          # Hydraulic press

A hydraulic press is a machine press using a hydraulic cylinder to generate a compressive force. It uses the hydraulic equivalent of a mechanical lever, and was also known as a Bramah press after the inventor, Joseph Bramah, of England. He invented and was issued a patent on this press in 1795. As Bramah (who is also known for his development of the flush toilet) installed toilets, he studied the existing literature on the motion of fluids and put this knowledge into the development of the press.

## Main principle

The hydraulic press depends on Pascal's principle-the pressure throughout a closed system is constant. One part of the system is a piston acting as a pump, with a modest mechanical force acting on a small cross-sectional area; the other part is a piston with a larger area which generates a correspondingly large mechanical force. Only small-diameter tubing (which more easily resists pressure) is needed if the pump is separated from the press cylinder.

Pascal's law: Pressure on a confined fluid is transmitted undiminished and acts with equal force on equal areas and at 90 degrees to the container wall.

Pressure of fluid due to the application force F1

$P={F_{1} \over A_{1}}$ (1)

Resulting force F2 on the larger cylinder due to the pressure of the fluid. With A1 and A2 being the areas of cylinder 1 and 2 respectively.

$F_{2}=PA_{2}=F_{1}{A_{2} \over A_{1}}$ (2)

${F_{2} \over F_{1}}={A_{2} \over A_{1}}$ (3)

A small effort force acts on a small piston. This creates a pressure which is transferred through the hydraulic fluid to apply a greater force on the larger piston.

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