IMPROVEMENTS IN APPARATUS FOR SCREENING COALS
Year: 1872

page_text: LETTERS PATENT to John Ephraim Walker, Colliery Agent, of
Wearmouth Colliery, Sunderland, and John William Cole, Me-
chanical Engineer, of Byker, near Newcastle-upon-Tyne, for the
Invention of "IMPROVEMENTS IN APPARATUS FOR SCREENING COALS,"
Sealed the 6th August 1872, and dated the 4th May 1872.
PROVISIONAL SPECIFICATION left by the said John Ephraim Walker
and William Cole at the Office of the Commissioners of Patents,
with their Petition, on the 4th May 1872.
We, JOHN EPHRAIM WALKER, Colliery Agent, of Wearmouth Colliery,
Sunderland, and JOHN WILLIAM COLE, Mechanical Engineer, of Byker,
near Newcastle-upon-Tyne, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN APPARATUS FOR Screening Coals,” to be as
follows:-
This Invention has for its object improvements in apparatus for
screening coals. For this purpose the coals to be screened are delivered
from a shoot or screen on to an endless chain, the several links of which

page_text: are composed of a number of parallel bars. This endless chain passes
over and is carried by two horizontal polygonal drums or drivers, the
sides of which are of a length to correspond with the length of the links.
To one of these drums a continuous revolving motion is imparted, and
thus a continuous motion is imparted to the chain. The upper surface
of the chain on to which the coal is delivered from the screen or shoot
is caused to assume a wave-like form by short guide rollers between
which it passes, and which cause the successive links of the chain to
incline alternately upwards and downwards. As the chain travels along
the coals are carried forward by it, and as the links incline first upwards
and then downwards the coals are overturned, the dross is exposed to
view, and the small coal is permitted to pass through the openings
between the links, and is received into a hopper, by which it is con-
ducted to a waggon or receptacle, whilst the screened coal is carried
forward by the chain, and is tipped over the outer drum or tumbler and
delivered into another waggon or receptacle.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Ephraim Walker and John William Cole in
the Great Seal Patent Office on the 31st October 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
EPHRAIM WALKER, Colliery Agent, Wearmouth Colliery, Sunderland,
and JOHN WILLIAM COLE, Mechanical Engineer, of Byker, Newcastle-
upon-Tyne, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourth day of May, in the year of 1
our Lord One thousand eight hundred and seventy-two, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto us, the said John Ephraim Walker and John William
Cole, Her special licence that we, the said John Ephraim Walker and
John William Cole, our executors, administrators, and assigns, or such
others as we, the said John Ephraim Walker and John William Cole,
our executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great

page_text: Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for "IMPROVEMENTS IN APPARATUS FOR SCREENING COALS," upon the condition
(amongst others) that we, the said John Ephraim Walker and John
William Cole, our executors or administrators, by an instrument in
writing under our or their hands and seals, or under the hand and seal
of one of us or them, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said John Ephraim Walker, on behalf
of myself and the said John William Cole, do licreby declare the nature
of the said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following
statement thereof, that is to say :-
This Invention has for its object improvements in apparatus for
screening coals. For this purpose the coals to be screened are delivered
from a shoot or screen on to an endless chain, the several links of which
are composed of grates or a number of parallel bars. This endless chain
passes over and is carried by two horizontal drums or drivers, by
preference polygonal, and with the sides of a length to correspond with
the length of the links. To one of these drums a continuous revolving
motion is imparted, and thus a continuous motion is imparted to the
chain. The upper surface of the chain on to which the coal is delivered
3 from the screen or shoot is caused to assume a wave-like form so that
the successive links of the chain are caused to incline alternately
upwards and downwards. This inclination may be varied according to
circumstances. As the chain travels along the coals are carried forward
by it, and as the links incline first upwards and then downwards the
O coals are overturned, the dross is exposed to view, and the small coal is
permitted to pass through the openings between the links and is received
into a hopper, by which it is conducted to a waggon or receptacle, whilst
the screened coal is carried forward by the chain and is tipped over
the outer drum or tumbler and delivered into another waggon or
5 receptacle.
In the Drawings hereunto annexed I have shown various views of

page_text: Figure 1 represents a side elevation of the machine; Figure 2, a plan
view with the endless chain removed, and Figure 3 an end view of the
same.
A, A, are the side frames of the apparatus, carrying at their ends
bearings for the shafts B, B', which carry the polygonal drums C, C;
D is the endless chain passed over the drums C. The shaft B has upon
it a toothed wheel E which is driven by a pinion F" on the driving
shaft F. The revolving of the drum C upon the shaft B draws the lower
portion of the endless chain in the direction shown by the arrow in
Figure 1; G is the shoot by which coals are delivered on to the upper
surface of the chain. The coals as they are received upon the chain
are by it carried forward until they arrive at H, when they fall into a
waggon or other vehicle placed for their reception; I is a shoot for
breaking the fall of the coals and guiding them as they descend. The
several links of the endless chain may each be composed of a number
of parallel bars jointed together in the manner shown at Figure 4, or
cach link may be composed of a cast-iron or other grating, as shewn at
Figure 5. In order to compel the upper portion of the endless chain to
assume a wave-like form the chain is provided on each side with small
friction rollers J, which travel along in zig-zag grooves in the side frames,
or a number of small friction rollers may be carried by the side frames of
the machine for the ends of the links to travel between, whereby the
upper surface of the chain is caused to assume a wave like form as
shewn. The lower part of the endless chain may be supported by a
series of rollers placed so as to support all or any desired part of the
dead weight of this portion of the chain, or the whole weight of the
lower portion of the chain may be permitted to hang upon the drums.
K is the shoot placed between the upper and lower portions of the
endless chain to shoot the small coal which passes through the bars of
the several links out at the two sides of the machine, where they may fall
into a waggon or other receptacle placed to receive them. The bars or
grates of which the several links are composed are by preference made
with a horizontal slot or opening through them, as shewn at Figure 6,
to allow a thin sheet or plate of iron or other suitable material to be
passed through them, so that the vertical openings between the several
links may be closed thereby. The chain or screen may be rendered blind
so that the coal shall not be screened as it is carried forward by the
machine.

page_text: In some cases in place of the several links of the endless chain of bars
or grates being caused alternately to incline upwards and downwards as
above described, the endless chain may simply act as a parallel screen
and carrier, whilst the turning over of the coal so as to expose the
pyrites and dross may be effected by teeth fixed above it, as shewn in
the diagram view Figure 7.
Having thus described the nature of our Invention and the manner
of performing the same, we would have it understood that what we
claim is,―
1. The combined arrangement of apparatus for screening coals, sub-
stantially as herein described.
2. The employment in apparatus for screening coals of a travelling
endless chain of grates or bars on to which the coal is delivered, and the
successive links of which are caused to incline alternately upwards and
downwards as the coal is carried forward by them substantially as herein
described.
In witness whereof the said John Ephraim Walker, has hereunto
set his hand and seal, this Thirtieth day of October, in the year
of our Lord One thousand eight hundred and seventy-two.