In a catalytic cracking unit, what is the purpose of turning the gears after the main fan set is shut down?
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In a catalytic cracking unit, what is the purpose of turning the gears after the main fan set is shut down?
After shutdown, the unit goes from a hot state to a cold state, and the same is true for the shafts of the disks. Once it is understood that thermal expansion and contraction can cause deformation, it becomes clear why it is necessary to turn the disks.
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During shutdown, turn the shaft continuously for 30 minutes; after that, do so every 10 minutes, and thereafter once per hour. Cranking the machine is done to ensure an adequate shutdown time and prevent deformation or bending
Dude, it’s to prevent the shaft from bending, right? It seems unlikely that the bearing shells would deform.
Sticking may occur, but deformation seems unlikely
Under the influence of gravity, the shaft undergoes slight bending deformation; the purpose of using a shaft turning device is to distribute the forces evenly on the shaft and prevent such deformation.
If there is a temperature present, it is to prevent thermal deformation; thus, the disc needs to be checked frequently. At room temperature, it is to prevent deformation due to the weight of the shaft, and checking it once a week is sufficient
During shutdown, turn the shaft continuously for 30 minutes; after that, do so every 10 minutes, and thereafter once per hour. Turning the shaft is done to ensure an adequate shutdown time and to prevent deformation or bending. If it becomes impossible to turn the shaft at that point, then it will be necessary to remove the cover. Additionally, when the equipment is not in use for extended periods, nitrogen gas must be used for protection; otherwise, it will be difficult to open the stationary blades, and again the cover will need to be removed.
We have established the same rule: during shutdown, the shaft should be turned continuously for 30 minutes, and thereafter every 10 minutes. The main purpose of this is to protect the shaft, taking into account its service life. Turning the shaft continuously for the first 30 minutes helps to reduce its temperature, as the temperature of a rotating shaft is relatively high. After shutdown, the lubricant continues to flow, which allows the shaft to cool down more quickly when it is turned. When the shaft stops rotating and its temperature is still high, it is more prone to deformation due to gravity. Turning the shaft every 10 minutes ensures that the stress on it is distributed evenly even at high temperatures. Once the temperature drops to room temperature or slightly above, regular daily turning of the shaft for maintenance can be carried out
1. Cool down. 2. Prevent shaft deformation. We must keep turning the shaft (using an electric turntable) within 4 hours after shutting down the machine； Mainly, if it is done intermittently, after the main fan stops, there will definitely be many things to take care of with the device; tasks such as manual timed shaft turning are likely to make one so busy that important things get forgotten.
Because after the main fan stops operating, the temperature of the bearing shells is high; if the shaft is not rotated, it can lead to a lack of lubricant circulation for certain bearing shells, resulting in their deformation. Therefore, we stipulate that the shaft should be rotated frequently within 30 minutes after shutdown, and regular rotation during shift changes is necessary to prevent the shaft from bending