Many customers don’t know how to choose when purchasing a screw air compressor. Today I will talk to you about what you need to pay attention to when selecting an air compressor, mainly in the two directions of working pressure and volume flow. Please read the following overview carefully for details.
Selection of working pressure (exhaust pressure):
When users are ready to purchase a screw air compressor, they must first know the working pressure required at the air end, add a margin of 1-2 bar, and then select the pressure of the air compressor. (This margin is based on the air pressure. The pressure loss from the distance between the machine installation location and the actual gas end pipeline should be appropriately considered (the pressure margin should be between 1-2 bar according to the length of the distance). 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; conversely, 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 close to the gas end.
Selection of volumetric flow rate:
① When selecting the volumetric flow rate of the air compressor, you should first understand the volumetric flow rate of the gas equipment to be used, and multiply the total flow rate by 1.2 (i.e. enlarge the margin by 20%);
② New projects can be selected based on the flow value provided by the design institute;
③ Understand the volumetric flow parameters of the gas equipment from the gas equipment supplier for selection;
④ For air compressor station renovation, model selection can be made by referring to the original parameter values and actual gas consumption;
Appropriate selection is beneficial to both the user and the air compressor equipment. Selection that is too large is a waste, while selection that is too small may cause the air compressor to be in a loaded state for a long time or not use enough air or the pressure cannot be pumped up.
(3) The relationship between power, working pressure and volume flow
When the power remains unchanged, when the rotational speed changes, the volumetric flow rate and working pressure also change accordingly; for example: a 22KW air compressor has a working pressure of 7bar when manufactured. The rotational speed and exhaust gas are calculated based on the compressor host. The air volume is 3.8 m3/min; when the working pressure is 8bar, the rotational speed needs to decrease (otherwise the drive motor will be overloaded). At this time, the exhaust volume is 3.6 m3/min; because as the rotational speed decreases, the exhaust gas also decreases accordingly. , and so on.
The power selection is based on the conditions suitable for the working pressure and volumetric flow rate, and the power supply capacity can be suitable for the power of the matching drive motor.
Therefore, the general steps for selecting a screw air compressor are: first know the working pressure, then determine the corresponding volumetric flow rate, and then the power supply capacity.