HangZhou Changchen Industrial Co.Ltd. , https://www.hzcc16.com
The motor and gearbox are forced cooling systems that are cooled by closed cooling water. Two major failures in the replacement of the pump shaft have occurred since the feed pump was put into operation. After turning to standby, it will start again due to vibration. The isolation check and the manufacturer's confirmation are similar to the previous failure, and the pump core needs to be replaced. The same two faults in succession exposed some problems in the logic design, operation, and thermal system design and layout of the feedwater system. Fault Analysis Because the phenomena and results of the two faults are roughly the same, the description of the faults in this paper is mainly based on the first inspection analysis. The wear direction of the non-drive end thrust pad of the pump shaft is opposite to the running direction of the pump (clockwise for the coupling). The fixed end of the non-drive end thrust pad is also partially worn. The drive end radial bearing is good non-destructive but the non-drive end radial bearing is not, it may be caused by the debris of the thrust tile, the damaged thrust tile shows that the pump has been reversed for a period of time without lubrication. The balance drum and the casing are killed, and the final impeller is damaged by the non-drive end shield. These damages also indicate the pump's reversal. There are some carbon deposits on the inside and outside of the non-drive end seal. All of the above phenomena indicate that the pump has been operated in a non-linear region, or it may be caused by the breakage of the flange gasket of the balance drum return pipe, which causes the water pressure in the water to drop rapidly and cause the water vaporization. It can be seen that the non-drive end seal retainer has the same damage, indicating that the non-drive end is also subjected to a large thrust. In addition, the steam drum water supply valve is quickly switched, which can be derived from the deformation of the sealing ring of the sealing ring. From the severity of the damage, it is unlikely that the water supply electric machine date and time record is triggered by the check valve failure, and the switchgear is tripped. The switchgear is recorded as an overload and restarts the feed pump and trips again. The large displacement alarm starts to feed the pump, and the switch cabinet records that the overloaded factory power switch trips to start the feed pump, and the axial displacement is large. The pump is then overhauled. After the pump pack is replaced, the test is repeated several times. Power trip, plant power loss, start feed pump failure (electrical re-shock switch) start feed pump, the drive end axial vibration is large, continue to run the pump stop start feed pump, check that the balance drum trap opens to start the feed pump, but the vibration is better The large-scale operation of the hand-operated valve will open the main valve of the water supply rapidly, causing the flow rate of the feed pump to be over-flowed.
Analysis of Forced Lubricating Oil System with Closed Cooling Water Cooling