What can a double-acting cylinder be divided into according to its structure?

Double-acting cylinder can be divided into driving cylinder, gas cylinder and steam cylinder according to structure.

A cylinder that can exert force on both sides of the piston to control its active motion and act in two directions is called a double-acting cylinder. A typical driving cylinder, such as a steam locomotive, can suck in air and output force in two directions. The cylinder of modern internal combustion engine is single-acting, because only the top of piston is equipped with intake and exhaust system. When the piston rises, it cannot be output to the outside. It seems that double action saves more space and structural materials, but it is not. Because it must keep the piston rod and cylinder parallel, this leads to an extremely large and complicated structure.

Therefore, after the steam engine era, power plants no longer use this mechanism. For the actuator, the two-way action can exert force in two directions, and it can be pushed or pulled, which has practical benefits. For example, the master cylinder of modern hydraulic press is generally bidirectional, and the cross section of the return piston is occupied by the piston rod, resulting in a smaller output force than the top of the piston, which also brings some benefits: the return speed is greatly accelerated.