1, accident history:
A factory's turbine started and the oil pressure of the #7 bearing jacking shaft was 9Mpa when the dump truck was running. However, the pressure showed a decreasing trend after the rush. Although four jacking oil pumps were turned on (three were originally running), little effect was achieved. The oil pressure dropped to 4.4 Mpa, and the temperature of the oil pipe of the #7 bearing jacking shaft was significantly higher than that of other bearings.
2, cause of accident:
In view of the above phenomenon, it is speculated that the #7 bearing top shaft oil flow is large, and there may be oil leakage, resulting in low pressure and high temperature. After opening the bearing cover and conducting a detailed inspection, it was found that the oil pipe at the elbow from the top shaft oil pipe to the bearing oil hole had cracked due to quality problems, causing the top shaft oil to spurt out from here and leak, and insufficient pressure could not be established. The problem was solved after the fracture was firmly welded, and the #7 bearing jacking shaft oil pressure rose to 8.5Mpa (three jacking shaft oil pumps were running).
3, precautions:
(1) Strengthen construction supervision to ensure construction quality.
(2) It is necessary to accumulate the top shaft oil pressure change curve during the turbine's overturning process. Once an abnormality is found, the machine should be stopped for inspection to ensure the safety of future shutdowns.
Source: Thermal Power Circle
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