The hydraulic system uses Pascal’s law in hydrostatics, uses oil or other liquids to transfer the pressure in the liquid, so as to realize the small pressure to control the large pressure, which is similar to the lever principle.
The compressibility of liquid is generally very small, so in hydrostatics, it is considered that the liquid is incompressible; in the incompressible static liquid, the effect produced by external force at any point will be transmitted to all points of the fluid instantaneously, which is Pascal’s law.
The characteristics of hydraulic technology are suitable for automation, high performance, large capacity, small volume and light weight of various machinery and equipment.
Why can hydraulic pressure produce great force with a small force?
According to Pascal’s law, for two connected liquid surfaces as shown in the figure, the pressure on any horizontal plane must be equal. If two pistons are in the same horizontal line, then the pressure on the piston is as follows:
P1=P2；
According to the pressure formula: P = f / s
F1/S1=F2/S2;
Both:
F1/F2=S1/S2=C;
It can be seen that the pressure ratio of two pistons is equal to the ratio of piston area, and it has nothing to do with the pressure. Using this principle, we can use a smaller force to produce a larger force, and the cost is that the smaller force displacement is larger, similar to the lever principle.
A complete hydraulic system consists of five parts, namely power components, executive components, control elements, auxiliary components and hydraulic oil. The function of power components is to convert the mechanical energy of prime mover into the pressure energy of liquid. It refers to the oil pump in the hydraulic system, which provides power to the whole hydraulic system.
In the hydraulic system, water as the medium is called the hydraulic press, and the oil as the medium is called the hydraulic press. Because the pressure in the hydraulic press is very high, the pressure difference caused by gravity can be ignored.
Hydraulic system is applied in many places, and it is easy to realize stepless control and high-precision control. For example, one of the jacks uses the hydraulic principle, as shown in the figure below
Hydraulic press is a major application of hydraulic principle, which can produce more than 100MPa of ultra-high pressure and hundreds of tons of pressure. It is an important equipment in heavy industry production.
