Which types of compressors can be chosen
Compressors are used for compressing air, from small uses such as inflating tyres up to more demanding uses such as driving pneumatic equipment.
On the market today there are basically two main types of compressors, and these are piston and screw compressors.
Piston compressors
Piston compressors tend to be of smaller dimensions compared with screw compressors and are usually portable – that is, they tend to be equipped with wheels and handles for transport from place to place. As far as output is concerned, they range from small and weaker ones, which usually work with one cylinder and are intended for standard use, up to larger two-cylinder compressors with higher output. These can then work at lower speeds and give off less noise. In terms of output they are, however, usually weaker than screw compressors. A certain disadvantage of theirs is the noise level.
Piston compressors can be chosen in an oil-lubricated and an oil-free variant.
- Oil-lubricated piston compressors
This type of piston compressor needs an oil tank for its operation, which serves for lubricating the equipment and for its smooth running. With a lack of oil the compressor may seize; with an excess of oil it becomes fouled.
- Oil-free piston compressors
This type of piston compressor is used in cases where the driven equipment must not come into contact with oil, especially in the food industry, where it is commonly used for dispensing beer. The oil-free compressor is, however, also used for spraying with the airbrush technique.
The oil-free piston compressor has special sliding materials for its operation instead of an oil tank. Compared with the oil-lubricated one, however, it tends to have a shorter service life.
Screw compressors
Screw compressors are professionally used equipment, for which a very high output and a low noise level are typical. Compared with piston compressors they are of much larger dimensions and are therefore not intended for carrying or transporting to another place. They are installed permanently at the required location.
Screw compressors are used in professional operations where high demands are placed on reliability and high output.
The screw compressor uses either oil for its operation. This is then, however, separated during the process from the discharged air. The air leaves the device clean through an air filter. The second option is screw compressors that do not need oil and work with water injection.
Compared with piston compressors, screw compressors have a significantly higher service life, they are very reliable and the output can be regulated very precisely. They are, however, more expensive in price.
What the compressor will be used for
When choosing between these types of compressors it is necessary to consider all future eventualities of their use. Although at present your demands may be small, it may happen that in future requirements are added and the purchased compressor will no longer be sufficient in terms of output.
Home use
For the use of a compressor in domestic conditions, in workshops for hobby use, a piston compressor is normally bought. A screw one would be unnecessary both because of the high price and because of the high output, which will not be used in domestic conditions, which makes the screw compressor suffer.
Companies, operations, tradespeople
In large operations screw compressors are used, which can handle a high volume of air.
What output do you need
For small use, where you do not need a very high supply of air over a long time and intend to use the compressor occasionally, an oil-free piston compressor is a suitable solution. Its efficiency is roughly 50 – 60 %.
If you need a compressor that can run for a longer time without overheating, you can choose an oil-lubricated piston compressor. It is, however, necessary to give the compressor enough time to cool down. Its efficiency is 70 – 75 %. With correct maintenance it has a long service life.
If you need a compressor that you will use for pumping a large quantity of air over a long time, use a screw compressor. It is, however, necessary that almost its full capacity is used. If it is not used, internal corrosion is a risk. A screw compressor must always work at at least 80 %.
Which one to choose
In general the choice of a compressor can be narrowed down as follows:
- For industrial use in large and demanding operations, screw compressors are chosen.
- For home use it is possible to choose between an oil-lubricated or an oil-free piston compressor according to output
- For commercial use in the food industry, pharmacy, in the chemical industry, healthcare and airbrush spraying, an oil-free piston compressor is used.
