Fluid power systems-overview

MEE346

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History of fluid power systems

First hydraulic pump :Double pump delivering a fluid flow rate of

10 lpm;Piping network :100,000 km( 2.5 times

around the earth)Continuous operation: almost maintenance

freeCan you guess which is that pump?

History

Human blood circulatory system

Age 50: Hearts of 10 men should have pumped a volume of blood equal to that of the Great Egyptian Pyramid( how much?)

Evolution of fluid power( Oil hydraulics first and then pneumatics)

Blaise Pascal-1647” Law of hydrostatics”Bernoulli’s book-Hydrodynamics=>kinetic

theory of gases,jet propulsion,law of conservation of energy-1738

Mid 19th century,fluid power important in industrial and civil sectors eg: England,many cities had central hydraulic distribution systems with pumps driven by

……….?

History…

London Hydraulic Power company used fluid power ( hydraulics) for dock cranes and bridges to lifts in private house holds in Kensington and Mayfair

1930s -12m3 / min average hydraulic flow was used to lower or lift anything.Water was pumped beneath the streets of London for the above.

History…

Benjamin’s Franklin discovery of electricity changed everything.More and more electric power was used for material handling.

1925 Harry Vickers developed a vane type pump.Thence onwards hydraulic power became to be used in industry till today.

Power

Mechanical Power

Power

Power….

Power

Fork lift

Mechanical Parameters

Advantages of oil hydraulics

High power-weight ratio( minus power pack)

Self lubrication,No saturation phenomenon,high force to mass and torque to inertia ratios,high stiffness,high acceleration,high reponse,high stiffness of cylinders,protection against overloading simple,high energy storage,transmission flexibility( better than mech)

DISadvantages..con

Hydraulic power not readily avaialble,High costs,high inertia of transmission lines,temperature limits,fire hazard( mineral oils),Oil filtration .

Symbols-basic

Questions

What is a fluid power system?

Describe the function of power systems.

State the advantages/disadvantages of hydraulic and pneumatic power systems.

What are the symbols used in fluid power systems and why are they used?