First, we have to consider the exhaust pressure and the volume of the exhaust.
According to the national regular, the exhaust pressure of general purpose surroundings Cycloidal Gear box compressor is 0.7 MPa (7 atmospheric pressure) and the old standard is 0.8 MPa (8 atmospheric pressure). As the design working pressure of pneumatic equipment and wind machinery is 0.4 Mpa, the working pressure of atmosphere compressor can fully meet the requirements. If the atmosphere compressor used by the user is bigger than 0.8MPa, it should be specially manufactured. The technique of forced pressurization can not be adopted in order to avoid accidents.
How big is the exhaust is also one of the primary parameters of the air compressor. Choosing the air volume of the surroundings compressor should match its exhaust volume and leave a 10% margin. If the air flow volume is huge and the air compressor exhaust quantity is small, when the pneumatic equipment start, the exhaust pressure of the surroundings compressor will be greatly reduced, however the pneumatic tools can not be driven. Of course, it is also wrong to pursue large exhaust capacity blindly, since the bigger the exhaust capability, the larger the electric motor allocated by the 
surroundings compressor, not only the higher the purchase price, but also a waste materials of purchasing funds, and the utilization of electric power and energy will end up being wasted.
Consider the mixture of gas areas and conditions.
If the use of air space is narrow, it should be vertical; when there is a long-distance switch in the usage of air (a lot more than 500 m), mobile type is highly recommended; if the usage of electricity can’t be utilized, diesel engine driving type should be selected; when there is simply no circulating water in the use of occasions, air-cooled type ought to be chosen. In the air-cooled and water-cooled cooling modes, many users have an incorrect idea that water-cooled is great, but in fact it is not. The air-cooled type makes up about more than 90% of the tiny compressors in the home and abroad. That is because the air-cooled type is easy in design and no water source is necessary in use. There are four fatal shortcomings of water-cooled compressor: it must have a complete upper and lower water system with large purchase; water-cooled cooler has short life; it is easy to freeze the cylinder in winter in the north; it will waste a whole lot of water in regular operation.
Then consider the compressed air quality.
Generally, compressed air made by air compressor contains a certain amount of lubricating oil and water. In some instances, it is prohibited from oil and water. At the moment, attention ought to be paid not merely to the selection of compressor, but also to the addition of auxiliary gadgets when necessary.
Lastly, it really is to expand the data of reference.
1. Stability: With the solid rise of China’s overall economy and the constant emancipation of the thoughts of all types of manufacturers, manufacturers from coast to coast are busy with production work. Along the way of production, air flow compressors, which play an essential role, are often fully loaded and operate all-weather. In the entire production of factories, air compressor gas production is unstable, which is an extremely troublesome thing, often will bring incalculable 
losses. Therefore, when we purchase air compressors, the initial criterion may be the stability of surroundings compressors. At present, some high-end brands both at home and overseas can meet this requirement. With the mature technology of adjustable frequency air compressor, it could be said to meet this requirement.
2. Gas production: The second is gas creation. Some enterprises possess very high quality of gas. For example, in the pharmaceutical market, basically the gas they want is oil-free. In this respect, it is still predicated on the enterprise’s very own situation. If the enterprise has a high demand for this, then it’s been a long period to purchase more well-known devices. If the demand is not high, it depends upon other circumstances. As the future development craze of the surroundings compressor industry, the adjustable frequency air compressor is still very excellent in gas production, because the variable frequency air compressor has a prominent characteristic of tracking gas creation, and at the same time the gas quality created is very considerable.
3. Power consumption: This is a comparatively important place and also the focus of discussion, because air flow compressor, as a basic equipment, is generally managed all-weather, and air compressor itself is an extremely power-consuming equipment, the general manufacturer of air flow compressor power consumption accounts for 20-30% of the full total plant power usage. If effective control, the effect is very obvious. Many domestic enterprises are actually pursuing the base price. In fact, the bottom price is rather one-sided. For general creation enterprises, the purchase price of surroundings compressor only makes up about 5% of the total cost of surroundings compressor, 9% of the maintenance and labor costs, and 86% of the total cost of power. Therefore, considering the final expenditure, the frequency transformation air compressor must be much lower than the ordinary air compressor. Frequency conversion atmosphere compressor is only the first expenditure, but if you take the electricity price into account, you really can calculate a bill. Currently, the general energy-saving amount of frequency converter air flow compressor is quite objective, and the domestic professional regularity converter air compressor, its power-saving rate is as high as 30%, usually within a season can recover the difference. Therefore, whenever choosing air flow compressor, choosing an excellent variable frequency air compressor is really the very best option to the problem of power consumption.