will make you familiar with hydraulic and Pneumatic system

2. Hydraulic system
 a movable piston connected to the output shaft in an
enclosed cylinder
 storage tank
 filter
 electric pump
 pressure regulator
 control valve
 leak proof closed loop piping.

4. Applications of Hydrulic systems
 Industrial: Plastic processing machineries, steel
making and primary metal extraction applications,
automated production lines, machine tool industries,
paper industries, loaders, crushes, textile machineries,
R & D equipment and robotic systems etc.
 Mobile hydraulics: Tractors, irrigation system,
earthmoving equipment, material handling
equipment, commercial vehicles, tunnel boring
equipment, rail equipment, building and construction
machineries and drilling rigs etc.


5. Applications of Hydrulic systems
 Automobiles: It is used in the systems like breaks,
shock absorbers, steering system, wind shield, lift and
cleaning etc.
 Marine applications: It mostly covers ocean going
vessels, fishing boats and navel equipment.
 Aerospace equipment: There are equipment and
systems used for rudder control, landing gear, breaks,
flight control and transmission etc. which are used in
airplanes, rockets and spaceships.


6. Advantages
 The hydraulic system uses incompressible fluid which
results in higher efficiency.
 It delivers consistent power output which is difficult in
pneumatic or mechanical drive systems.
 Hydraulic systems employ high density incompressible
fluid. Possibility of leakage is less in
hydraulic system as compared to that in pneumatic
system. The maintenance cost is less.
 These systems perform well in hot environment
conditions.

7. Disadvantages
 The material of storage tank, piping, cylinder and
piston can be corroded with the hydraulic fluid.
Therefore one must be careful while selecting
materials and hydraulic fluid.
 The structural weight and size of the system is more
which makes it unsuitable for the smaller
instruments.

8. Disadvantages
 The small impurities in the hydraulic fluid can
permanently damage the complete system, therefore
one should be careful and suitable filter must be
installed.
 The leakage of hydraulic fluid is also a critical issue
and suitable prevention method and seals must be
adopted.
 The hydraulic fluids, if not disposed properly, can be
harmful to the environment.

9. Types of valves
 Directional control valves
 Flow control valves
 Pressure control valves

10. Directional Control Valve
 Directional control valves are used to control the distribution of
energy in a fluid power system. They provide the direction to the
fluid and allow the flow in a particular direction. These valves are
used to control the start, stop and change in direction of the
fluid flow. These valves regulate the flow direction in the hydraulic
circuit. These control valves contain ports that are external openings
for the fluid to enter and leave. The number of ports is usually
identified by the term ‘way'. For example, a valve with four ports is
named as four-way valve. The fluid flow rate is responsible for the
speed of actuator (motion of the output) and should controlled in a
hydraulic system. This operation can be performed by using flow
control valves. The pressure may increase gradually when the system is
under operation. The pressure control valves protect the system by
maintaining the system pressure within the desired range. Also, the
output force is directly proportional to the pressure and hence, the
pressure control valves ensure the desired force output at the actuator.

11. Directional control valves
Directional control valves can be classified in the
following manner:
1. Type of construction:
 Poppet valves
 Spool valves
2. Number of ports:
 Two- way valves
 Three – way valves
 Four- way valves.

12. Directional control valves
3. Number of switching position:
 Two – position
 Three - position
4. Actuating mechanism:
 Manual actuation
 Mechanical actuation
 Solenoid actuation
 Hydraulic actuation
 Pneumatic actuation
 Indirect actuation