Components of a Hydraulic System

  • Explain the application of hydraulics in fluid power systems.

  • Explain the operating principles of hydraulics systems.

  • Identify the components of hydraulics systems along with their functions.

  • Compare hydraulic, pneumatic, electrical and mechanical systems.

Following are some basic components of a hydraulic system.

Pump

A pump connected to an electric motor or a diesel generator is prime mover for hydraulic circuit. Pump can be positive displacement type such as piston type, internal/ external gear pump or rotary type such as centrifugal pump. Mechanical power is converted into hydraulic power by the pump. The pump is required to move the fluid within the system.

Flow Regulator

A flow regulator or a flow control valve regulates the flow or pressure of a fluid.

Hydraulic Actuator

Hydraulic Actuator

Hydraulic power is converted to mechanical power by the actuator or piston. The actuator moves the fluid within the circuit to the work. The pressure of the fluid pushes up on the piston within the cylinder to lift the weight. A hydraulic actuator consists of a cylinder or fluid motor that uses hydraulic power to facilitate mechanical operation. The mechanical motion gives an output in terms of linear, rotary or oscillatory motion. Because liquid cannot be compressed, a hydraulic actuator can exert considerable force, but is limited in acceleration and speed.

Reservoir or tank

An area within the system that holds the hydraulic fluid. As the pump works to produce mechanical power, a supply of additional fluid is needed. The system receives this extra fluid from the reservoir.

Hydraulic pipes (or conductors)

Hydraulic power is transmitted by the fluid that is contained within the pipes.

Valves

4/3 Direction Control Valve

Hydraulic power is regulated by valves. The valves determine whether the piston rod is extending or retracting.

Solved Examples

Solved Example:

100-1-01

A double acting cylinder: (Based on MPSC AMVI Paper 3- 2002)

Solution:

A double acting cylinder can accept compressed fluid from both sides of the piston as it has ports on both sides of piston.

Correct Answer: B

Solved Example:

100-1-02

A solid (shaded) arrow or triangle in the Fluid Mechanics circuits or component symbols indicates: (Prof. Prashant More's notes MIMT3104- Pneumatics and Hydraulics- Biomedical)

Solution:

In Fluid Mechanics symbols, an empty triangle represents pneumatic direction of flow(air) whereas a solid filled black triangle represents hydraulic direction of flow (oil).

Correct Answer: A

Solved Example:

100-1-03

Hydraulic and pneumatic systems are common components of what land transportation component?

Correct Answer: A

Solved Example:

100-1-04

A hydraulic accumulator normally consists of:

Solution:
A hydraulic accumulator is a pressure storage reservoir in which a non-compressible hydraulic fluid is held under pressure that is applied by an external source. The external source can be a spring, a raised weight, or a compressed gas. An accumulator enables a hydraulic system to cope with extremes of demand using a less powerful pump, to respond more quickly to a temporary demand, and to smooth out pulsations. It is a type of energy storage device. Source: Wikipedia

Correct Answer: B

Solved Example:

100-1-05

A hydraulic intensifier normally consists of: (RSMSSB JE Mech Dec 2020)

Correct Answer: C

Solved Example:

100-1-06

Hydraulic accumulator is used for: (Based on MPSC AMVI Set A/2013)

Correct Answer: D

Solved Example:

100-1-07

Higher viscosity in a hydraulic system will cause which of the following?

Correct Answer: A

Solved Example:

100-1-08

Lower viscosity in a hydraulic system will cause which of the following?

Correct Answer: B