Improvements in and relating to Apparatus for Screening Coal and similar Materials.
Year: 1887

page_text: Date of Application, 2nd Sept., 1887
Complete Left, 19th May, 1888
Complete Accepted, 22nd June, 1888
Improvements in and relating to Apparatus for Screening Coal and
similar Materials.
I, GEORGE CLEMENTSON GREENWELL the younger of Poynton in the County of
Chester, Mining and Civil Engineer do hereby declare the nature of this invention
to be as follows:-
This Invention relates to apparatus employed in screening and carrying coals and
the like materials. In this operation as commonly conducted at present, an inclined
plane grid or screen constructed of fixed or partly fixed and partly moveable parallel
bars having a triangular pentagonal or similar section is employed, as is well
understood.
These Improvements consist in combining and arranging with the inclined grid, a
system of endless ropes bands or chains parallel with the bars of the grid. The
ropes bands or chains are carried by pulleys or drums at the head and foot of
the grid respectively and so that by rotation of the pulleys or drums they may pass
downwards along the upper side of the grid and return below the grid; they are
moreover so arranged that one rope band or chain is within each space or interval between
two contiguous bars of the grid.
The grid may conveniently be divided into sections, of which the section at the
head or upper part of the grid may be constructed with bars of the maximum width
and the following section or sections with bars of less width; that is to say: when
there are more than two sections, the width of the bars in each succeeding section
may be less than the width of those in the preceding section. By this arrangement
the spaces between the bars increase in width from the upper to the lower end, thus
enabling the Coal or other material to be separated into various sizes as required.
A
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page_text: COMPLETE SPECIFICATION.
Improvements in and relating to Apparatus for Screening Coal and
similar Materials.
I, GEORGE CLEMENTSON GREENWELL the younger, of Poynton in the County of
Chester, Mining and Civil Engineer, 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 apparatus employed in screening and carrying coals
and the like materials. In this operation as at present commonly conducted, an
inclined plane, grid or screen, constructed of fixed or partly fixed and partly movable
parallel bars having a triangular, pentagonal or similar section is employed.
These Improvements consist in combining and arranging with such a grid or a
screen of parallel bars, a system of endless ropes bands or chains parallel with and
capable of travelling between the bars of the grid. The ropes bands or chains are
carried by pulleys or drums at the head and foot of the grid respectively and so that
by rotation of the pulleys or drums they may pass along and between the bars of the
grid and return below; they are moreover so arranged that one rope band or
chain is included within each space or interval between two contiguous bars of
the grid.
The grid may conveniently be divided into sections, of which the section at the
head or upper part of the grid may be constructed with bars of the maximum width
and the following section or sections with bars of less width. When there are more
than two sections, the width of the bars in each succeeding section may be narrower
than those in the preceding section. By this arrangement the spaces between the
bars increase in width from the head or upper end to the foot or lower end of the
screen, thus enabling the coal or other material to be separated into various sizes as
required.
.
In order to enable my Invention to be more readily understood I have appended
two sheets of Drawings to which reference is hereinafter made. In each of the Figures
similar parts are denoted by similar letters of reference.
Fig. 1 represents a diagramatic side elevation and Fig. 2 a plan of a screen
constructed according to these Improvements. Fig. 3 is a section along the
line A B Fig. 2; Fig. 4 is a section along the line C D, and Fig. 5 is a section
along the line E F.
As shown in the drawings, a rope is represented as being employed in each of the
spaces between the bars but in many cases it will be found more advantageous to use
a chain.
The ropes chains or bands are endless and pass over the pulleys G H at opposite
ends of the screen and they may be driven by either of these sets of pulleys. Between
the bars the ropes are supported by the small pulleys I I, by means of which the
ropes or chains are kept in contact with the materials upon the screen, and the

page_text: motion of the ropes or chains is imparted to the material, which is thereby carried
along the screen until it has arrived at the delivery end, or until it has fallen through
the spaces between the bars.
In
In the sectional views Figs. 3, 4, and 5, only so much of the cross section of the
apparatus is shown as will suffice to give a clear idea of the construction and
arrangement. It will be seen that the spaces between the bars, and therefore between
the bars and the ropes is least in Fig. 3 which is the condition existing at the part
of the screen nearest to the tippler at which the coal is delivered to the screen.
this section the dust or slack is separated. In the next section Fig. 4, the bars are
narrower and the spaces consequently wider and the rough slack or nuts is or are
separated. In the last section, Fig. 5 the bars are narrowest, and the cobbles
are separated. The remaining material is delivered in lumps free from slack or
cobbles at the end of the screen.
The apparatus may be worked on the level as shown in the drawings or at any
convenient angle. The bars may have any suitable shape and length, and they
may be of the same form and dimensions throughout or there may be one or more
changes in their breadth according as it is required to separate the material into two
or more grades.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
(1) In an apparatus for screening coals and similar materials; the combination
and arrangement of stationary bars and travelling ropes chains or bands; substantially
as and for the purpose hereinbefore set forth and as illustrated by the accompanying
drawings.
(2) In an apparatus for screening coals and similar materials; endless ropes chains
or bands arranged to travel between stationary bars; substantially as and for the
purpose herein before described with reference to the accompanying drawings.
Dated this 15th day of May A.D. 1888.
WILLIAM E. HEYS,
Agent for the Applicant.