1. When the negative pressure fan produces abnormal sound during operation, it is difficult to judge its cause quickly and correctly, and it must be fully adjusted. Common under: intake pipe suction solid impurities;

When abnormal sound occurs in operation, it is difficult to judge its cause quickly and correctly. Common under: intake pipe suction solid impurities; Negative pressure fan stator and rotating friction; The bearing is abnormal. At this time, the abnormal sound is often accompanied by vibration.

2. Check the vibration and abnormal sound, the cause of severe vibration of negative pressure fan is also difficult to intuitively judge, and it is necessary to pay close attention to and fully check. There are many types of vibration: mechanical vibration of fluid caused by field surge; Negative pressure fan and prime mover alignment is not good vibration; Improper installation of negative pressure fan, abnormal bearing; The vibration of the wheel is intensified by the balance cutting ring during long running. Mechanical vibration caused by contact with the gap or surface between the stator. For the determination of the towing state of the bearing part, see negative pressure fan vibration Detection and its limits.

Bearing temperature measurement is very important to understand the working condition of bearings. It is generally stipulated that the temperature rise of uranium bearing shall not be higher than the ambient temperature. In addition, we should also pay attention to the amount of lubricating oil and its pollution status, whether mud, oil temperature and oil pressure under non-directional conditions. For the negative pressure fan cooled by cooling water, attention should also be paid to the water quantity and temperature of cooling water. For the negative pressure fan with oil ring type oil lubricated bearings, it should also be confirmed whether the oil ring works normally.

4. The inspection of the shaft seal part should often check the leakage condition of the pumping seal part, the clearance or contact between the static part and the shaft, whether there is abnormal, abnormal sound and so on.

5. For other parts of the inspection, pay attention to the air outlet pressure, air intake pressure and abnormal changes. Find abnormal situation in time, whether the air volume, current and so on have been prevented in the end.