Gallery, Projects and General > Neat Stuff

500,000 to 600,000 rpm!!!!!!

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ieezitin:
Bernd. It was not up to full speed yet. Not quite sure of the full rpms, all I know is no oil = loud noise = me reverting back to the womb, coupled with Southern California Edison forking out millions in repairs and creating havoc on the electric grid demand, this was back in 2004 when electric was scarce at that time.

Rleete. Interesting!. I know of large freighters being built in Japan where they freeze the bearing housings and introduce magnetism to form the bearing journals. But I am sure those power plants no where near reach the rpm speeds.


Question, if I am getting this right if the bearing was magnetic and the revolution of the rotor was such a high speed would it be gravity that would interfere with the magnetism?

Thanks for the info.

Anthony.

rleete:
I have no idea, just throwing that out there as a possibility.

one_rod:

--- Quote from: ieezitin on January 06, 2010, 01:41:34 PM ---

...... they had to break down the main rotor shaft and blades ship them back to England to get reworked and sent back.........

Just  thought I would share.     Anthony.

--- End quote ---

Great story Anthony.

My brother worked for a while in the machine shop where they make these rotors. Probably the same place that did that rework.

The rotors are turned from a forged billet on a very big lathe. The turner starts a cut at the beginning of his shift, another man takes over while he gets his breaks, and if all goes well he will have finished one pass by the end of his shift. The next shift turner takes over and starts the next cut and so on.
There was actually a chair bolted to the saddle of the lathe for the turner to sit in while he drives the machine.

Another world from "our" scale of engineering.



one_rod.

ieezitin:
One rod.
Ha HA . Small world about your brother. In the paper mill where I did my apprenticeship we had a lathe that was on the back of a rail car, it came in driven by an diesel engine, we then affixed the bed rails to fixtures in the floor, then with a regular dial indicator we aligned the bed.

This particular lathe was made special for a set of charge rolls for a particular machine in the line. The radius of the roll was around 8ft x 27ft wide it basically was made by cold rolling steel plate 5/8” thick and making a cylinder by welding all the pieces of the jigsaw together, they would weld  caps on the end and then grind down or flattop the welds. It was then they turned it down to a  wall thickness of around 3/8 thick. This procedure alone took around 4 days two shifts.

Then over the skin of the roll we had to cement and adhere Italian granite tiles dug out of the alps in northern Italy. They were specially profiled to fit the cylindrical rolls. This was turned down too. But at a slower pace. That added a wall thickness of 2”. Through the shaft axis there was piping supplying steam to the roll. All in all this job took around three weeks and a set of rolls lasted around five years.

How it works is like this, the rolls are installed one on top of another, A roll B roll, B roll was the bottom unit, it was driven by a motor gearbox direct drive. The line  ( paper making machine )  was around 800ft long 50ft high in some places. Through the entire maze of rolls belt tentioners idler rolls there was strung a stainless belt called the wire, this was the width of the machine less 6 inches either side, It was made like a fine mesh to act like a strainer, a little like the strainer your mother used for castor sugar. From the pulper ( giant food mixer on steroids ) came fine white bleached wood fiber pulp, it was sucked out under pressure and delivered to the layer line positioned just in front of the said A-B rolls, it was spewed and layered on the wire, The rolls that were super heated because of the steam would squeeze and flatten the pulp, flash heating it and immediately turning it from a liquid to a sheet of paper, the rest of the machine was just for conditioning  the paper giving it a glaze while adding grain qualities.

The old-timers in the mill told me that the lathe I talked about was commandeered
By the government back in both wars it was making parts for the war efforts. What it made I have no clue. In fact the whole machine shop was making stuff for the war, papermaking production dropped drastically through this period.

But I am sure now the Chinese  can make paper like this from the back of a rickshaw and sell it for $0.25 a ream.

All the best.                   Anthony.

cidrontmg:
ehh, on the side of "small" turbines, and high revs, what about the dentists drills? They usually do at least some 300 000 revs/min, commonly around 400 000, and at the higher end they whine at 800 000 rpm. They fit (relatively easily at that) in your mouth (even a small childīs mouth), among at least a dental mirror, a saliva aspirator and the dentistīs finger(s). And they do WORK in there...
Itīs >20 years since I last worked as a dentist, but "Borden turbine drills" were old hat already then, first being introduced around 1957-58 - over 50 years ago...

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