INTRODUCTION TO HYDRAULICS

What is hydraulic?

The study of hydraulics deals with the use and characteristics of liquids. Since the beginning of time, man has used fluids to ease his burden.

History of hydraulics and pneumatics.

Earliest recorded history shows that devices such as pump and water wheels were known in very ancient times. It was not however, until the 17th century that the branch of hydraulics with which we are to be concerned first came into use

Both are Cheaper medium of Industrial automation Maximum application of pneumatics –Construction

(power hammers, drills, riveting hammers, pneumatic cranes, air brakes, printingpresses etc.)

With introduction of hydraulics and pneumatics the industries is benefited with cheaper medium of industrial automation. Due to that production become more and cost of product is reduced to low

HYDRAULICS

The technology of hydraulics deals with the study of the behavior and application of a Pressurized oil.

Form Greek Work Hydra- means water

Aulics- means pipe

i.e. this implies fluid (water or oil) are commonly used in pipe line.

Based upon a principle discovered by the French scientist Pascal , Pressure exerted at any point on a confined liquid is transmitted undiminished in all directions.

. Based upon a principle discovered by the French scientist Pascal , Pressure exerted at any point on a confined liquid is transmitted undiminished in all directions.

Pressure applied to piston “A” is transferred equally to a piston of the same size “B” because PSI is the same throughout the system.

If the surface area of piston “B” is 10 times the surface area of piston “A”, then the force applied to piston “A” is multiplied 10 times as the force exerted on piston “B”. PSI is equal throughout the system.

PneumaticTechnology of Pneumatics deals with the study of the behavior and application of compressed air

From Greek Work Pneuma = > for wind or breathMostly air is used.

TYPES OF HYDRAULICS

A basic distinaction is made between: stationary hydraulics :-Stationary hydraulic

systems which remain firmly fixed in one position. stationary hydraulics, however, mainly solenoid valves are used.

mobile hydraulics :-Mobile hydraulic systems move on wheels or chains. A character feature of mobile hydraulics is that valves are frequently manually operated.

Types of pneumatics

Normal pressure pneumatics Low pressures pneumatic

Important advantage of hydraulics.

Very large forces (High pressure oil 10 bar – 600 bar),

Very low Speed - even lower than 0.1m/sec hence Very much Suitable for Machine tool application Stopping and fixing can be achieved with much

accuracy – 0.02 mm. Compare to electrical System much Cheaper hence

it is called low cost automation.

Dis advantage of hydraulics

Pollution of the environment by wise oil (danger of fire or accident)

Danger resulting from excessive pressure Temp dependence (Change in viscosity) Un favorable efficiency factor

Advantage of pneumatics

Wide availability of air Compressibility of air Easy transportability Explosion proof characteristics of the medium Simple construction of pneumatic elements and easy handling High degree of controllability of pressure, speed and force Possibility of easy but reasonably reliable remote controlling Easier maintenance Comparatively cheaper in cost than other systems

Dis advantage

Compressible Nature not Suitable for precise positioning and machine tool application

not Satable for heavy load

General and industrial application

The following application areas are important for stationary hydraulics:

Production and assembly machines of all types Transfer lines Lifting and conveying devices Presses Injection moulding machines Rolling lines Lifts

Mobile hydraulics Typical application fields for mobile

hydraulics include: Construction machinery Lifting and conveying devices Agriculture machinery

General applications for electro pneumatic systems include

Packing Feeding Door and hopper control Materials transfer Turning or inverting parts Sorting of parts Component stacking Stamping, shearing and embossing parts