Discussion on several issues regarding the cranking of large pumps (with built-in oil systems)
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Recently, the manager asked me to draft operation guidelines for turning large pump gears. I think the former Ministry of Chemical Industry must have had regulations or departmental standards on this, but no matter how much I looked, I couldn’t find any. I’ve seen quite a few posts about disc cars on Haichuan, but I always feel they’re not comprehensive enough. I have the following questions and would appreciate some guidance from those with more experience: 1. What are the regulations regarding the frequency of rotating small pumps? 2. What are the regulations regarding the turning frequency of large pumps with built-in oil systems (sliding bearing)? 3. Must the oil system be operational during the standby period of the large pump (it has a self-start function, but the interlock is not activated)? Is the barring gear operation dependent on the oil system being operational? 4. How many times should a small pump be turned manually each time? 5. How many degrees should the large pump be turned per rotation? 6...There are still issues; everyone else please fill them in.
An additional 6 points will be given to everyone who participates actively! ! Everyone is welcome to discuss...........
Cranking the machine is done to ensure its proper startup and to protect the equipment. The oil system usually operates normally during cranking. Cranking must cover at least 360 degrees; to enable timely detection of any issues, it is generally required to crank the machine more than 3 times.
This post was last edited by Chuanhua on 2010-1-2 at 20:15. The purpose of rotating the shaft before driving is to determine the degree of bending of the bearings and to distribute lubricant evenly over them, thereby preventing rusting of the bearings. When large units are just shut down, turning the shaft is necessary because the bearings may bend as they cool down; it is best to use an automatic shaft turner for this purpose. If no such device is available, the shaft should be turned 90 degrees every half hour until the temperature drops to 100 degrees, while under normal conditions it should be turned more than 360 degrees once a day. When the large unit is in standby mode, the oil system should remain operational, with the oil temperature and pressure carefully controlled. Turn the machine once a day to check the insulation, etc. For small pumps, once a day is enough. Of course, it’s not a hassle at all; each class can do it as well. We seem to do it once a week.
I have department documents related to disk spinning on my work computer; if I don’t forget, I’ll copy them over tomorrow
I wonder if there are any factories that allow the turbine to be rotated without the oil system in operation? In other words: Must the oil system be running when turning the machine shaft of a unit with sliding bearings? ?
This post was last edited by ZZJJAA70 on 2009-12-16 07:10. Today, I searched on the computer at work, but unfortunately I couldn’t find it. If I do find it, I’ll get in touch with you then. For now, I’ll use some of the knowledge I have to address your question! Actually, what the colleague mentioned above is quite good; I’ll add a few more points. When turning the pump shaft, it’s also important to pay attention to the direction of rotation – it should be in line with the rotation direction of the shaft. Here, whether it’s large pumps or small pumps, we require that the spare pumps be turned each shift. We have a four-shift, two-shift rotation system. As for how many degrees the shaft should be turned, it’s probably just a few rotations. The key thing is to check whether there is any sticking during the rotation process; if there is sticking, it means the shaft has bent and needs to be repaired ； Of course, large pumps are different from small pumps; the packing in large pumps is tighter, and the shaft weight means that turning the pump is more labor-intensive. For example, turning the semi-depleted liquid pump in the decarburization system is quite strenuous. . . Regarding whether the oil system must be operational during the standby period of large pumps (with a self-start function but with interlocks not activated)? Is the barring gear operation dependent on the oil system being operational? ”Here, for the large pumps in the oil system that are equipped with interlocks, we also require that the pumps be turned by hand once per shift. Since these pumps are in standby mode, the oil system is operating and the control panel is set to “AUTO”. According to the operating procedures, before turning the pump by hand, the control panel must be switched to “MAN”. With the oil system still running, the pump is turned using a special wrench. After turning it, the control panel is switched back to “AUTO”. The reason for this procedure is to prevent the interlocks from activating during the turning process, which could cause injury. In other words, it’s a way of disabling the interlocks; the oil system doesn’t need to be adjusted at this time. Usually, the oil system is driven by a auxiliary oil pump, and whether the pump operates in manual or automatic mode makes no difference. Generally, the auxiliary oil pump is set to “MAN” at this time. Personally, I disapprove of this practice
Failing to turn the shaft of the machine or pump regularly can cause bending and deformation of its shaft; starting the pump without turning the shaft can easily lead to damage to the motor