File:Material handling cyclopedia; a reference book covering definitions, descriptions, illustrations and methods of use of material handling machines employed in industry (1921) (14587345758).jpg

Identifier: cu31924004680017 (find matches)
Title: Material handling cyclopedia; a reference book covering definitions, descriptions, illustrations and methods of use of material handling machines employed in industry
Year: 1921 (1920s)
Authors: Wright, Roydon Vincent, 1876- ed Little, John G., joint ed Augur, Robert C., joint ed
Subjects: Hoisting machinery Conveying machinery
Publisher: New York, N.Y., Simmons-Boardman Publishing Co

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
r sizes. In addition to the superior screening efficiency by pro-gression from large to small in the separation of sizesthere is the mechanical advantage of greater durabilityand longer life for the screens, because the greater massof material is handled by the heavier screens, whereas thereverse process throws the most destructive work on thefine screens, which naturally are least able to endure it. An individual screen for each size or grade of productis also essential, that the whole volume of water usedmay be utilized in each screen as each size is taken out,thereby giving best results in washing and highest effec-tiveness to the water supplied. Some materials carrying large amounts of clay, loam ormolding sand, cannot be reduced properly in the first sizingscreen, so they must be subjected to a preliminary agitationand washing, to break them up and scour them beforethey reach the screens. After the material passes through the sizing screens, 679 680 SAND AND GRAVEL WASHING PLANTS
Text Appearing After Image:
SAND AND GRAVEL WASHING PLANTS 681 the sand still remains with the soil water, from which itis separated by a sand separating tank or settling tank.This device automatically draws the sand from the bottomand allows the soil water to flow continuously out of aspillway at the top. The number of screens used is governed by the numberof sizes of material desired. In some cases the screens aremounted on skeleton framework or tipples, and the mate-rial drops directly into cars under the tipple. In the opera-tion of such a plant a car must be provided for each size,_and there must be a track for each size made. In some cases the screens are mounted on dredges,from which the different sizes of material are spouteddirect to scows; or, for portable plants, mounted on flatcars, truck wheels or rollers. The bins can be made to hold from a few carloads tofifteen or twenty carloads and may be built of wood,steel or concrete. Screens The two most extensively used types of screens areconical in shape

Note About Images