Pneumatic Cylinder – A Brief Introduction

Pneumatic cylinders, also known as air cylinders are mechanical devices which are used to produce force combined with linear, usually powered by high pressure compressed air or gas. These are made from premium quality nickel-plated brass, aluminum, steel, stainless steel and various other materials depending upon the job specifications, stroke length and level of loads, humidity & temperature.

It use the stored potential energy of compressed air and convert it into kinetic energy as the air expands in an attempt to reach atmospheric pressure. The air expansion in the cylinder forces a piston( a disc or cylinder) to move in the desired direction; piston rod further transfers this force it the object which is required to be moved. These are widely sought after in different industry segments owing to their noiseless operation, simple installation, easy maintenance and compact size. These cylinders don't require large space to store fluid like hydraulic ones.

Working and Types of Air Cylinders

The various components of are a steel piston, a piston rod, a cylinder barrel and end covers. When the compressed air/gas moves into an air cylinder, it pushes the piston along the length of the cylinder. Compressed air or a spring, located at the rod end of the cylinder then pushes the piston back and valves regulate the flow of compressed air to the cylinders.

These cylinders are available in different models, sizes and these vary in appearance as well as functions. These can be broadly categorized as Single-acting, Double-acting and Multi-stage cylinders.

Single-acting (SAC)

Single-acting cylinders use the pressure imparted by compressed air to create a driving force, generally in outside direction, and a spring to return to the "home" position. These cylinders have limited extension and recommended for applications which don't require more than 100mm of stroke length.

Double-acting (DAC)

Double-acting cylinders use the force of compressed air to move in both extend and retract strokes. These cylinders have two ports to allow air in, one for out-stroke and one for in-stroke. Stroke length for these models is not limited, however, the piston rod is more vulnerable to buckling and bending here.

Multi-stage (MAC)

Multi-stage cylinders are also known as Telescoping and telescopic cylinders. These incorporate a piston rod nested within a series of hollow stages of increasing diameter. Upon actuation, the piston rod and each succeeding stage "telescopes" out as a segmented piston. These designs are most appropriate for longer strokes and primarily utilized in applications where the piston bears minimal side loading.

Some other types of Pneumatic Cylinders are Through rod air, Cushion end air, Rotary air, Impact air, Rodless air and Tandem air cylinders. Pneumatic Cylinders are appreciated for their simple designs, easy operation & control, long operating lives, safe to use and less maintenance.