Improvements in the Screening of Coal or other Material and in the Means Employed therefor.
Year: 1896

page_text: Date of Application, 1st Oct., 1896
Complete Specification Left, 1st July, 1897-Accepted, 7th Aug., 1897
PROVISIONAL SPECIFICATION.
Improvements in the Screening of Coal or other Material and in the
Means Employed therefor.
I, JAMES DUNN, of 21 Bothwell Street, Glasgow, N.B. Coal Master, do hereby
declare the nature of this invention to be as follows:-
This invention relates to improvements in the screening of coal or other material
and in the means employed therefor.
I arrange screening bars above the ordinary coal screen for the purpose of
separating the larger lumps of coal from the smaller lumps before the ordinary
screening takes place. Hitherto when all the coal both large and small had been
screened together the larger or heavier lumps have interfered with the proper
screening of the coal as the said large lumps have had the effect of grinding down
the dross, so that the dross is rendered of less value. By separating the large lumps
before the screening takes place, this grinding down of the dross is prevented.
The arrangement may consist of a series of longitudinal parallel bars placed above
the ordinary screen so that as the coal is shot from the pit head, the medium
sized coal readily drops down from between the bars on to the screen whereas
the larger lumps are carried over the screen and therefore do not come in contact
with the rest of the coal until the screening operation is completed.
The said grinding preventing bars may be applied for the screening to other
material than coal.
Dated this 30th day of September 1896
JOHNSONS,
115 St. Vincent Street, Glasgow, Petitioner's Agents.
Improvements in the Screening of Coal or other Material and in the
Means Employed therefor.
I, JAMES DUNN, of 21 Bothwell Street, Glasgow, N.B. Coal Master, do hereby
declare the nature of this invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
This invention relates to improvements in the screening of coal or other material
and in the means employed therefor.
I arrange screening bars above the ordinary coal screen for the purpose of
separating the larger lumps of coal from the smaller lumps before the ordinary
screening takes place. Hitherto when all the coal both large and small had been
Price 8d 1

page_text: screened together the larger or heavier lumps have interfered with the proper
screening of the coal as the said large lumps have had the effect of grinding down
the dross, so that the dross is rendered of less value. By separating the large lumps
before the screening takes place, this grinding down of the dross is prevented.
But in order that my said invention may be more readily understood and easily
carried into effect I will proceed to describe the same with reference to the accom-
panying drawings in which
Fig. 1 is an elevation partly in section
Fig. 2 a plan and
Fig. 3 an end view of a coal screen constructed in accordance with my invention.
Referring to the said drawings I employ a series of longitudinal bars A which
are broad at the heel where they are connected to the jigger or shaking screen B
gradually tapering to the point a where they are left open to give free delivery to
the coal and to allow them to yield as the heavy picces pass over them.
The yielding of the bars allows the coal to slide gently on to the bottom jigger
plate C.
In the case of long bars, slide bolts or pins C are employed near the points a to do
away with vibration and the up and down motion after a heavy piece of coal has
passed over. These bolts or pins are caused to slide through holes in the bottom
jigger plate C, below which they are fastened, in such a manner as to prevent the
bars rising beyond a fixed point but in no way interfering with their downward
motion. The said bolts or pins C are arranged in a zig-zag fashion so as not to
impede the progress of the coal over the perforated plate.
The dross after passing through the perforated plate is delivered into the waggon
by the shoot D while the pieces of coal larger than the mesh of the screening plate
as well as the large lumps upon the bars A are delivered into the coal waggon by
the shoot E.
The said grinding preventing bars may be applied for the screening of other
material than coal.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed I declare that what. I.
claim is :-
1. The general arrangement, construction and combination of apparatus for
screening or distributing coal, or other material, substantially as hereinbefore
described and shewn in the accompanying drawings.
2. In the screening or distributing of coal, or other material, the arrangement:
whereby the large coal is kept out of contact with the small coal to prevent grinding
of the small coal, substantially as hereinbefore described and shewn in the
accompanying drawings.
3. The arrangement of the bars A, substantially as hereinbefore described and
shewn in the accompanying drawings.
Dated this 30th day of June 1897.
JOHNSONS,
115 St. Vincent Street, Glasgow, Applicant's Agents.