Forfatter: A.-M.Inst.C E., George Frederick Zimmer
År: 1916
Forlag: Crosby Lockwood and Son
Sted: London
Sider: 752
UDK: 621.87 Zim, 621.86 Zim
Being a Treatise on the Handling and Storing of Material such as Grain, Coal, Ore, Timber, Etc., by Automatic or Semi-Automatic Machinery, together with the Various Accessories used in the Manipulation of such Plant
62
THE MECHANICAL HANDLING OF MATERIAL
every alternate scraper is supported by a pair of rollers. The return strand of the
conveyor is shown beneath the conveying strand. This order must be reversed in all
cases where the load has to be delivered at intermediate points, as the shoots leading
the material away would otherwise foul the return strand, unless the shoot is altogether
dispensed with, as in coal stores.
The trough is often made of two pieces of channel iron, with a renewable iron
plate riveted or bolted underneath (see Fig. 73), The skidder bars of the leading
strand of this conveyor run on slats of hard wood which are fastened on the channel
irons, whilst the chain of the return strand runs over guide rollers. Sometimes the
Fig. 72. Conveyor of the Push-Plate Type.
wooden slats are dispensed with, and the skidder bars allowed to run on the trough
itself.
The U-link conveyor illustrated in Fig. 74 has a trough similar to that just described,
but the pushing agent is altogether different. It consists of a large chain composed of
Fig. 73. Further Type of Push-Plate Conveyor.
U-shaped links of flat iron or steel, between which, and on the top of which, the material
is conveyed. The links are generally of a pitch equal to their width, and are 3 to 4 in.
deep by J in. in thickness. The speed at which the chain travels is from 100 to 150 ft.
per minute. The terminals are hexagonal, whilst the intermediate supports for the
return strand consist of ordinary rollers which are about 6 in. in diameter, and some-
times 15 ft., and even 20 ft., apart.
This type of conveyor is exceedingly strong, and on account of its simplicity and
reliability is largely used for bringing the coal to automatic stokers, and also for conveying
the ashes and clinkers from the furnaces. The driving power required is small, and it
has, moreover, the advantage of small initial cost. There are many boiler-houses where
this conveyor is doing excellent work at a cost so low that it need hardly be taken into