# Briefly describe the working principle of hydraulic press

A Hydraulic Press is a device that uses liquid to transfer pressure: when a liquid transfers pressure in a closed container, it follows Pascal’s law. The hydraulic transmission system of hydraulic equipment is composed of power mechanism, control mechanism, executive mechanism, auxiliary mechanism and working medium.

The power mechanism usually uses an oil pump as the power mechanism, generally a positive displacement oil pump. In order to meet the requirements of the moving speed of the actuator, one oil pump or multiple oil pumps are selected. Gear pumps for low pressure (oil pressure less than 2.5MP); vane pumps for medium pressure (oil pressure less than 6.3MP); plunger pumps for high pressure (oil pressure less than 32.0MP).

The hydraulic press is composed of two hydraulic cylinders of different sizes, which are filled with water or oil. The one filled with water is called “hydraulic machine”; the one filled with oil is called “hydraulic machine”. There is a slidable piston in each of the two liquid cylinders. If a certain value of pressure is applied to the small piston, according to Pascal’s law, the small piston transmits this pressure to the large piston through the pressure of the liquid and pushes the large piston up.

Suppose the cross-sectional area of ​​the small piston is S1, and the downward pressure on the small piston is F1. Therefore, the small piston pair can be transmitted in all directions by the liquid without changing its size.” The pressure of the large piston must also be equal to P. If the cross-sectional area of ​​the large piston is S2, the pressure P generated on the large piston will increase upward. The pressure cross-sectional area is a multiple of the cross-sectional area of ​​the small piston. From the above formula, a small force is applied to the small piston, and a large force will be obtained on the large piston. For this reason, a hydraulic press is used to press the plywood and press the oil. , Extract heavy objects, forging steel, etc.