What is the background and significance of hydraulic cylinders for engineering?

At present, large cranes in the world are generally hydraulic cylinders. Let's first understand the working principle of the crane, then compare it with the cylinder and the cylinder, and you will know what is wrong with it.

The working principle of the hydraulic cylinder is as follows: speaking of its working principle, I will first say its five most basic components: 1- cylinder barrel and cylinder head 2- piston and piston rod 3- sealing device 4- buffer device 5- exhaust device

The operation of each kind of cylinder is basically the same. Take a manual jack for example for its exercise book. The jack is actually the simplest cylinder. The hydraulic oil enters the cylinder through a single valve via a manual pressurizing rod (hydraulic manual pump). At this time, the hydraulic oil entering the cylinder cannot be reversed due to the single valve, forcing the cylinder rod upward. Then the hydraulic oil continues to enter the hydraulic cylinder in the process of work, thus rising continuously. When lowering, the hydraulic valve is opened to return the hydraulic oil to the oil tank. This is the simplest exercise book and the rest is based on this.

The principle of cylinder is similar to that of cylinder.

Advantages and disadvantages of oil cylinder and air cylinder:

1-Since the operating pressure of pneumatic system is generally in the range of 0.2-1.0Mpa, the cylinder cannot be used as a high-power power element. The hydraulic cylinder can be used as a relatively high-power element, using hydraulic system,

2-From the perspective of medium, air is inexhaustible, without any cost or supply difficulties. Used gas is directly discharged into the atmosphere, which is convenient to handle and will not pollute. Hydraulic oil is the opposite.

3-air viscosity is small, resistance is less than the hydraulic oil

4-but the compression rate of air is much higher than that of hydraulic oil, so its operation stability and response are much worse.