To determine whether the speed of the expansion machine in the air separation equipment is normal, a comprehensive analysis should be conducted based on the equipment design parameters, operating conditions, monitoring data, and abnormal phenomena.
The speed of the expander may be adjusted according to changes in parameters such as intake pressure, temperature, and flow rate, and should be judged based on the current operating conditions. As the intake pressure increases, the speed may rise due to an increase in load. The ambient temperature decreases, the expansion ratio increases, and the rotational speed may briefly increase before stabilizing.
Real time monitoring of speed through the built-in speed sensor of the expansion machine ensures that the signal is free from interference or malfunction. Check if the sensor installation position is loose or dirty to avoid measurement errors. Comparing historical speed records under the same operating conditions, if the current value deviates from the mean by more than 10%, further analysis of the reasons is required.
The rotational speed is proportional to the expansion ratio. If the expansion ratio is normal but the rotational speed is abnormal, it may be a mechanical failure. Excessive rotational speed may cause an increase in bearing temperature. If the temperature exceeds the limit and the rotational speed synchronization is abnormal, the lubrication system needs to be checked. Abnormal rotational speed may be accompanied by increased vibration, and it is necessary to combine vibration spectrum analysis to determine whether it is due to rotor imbalance or bearing damage. Possible reasons for high rotational speed: The regulating valve may be stuck or out of control, resulting in excessive intake flow; Bearing wear or insufficient lubrication reduces friction; Control system malfunction. Possible reasons for low rotational speed: insufficient intake pressure; Internal leakage of the expansion machine; Excessive load. Possible causes of speed fluctuations include slow or oscillating response of the regulating valve, voltage fluctuations in the power grid, mechanical looseness or resonance.
