First, we ought to consider the exhaust pressure and the quantity of the exhaust.
According to the national regular, the exhaust pressure of general purpose surroundings compressor is 0.7 MPa (7 atmospheric pressure) and the old regular is 0.8 MPa (8 atmospheric pressure). Because the style working pressure of pneumatic tools and wind machinery is certainly 0.4 Mpa, the working pressure of atmosphere compressor can fully meet the requirements. If the atmosphere compressor used by the consumer is bigger than 0.8MPa, it must be specially manufactured. The technique of forced pressurization can’t be adopted to avoid accidents.
How big is the exhaust is also one of the main parameters of the air compressor. Choosing the air volume of the air flow compressor should match its exhaust quantity and leave a 10% margin. If the air flow volume is large and the air compressor exhaust quantity is little, when the pneumatic tools start, the exhaust pressure of the surroundings compressor will be greatly reduced, but the pneumatic tools can not be driven. Of course, additionally it is wrong to pursue large exhaust capacity blindly, because the larger the exhaust capacity, the larger the engine allocated by the atmosphere compressor, not merely the higher the price, but also a waste materials of buying funds, and the use of electricity and energy will be wasted.
Consider the mixture of gas fields and conditions.
If the use of air space is narrow, it must be vertical; if there is a long-distance transformation in the use of air (more than 500 m), mobile type is highly recommended; if the use of electricity can not be used, diesel engine generating type should be selected; when there is simply no circulating 
water in the usage of occasions, air-cooled type ought to be chosen. In the air-cooled and water-cooled cooling modes, many users have a wrong proven fact 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 at home and abroad. That is because the air-cooled type is simple in design and no water source is needed in use. There are four fatal shortcomings of water-cooled compressor: it will need to have a complete higher and lower water system with large expense; water-cooled cooler has short life; it is simple to freeze the cylinder in winter in the north; it’ll waste a lot of water in regular operation.
Then consider the compressed air quality.
Generally, compressed air made by air compressor contains a specific quantity of lubricating oil and water. In some cases, it is prohibited from oil and water. At this time, attention should be paid not merely to the selection of compressor, but also to the addition of auxiliary devices when necessary.
Lastly, it is to expand the data of reference.
1. Balance: With the strong rise of China’s economy and the constant emancipation of the thoughts of all kinds of manufacturers, manufacturers all over the country are busy with creation work. Along the way of production, air compressors, which play a significant role, are often fully loaded and operate all-weather. In the full production of factories, air compressor gas production is usually unstable, which is a very troublesome thing, often will bring incalculable losses. Therefore, when we purchase surroundings compressors, the initial criterion is the stability of atmosphere compressors. At the moment, some high-end brands both at home and overseas can meet this requirement. With the mature 
technology of adjustable frequency air compressor, it can be said to meet this requirement.
2. Gas production: The second is gas production. Some enterprises have very good quality of gas. For example, in the pharmaceutical market, basically the gas they need is oil-free of charge. In this respect, it is still based on the enterprise’s own situation. If the business includes a high demand because of this, then it has been a long period to buy more well-known devices. If the demand is not high, it depends upon other situations. As the future development development of the atmosphere compressor industry, the variable frequency air compressor is still very superb 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 produced is very considerable.
3. Power consumption: This is a relatively important place and also the focus of conversation, because surroundings compressor, as a basic equipment, is generally managed all-weather, and atmosphere compressor itself is an extremely power-consuming equipment, the general manufacturer of atmosphere compressor power consumption makes up about 20-30% of the total plant power usage. If effective control, the result is very obvious. Many domestic enterprises are now pursuing the base price. In fact, underneath price is rather one-sided. For general creation enterprises, the purchase price of air flow compressor only accounts for 5% of the total cost of air compressor, 9% of the maintenance and labor costs, and 86% of the total cost of energy. Therefore, considering the final expenditure, the frequency conversion air compressor must be much lower compared to the ordinary atmosphere compressor. Frequency conversion air compressor is only the first expenditure, but if you take the electricity price into account, you can really gear box for greenhouse calculate a bill. Nowadays, the overall energy-saving amount of regularity converter surroundings compressor is very objective, and the domestic professional rate of recurrence converter air flow compressor, its power-saving price is as high as 30%, usually within a yr can recover the difference. Therefore, whenever choosing air flow compressor, choosing a good variable frequency surroundings compressor is really the very best option to the issue of power consumption.