Hydraulic machinery

Hydraulic machines use liquid fluid power to perform work. Heavy construction vehicles are a common example. In this type of machine, hydraulic fluid is pumped to various hydraulic motors and hydraulic cylinders throughout the machine and becomes pressurized according to the resistance present. The fluid is controlled directly or automatically by control valves and distributed through hoses, tubes, or pipes. (From wikipedia)

The popularity of hydraulic machinery is due to the large amount of power that can be transferred through small tubes and flexible hoses, the high power density and a wide array of actuators that can make use of this power, and the huge multiplication of forces that can be achieved by applying pressures over relatively large areas. One drawback, compared to machines using gears and shafts, is that any transmission of power results in some losses due to resistance of fluid flow through the piping.(From wikipedia)

Pascal’s law

Though humans have being using hydraulics for centuries, it was only around 1650 when Blaise Pascal and Daniel Bernoulli formulated the laws which helped develop modern hydraulic systems.

Pascal’s law states that a pressure change at point in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere.

Examples

Car lift

In a car lift a small force applied at the smaller piston causes a large force to be applied over a smaller distance.

Heavy construction machines

Hydraulic systems are used to transfer power to operate various parts of the machinery.

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Car Brakes

Another very common use of hydraulic system is to operate brakes in automobiles. Fluids transfer the force from the brake pedal to the brake disc.

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