The pressurized air contains kinetic energy that can be used to accomplish certain goals. Typically speaking, this type of equipment is used in virtually every type of engineering, manufacturing, or plant operation worldwide. Functions range from inflating tires to assisting in the function of equipment.
There are several different air compression methods that are typically divided into two main categories: Positive Displacement Air Compressors and Negative Displacement Air Compressors.
Among the Positive Displacement Air Compressors, there are also few different types. These all function by forcing air into a chamber where the volume within the chamber is lowered so that the air can be compressed. These deliver a fixed volume of highly pressurized air. The positive displacement air compressor types include:
Piston-Type Air Compressors – these are frequently compared to a vehicle engine. They use constantly moving pistons to pump air into a chamber. Each of the pistons has a one way valve that will help to send the air into the chamber so that it can be compressed.
Rotary Screw Compressors – this type uses two matching helical screws, which turn to create a pocket between them. That allows the air to be transferred into the chamber where it will be compressed. As the screws turn, the volume has a tendency to decrease.
Rotary Vane Compressors – these use a rotor with slots in it that holds a mechanism for varied blade placement. As they turn, the blades grow longer and shorter, depending on whether or not each specific blade in question is actually compressing air. The blades help to guide the air into the chamber and then compress the volume.
Negative Displacement Air Compressors include:
Centrifugal Compressors – these devices use a process called dynamic displacement. They build up centrifugal force through the use of a spinning impellor. That force is then used to accelerate captured air which is pressurized as it makes its way through the impeller as it spins. The kinetic energy is transferred from a rotor to the air in order to compress it.
Some of the leading brands of air compressors are Atlas Copco, Ingersoll Rand, Gardner Denver, and Sullair.
While some compressors are lubricated with oil, others do not require it. Those that do not use oil have sealed bearings. Because of this, there is notably less maintenance required for that equipment. The motors are typically electric and are considerably quieter than oil-lubricated equipment. That said, the compressors that are lubricated by oil have the advantage of a much greater capacity for higher pressures. Furthermore, they can run for a much longer period of time than the oil-less compressors. The oil-lubricated compressors also need less equipment.
No matter what type of compressor is chosen, waste heat – known as adiabatic heat – is generated. This is caused when the gas pressure rises as a result of the work being done on it by its surroundings. In order to keep this effect to a minimum, there is typically some type of water or air cooling system that makes up a part of the overall compressor system. Rotary type compressors will require cooling by oil.
When shopping for a used air compressor, it is recommended that you find out how many hours the compressor you are considering has already been used. You should also look into its age, model, manufacturer, horsepower and cubic feet per minute (CFM). You will also want to find out what is involved in the maintenance of this equipment and how much this will cost. Clearly those that need oil replacement will be higher, but they will also provide greater power. There is no specific lifespan for an air compressor. However, good makes and models that have been properly maintained can easily last for 60,000 to 80,000 hours.
When you are looking to buy a used air compressor, make sure that you ask about its condition, its prior use, and the number of hours that it has already been used. In order to know that your choice will be of the highest quality, it is also vital that you select a vendor that is both knowledgeable and reputable.
Choosing a proper vendor of used air compressors gives you the opportunity to take advantage of competitive pricing and immediate installation. Prices will range from a few hundred dollars to a couple of hundred thousand dollars, depending on the type, size, age, and condition of the machinery you are considering.
Perry Videx has a large inventory of used air compressors that have been sourced from a number of different industries. This selection includes those that have been reconditioned. To learn more, please visit http://www.perryvidex.com.
