FLUID POWER
FLUID POWER IntroductionIt is the technology that deals with the
generation, control and transmission of power, using pressurized
fluids.Fluid power is used to push, pull, regulate, or drive
virtually all the machines of modern industry.e.g.. Power steer,
automobile brakes, spacecraft launch, earth movers, crop
harvesting, machine tool drives, food processing, etc..,
HistoryFluid power technology began in 1650 with the discovery of
Pascals law: Pressure is transmitted undiminished in a confined
body of fluid.In 1750, Bernoulli developed his law of conservation
of energy for a flowing fluid in a pipeline. During the industrial
revolution of 1850 in great Britain, these laws were actually
applied to industry. In the late 19th century electricity emerged
as a dominant technology which results in replacement of fluid
power. The modern era of fluid power is considered to have begun in
1906 when a hydraulic system was developed to replace electric
systems for elevating and controlling guns on the battleship USS
Virginia.In 1926 US developed the 1st unitized, packaged hydraulic
system consisting of a pump, controls, and actuator. The military
requirement leading up to World War II kept fluid power
applications and developments going at a good pace.Today fluid
power is used extensively in practically every branch of industry.
Advantages of Fluid PowerEase and accuracy of control: By the use
of simple levers and push buttons, the operator of a fluid power
system can readily start, stop, speed up or slow down, and position
forces that provide any desired Hp with tolerances as precise as
one ten-thousandth of an inch.Multiplication of force: A fluid
power system can multiply forces simply and efficiently from a
fraction to several hundred tons of output.Constant force or
torque: Only fluid power systems are capable of providing constant
force or torque regardless of speed changes. Simplicity, safety,
economy: In general, fluid power systems use fewer movement parts
than comparable mechanical or electrical systems. Thus, they are
simpler to maintain and operate. This, in turn, maximizes safety,
compactness, and reliability.Additional benefits of fluid power
include instantly reversible motion, automatic protection against
overloads, and infinitely variable speed
control.DisadvantagesLeakage problem.Hydraulic lines can burst,
resulting in injuries to people due to high-speed oil jets.Noise
problem.Hydraulic oils can cause fires if an oil leak occurs in an
area of hot equipment.Applications:Hydraulic brakesAutomotive
transmissionsPower steeringAir conditioningLubricationsSpacecraft
launchingMachine tools
Components of a fluid power systemHydraulic systemA tank or
reservoir to hold the hydraulic oilA pump to force the oil through
the systemAn electric motor or other power source to drive the
pumpValves to control oil direction, pressure and flow rateAn
actuator to convert the pressure of the oil into mechanical force
to do some work. Actuators can either be cylindrical to provide
linear motion or rotary motors to provide the rotary motionPiping,
which carries the oil from one location to another.Basic hydraulic
system with linear actuator
Pneumatic systemAn air tank to store a given volume of
compressed air.A compressor to compress the air that comes directly
from the atmosphere.An electric motor to drive the compressorValves
to control air direction, pressure and flow rateActuators which are
similar in operation to hydraulic actuators.Piping to carry the
pressurized air from one location to another
