The functioning mechanism of pneumatic cylinders

A pneumatic cylinder is a type of mechanical device that is used to generate force and is powered by using compressed gas or air. It is also known as an air cylinder. These devices are used to perform a lot of important functions in electronics, automotives, packaging industries, as well as in domestic households. Among their various functions included are the control and regulation of pressure in the air brakes as well as closing certain door types. They also help the car engines to push the pistons and facilitate spinning of the car tires. Although air cylinders are utilized in a diverse range of functions, their basic mode of operation remains the same. In these devices, air pressure is converted into linear motion with the help of a metal piston. Air pushes the piston back and forth, leading to a constant supply of force.

Air cylinders come in a variety of shapes and sizes, and they typically range between 2.5 mm and 400 mm in diameter. Some models of air cylinders have a diameter of 1000 mm, and are intended to be used as a replacement for hydraulics. The air cylinder models that are most commonly used have a tube shaped body with a shaft, a plunger and a rod. The rod fits perfectly into the cylinder shaft, and can be easily moved in and out, and the plunger is attached to the end portion of the rod. The purpose of the plunger is to withstand the impact of air pressure that streams within the air cylinder.

As a way of functioning, a pneumatic cylinder delivers a force by generating kinetic energy from the potential energy present in compressed gas. The kinetic energy thus produced is of scalar quantity and has magnitude but lacks direction. The direction is attained with the help of electrical or manual valves that helps in controlling the direction of the movement. A hand lever or electric solenoid is used to maneuver the directional control valves for keeping adjustable travel rates.As a greater air pressure than atmospheric pressure creates a force which expands the compressed gas, the air expansion propels the piston into moving in a preferred direction. Certain models of cylinders are equipped with cushions on either or both the port ends. The cushions restrict the flow of air to reduce the air travel speed to a lower level.

Pneumatic and its internal structure

There are two main variants of air cylinders, namely single acting air cylinders and double acting air cylinders. The two variants are discussed below in brief:

Single acting air cylinders

The single acting air cylinders are comprised of a single port that is used for compressed air. The port moves in a single direction only, i.e. the cylinders do not retract their pistons after the removal of the air pressure. With the use of spring return hookups, the piston is pushed back to its original position by the spring. However, the device then requires additional air pressure to operate as both the load as well as the spring has been pushed.