Analysis of the Causes of Oil Cooler Failure

During the operation of the units, units #1, #2, #5 and #6 have repeatedly experienced water leakage or oil leakage from the bottom end cover of the cold oil tank. Especially during the start-up or shutdown of the units, the occurrence of such faults is even more frequent. The isolation between the oil and water in the cooler and the leakage of oil and water all rely on two O-rings. Once the two O-rings are damaged or displaced, causing a change in the gap, it will inevitably lead to leakage. Because the sealing surfaces of this O-ring are on the left and right sides instead of the traditional top and bottom sides, once leakage occurs, increasing the tightness of the flange bolts cannot reduce the leakage volume.

After analysis, the following several reasons that are prone to cause changes in the gap and damage of O-rings have been summarized.

During the start-up or shutdown of the unit, pressure fluctuations often occur on the oil side and water side of the cooler, causing the O-ring to move and resulting in leakage.

2) When installing the unit, if the cold oil cooler is eccentrically installed inside, it will cause abnormal clearance of the O-ring seal. During operation, if there is even a slight fluctuation in pressure (on the oil side or water side), it will cause leakage.

3) During each maintenance process, when replacing the O-ring, due to the narrow position of the bottom end cover, installation is often inconvenient during maintenance, and the O-ring is often crushed by the copper bed, resulting in leakage. After each maintenance, the probability of leakage on the water side is higher than that on the oil side, which further proves that the current design is not convenient for maintenance and cannot ensure the quality of maintenance.