IMPROVEMENTS APPLICABLE TO MACHINERY FOR GRINDING OR PULVERIZING VARIOUS SUBSTANCES
Year: 1859

page_text: LETTERS PATENT to Edward Hammond Bentall,..of Heybridge, near
Maldon, in the County of Essex, Ironfounder, for the Invention of
"IMPROVEMENTS APPLICABLE TO MACHINERY FOR GRINDING OR PULVERIZING
VARIOUS SUBSTANCES."
Sealed the 5th July 1859, and dated the 1st February 1859.
PROVISIONAL SPECIFICATION left by the said Edward Hammond Bentall
at the Office of the Commissioners of Patents, with his Petition, on the
1st February 1859.
I, EDWARD HAMMOND BENTALL, of Heybridge, near Maldon, in the County
of Essex, Ironfounder, do hereby 'declare the nature of the said Invention
for "IMPROVEMENTS' APPLICABLE TO MACHINERY FOR GRINDING OR PULVERIZING
VARIOUS SUBSTANCES," to be as follows:-
My Invention of improvements applicable to machinery for grinding or
pulverizing various substances' is more particularly applicable to mills for
grinding mineral or earthy substances, such as coal, lime, cement, or various
kinds of ores, the object of the Invention being to separate the fine powder or
dust from the larger particles immediately pulverization of any part of the
substance has been effected., This object is attained by enclosing the grinding
or pulverizing apparatus in a chamber, and admitting a blast or current of
áir to the bed of the grinding mill, so as to blow away the fine particles

page_text: directly they are formed. These fine particles are conveyed away from the
grinding chamber to another and close chamber, in which they are to be
allowed to settle, and as the distance they are carried by the blast will depend
upon the weight of the particles, it will be evident that by dividing the settling
chamber into compartments or bins, powders of different qualities or degrees
of fineness may be obtained with the greatest facility. The air that is passed
through the grinding and settling chambers is conducted back to the blowing
machine, so that it will be made to pass over and over again through these
chambers, and consequently there will be no loss of the substance that is being
ground.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edward Hammond Bentall in the Great Seal Patent Office
on the 1st August 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
HAMMOND BENTALL, of Heybridge, near Maldon, in the County of Essex,
Ironfounder, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of February, in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-second year of Her
reign, did, for Herself, Her beirs and successors, give and grant unto me, the
said Edward Hammond Bentall, Her special license that I, the said Edward
Hammond Bentall, my executors, administrators, and assigns, or such others
as I, the said Edward Hammond Bentall, 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, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS APPLICABLE TO MACHINERY FOR GRINDING OR PULVERIZING VARIOUS
SUBSTANCES," upon the condition (amongst others) that I, the said Edward
Hammond Bentall, by an instrument in writing under my hand and seal,
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 Edward Hammond Bentall, do hereby
declare the nature of my said Invention, and in what manner the same is

page_text: to be performed, to be particularly described and ascertained in and by the
following statement, reference being had to the Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say) :-
My Invention of "Improvements applicable to Machinery for Grinding or
Pulverizing various Substances" is more particularly applicable to mills for
grinding or pulverizing mineral or earthy substances, such as coal, lime, cement,
or various kinds of ores, the object of the Invention being to separate the fine
powder or dust from the larger particles immediately pulverization of any part
of the substance has been effected. This object is attained by enclosing the
grinding or pulverizing apparatus in a chamber, and admitting a blast or
current of air to the bed of the grinding mill, so as to blow away the fine
particles directly they are formed. These fine particles are conveyed away
from the grinding chamber to another and close chamber, in which they are
to be allowed to settle, and as the distance they are carried by the blast will
depend upon the weight of the particles, it will be evident that by dividing
this settling chamber into compartments or bins, powders of different qualities
or degrees of fineness may be obtained with the greatest facility. The air that
is passed through the grinding and settling chambers is to be conducted back
to the blowing machine, so that it will be made to pass over and over again
through these chambers, and consequently there will be no loss of the substance
that is being ground or pulverized.
The arrangement of the apparatus whereby the object of my Invention may
be effected admits of considerable modification, and must depend not only
upon the material or substance intended to be operated upon, but also upon
the convenience of the locality and other circumstances.
In the accompanying Drawing I have shewn two arrangements of apparatus
which will be found useful for the purposes of my Invention, one of them.
being intended for pulverizing and collecting coal and coal dust, and the other
for pulverizing cement or ores or other mineral substances of greater specific
gravity than coal. Fig. 1 is a longitudinal vertical section of the apparatus
for grinding or pulverizing coal, and collecting the fine particles thereof. Tho
mill or pulverizing apparatus is of the ordinary kind for pulverizing cement
or ores, and consists of two or more heavy rollers a, a, mounted horizontally
on suitable spindles or arms connected with an upright shaft b, supported in
a step c below, and carrying at its upper end a bevil toothed wheel d, which
is driven by a similar wheel e, on the main driving shaft f. The grinding
apparatus is enclosed in an air-tight chamber g, g, to the lower part of which
a blast or current of air is admitted through an opening / in the side of the
chamber from the fan or blower i, which is driven by a band j from a pulley

page_text: on the main driving shaft fabove. The vertical shaft 6 is provided with
scrapers for collecting and carrying round the pulverized materials on the
floor of the mill as usual, and by this means all the pulverized materials are
brought under the action of the blast from the fan or blower i. The finer
particles will by this means be blown away from under the rollers a, a, in the
form of a cloud of dust, which will be conducted out of the chambers g, g, into
a long close covered chamber k, k, k, which is divided into compartments by
partitions or divisions, as shewn in the Drawing. It will now be understood
that as the air loaded with the fine particles of the pulverized substance
passes along the long chamberk, the heaviest parts will become deposited in
the compartment nearest to the grinding or pulverizing apparatus, while the
lighter ones will be carried on to the second compartment, and those that are
lighter still to the third and last compartment. I have found, however, that
although the pulverized matter in the third and last compartment is an almost
impalpable powder, there will still be held in suspension in the air a con-
siderable quantity of even finer and lighter dust, and that it will require some
time even in a still atmosphere to allow these very fine particles to settle; if,
therefore, the air with these fine particles floating in it be allowed to escape
into the atmosphere, the dust would in time settle on the surrounding objects,
and would not only be a perpetual annoyance, but would also entail a heavy
loss of valuable material. In order to obviate these inconveniences, I close
the end of the long chamber k, and adapt thereto an exit pipe l, l, whereby I
am enabled to draw off and conduct the air and floating particles back to the
fan or blower, and thus cause it to pass over and over again through the
apparatus, so that no loss of material will ensue. It will of course be under-
stood that doors communicating with each of the compartments of the long
chamber k are made in the side thereof, so that the pulverized substance may
be removed therefrom from time to time when required.
'
In Fig. 2 I have shewn an arrangement of apparatus in which the long
closed chamber k divided into compartments as shewn in Fig. 1 is dispensed
with, and in place thereof the capacity of the chamber 9, 9, (that encloses the
grinding or pulverizing apparatus) is considerably increased, and an additional
chamber k*, k, is made below the chamber g, to receive the pulverized
substance as it is blown away from the mill by the blast of the fan i. This
form or arrangement of apparatus will be found useful for collecting the
pulverized or reduced particles of cement, metallic ores, sulphate of barytes,
or other heavy earthy matters. The grinding or pulverizing rollers a, a, are
represented in the Drawing as being placed in the centre of the chamber g,
but if preferred they may be placed at one side thereof. The floor of the mill

page_text: is surrounded by an upright flange, and a blast or current of air is conducted
through a pipe h from the fan or blower i, to the enclosed space in which the
rollers a work. The fine particles of the pulverized substance will then be
blown away, and will rise in the form of a cloud of dust in the upper part of
the large chamber g, and they will be caused by their gravity to descend and fall
through the open or perforated bottom g* of the chamber into the lower chamber
k, k, from whence when a sufficient accumulation has taken place, the finely
pulverized matter may be removed through the doors m, m. The air with
the finest and lightest particles is drawn off from the upper part of the
chamber 9 through the pipe l, and is conducted to the fan or blower i, whereby
it is passed a second time through the apparatus, so that none of the pulverized
material may be lost.
Having now described my Invention of improvements applicable to machinery
for grinding or pulverizing various substances, and having explained the
manner of carrying the same into effect, I would observe that although I have
shewn two plans or arrangements of machinery or apparatus which will be
found convenient for effecting the object of my Invention, I do not mean or
intend to confine myself thereto, as the arrangement and construction of parts
may be varied considerably without departing from the nature and object of
my improvements.
•
In conclusion I claim as the Invention secured to me by Letters Patent as
aforesaid the mode above described of arranging the apparatus for grinding or
operating upon mineral substances, so that the fine particles, so soon as they
are produced by the grinding or pulverizing apparatus, may be separated from
the coarser and unreduced particles, and conducted to a chamber or chambers
in which they will be deposited by their gravity, while the air that has been
used in the operation is conducted from the enclosed chamber back to the
blowing machine, and passed again through the apparatus as above described.
In witness whereof, I, the said Edward Hammond Bentall,. have here-
unto set my hand and seal, the First day of August, in the year of
our Lord One thousand eight hundred and fifty-nine.