How to optimally select an air compressor?
Views : 434
Author : Runningway
Update time : 2021-09-13 13:04:55
Many users do not know how to choose when purchasing an air compressor. This time we will analyze how to choose an air compressor. The basic criteria for choosing an air compressor are economy, reliability and safety.
1. The level of exhaust pressure and the amount of exhaust should be considered.
The discharge pressure of the general-purpose aerodynamic compressor is 0.7MPa, and the old standard is 0.8MPa. At present, there is an air compressor with an exhaust pressure of 0.5MPa, which is unreasonable from the point of view of use, because the pressure margin is too small for the pneumatic tool, and the air delivery distance is slightly longer and cannot be used. In addition, from a design point of view, this compressor is designed for one-stage compression, and the pressure ratio is too large, which will easily cause excessive exhaust temperature, causing carbon deposits in the cylinder and causing accidents. If the compressor used by the user is larger than 0.8MPa, it should be specially manufactured, and the method of forced pressure increase cannot be adopted to avoid accidents.
The air displacement is one of the main parameters of an air compressor. The air volume of the air compressor should be selected to match the required air displacement, and a 10% margin should be left. If the air volume is large and the air compressor has a small exhaust volume, the air-driven tool will greatly reduce the exhaust pressure of the air compressor when the air-driven tool is activated, and the air-driven tool cannot be driven. Of course, blindly pursuing a large displacement is also wrong, because the larger the displacement, the larger the motor equipped with the compressor, not only the price is high, but also a waste of purchase funds, as well as a waste of electricity and energy when used. In addition, when selecting the exhaust gas volume, the peak volume, the usual volume and the low volume volume should also be considered. If the trough usage is large, but the usual usage and peak usage are not large, the usual method in foreign countries is to connect air compressors with a smaller displacement in parallel to obtain a larger displacement, and start them one by one as the gas consumption increases. Not only is it good for the grid, but it also saves energy.
2. Consider the use of gas occasions and conditions.
If the gas space is narrow (for boats, vehicles), vertical type should be selected; if there is a long-distance change (more than 500 meters) in the gas usage occasion, mobile type should be considered; if the occasion cannot be used for power supply, diesel engine-driven type should be selected ; If there is no tap water in the application, the air-cooled type must be selected.
Regarding the two cooling methods of air cooling and water cooling, users often have the wrong understanding that water cooling is good, but it is not. Air-cooled compressors account for more than 90% of domestic and foreign small compressors. This is because air-cooling is simple in design and does not require water source when used. There are four fatal disadvantages of water-cooled compressors: it must have a complete water supply system and large investment; water-cooled coolers have a short life; in the northern winter, the cylinder is easy to freeze; a lot of water will be wasted during normal operation.
3. Consider the quality of compressed air.
Generally, the compressed air produced by an air compressor contains a certain amount of lubricating oil and a certain amount of water. In some cases, oil and water are forbidden. At this time, not only the selection of the compressor should be paid attention to, but also auxiliary devices should be added when necessary.
The solution: one is to use a non-lubricated compressor. This kind of compressor cylinder basically does not contain oil, and its piston ring and packing are generally polytetrafluoroethylene. But this kind of machine also has shortcomings, poor lubrication, and high failure rate; PTFE is also a harmful substance, which cannot be used in the food and pharmaceutical industries; non-lubricated compressors can only deliver gas without oil, not water. The second and commonly used method is to add a primary or secondary purification device or dryer to the air compressor (no matter which type). This device can make the compressor air contain neither oil nor water, so that the oily water content in the compressed air is below 5 ppm, which can meet the process requirements.
4. Consider the safety of compressor operation.
Air compressor is a kind of machine that works under pressure. It is accompanied by temperature rise and pressure during work. The safety of its operation must be given top priority. The country implements a standardized "two certificates" system for compressor production, namely compressor production license and pressure vessel production license (gas storage tank). Therefore, when purchasing compressor products, the "two certificates" must be strictly reviewed. Usually the product quality assurance system of the certified manufacturer is complete, and there will be no major quality problems. Even if there are some problems, the manufacturer will be responsible for the three guarantees.