"There are a number of advantages to be obtained by the removal of fine dust and the proper proportioning and mixing of the smaller grades of coal. The dedusted coal is much better for mechanical stokers since it contains very little dust to drop through the grates or to be carried up the stack. The fuel bed is more open with the dust removed, combustion is better, and the draft is more easily regulated. Dust removal also increases the fusion temperature of the ash, reducing the amount of slag formed on the grate. Elimination of clouds of dust at points of discharge is advantageous in places where the dust is a nuisance.
The proper proportioning and mixing of the constituent sizes of coal is an important factor in the preparation of a good fuel. If taken as mined there is considerable variation in the percentage of the various sizes. An excess of fine or coarse coal will decrease efficiencies and cause trouble with certain kinds of equipment.
Mixtures of coal that pass through a 2” screen are classified as screenings. A 2” screening would be 2” x 0; 1 ½” screening x 0 and a 3/4" screening 3/4" x 0. Most modern power stations burning coal use screenings, carbon (which is 5/16” x 0 coal) or pulverized fuel "--General, pages 1-2.
Mining and Nuclear Engineering
Professional Degree in Mining Engineering
Missouri School of Mines and Metallurgy
© 1935 Erwin Gammeter, All rights reserved.
Thesis - Open Access
Library of Congress Subject Headings
Coal mines and mining -- Dust control -- Equipment and supplies
Print OCLC #
Electronic OCLC #
Link to Catalog Record
Gammeter, Erwin, "Dedusting and preparation of screenings" (1935). Professional Degree Theses. 317.
General drawing deduster and collector. Mine No. 1
Gammeter_Erwin_1935_Plate_2.tif (88736 kB)
Deduster Mine No. 1. Details of 4’-0” wide chute with adjustable gates
Gammeter_Erwin_1935_Plate_3.tif (94780 kB)
Deduster Mine No. 2. Section rescreening building showing piping for suction fans
Gammeter_Erwin_1935_Plate_4.tif (108825 kB)
Deduster Mine No. 2. Plan showing location of blower fans and air ducts to carbon chutes. Detail of plates
Gammeter_Erwin_1935_Plate_5.tif (95247 kB)
Deduster Mine No. 2. Floor plan for suction fans to show changes in bracing