing. Therefore the fluid can be either a liquid or gas. It used to development of power transmission, control and utilization. When the fluid is transmitted with high pressurized. Also fluid power is defined as technology that deal with generation, transmission and control of power using pressurized fluids.

Types of Fluid power system

The Fluid power system is divided in to two types. They are hydraulic and pneumatic system depends upon the fluid medium used to transmit force.

  • The hydraulic fluid power system employs liquid (like as water, petroleum oils and synthetic oils) as fluid medium.
  • The pneumatic fluid power system employs gas (Compressed Air) as the fluid medium.

Hydraulic Fluid Power System

The Hydraulic fluid power system uses the pressurized liquid as fluid medium. Also Hydraulic system always a closed loop system.

Arrangement of Hydraulic system

It consists of six basic components.

Reservoir or Tank:

It is an oil storage and supply tank.


The pump is used to forcing the liquid into the system.

Prime Mover:

Prime mover usually an electric motor, It used to drive the pump.


Valves are fitted in the system to controlling the liquid pressure, direction and flow rate.

Fluid- transfer pipe:

It provides to carry the liquid from one place to another.


The Actuator usually works for convert the liquid energy into mechanical force or torque into work. It is a working element of overall hydraulic system. The Actuator can be either Hydro motors (provide rotary motion) or cylinder (Provide linear motion).

Hydraulic Fluid power system
Hydraulic Fluid power system

Working of hydraulic cylinder (Actuator):

The Arrangement of hydraulic system as shown in figure.  It may be consist of a moving piston connected to output shaft and two parts A & B. If liquid pumped through a port A, the piston move up and then if liquid pump through port B, the piston move down. When the pressurized liquid is pumped at one side of piston, then non-pressurized liquid on other side of piston must retrieved go back to liquid tank or reservoir.

Working of overall hydraulic system:

The overall hydraulic system for task of moving weight (W) by distance (D) as shown in figure. The part will be enclosed in the dotted line box are common to plant area. Which have many linear and rotary actuator. In this reason, we use only one linear actuator.

The Motor (M) drives the pump (P), when the fluid is pumped from reservoir at required pressure. The Fluid circulated into system should be clean to reduce wear of cylinder and pump; hence a filter is used to reservoir. The pump deliver constant volume of fluid for each shaft revolution, the pressure of fluid rises indefinitely, until a pump or pipe itself fails. To avoid in this case, pressure regulator is used to spill out the excess fluid back to tank.

The cylinder is controlled by three position control valve. When the valve one side is connected to a pressurized fluid line and fluid retrieval line; and other side is connected to port A, Port B of the cylinder. The hydraulic liquid transferred from reservoir to one side of piston and other side piston fluid is retrieved to the storage tank.

Valve Position

Raise: To life the weight, the pressurized fluid line have to be connected to port A and retrieval line has to be connected to Port B, by means of moving the valve position to ‘Raise’.

Lower: To bring down the weight, the pressurized fluid line connected to Port B and retrieval fluid line to be connected to port A, by means of valve position moved to ‘lower’.


The weight stopped at particular position by moving the valve to ‘Off’. So, this disconnects the port A & Port B from the pressurized and retrieval line, which locks the fluid in Cylinder.

Pneumatic fluid Power System

The pneumatic Fluid power systems are uses the compressed air as its fluid medium. It always an open loop system.

Arrangement of pneumatic system:

The general arrangement of basic pneumatic system is shown in fig.

Pneumatic fluid Power System
Pneumatic fluid Power System
Basic component of pneumatic system

It having six basic components illustrate as shown in fig. The basic components and its function detailed as blow.

Reservoir (or Air Tank):

It stored the compressed air required for the operation.


The compressor is used o compress the incoming atmosphere Air and increased air Pressure.

Prime Mover:

An prime mover, usually an electric motor, it is used to drive the compressor.


Valves are fitted in the system, it used to control air direction, pressure and flow rate.


An actuator is providing to convert the air energy into mechanical force or torque to do useful work.

Fluid-transfer piping:

Piping is providing to carry the compressed air from one place to another.


The overall pneumatic system for the task of lifting a weight (W) by a distance (D). The parts enclosed in the dotted line box considered as common to an area of plant, which may be linear and rotary actuator. For this case, We can use only one linear hydraulic actuator.

Air is drawn from the Atmosphere through air filter and raised for required pressure by an air compressor. Air contain sufficient amount of water vapour and temperature of air raised considerably by compressor. So Air will be cooled before using in this system, which result as condensation. The air is stored in reservoir , it have water outlet a bottom and pressure switch to control the compressed air pressure (By means of control the motor). The motor is stopped by pressure switch when the required pressure is attained and the motor started when the pressure fall down the mark level.

.  The reservoir outlet is connected to F.R.L. Unit ( Filter – Regulator – Lubricator), which having activities as follow,

  • Filter the tiny particles from compressed air
  • Regulate the pressure of air before entering the pneumatic system
  • Lubricates the compressed air for pneumatic cylinder.

The pneumatic valve is controlled the cylinder movement. When the cylinder one side of pneumatic valve is connected to compressed air line (Exhaust Air ) and other side of valve is connected to port A and Port B of cylinder


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