The hydraulic system uses Pascal's law in hydrostatics to use oil or other liquids to transfer pressure in liquids to achieve small pressure control of large pressures, which is somewhat similar to the principle of leverage.
The compressibility of liquids is generally very small, so in hydrostatics, liquids are considered Incompressible; In an Incompressible still liquid, any point that is produced by an external force will instantly be transmitted to all points of the fluid. This is Pascal's law.
According to Pascal's law, for the two connected cylinders above, the pressure on any horizontal plane must be equal. If the two pistons are at the same horizontal line, the pressure on the piston is:
P1 = P2;
According to the pressure formula:
F1 / S1 = F2/S2;
Both:
F1 / F2 = S1/S2 = C;
It can be seen that the ratio of pressure to the two pistons is equal to the ratio of the piston area and has nothing to do with the size of the pressure; Using this principle, we can use smaller forces to produce larger forces at the expense of smaller force displacements, similar to the principle of leverage.
For example, when we take a syringe for injection, after removing the needle and gently blocking the exit with our hands, we need to use more force to push the piston forward. This is the same principle as the hydraulic system.
In hydraulic systems, water as a medium is called a hydraulic press, and oil as a medium is called a hydraulic press. Because the pressure in the hydraulic press is high, the pressure difference caused by gravity can be ignored.
Hydraulic systems have applications in many places, and they are easy to achieve stepless control and high-precision control. For example, one of the jacks uses the hydraulic principle, as shown in the figure below:
The hydraulic press is a major application of the hydraulic principle. It can produce ultra-high pressure above 100 Mpa and hundreds of tons of pressure. It is an important equipment in heavy industry production.