Oil free Screw Compressor keeps running without stopping, which may be caused by pressure switch failure, system leakage, abnormal inlet valve, controller failure or sudden load change, etc. Combined with the characteristics of
oil free compressor,
oil free scroll compressor,
centrifugal compressor, water lubricated oil free compressor and other models, it is analyzed as follows.
lubricated oil free compressor and other models of characteristics, specific analysis is as follows:
First, pressure switch failure
pressure switch as the core of start-stop control of oil free compressor, if there is contact sticking (common in oil free scroll compressor electronic pressure switch), spring fatigue (Water lubricated oil free compressor mechanical switch is easy to appear). compressor mechanical switches), spring fatigue (as is often the case with water lubricated oil free compressor mechanical switches), or set point drift (as in the case of centrifugal compressors with faulty precision pressure sensors) can cause the equipment to run continuously without regard to the system pressure. For example, a food factory's oil free scroll compressor because of the pressure switch set value is low, although the system pressure has reached 8bar, but still continue to pump to the safety valve open.
Second, the system leaks
oil free screw compressor piping interface if the PTFE seals are aging, or Water lubricated oil free compressor water ring seal failure, it will cause continuous air leakage. In a pharmaceutical plant, the water lubricated oil free compressor was running continuously for 48 hours due to insufficient water level in the tank and broken water ring seals, resulting in the system pressure never reaching the 10 bar stopping value.
centrifugal compressor impeller seal ring wear (gap > 0.1mm), the internal leakage increases, the need to maintain the pressure through continuous pumping.
Third, the inlet valve abnormal
oil free screw compressor's inlet valve servo cylinder stagnation (e.g., the Middle East high-temperature environment sealing ring hardening), resulting in the valve can not be closed, a photovoltaic project of this model, so the continuous inlet pumping.
centrifugal compressor inlet guide vane actuator failure (such as motor gearbox oil shortage), so that the guide vane is always fully open, the air flow exceeds the system requirements, the pressure is difficult to meet the standard.
Fourth, the controller fails
oil free scroll compressor PLC controller program errors (such as pressure sampling module failure), an electronics factory, the model due to CPU chip overheating, misjudging the pressure is always <6bar and continuous operation.
Water lubricated oil free compressor frequency conversion controller parameters drift (such as pressure PID regulation failure), resulting in high loading frequency.
V. Sudden change of load
oil free screw compressor is loaded with the vacuum system of semiconductor factory, if the new coating equipment is started, the instantaneous gas consumption surges by 30%, and the system pressure plummets from 7 bar to 4 bar, which triggers the continuous gas pumping.
When the centrifugal compressor is used in a chemical reactor, if the vacuum demand in the reactor rises from - 0.06MPa to - 0.08MPa, the compressor has to run continuously to maintain a higher negative pressure.
Model-specific faults
Water lubricated oil free compressor: water lubrication system clogging (such as cooler fouling) leads to exhaust gas temperature exceeding 80 ℃, the controller forced to load air to dissipate the heat, a beverage factory, the model is therefore running continuously.
oil free scroll compressor: scroll disk wear (gap > 0.02mm) leading to a decline in compression efficiency, the need to extend the pumping time to maintain pressure, a South Korean LCD plant has been shut down for maintenance due to this failure.
Troubleshooting and Solution Suggestions
Pressure Switch Calibration: Calibrate the pressure switch of the oil free compressor (refer to ISO 8573-1 standard), and the centrifugal compressor needs to use a high-precision pressure calibrator (accuracy ±0.5% FS).
Air tightness test: Water lubricated oil free compressor's water ring seal is tested by soap bubble method, and helium mass spectrometry leakage detection is carried out on oil free scroll compressor pipeline (leakage rate <1×10-⁹Pa・m³/s).
Intake valve maintenance: the intake valve of the oil free screw compressor needs to be cleaned every 2000 hours for solenoid valves (using anhydrous ethanol), and the centrifugal compressor is checked for guide vane opening feedback (error ≤1%).
Controller diagnosis: check the pressure curve through the HMI interface of the oil free compressor, and reset the PLC program of the water lubricated oil free compressor (backup parameters are required).
If the problem cannot be solved after self-examination, it is recommended to contact ZAKF and other professional manufacturers (with 60,000 square meters of production base and a monthly output of 2,500 units of oil free compressor), whose three overseas operating companies can provide 24-hour online diagnosis, and rely on seven warehousing bases to realize the 15-day delivery of spare parts in a very short period of time, so as to ensure that the equipment quickly return to operation.
