| are three main types of air compressors. Which | | | | centrifugal compressor. A centrifugal compressor |
| you need will depend on the air pressure you | | | | uses a rotating disk with vanes. Output from |
| need and how portable your compressor needs | | | | centrifugal compressors can be as high as 70 |
| to be. | | | | Mpa, 10,000 psi. Snow blowing machines use this |
| Reciprocating compressors come in a range from | | | | type of compressor. Superchargers and |
| 5 HP to 1000 HP. The smaller compressors are | | | | turbochargers in car engines are centrifugal |
| portable, sometimes being mounted on wheels. | | | | compressors. |
| These may be petrol driven or electrically | | | | When you buy compressed air for diving the air |
| powered. They compress air by a series of | | | | has been compressed using a three stage, |
| pistons in cylinders. The pistons are driven by a | | | | reciprocating compressor. The cylinders in the |
| camshaft. Reciprocating compressors are often | | | | compressor are ceramic lined, so no lubrication is |
| used in Auto Body Repair shops. | | | | needed. This avoids the air in the cylinders being |
| Larger reciprocating compressors are gradually | | | | contaminated with lubricating oil. If a |
| being replaced by simpler rotary screw | | | | non-recommended lubricating oil is used it can |
| compressors. A large reciprocating compressor | | | | undergo partial combustion and cause carbon |
| can discharge air at 35 Mpa, more than 5,000 psi. | | | | monoxide to enter the air cylinder. |
| If you are looking for a compressor for | | | | The compressed air is filtered through silica gel to |
| continuous use a rotary screw compressor may | | | | remove water, then through activated charcoal to |
| be suitable. These compressors use helical screws | | | | remove any traces of oil. |
| to compress the gas into a smaller volume. | | | | Sometimes air from a cheap, low powered |
| Portable and fixed rotary screw compressors are | | | | compressor will be stored in a bank of large high |
| available. These compressors vary in size from 5 | | | | pressure cylinders. Air from these cylinders is then |
| HP to 500 HP. You will find rotary screw | | | | used to quickly fill diving cylinders. The diving |
| compressors that give you a low pressure gas | | | | cylinders need to be filled slowly to prevent the |
| output, or a high pressure output, up to 8 Mpa. | | | | compressed air inside them from getting hot. If |
| These compressors are used to power pneumatic | | | | the gas inside is hot, it will expand and the cylinder |
| drills when workers are digging up roads and | | | | maximum pressure will be reached with less air |
| pavements. | | | | inside. The gas cools and the cylinder may only be |
| For continuous, heavy industrial uses you need a | | | | half full. |