How to calculate the compressed air consumption
Calculation method of air consumption in compressed air system
In industrial production, accurate calculation of compressed air demand is the basis for ensuring normal operation of equipment and rational utilization of energy. The following are the general calculation principles and methods:
1. Basic computing logic
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Determine the air consumption of a single equipment
Check the equipment manual for “air consumption under standard conditions”(usually expressed in cubic meters per minute or cubic feet per minute), which represents the rate of air consumption at the equipment’s continuous operation at rated pressure. -
Statistics of simultaneously running equipment
Add the air consumption of equipment that may be working simultaneously during the same time period to obtain the basic demand value. For example: 3 pneumatic wrenches (0.5 cubic meters per minute each)+2 spraying equipment (1.2 cubic meters per minute each)= 3.9 cubic meters per minute -
Consider peak coefficient
According to the production rhythm, a margin of 10%-30% is increased to the basic value to cope with equipment start-up impact, temporary overload and other conditions.
2. Actual measurement verification
For old equipment lacking technical parameters, the following methods can be used:
- gas tank depressurization method
- Record the time it takes for the air tank to drop from the initial pressure to the target pressure
- Calculated through the formula: air consumption = air storage tank volume × pressure difference ÷ time
- ultrasonic flowmeter
Install a non-contact flowmeter on the main pipeline and take the average value continuously for 72 hours. This method can reflect the dynamic demand under real working conditions.
3. Adjustment of special working conditions
- Pulse-type gas equipment (such as cylinders) needs to consider the product of air consumption per single action and operating frequency
- Vacuum generator equipment should be converted to equivalent air consumption
- For every 10℃ increase in ambient temperature, the volume of air expands by about 3.5%, and the calculated value needs to be adjusted accordingly.
4. System optimization suggestions
It is recommended to adopt a hierarchical air supply plan: Separate air storage tanks for continuous air equipment (such as purge systems) and intermittent air equipment (such as pneumatic valves) can reduce the installed capacity requirement of air compressors.
This calculation method is suitable for most industrial gas scenarios, and should be dynamically adjusted based on the actual operating data of the equipment during specific implementation.
