Reasons for friction between the rotor and casing of a Roots blower
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The Roots blower in our company experienced an unexpected shutdown due to friction between its impeller and casing (both made of stainless steel). Upon inspection, the bearings and gears were in good condition, and the nuts were not loose; no cause could be identified. It is preliminarily assumed that foreign objects entered the system, so a filter will be installed at the blower’s inlet. For the Rotary Vane Blowers of this model that were shut down due to normal operational issues at our company recently, after replacing the V-belts, one of them stopped operating after less than half an hour due to friction between the rotor and the casing. Before it stopped, the vibration level was low, at less than 4 mm/s; the allowable limit is 11.3 mm/s ； In another unit, friction between the rotor and the casing occurred within less than three hours, and no cause could be identified even after inspection. Please discuss this! Thank you! !
I can only think of two things. 1 is excessive temperature; 2 is whether the wall panel and the enclosure are fixed with positioning pins or connected by a direct joint – if it’s a direct joint, there’s more to explain
Haha, still keeping it a secret? Just tell me already;P
This post was last edited by zhangtian* on 2020-6-15 12:08: End fitting connection. The fan was operated at no load for ten minutes; the DCS indicated a shutdown due to overtemperature. However, the time at which the current changed significantly was one minute earlier than the time when the temperature changed significantly.
I repaired one; its vibration level was 2.5, and the vibration felt weak to the touch, while those repaired by others had a noticeable vibration of around 4. Fixing it right away can solve half of the problems; you’ll have to figure out the other half on your own. I’ve also been reading in straight prose for over 20 years: L:L This is the first time I’m writing it down
I’d like to complain about some repair workers these days – they’ve turned what was once a technical job into a simple task, where all that’s required is to know how to disassemble something and then reassemble it as before. To put it bluntly, even a dog could do that task of tying up a bun; yet they won’t let you speak about it, acting like they know everything when they don’t. All day long, I’m fine, you’re fine, everyone’s fine. For example. If a centrifugal pump leaks, how do you fix it? Do you just install another one in its place? . Don’t you check where the leak is coming from – is it an O-ring issue or a problem with the end face? If there are no issues with the end faces of the O-rings. Aren’t you going to calculate the compression amount? Is wear proportional to time? Everything is fine; let’s check the circulating water. Think more about how much less work you can do in the future
I’m angry. Let me give an example. A shielded hot oil pump. There is always leakage (smoking) at the lower part of the connection, and the vibration level is high as well. Trying different bearings several times didn’t help. When it was my turn to work there, I found that the pipeline had sunk, so the pump couldn’t be installed directly; it needed to be lifted. In the past, they used levers to lift it so that it could be reinstalled. I used a jack to lift the pipeline directly, and it has been installed there for over a year now; the maximum vibration level is 0.5, and there is no more smoking. That’s why what is understood and what is actually done are different.
Ordinary stainless steel has a high coefficient of expansion, and overheating can more easily lead to scraping between the rotor and the casing; however, no problems will occur if it is not operated beyond its limits
With changes in stainless steel temperature, is the gap sufficient?
80% of your components consist of synchronous gears that are worn out