The inlet pressure required by the equipment shall be comprehensively evaluated in combination with the equipment operation requirements, pipeline loss and compressor performance. The specific steps are as follows:
1. Clear equipment pressure requirements
- refer to the equipment manual: Equipment manufacturers usually indicate the required intake pressure range (e. g. 6-8bar) in the technical documentation.
- process characteristic analysis:
- high-precision equipment(such as laser cutting, precision spraying): need to stabilize the pressure, the fluctuation range is recommended to be controlled within ± 0.1bar.
- General Purpose Pneumatic Tools(such as air cannon, grinding machine): the pressure demand is low, usually in 5-7bar can be met.
2. Evaluate the pressure loss of the pipeline
- pipe resistance calculation: When compressed air flows in the pipeline, there will be a pressure drop due to friction. The amount of loss depends on the pipe diameter, length, number of elbows and flow:
- empirical formula: Every 30 meters of straight pipe loses about 0.1bar, and each 90 elbow loses an additional 0.05bar.
- Example: If the equipment requires a pressure of 6bar and the total pipeline loss is 0.5bar, the compressor outlet pressure must be at least 6.5bar.
- Optimization recommendations: Shorten the length of the pipeline, increase the pipe diameter (such as DN50 instead of DN25), reduce the number of elbows can reduce the loss.
3. Consider compressor performance boundaries
- rated pressure matching: When selecting a compressor, its rated pressure should be higher than the equipment demand + pipeline loss. For example, if the equipment needs 7bar and the pipeline loss is 0.3bar, the compressor needs to be selected for models above 7.5bar.
- Adjustment Capability Verification: Confirm whether the compressor has pressure adjustment function (such as frequency conversion control) to adapt to the pressure demand under different working conditions.
4. Reserved safety margin
- future expansion: If you plan to add new equipment or expand production, it is recommended to reserve a pressure margin of 1.2-1.5 times the current demand.
- Performance attenuation compensation: After the compressor is used for 3-5 years, the pressure output may drop due to component wear, and the initial design should increase by 5%-10% margin.
5. End voltage stabilizing measures
- gas tank configuration: Install a gas storage tank near the gas consumption point (the volume is recommended to be 5-10 times the air consumption of the equipment) to buffer pressure fluctuations.
- Precision pressure regulating valve for pressure sensitive equipment, a proportional regulating valve is installed to control the pressure fluctuation within ± 0.05bar.
6. Professional verification and testing
- pressure mapping test: Use the pressure sensor to arrange measuring points along the pipeline, draw the pressure distribution diagram, and identify the abnormal pressure point (such as the area where the local pressure drop exceeds 0.2bar).
- Leak Detection: Check pipeline leaks through ultrasonic detectors. Small leaks (such as holes with a diameter of 0.5mm) may cause annual loss of thousands of cubic meters of compressed air.
Example Scenario
A factory to add a 7bar pressure CNC machine tools:
- equipment requirements: The machine manual requires an inlet pressure of 6.5-7.5bar.
- Pipeline loss: The pipeline is 40 meters long, including 3 elbows, and the estimated loss is 0.4bar.
- Compressor selection: Select a model with a rated pressure of 8bar to ensure that the pressure at the end of the pipeline is ≥ 7.1bar(7.5bar demand-0.4bar loss).
- Voltage stabilizing configuration: install 0.3m & sup3 at the inlet of the machine tool; air storage tank and precision pressure regulating valve to stabilize the actual air supply pressure at 7.2±0.1bar.
Through the above systematic evaluation, the equipment can be ensured to operate under the best pressure conditions, and the efficiency loss caused by insufficient pressure or the waste of energy consumption caused by excessive pressure can be avoided.
