What are the basic functions of hydraulic cylinders?

Standard double acting: power stroke in both directions and used in most applications:
Single-acting cylinder: When thrust is required in only one direction, a single-acting cylinder can be used;
Double rod cylinder: Used when equal displacement is required on both sides of the piston, or when it is mechanically advantageous to connect a load to each end. The additional end can be used to install a cam that operates a travel switch, etc.
Spring Return Single Acting Cylinders: Typically limited to very small short stroke cylinders used for holding and clamping purposes. The length required to accommodate return springs makes them a nuisance when long strokes are required;
Piston-type single-acting cylinders: There is only one fluid chamber. This type of cylinder is usually installed vertically. The load reset causes the cylinder to retract. They are also called "displacement cylinders" and are practical for long strokes.
Multi-stage telescopic cylinder: can carry up to 4 sleeves, and the folded length is shorter than the standard cylinder. There are single-acting or double-acting cylinders. They are more expensive than standard cylinders. They are usually used in situations where the installation space is small but a larger stroke is required.
Tandem cylinder: A tandem cylinder consists of two cylinders installed coaxially. The pistons of the two cylinders are linked by a common piston rod. A rod seal is provided in front of the two cylinders so that each cylinder can be double-acting. When installed When the width or height is restricted. Tandem cylinders can increase output;
Double cylinder: A double cylinder is composed of two cylinders installed coaxially. The two pistons are not connected. A rod seal is provided between the two cylinders so that each cylinder can be double-acting. The two cylinders can be installed rod-to-piston (as shown) or back-to-back. Typically used to provide three position work.