280 ANNUAL REPORT 
Pan or Plate Conveyors.—Pan or plate conveyors consist of steel 
pans fastened to link belts. These pans may have rollers attached to 
them which run on a track, the pans moving along between the two rails, 
or the pans run over fixed rollers. Usually the pans overlap each other 
so as to avoid spilling the material. The link belt runs over a polygonal 
sprocket wheel at the ends. : 
The bucket conveyor consists of a series of buckets suspended from 
two parallel link belts or from a rope, and which are fed from a bin 
either automatically, or, if the buckets are large, by a man who works 
the discharge gate of the bin. The buckets are dumped automatically by — 
a tripper and also right themselves automatically. These conveyors are 
cheap to maintain and, though periodic in operation, have very large 
capacities. 
Screw Conveyors.—Screw conveyors should in all cases be built of 
strong material and should not be more than 30 feet long. Their 
great advantage is the mixing they do. As a conveyor for short lengths 
they are very reliable if built strong. The consumption of power is very 
high for the work performed. | 
Jerking Conveyor.—The jerking or Kreise conveying trough con- 
sists of a trough or pipe sloping slightly downward and is given a rapid 
reciprocal motion, longitudinally, by a disk crank which jerks the ma- 
terial forward, about 350 strokes per minute, with a stroke of 11% inches. 
Such a machine, 45 feet long, requiring 2 horsepower, moves about 8 tons 
per hour. They may be built up to 150 feet long. 
For continuous operation the belt conveyor has proven the most 
satisfactory m handling large quantities. 
Cars.—Cars may be used for conveying larger quantities of raw 
stock, especially from the storage bins to the weighing platform. These 
are invariably moved by hand and hence the track should be so arranged 
that it slopes slightly in the direction in which the loaded car is to go. 
It is always essential that the bins have a decided slope or feed into a 
conical base from which the material is discharged by gravity into the 
cars. 
Elevators. Bucket elevators are practically the only means of con- 
veying ground material in the vertical direction. We distinguish two kinds, 
belt and chain elevators. In the former the buckets are bolted to belts, in _ 
the latter they are fastened to chains. Belt elevators can be used for 
greater velocities than the link belt elevators, which, 1f run too rapidly, 
give constant trouble. It should always be made an object to build 
elevators as nearly vertical as possible, since, when inclined, they are 
certain to drag and wear rapidly. The elevator boots should be made 
easily accessible and be perfectly drained. Any dampness is certain to 
clog and choke up an elevator, especially after standing. 
