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Fluid Power
Pneumatics
Hydraulics
Fluid Power
 Fluid power is the
technology that deals
with the generation,
control, and
transmission of
pressurized fluids.
Practical Uses
 Transport fluid
Delivering the fluid from one location to
another to achieve a useful purpose.
An example of this in the case of
hydraulics in a lube oil or grease system
to provide oil or grease to lubricate
bearings on heavy equipment.
Practical Uses
(cont..)
 Transport energy
In this case the fluid flow is used to actuate a
device specifically designed to operate from the
flow provided. In general, these actuators fall into
the following categories:
 Cylinder (hydraulic or pneumatic): Provides force in a
linear fashion
 Motor (hydraulic or pneumatic): Provides continuous
rotational motion
 Rotary actuator: Provides rotational motion of less
than 360 degrees.
Pneumatics vs. Hydraulics
Hydraulic Power
 Uses a liquid, usually
oil, to convert, store
and transmit power
Pneumatic Power
 Uses gas, usually air,
to convert, store, and
transmit power.
Hydraulics
 HYDRAULICS is a branch of science
that deals with the study and use of
liquids as related to the mechanical
aspects of physics.
Hydraulic Systems
Mechanical Advantage
 Mechanical advantage
means that’s its easier to
do something.
 The volume or distance
moved, compared to the
pressure applied will
determine the amount of
work that can be done
Basic Principles of
Hydraulics
• Liquids have no shape of their own.
• Liquids will NOT compress.
• Liquids transmit applied pressure in all
directions.
• Liquids provide great increase in work
force.
Basic Principles of
Hydraulics
• Liquids have no shape of their own.
______________________________
Basic Principles of
Hydraulics
______________________________
• Liquids provide great increase in work
force.
Basic Principles of
Hydraulics
• Liquids will NOT
compress.
Basic Principles of
Hydraulics
• Liquids transmit
applied
pressure in all
directions.
Pressure vs. Force
 Force means a total push or pull. It is
push or pull exerted against the total area
of a particular surface and is expressed
in pounds or grams.
 Pressure means the amount of push or
pull (force) applied to each unit area of
the surface. Pressure may be exerted in
one direction, in several directions, or in
all directions.
Computing Force and
Pressure
 Pressure equals force
divided by area.
 By rearranging the above
formula, this state may be
condensed into the
following: P = F divided by A
The Basic Idea
 The basic idea behind any hydraulic
system is very simple: Force that is
applied at one point is transmitted to
another point using an incompressible
fluid.
The fluid is almost always an
oil of some sort. The force is
almost always multiplied in the
process.
Hydraulic Motors
Hydraulic Actuating
Cylinders
 Actuating
Cylinders:
A piston
and shaft
within a
cylinder,
that
performs
an action.
Actuators
Extend Pressure
Retract Exhaust
Retract Pressure
Extend Pressure
Computing Force and
Pressure
 A formula is used in computing force,
pressure, and area in hydraulic systems.
In this formula, P refers to pressure, F
indicates force, and A represents area.
 Force equals pressure times area. Th
us, the formula is written F = P x A
Actuators
Example #1
 How much extend force will a 2” bore
cylinder develop with a 80 PSI supply?
 Bore (inside diameter of piston): 2”
 Area = Pi (3.1415) x r2
 3.1415 x (1)2 = 3.1415
 Force = 80 PSI x 3.1415 per sq./in.
 Force extend = 251.33 lbs
Actuators
Example #2