1. Compressed air use.
2. The lowest working pressure.
3. The demand air volume for cutting-edge and off-peak. If the difference between the highest and lowest operating pressure reaches 3bar, you must consider the "high and low pressure split", and then choose different types of air compressors according to the changes in the peak and off-peak burdens, such as "base load" using centrifugal (single machine> 75CMM) or spiral type (single machine <60CMM): "Variable load" uses a high-pressure air machine and a large air tank to respond.
4. Different types and grades of dryers and precision filters are selected and configured according to different gas quality. Too good quality wastes energy, and insufficient quality affects the manufacturing process, which must be carefully considered.
5. The control technology of air compressors is changing with each passing day. "Multi-machine interlocking", "frequency conversion" and "remote monitoring" technologies can effectively suppress centrifugal BOV and spiral empty vehicle waste (saving electricity costs by 25-40%) and reduce Standby capacity and investment (15-30%), stable air supply pressure (plus or minus 0.1 bar.
6. The operating efficiency cannot only be compared with the nominal horsepower and air volume in the catalog, but the focus is on the actual "performance curve" and "air volume per horse".
7. The installation considers the size of the computer room space. Ventilation conditions, noise isolation, waste heat, waste water recycling, etc. all induce energy use. In addition, "centralized" has lower installation, maintenance and control costs than "distributed", and can also reduce peripheral equipment.
8. As for the cooling method, there are air cooling and water cooling. Air cooling does not require additional investment in cooling tower rainwater, but it must have good ventilation: water cooling is that the operating temperature is not affected by the environment, which is beneficial to the life of the air compressor, only icing Disadvantages of bursting and blocking.
9. The power planning voltage demand and the stability of the voltage drop must be required. The centrifuge is usually high-voltage and cannot be moved at all. It will cause an impact on the power grid when starting, and it should be kept in regular operation.
10. The maintenance room should have proper maintenance space and necessary lifting facilities and access channels. Engineering personnel and maintenance should also be given different professional maintenance training.
How to buy
When preparing to purchase an air compressor, first determine the working pressure required by the air end, add a margin of 1-2 bar, and then select the pressure of the air compressor. (The margin is considered from the installation location of the air compressor The pressure loss of the pipeline distance to the actual gas end, according to the length of the distance between 1-2 bar, appropriately consider the pressure margin). Of course, the size of the pipeline diameter and the number of turning points are also factors that affect the pressure loss. The larger the pipeline diameter and the fewer turning points, the smaller the pressure loss; on the contrary, the greater the pressure loss.
Therefore, when the distance between the air compressor and each gas end pipeline is too far, the diameter of the main pipeline should be appropriately enlarged. If the environmental conditions meet the installation requirements of the air compressor and the working conditions permit, it can be installed near the gas end.
Volume flow selection
1. When selecting the volumetric flow rate of an air compressor, you should first understand the volumetric flow rate of all air-consuming equipment, and multiply the total flow rate by 1.2 (that is, enlarge the margin by 20%);
2. The new project can be selected according to the flow value provided by the design institute;
3. To learn about the volumetric flow parameters of the gas-consuming equipment from the gas-consuming equipment supplier for selection;
4. The air compressor station can be selected with reference to the original parameter values and actual gas usage conditions;
Appropriate selection is beneficial to both the user and the air compressor equipment. Excessive selection is wasteful, and too small selection may cause the air compressor to be in a long-term loading state or insufficient air or pressure can not reach the disadvantages.
The relationship between the three
In the case of constant power, when the speed changes, the volumetric flow and working pressure also change accordingly; for example: a 22KW air compressor, the working pressure is determined to be 7bar at the time of manufacture, calculated according to the main compressor technical curve Speed, the displacement is 3.8 m3/min; when the working pressure is determined to be 8bar, the speed must be reduced (otherwise the drive motor will be overloaded), at this time, the displacement is 3.6 m3/min; because the speed is reduced, the displacement Qi is also reduced accordingly, and so on.
The selection of power is to meet the working pressure and volume flow conditions, and the power supply capacity can meet the power of the matched drive motor. Therefore, the steps for selecting an air compressor are: first determine the working pressure, then determine the corresponding volume flow, and finally the power supply capacity.