"Mr Olds Remarkable Elevator"

Excellent … Thanks for the link.

I was relieved to hear him finally mention Archimedes

MichaelG.

Very interesting short vid. Am I being thick (probably), but I still don't really see the advantage of this against the 'traditional' method whereby you rotate the archimedes screw inside the tube? I know they tried to explain it, but I still cannot for the life of me see why the result should be different. Apparently its widely used so it must be better.

Anybody?

regards Mike

In some cases it will be easier to rotate the tube

It may be better for certain products if the tube rotates, less damage to product, less sticking to the screw

What would be interesting is an efficiency test, to see which method is cheaper, the tube has an advantage where it can rotate a "scoop" of greater volume but does this translate into anything positive

Would this system reduce cavitation from a ships propeller?e

Edited By Ady1 on 08/11/2022 10:05:13

An interesting machine.

There's quite a few folks on the web examining why it's better... eg dust danger - https://www.prweb.com/releases/2009/08/prweb2799054.htm

At the heart of the problem eventually solved with an Olds Elevator are "dust explosions". A dust explosion is the catastrophic end result of the ignition of a dust cloud, created by the mixture of dust from materials and air, often within a bucket elevator. As Olds Elevator spokesman Richard McIntosh explains, standard bucket elevators "are notorious for allowing the conditions for dust explosions to exist." As for an Olds Elevator, McIntosh adds "Since Olds elevators convey material in fully-flooded mode there is nowhere for dust to form. No dust, no dust explosion".

Ches

Shouldn't think so. I think the reason that it works is that the material acts like a solid which is readily cleavable but with the bulk of the material having a frictional contact between the particles wereas water is fully fluid.

regrds Martin

As Ches says the main advantage is the system avoids creating a mix of flammable dust and air. Dust explosions were first studied in the UK in connection with coal mining, where it had been noticed that shot firing or a relatively small gas explosion occasionally resulted in massive explosions, sometimes ripping through miles of tunnels. The initial bang lifted and mixed fine particles of adjacent coal dust with air, that in turn ignited violently. The resulting flame front accelerated through the mine until it ran out of air or dust. Once the mechanism was understood, the danger was much reduced by keeping dusty tunnels wet, by balancing dry stone dust on beams that would be knocked into the mix and dilute the flame, and by keeping the mine clean. (Not sure how you keep a coal mine clean!)

Dust explosions are also common in flour mills, grain elevators, and similar industrial processes were fine dusts can mix 'just so' with air and be ignited by a spark.

The surprising thing is materials that are normally difficult to ignite are dangerous in dust form. A bag of flour is reluctant to burn, yet the contents produce a spectacular fireball if scattered up through a flame with compressed air. Don't try it indoors!

The Olds Elevator stops dust and air forming an explosive mix and keeps the building clean. Other methods of moving materials are likely to scatter dust where it might eventually become dangerous by mixing with air. Like a flame front driving through a coal mine, a small fire in a grain elevator can lift and mix dust into an explosive mix with air.

Simple yet no one else thought of it before. Genius!

Dave

Edited By SillyOldDuffer on 08/11/2022 10:55:22

I also wonder if there is an overall increase in materials handling efficiency ie higher friction on the cylinder wall requires more driving power, but that is more than offset by the screw being 'full'?

Ches

I used to live not far from Maryborough where Olds Engineering is. The local sugar mill in the 1990s was still powered in part by a horizontal (steam) mill engine built in Maryborough in 1948 when post-war austerity prohibited the import of the more usual steam turbines. Probably still running today I suspect. Maryborouh is a town with a colourful engineering history. Steam locos were made there well into the 20th century. Good to see some old time engineers like the Olds hit a bit of an international jackpot with their new invention.

Perhaps I'm being a bit dense, but I can't see any difference as far as dust goes between rotating the tube and rotating the screw. The physics is exactly the same. If you rotate the screw you don't need guards on the system, these were notably lacking in the video. Comparisons with a bucket elevator are not valid

The Old's Elevator will either run in fully flooded mode, or not at all; and will run fully flooded in a wide range of material and feed conditions.

A conventional archimedes screw would require specific feed conditions to run fully flooded, and would require a much more involved design process to do so reliably as the difference between "doesn't run fully flooded" and "binds up easily causing compaction and over-torque in the motor" is narrower.

It would be easy to demonstrate with cut-aways, but otherwise is a bit mind-boggling unless you're already familiar with screw-conveyors (which fwiw are themselves generally far better than belt conveyors for flowable solids)...

It took me a good few minutes after watching the video to fully get my head round how the vectors and forces in the two situations differ.

The difference is best illustrated by the following:

• No matter how fast it's running, the olds elevator wouldn't be able to lift material to the top, if the feed hopper at the bottom was fully empty.
• By contrast a conventional archimedes screw can be run in a condition where it can only feed if the bottom hopper is full, or above a certain screw speed (for a given material determined by viscosity and angle of repose) can theoretically run fully dry.

Edited By Jelly on 08/11/2022 13:43:13

The physics is not the same! firstly there is no seal between the screw and the tube, so if you rotate the screw some of the stuff you are moving falls back down the gap between screw and tube and air is constantly entrained and mixed with the stuff you are trying to move. During my apprenticeship I worked on many types of grain augers (Mayraths, so called as vacuum cleaners are called Hoovers, but there were many makes!) and when worn, they tended to damage the grain, and get hot to the point where they could actually cause a dust explosion. If you have scoops on the bottom that force the material up the screw, the tube is completely filled from the bottom upwards, and there is no fall back between the tube and the screw, so very little heat, and much more efficient movement of material because the pipe is completely full all the time. This may require slightly more power, but you do not get the extra efficiency for nothing, you are after all lifting more weight. An added advantage is that with the rotating tube the bearings can be kept out of the material you are moving, and kept cleaner and better sealed, especially important when you are moving fine casting sand! The bearings in grain augers had a very finite life, and I got very good at changing them!

Phil

On a slightly related topic, I remember seeing a vertical conveyor for sugar in Tate & Lyle's premises in Greenock many years ago in the 1970s. From my now faint memory, it consisted of a spiral trough and this oscillated at a fairly high frequency around its axis and the sugar moved up the trough.

Jim.

Having had another think, there is a difference in the physics. as the tube is rotating, there will be some centripetal effect pushing the grain or whatever against the inner wall. Good point about the bearings, a much happier situation with the tube rotating.

I didn't understand why the weight of the product didn't cause a problem. But the screw supports the weight at every level, so there is no limit to the height except mechanical limits. Its not like a column of water where the pressure is greatest ot the base.