The study of amplifying forces and transmitting the resulting pressure by the use of liquids. The word comes from:

Hydro meaning water and aulos meaning pipes.

Hydraulics is divided into two basic categories:

  1. Hydrostatics: The study of liquids and fluids at rest-high pressure, low flow.
  2. Hydrodynamics: The study of liquids and fluids in motion-low pressure, large flow.

Liquids are used because they are practically incompressible. This means that almost no energy is used in compression, making the system extremely efficient.  Water is not used in plant machinery applications because it corrodes, boils, freezes and is very viscous, thus making it hard to seal in a system. Instead, we make use of hydraulic oil, or in some braking systems, vegetable based brake fluids.

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