# HYDRAULICS

1. What is hydraulic technology?

In the hydraulic technology we transmit and control forces and velocities by transmitting and controlling pressure and flow. In nearly every kind of technology we use hydraulic drive and control techniques. A few examples are:

• mechanical engineering
• car technology
• agriculture technology
• earthmoving and mining technology
• ship building technology
• offshore-technology
• aircraft and spacecraft technology

The principles of hydraulic technology are not new. In the 18 Th. century in London a hydraulic press was built and the Eifeltower was adjusted by water hydraulic jacks. About 200 years BC the Greek already used machines that were driven by water hydraulics.

Pascals law

Hydraulic systems operate according to Pascals law. The law of Blaise Pascal says: 'The pressure, in a static hydraulic fluid in a closed system is everywhere the same'.
However, when the velocity of the flow is constant one may apply Pascals Law as well.
Animation: When the man jumps on the small piston, he induces a pressure in the system. This pressure also works on the large piston: because of the large area of this piston, the force induced by the pressure is capable to lift the car.

The pressure can be calculated with the formula:

where:

• p = pressure (psi)
• F = force (pound)
• A = area (square inch)