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OLDS ELEVATOR™ PublicationsA Radical Approach to the Vertical Conveyance of Bulk Materials: the OLDS ELEVATOR™
12. Appendices Biography of inventor - Peter Olds
Olds Engineering has been serving a wide range of industries since 1918, including mining, maritime, sand and gravel extraction, sawmills, sugar and flour milling industries. Early experience in designing and manufacturing coal, wheat and flour conveyors and other machines is now being applied to an exciting new method for the vertical conveyance of bulk materials. A fit 76 year old, he continues to work full time, involved in the R & D of the OLDS ELEVATOR™. Historical account: inventor, Peter Olds, describes the original concept  When the inventor awoke suddenly at about 3 a.m. from a seemingly peaceful sleep on the morning of 5th December 2002, he had clear concept on his mind of how an elevator for the small foundry in Maryborough, Queensland could work. This concept was shown in the sketch he made on the kitchen table when he quietly sneaked out of bed and put his ideas roughly on paper to take to work later that morning. Quite satisfied he went back to bed without waking family and was asleep again by about 3.30 a.m.Those ideas, shown clearly with notes, describe the rotating tube or casing carried in bearings not affected by the fine sand to be elevated. The tube carrying the in-feed pickup unit beneath the sand to be elevated from the base of the machine would rotate fast enough to cause the sand entering the tube to be thrown out with sufficient centrifugal force to line the inside of the rotating tube. The volume of rotating sand would then engage with the stationary screw, stretched under tension from the top to the bottom of the machine, thus keeping it straight and clear of the inside of the tube. Only that sand engaging with the screw would be elevated, leaving a boundary layer rotating with the tube, the thickness of which would be equivalent to the clearance between the outside diameter of the screw and the inside diameter of the tube. This boundary layer would drive the inner core of rising, rotating sand like a long continuous nut up a long thread. To gauge the effect of the speed of rotation and the centrifugal force generated, a test device was made up. A short section of 3 inch diameter (76 mm) tube was closed by welding in a disc at one end to which was welded a short stub shaft located centrally on the disc. This then was simply machined so that the whole assembly would run true. A test was then carried out using a ½ inch (13mm) variable speed electric drill, which gripped the stub shaft of the tube assembly. The test rig was then held over a sand bin and run at full speed with the open end of the rotating tube upwards. Sand was then carefully poured into the rotating tube where it immediately leveled out evenly while rotating with the tube. With the drill still running, the whole arrangement was inverted so that the open ended tube carrying the sand was now upside down. The sand still naturally clung to the inside of the tube and continued to do so until the speed of the drill diminished to a surprisingly low rate.This simple demonstration proved the effectiveness of creating a rotating body of sand, the inside of which could be sheared off upwards by any suitable spiral or screw. When a prototype test machine was built it worked immediately. A fully operational machine was then made and installed in the foundry. This has only a 2 1/2 inch diameter (63mm OD) tube rotating at 500 RPM delivering just over 1 tonne of sand per hour. It has continued to run ever since with no trouble whatsoever, being driven by only a 1KW motor. Further test machines were then built in larger diameters and fitted with variable speed drives. This led to the discovery that the device would also work very effectively at very low speeds and with a very large range of products. It was also found that surprisingly large clearances could be used between the inside of the rotating tube and the screw, thus avoiding damage to fragile products. From these findings it was realized that the device worked in two distinct modes and that, at very slow speeds, centrifugal force and the boundary layer theory did not count. These two very distinct modes in which the elevator worked were named the "Open Mode" and the "Full Flow Mode". The speed at which the mode changes, due to centrifugal force forming the Boundary Layer, has been called the Critical Speed. The Critical Speed varies with the diameter of the rotating casing and the properties of the product being elevated. Both modes of operation have their own distinct advantages. |
Engineering and Support Free Video Taped Test Materials Handled Performance Features Standard Configurations Test Laboratory OLDS ELEVATOR™ LLC 12 B Park Ave. Hudson, NH 03051 Call 603.882.8899 Fax 603.882.8855 Email us today! OLDS ELEVATOR™ Advantages 1. Olds Elevator Innovative Material Elevation
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