a pneumatic cylinder, or air cylinder, is a mechanical device that produces force and are powered by air or compressed gas. They carry out a lot of functions in automotives, electronics, packaging industries, various establishments, and even in households. They are used to control pressure in air brakes, help car engines push the pistons enabling the tires to spin, and allow certain types of doors to close, among other functions. The pneumatic cylinder may have a variety of uses, but their basic function does not change. They convert air pressure into linear motion by attachment to a metal piston, pushed back and forth by columns of air.
Pneumatic cylinders come in many shapes and sizes, which typically range from 2.5 mm to 400 mm diameter air cylinders. Some pneumatic cylinders are 1000 mm in diameter, intended for use in place of hydraulics. The most common pneumatic cylinder is tube shaped and contains a shaft, a rod, and a plunger. The rod fits into the shaft of the cylinder, which can move in and out. The plunger is connected to the end of the rod, and its purpose is to take the impact of the air pressure that flows within the pneumatic cylinder.
In order to perform, pneumatic cylinders deliver a force by transforming the potential energy of compressed gas into kinetic energy, which is a scalar quantity, and therefore has magnitude but no direction. That direction is attained by manual or electrical valves that control the direction of movement. These directional control valves are maneuvered by electric solenoid or hand lever to keep adjustable travel rates. When the compressed gas expands due to the force created by a greater pressure than the atmospheric pressure, the air expansion drives a piston to move in the preferred direction. Some cylinders have cushions on one or both port ends. These cushions constrain airflow to reduce the motion of travel to a lower speed.
The two main types of pneumatic cylinders are:
- Single acting pneumatic cylinders. A single acting pneumatic cylinder has a single port for compressed air, it moves in one direction only, meaning the cylinder does not retract the piston once air pressure is removed. With spring return hookups, the spring pushes the piston back into its home position, but it requires more air pressure to set off because you push both the load and the spring.
- Double acting pneumatic cylinders. A double acting cylinder, on the other hand, has two ports for compressed air - one for instroke and another for outstroke. It uses the force of air to expand and to retract like a vacuum that pulls the rod back inside the shaft, thereby requiring more air and a more complex solenoid valve than the single acting cylinder.
In order to preserve the performance of your pneumatic cylinder, it is important to maintain it. Regularly check valves to ensure they are inserted in the desired position so as not to glide and create a loss of air pressure. The pneumatic system is also not permitted to freeze, as it can damage the control and seal functions.
Commercial pneumatic cylinders are now available in new designs and equipment specifications. Popular brands are Sterling and Parker, which are among the largest manufacturers of hydraulic and pneumatic cylinders.