IMPROVED MEANS FOR MECHANICALLY SCREENING COAL OR OTHER MATERIALS
Year: 1871

page_text: LETTERS PATENT to Alphonso Briart, of Mariemont, in the Kingdom
of Belgium, Engineer, for the Invention of "IMPROVED MEANS FOR
MECHANICALLY SCREENING COAL OR OTHER MATERIALS."
Sealed the 22nd December 1871, and dated the 2nd September 1871.
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PROVISIONAL SPECIFICATION left by the said Alphonse Briart at the
Office of the Commissioners of Patents, with his Petition, on the
2nd September 1871.
I, ALPHONSE BRIART, of Mariemont, in the Kingdom of Belgium,
Engineer, do hereby declare the nature of the said Invention for
"IMPROVED MEANS FOR MECHANICALLY SCREENING COAL OR OTHER MATERIALS," to
be as follows:—
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This Invention consists of improved means for mechanically screening
coal or other materials.
I employ two or more inclined gratings placed one above another and
sloping in opposite directions. Each of these gratings has a set of fixed

page_text: and movable bars alternating throughout the series. The movable
bars are connected with excentrics which cause the whole of the
movable part of the grating to shift to and fro, and at the samo
time to rise and fall a little. The result is that one grating rises through
the other, carries the coal along for a short distance, and then sinks 5
below the fixed bars; the coal is thus screened or sifted mechanically
without any breaking or crushing, and with great rapidity. The
movable or vibrating bars perform one half of their oscillation above
the fixed grating and the other half below it, and they carry that part
of the coal which cannot pass through the grating down the incline 1
by a gentle lifting action. The movement of each bar is the same as
that of the connecting rod of a steam engine.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alphonse Briart in the Great Seal Patent Office on
the 2nd March 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALPHONSE
BRIART, of Mariemont, in the Kingdom of Belgium, Civil Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Second day of September, in the
year of our Lord One thousand eight hundred and seventy-one, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Alphonse Briart, my executors, ad-
ministrators, and assigns, or such others as I, the said Alphonse Briart,
my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
⚫use, exerciso, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVED MEANS FOR MECHANICALLY SCREENING COAL OR OTHER MATERIALS,"
upon the condition (amongst others) that I, the said Alphonse Briart,
my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, should particularly describe
and ascertain the nature of the said Invention, and in what manner the
1

page_text: 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 Alphonse Briart, do hereby declare
the nature of my 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, reference being bad to the accompanying
Drawings, that is to say :-
My system or Invention avoids the breakage of the coal whilst
rendering the separation of the different classes complete, working
rapidly and abolishing as far as possible the expense of manual labour.
In Belgian collieries coal is generally separated into three classes. To
effect this division two systems of superposed grating are necessary.
Each of them is composed of a series of fixed bars and a series of
moveable. The moveable bars are held by frames which are supported
at their lower extremity by two oscillating connecting rods, and at their
upper extremity by two eccentric pulleys fixed in shafts. The series of
moveable bars during one half of the revolution of these shafts is over
the series of fixed bars, and under during the other half. It must also
be remarked that during the upper half of the course the bars have a
translation movement from the top to the bottom of the grate, whilst
the reverse is the case during the lower half. It is easy to perceive
then that the wagons being emptied at the higher end of the upper
grate the coal is simultaneously raised and transported by the series of
moveable bars during the upper half revolution of the eccentric pulleys,
whilst it remains on the series of fixed bars quite motionless therefore
during the lower half revolution of the same pulleys. The matter being
thoroughly shaken at each revolution is found to be sorted. If we
consider the upper grate the spaces between the bars of which are
5.5 in. to 6.3 in. we shall see that the large coals will remain alone on
it, they will be pushed towards the bottom by the moveable bars where
they will be received by a hopper more or less inclined, which will
transport them into the wagon. The remainder of the matter to be
sorted passing through the upper grate falls on a floor which carries
it towards the top of the lower grate, the bars of which are 1.37 in. to
1-57 in. apart. There the separation between small coal and nuts coal
(gailleteries) is effected; the latter remaining on the grate are trans-

page_text: ported towards the bottom where they are received by a hopper more
or less inclined which conduct them to a wagon, whilst the small
passing through the grate are received directly by another wagon. If
it was required to separate the coals into more than three categories,
which is often necessary, a third superposed grate should be added.
By my system the separation of the different classes is as completo
as could bo desired, and thanks to the slow and gentle action of the
grate the preservation of the coal may be said to be perfect. As to
the rapidity of the operation experience has confirmed that a single
apparatus of my system will suffice for a pit whose production is 1
3,175,000 lbs. per day.
And having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim the
mode and means herein-before described.
In witness whercof, I, the said Alphonse Briart, have hereunto set 1
my hand and scal, this 1st day of March One thousand eight
hundred and sovente two
AL. BRIART. (L.S.)