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.