88. Why does the oil pump keep running for a while after shutdown?
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88. Why does the oil pump keep running for a while after shutdown?
Once the shaft comes to rest, the bearing shells and shaft journals experience high temperatures generated within the machine and by the rotor, which causes their temperature to rise rapidly. This can degrade the quality of the oil in the local oil film, as well as cause damage to the tungsten alloys used in the shaft journals and bearing shells. Therefore, after the machine is shut down, the lubrication pump must continue to operate for some time to remove the heat from inside the machine through circulation.
After the unit is shut down, the various bearing shells are cooled to protect them from being damaged by high temperatures
After the equipment stops operating, although its rotation ceases, the internal components such as bearings and rotors remain at high temperatures. In particular, components in large-scale equipment like piston rods, crossheads, and connecting rods need to be cooled. If the oil pump stops working at this time, it will cause the oil film on the surface of these components to be disrupted, leading to wear on their friction surfaces； The oil turns black and the operating conditions deteriorate ；
Once the shaft comes to rest, the bearing shells and shaft journals experience heat transfer from the high-temperature rotor inside the machine, causing their temperatures to rise rapidly. If no measures are taken, this will lead to deterioration of the local oil film and lubricants, as well as damage to the shaft journals and bearing shells. To prevent this phenomenon, the lubrication pump must continue to operate for some time after the machine is stopped, so that the oil circulation can carry away some of the heat.