The greater the pressure of the air compressor, the greater the displacement
Analysis of the relationship between air compressor pressure and displacement
air compressor exhaust volume(gas output per unit time). Exhaust pressure it is not a positive correlation, and its variation depends on the equipment design and working principle. Here is the key analysis:
1. Theoretical relationship: the pressure increases and the displacement may decrease
- compression efficiency impact: Gas compression requires energy consumption. The higher the pressure, the greater the energy required for the compression process. If the motor power is constant and the compression time is prolonged, the exhaust volume per unit time (such as m³/min) may be reduced.
- Decreased volumetric efficiency: The gas density increases under high pressure, and the leakage loss (such as piston ring gap and valve seal) increases, resulting in a decrease in the actual output gas.
- temperature effect: The compression process generates heat. If the cooling is insufficient, the expansion of high-temperature gas will occupy the volume of the compression chamber, further reducing the exhaust volume.
2. Impact of equipment type
- piston air compressor: When the pressure increases, the displacement decreases more obviously (because the reciprocating efficiency of the piston decreases with the increase of pressure).
- Screw air compressor: The screw rotor design can partially offset the pressure effect, but the high pressure still requires greater power consumption, and the exhaust volume may still be reduced.
- Variable frequency air compressor: By adjusting the speed to match the load, the pressure and displacement can be balanced within a certain range, but the overall is still limited by physical laws.
3. Rated condition and performance curve
- rated displacement: Usually labeled as a value at a specific pressure (e. g. 7 bar or 10 bar). If the actual pressure exceeds the rated value, the displacement may drop significantly.
- Performance curve: The exhaust volume under different pressures needs to refer to the equipment performance curve. For example, the exhaust volume of a certain model is 10 m³/min at 7 bar, and may drop to 8 m³/min when it rises to 10 bar.
4. Special design cases
- multistage compression: Reduce the single-stage pressure ratio through multi-stage compression, which can maintain a high displacement under high pressure (such as high-pressure piston air compressor).
- Special booster: Some equipment is specially designed for high pressure. Through enhanced cooling and sealing, a large exhaust volume can be maintained under high pressure, but the cost is high.
Conclusion
the greater the pressure of the air compressor, the smaller the displacement is usually., Especially in the case of single-stage compression and constant rated power. When selecting the type, it is necessary to match the pressure and displacement according to the actual demand, and refer to the equipment performance curve. If high pressure and large displacement are required, multi-stage compression or frequency conversion technology can be considered to optimize operating efficiency.
