• Single acting air cylinders use air pressure to force a piston from one side of the barrel and a spring supplies the return force. The tube-shaped mechanism you see opening and closing a storm door might be a single acting air cylinder. The rod inside the cylinder extends when the door opens as air flows in, pushing it. The spring then forces the rod back into the shaft, closing the door. The type of single acting air cylinder used depends on the application.
  
  

Repairable and Nonrepairable Air Cylinders

• Single acting air cylinders may be repairable or nonrepairable. Nonrepairable air cylinders, called "throw aways," are made with aluminum end caps and a stainless steel cylindrical barrel. The caps are made to keep costs low, some are even made with plastic. Nonrepairable air cylinders cannot be taken apart to repair them and they are thrown out and replaced with new cylinders. Repairable air cylinders, as their name implies, can be fixed when a part has stopped working or has been damaged.
  
  

Basic Linear Air Cylinders

• Basic linear air cylinders provide in and out linear movement of air for different applications. Single acting basic air cylinders create a push in one direction and use less air than the double acting type.
  
  

Compact Linear Air Cylinders

• Compact linear air cylinders work in the same way a basic air cylinder does, but compact linear air cylinders use less space so that you can mount them in tight areas.
  
  

Diaphragm or Rolling Lobe Air Cylinders

• Diaphragm or rolling lobe air cylinders are intended for applications where immediate movement is required, such as in electronic regulators and, according to Air Cylinders Direct, they work like actuators (an electrical, hydraulic or pneumatic device that controls the flow of air). No sticking or hesitation between the piston and the barrel occurs when compressed air enters the cylinder of a diaphragm air cylinder, allowing the piston and the rod to start to move almost immediately. Internally, the piston moves the length of the cylinder barrel, and then the diaphragm (or rolling lobe) unrolls, allowing the piston to move. When the piston returns, the diaphragm rolls back to its original shape.
  
  

Guided Air Cylinders

• Guided air cylinders use guide rods that are mounted alongside the piston rod to allow for steady, nonrotating movement. This type of cylinder has less chance of a rod or piston bending and of uneven seal wear, and it is available in models that work in cramped spaces.