Improvements in Machinery for Sorting and Screening Coal and other Minerals.
Year: 1892

page_text: Date of Application, 8th Mar., 1892-Accepted, 16th Apr.,
1892
COMPLETE SPECIFICATION.
Improvements in Machinery for Sorting and Screening Coal and
other Minerals.
We, ARTHUR STANLEY DOUGLAS, of Hucknale Forhard, Nottingham, Mining
Engineer, and WILLIAM HESLOP, of Pease's West Collieries, Crook, in the County
of Durham, Mechanical 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 which relates to that class of machines in which coal or other
mineral is sorted and screened to be subsequently cleaned by hand picking and in
which the operation of sorting and screening is principally effected by the action of
one or more rotary tables revolving about a vertical shaft; consists in a series of
improvements in several details of construction conducing to the more perfect
action of such machines in effecting their intended purpose and rendering the move-
ments of certain parts more easily controllable. These several improvements we
obtain by the construction substantially as shown in the drawings and hereinafter
described and recited in the claims.
We will in describing our invention refer to its use for sorting and screening
coal from which its use in similarly treating other minerals will be obvious.
In the drawings,
Figure 1 illustrates in sectional elevation a machine complete in all its parts for
sizing and screening coals into two grades, that is to say, there are two differently
graded tables for sorting and screening the coal and a deadplate B to receive the
residue all secured to and rotating with the vertical shaft C which is put in motion
by any suitable means such as by being geared to another shaft in the manner
shown in Figures 1 and 8.
Figures 2 to 9 illustrate to an enlarged scale some of the details of our improved
machine, the same letters of reference being used to indicate the same parts as are
used in Figure 1.
The truck or bogie D¹ from the pit discharges its contents by means of the usual
kickup D into the hopper E' from which its delivery into the shoot E is regulated
and controlled by a rotating feed drum G furnished with curved blades g and
shrouds which form scoops as shown in Figures 1 and 8, and rotated at a suitable
speed relatively to the rotation of the vertical shaft C, from which it may be
conveniently driven by a belt and pulleys.
The throttle plate H which in connection with the feed drum G forms the throat
of the hopper E, is controlled by the lever and balance weight H, so that when
coals of extra bulk get lodged against the throttle plate the said throttle plate
swings back and allows such lumps of coal to pass through into the shoot below and
is then automatically brought back to its normal position by the weighted lever.
In order to effect a preliminary or partial assortinent of the coal as it slides down
the shoot E, we avail ourselves of the usual inclined screens FF which are
graded to correspond with the tables A A so that material which would pass
through the gratings of both tables A'A can also pass through both screens FF,
and all material which does so pass through is delivered direct through the central
openings aa in the rotary tables onto the deadplate B.
In the same way material which would pass through the grating of table A', but
not through the finer grating of table A, can similarly pass through screen F' but
not through screen F; consequently a portion of the material which passes through
the screen F is delivered direct through the central opening a' in table A' onto
table A where the process of sorting and screening is completed. First grade coal
is thus partially screened of both dust and second grade coal before reaching the.

page_text: table A¹ and similarly second grade coal delivered from the screen F2 is partially
screened of dust before reaching the table A. C is an attachment to the vertical
shaft C so as to rotate with it, the function of which is to prevent lumps of coal
effecting a lodgement on the screen F1 behind the vertical shaft. Each table and
the deadplate has its separate discharge shoot or spout so that all material inter-
cepted by table A' which for distinction may be termed first grade coal is discharged
down spout into one truck and the material intercepted by table A2 which may
be termed second grade coal is discharged down spout into another truck, the
residue which reaches the deadplate B being similarly discharged down spout J³
into a third truck. By fitting a section of the floor of the shoot Jon hinges and
turning it up in the position shown in dotted lines in Figure 1, first grade coal is
diverted from shoot. J into shoot J and delivered into the same truck with second
grade coal, an arrangement which will be found convenient where the object in
view is simply to separate the dust and pulverised coal from the rest of the coal.
Figures 2, 3, 4, 5 and 6 illustrate convenient modes of making up the rotary
tables in segments, Figure 2 being a half plan of the lower table where two tables
are used.
Figure 3 shows a half plan view of the upper table with the sweeper bar K¹ in
position, the function of which will be hereafter described.
Figure 4 shows a sectional plan view of a cast grating where extra coarse sifting
is required, and occupies a position above the upper table A', but is not included in
the machine as illustrated in Figure 1.
Figure 5 shows how each segment of the grating can be adjusted to screen coals
to a particular grade by fitting loose bars into changeable distance pieces as
distinguished from the segment all cast in one piece as shown in Figure 6.
Figure 7 shows a suitable section of a radial bar of a rotary table.
We will here note that we prefer the arrangement hitherto adopted of increasing
the diameter of each rotary table taken in the descending order from the upmost
table to the deadplate which follows the same proportion in having a larger
diameter than the table next above it, the increase of grating surface being
advantageous for screening the material as it becomes more finely graded.
KK are adjustable sweeper bars connected to and controlled by the lever L. In
order that these sweeper bars may extend over the surface of the rotary tables in
an approximately parallel direction they swing on links or rocking bars instead
of upon fixed centres. The function of these sweeper bars which preferably are
curved to the form shown in Figure 3, is to intercept all lumps of coal of a certain
grade and to cause them to fall off the table into the respective shoots J J2 as the
case may be, instead of such coal being again carried round to no purpose on the
rotary tables; this disturbing of the material lodged on each rotary table assists in
discharging the smaller material and dust through the grating thereof.
M is a fixed bar with a serrated lower edge to spread the material more equally
over the whole area of the grating. The lever L by means of the connecting
bars L L and the bell crank lever L3 actuates the catch or locking bar N which
engages with the ratchet teeth of a wheel or circular rim axially fixed on the
kickup D2, and when so engaged prevents the kickup from acting and consequently
prevents the discharge of coal into the hopper E. The same movement of the
lever L which locks the kickup D also lifts the sweeper bars K' K² out of the
working position. When the vertical shaft C requires to be lifted for any purpose,
as for instance to examine or renew the footstep carriage Q; jacks, blocks, or the
like appliances which form no part of the machine have hitherto been used. For
such appliances we substitute the simple and convenient device of the under screw R
screwed through the under frame of the apparatus, and forming a permanent part
of same which can be turned by a key or bar and brought into action at any
time.
Having now described the general construction of our coal sorting and screening
machine, the manner in which the various parts are brought into action or in
what way they serve their intended purposes, we will now proceed to point out

page_text: those improvements which constitute the essential features of our invention and
which are novel as compared with other machines for sorting and screening coat
when constructed with rotary tables.
In the first place the rotary tables instead of being level on the gratings when
constructed according to our invention are cone shaped by which the materiał
lodged, on the grating is presented more readily to the inspection of the attendant
in charge and the coals of the grade which the particular table in question is
intended to intercept shoot off more readily when obstructed by the sweeper bar,
their discharge over the edge at any other part being prevented by the circum-
ferential guard plates or fenders P¹ P².
A further improvement in the tables consists in the conical hoods which enclose
the central openings a' a², and which by presenting a sloping surface to the falling
material conduce to its more equal distribution upon the grating of the table
receiving it, thereby facilitating the operation of both screening and hand picking
for which purposes the practical advantages of these improvements are apparent.
Other improvements in the machinery in question consist in the use and combination
therewith of the feed drum G and automatic throttle plate H, by which a more
regular feed of material to the screens below is ensured, also in the use and com-
bination therewith of the under screw R for lifting the vertical shaft and all its
attachments. It must be understood that the stationary inclined screens F F and
the partial preliminary grading of the material effected thereby is not a novel
feature and in itself does not constitute a part of our invention except in combina-
tion with the other parts which constitute the machine as a whole.
We
A further essential feature of our invention consists in the combination of parts
for locking the kickup D and simultaneously lifting the sweeper bars K' K² out of
the working position by which a charge of coal containing an extra proportion of
dirt can be subjected to any desired extra amount of screening on the tables.
would here observe that we do not restrict ourselves to the particular combination
of the lever L and its connections for effecting this purpose as these are to be
taken only as illustrating a convenient mode which may be readily modified without
departing from our invention.
Although the particular machine illustrated in Figure 1 is furnished with two
rotary tables A A2, it must be understood that more tables or only one table can
be provided if required to extend or restrict the process of screening as the case
may be, the number being varied according to the number of grades required, in
which case the inclined screens in shoot E may also be correspondingly varied in
number and graded to suit.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we would have it understood
that while we do not confine ourselves strictly to the particular arrangement of
parts shown, which can be obviously modified in detail, we wish it to be understood
that we are aware that the method or principle involved of causing the coal or
other mineral to pass through rotary tables is set forth in the Specification of the
Letters Patent granted to the said Arthur Stanley Douglas and Ralph Hall
Oughton, No. 14439 of 1887; we therefore make no claim to such method or
principle otherwise than as embodied in and carried into practice by our improve-
ments above specified, and we declare that what we claim is :-
:-
Firstly The general arrangement and combination of parts constituting the
improved machinery for sorting and screening coal and other mineral, substantially
as hereinbefore described and illustrated in the annexed sheets of drawings.
Secondly The particular form or construction of the rotary tables which are
cone shaped with or without cone hooded central openings as and for the purpose
substantially as described and shown in Figure 1.
Thirdly The use of the feed drum G with or without the automatic throttle
plate Has part of the machine for regulating the supply of the material to be sorted
and screened substantially as described.

page_text: Fourthly The combination of parts for locking the kickup D and simul-
taneously lifting the sweeper bars K' K2 out of the working position as and for the
purpose as herein before described.
Fifthly The use of the under screw R as part of the machine for lifting up the
vertical shaft C with all its attachments, substantially as described.
Dated this 7th day of March 1892.
G. J. CLARKSON,
Stockton-on-Tees, Agent for the Applicants.