How to calculate how much compressed air all equipment requires

To scientifically plan the compressed air system, the total demand for all equipment needs to be determined through systematic calculations. The following is a step-by-step explanation:

Step 1: Survey of equipment gas consumption

1. inventory preparation: List all equipment that uses compressed air, including production machinery, pneumatic tools, instrument control systems, etc.
2. parameter acquisition: Check the equipment manual or technical manual and record the rated air consumption of each equipment (usually in L/min or m³/min). If the equipment is not clearly marked, you can refer to the industry standard values of similar equipment.
3. use pattern analysis: Distinguish between continuously operating equipment (such as sandblasting machines) and intermittently operating equipment (such as pneumatic wrenches), and record the single working cycle and frequency.

Step 2: Calculation method of demand

1. basic calculation method：
   • formula: Total demand = ∑ (rated air consumption of single equipment × simultaneous utilization factor)
   • description: The simultaneous use factor needs to be determined based on production reality, for example:
     • Assembly line operation: 0.8-0.9 (strong equipment linkage)
     • Mechanical repair workshop: 0.6-0.7 (equipment use is highly random)
2. dynamic monitoring method(For complex systems):
   • Use a flowmeter to measure each gas consumption point and record the fluctuations in gas consumption at different periods of time.
   • Draw a load curve, identify peak demand and duration, and provide data support for air compressor selection.

Step 3: Correction under special working conditions

1. pressure compensation: If the operating pressure of the equipment is lower than the rated pressure of the air compressor, the required quantity needs to be corrected proportionately. For example:
   • If the air compressor output pressure is 7bar and the equipment working pressure is 5bar, the actual demand needs to be multiplied by the correction factor (5/7).
2. pipeline loss: During long-distance transportation, improper selection of pipe diameter may lead to pressure loss. Suggestion:
   • The main pipeline flow rate is controlled at 15-20m/s
   • For every additional 100 meters of pipeline, the pressure loss is about 0.1 bar, and the output pressure of the air compressor needs to be increased accordingly.

Step 4: Reserve safety margin

1. basic allowance: Increase a margin of 10%-20% based on the calculation results to cope with the increase in gas consumption caused by future production capacity expansion or equipment aging.
2. redundant configuration: For key production equipment, it is recommended to adopt an air compressor configuration plan of “one for use and one for standby” or “dual use and one for standby” to ensure continuity of air supply.

example computing
Suppose a workshop contains the following equipment:

• CNC machine tools (3 sets, single machine consumes 500L/min)
• Paint guns (2, single unit air consumption 800L/min)
• Pneumatic clamps (10 sets, each set consumes 200L/min)

calculation process：

1. Basic demand = (3×500 + 2×800 + 10×200) = 1500 + 1600 + 2000 = 5100L/min
2. Consider the simultaneous use factor (take 0.75): 5100×0.75 = 3825L/min
3. Reserve 20% margin: 3825×1.2 = 4590L/min
4. Convert to standard units: 4590L/min ≈ 4.59m³/min

conclusion: This workshop needs to be equipped with an air compressor with a rated flow rate of ≥4.6m³/min. It is recommended to choose a 5.5m³/min model to not only meet current needs, but also reserve room for expansion. The actual selection also requires a comprehensive decision based on the pressure requirements (usually 6- 8 bar) and the gas quality requirements (whether it needs to be equipped with dryers and filters).