Hydraulic cylinders are used for converting hydrostatic energy into the mechanical energy in a linear motion. They can be considered as actuators or motors capable of producing work with the only difference from the hydraulic motors being production of linear movement instead of rotational one. A hydraulic cylinder comprises of a tube capped at either end with a rod coming out of one side. It is the pressure of hydraulic fluid that forces the piston to either push or pull.

Types of Hydraulic cylinders

There are two main types of hydraulic cylinders available in the market depending upon the number of chambers pressurized by the hydraulic fluid – single acting and double acting. Common design principles of both the cylinders include tie rod, mill type and a roundline cylindrical design.

Single acting Hydraulic cylinder

This type of hydraulic cylinder has one chamber receiving the pressurized hydraulic fluid. Depending upon the intended use of the cylinder, the chamber side is decided. If pushing motion is needed, the chamber opposite to the cylinder rod is pressurized and if pull motion is required, chamber with the cylinder rod is pressurized.

Advantages:             

• Simple to design, install and manufacture
• Low initial purchasing cost
• Single input port with small housing
• Reduction in valve and piping costs

Disadvantages:

• Reduction in the generated thrust due to the spring supplying opposite force
• After the wearing off of the spring, the cylinder strokes become inconsistent

Double Acting Hydraulic Cylinder

Double acting cylinders have both the chambers pressurized. The direction and pressure control is important in this system as they decide the efficiency of the cylinder.

Advantages:

• Better control over the movements as pressurized air moves in both the directions
• Stronger and faster with less usage of energy
• Available in a variety of designs in terms of bore and stroke sizes.
• Force is offered in all directions

Disadvantages:

• Costlier than the single hydraulic cylinders
• Bigger housing is needed because of the coupling required

Applications of Hydraulic cylinders

Hydraulic cylinders are considered to be the force behind several manufacturing and commercial concerns. Some common industries where these cylinders form an integral part of the machinery are as follows:

• Aerial work platforms
• Small spraying equipment in agriculture
• Landing gears and wing flaps in aerospace industry
• Automotive industry
• Civil engineering machines
• Logging and forestry
• Handling of materials
• Mining
• Motorway maintenance and repairing
• Food manufacturing and production
• Oil and gas industry
• Steering devices in the shipbuilding industry
• Compression of scrap and other materials in the recycling plants

The variety and difference of these applications showcase the depth of industry’s reliance on the usage of hydraulic cylinders. They form a crucial component in different types of machineries. They are efficient, simple and effective machines that are capable of quite a lot of things that make up our everyday life.