IMPROVEMENTS IN THE APPLICATION OF EXHAUST TO THE MILLSTONES OF FLOUR MILLS, AND IN APPARATUS OR ÅDDLIANCES IN CONNECTION THEREWITH.
Year: 1871

page_text: LETTERS PATENT to Gustav Ludwig Behrns, of the Firm of Jaacks
and Behrns, Civil Engineers, of Lübeck, in the German Empire,
but at present of No. 7, St. Peter's Road, Mile End, in the County
of Middlesex, for the Invention of "IMPROVEMENTS IN THE APPLICATION
OF EXHAUST TO THE MILLSTONES OF FLOUR MILLS, AND IN APPARATUS OR
ÅDDLIANCES IN CONNECTION THEREWITH.
"
Sealed the 9th February 1872, and dated the 1st September 1871.
PROVISIONAL SPECIFICATION left by the said Gustav Ludwig Behrns
at the Office of the Commissioners of Patents, with his Petition,
on the 1st September 1871.
I, GUSTAV LUDWIG BEHRNS, of the Firm of Jaacks and Behrns, Oivil
Engineers, of Lübeck, in the German Empire, but at present of No. 7,
St. Peter's Road, Mile End, in the County of Middlesex, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN THE APPLI-

page_text: CATION OF EXHAUST TO THE MILLSTONES OF FLOUR MILLS, AND IN APPARATUS OR
APPLIANCES IN CONNECTION THEREWITH," to be as follows:-
My Invention relates to improved arrangements of the exhaust to the
millstones of flour mills, and of apparatus or appliances in connection
therewith, whereby a much more powerful exhaust may be employed!
than was heretofore possible, resulting in a greatly increased yield from
the millstones, while at the same time the presence of stive in the mill is
entirely avoided, all moisture is effectually removed, and the millstones.
are kept perfectly cool while grinding.
For these purposes I construct the millstone casing perfectly air-tight,
and I provide it with an inner lining of sheet metal and felt, in order to
protect the interior of the casing from the lower temperature of the
surrounding air, and thus prevent any condensation of moisture within
the casing, so that all moist vapour resulting from the grinding shall
pass off with the exhausted air.
The spout or funnel conducting the grain and air into the cyc of the
running millstone, as also the cyc of the millstone itself, is prevented
from communicating with the interior of the casing by means of a
cylindical air-tight enclosure, by preference of leather, fixed with its
upper end to the top of the casing, while its lower end is fixed to a metal
ring fitting loosely, but in an air-tight manner, into a V groove in a
second metal ring fixed on the running millstone concentric with the
eye thereof, and revolving with the same.
An exhaust pipe communicates with the interior of the casing through
an aperture in the top of the lattor, through which the air is exhausted
from the casing by a fan or other suitable exhauster. The external air
is thus caused to enter through the eye of the running stone and
between the grinding surfaces of the millstones in order to pass into the
casing, any other entrance of air being prevented, firstly, by the before-
mentioned enclosure round the funnel, and, secondly, by forming the
meal spout at the bottom of the casing with a bend, and by introducing
into the spout above such bend a screw blade on a shaft, rotated by
means of an external pulley in such manner as to force the meal down
into the bend of the spout, whereby the spout will be effectually closed
against the entrance of air.
The millstones will act all the more efficiently the more powerful the
exhaust from the casing is made, and in order therefore to allow of such

page_text: powerful exhaust being applied, I entirely prevent the escape of particles
of flour, together with the exhausted air, by introducing into the upper
part of the casing a screening surface, through which the whole of the
air and moist vapour exhausted from the casing has to pass before
escaping through the exhaust aperture, which screening surface inters
cepts all particles of flour that the air would otherwise carry away with
it. This screen is constructed of a framing suspended by chains from
the top of the casing, which framing is covered by a cloth of a woolley
nature, presenting a considerable area of screening surface by being
made of a zig-zag form, the cloth being fastened in an air-tight manner
to the top of the casing. A rod attached to the framing of this screen
passes through the millstone casing, in order that by imparting slight
blows occasionally to the outer end of this rod the flour that accumulates
on the screen may from time to time be shaken off.
The exhaust pipe is protected from the cooling influence of the
external air at the part nearest the millstone casing by means of a
covering of felt and sheet iron, in order to prevent the moist vapour
that passes away with the air from condensing in that part of the pipe
until it has past the vertical bend which is there formed in the pipe.
After passing this bend the moisture is allowed to condense and to flow
downwards in the pipe to the outside of the building if required.
The degree of exhaust in the casing can be regulated by a throttle
valve in the exhaust pipe, and a double vacuum gauge is fixed on the
top of the casing for observing the degree of exhaust existing both in the
lower part of the casing and in the space above the screening surface.
By the above described arrangements a very powerful exhaust may
be applied to the millstone casing, producing a strong current of air
through the millstones, whereby, as also by the absence of any con-
densed moisture on the grinding surfaces, a greatly increased yield is
obtained, while the grinding surfaces are at the same time kept perfectly
cool.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Gustav Ludwig Behrns in the Great Seal Patent
Office.on the 26th February 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Gustav
LUDWIG BEURNS, of the Firm of Jaacks and Behrns, Civil Engineers, of 6
Lübeck, in the German Empire, but at prosent of No. 7, St. Peter's
Road, Mile End, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of September, in the year
of our Lord One thousand eight hundred.and seventy-one, in the thirty- 1
fifth year of Her reign, did, for Horself, Her leirs and successors,
give and grant unto me, the said Gustav Ludwig Behirns, Her special
licence that I, the said Gustav Ludwig Behrns, my exccutors, adminis-
trators, and assigns, or such others as I, the said Gustav Ludwig Behrns,
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 makc, usc,
excrcise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE APPLICATION OF EXHAUST TO THE MILLSTONES OF; FLOUR,
MILLS, AND IN APPARATUS OR APPLIANCES IN CONNECTION THEREWITH," upon the
condition (amongst others) that I, the said Gustav Ludwig Belirns, 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 tlic 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 Scal
Patent Office within six calendar months next and immediately after the
date of the said Letters Patent..
1
NOW.KNOW YE, that I, the said Gustav Ludwig Behrns, do hereby
declare the nature of the said Invention, "and in what manner the
samo is to be performed, to be particularly described and ascertained
in and by the following statement thereof, reference being had to tho
accompanying Sheet of Drawings, and to the figures and letters marked
thcrcon, that is to say :-
My Invention relates to improved arrangements of the exhaust to the

page_text: therewith, whereby a much more powerful exhaust may be employed
than was heretofore possible, resulting in a greatly increased yield from
the millstones, while at the same time the presence of stive in the mill is
avoided; all moisture is effectually removed, and the millstones are kept
perfectly cool while grinding.
20
For these purposes I construct the millstone casing perfectly air-tight,
and I provide it with an inner lining of sheet metal and felt, in order to
protect the interior. of the casing from the lower temperature of the
surrounding air, and thus prevent any condensation of moisture within
the casing, so that all moist vapour resulting from the grinding shall
pass off with the exhausted air.
The spout or funnel conducting the grain and air into the eye of the
running millstone, as also the eye of the millstone itself, is prevented
from communicating with the interior of the casing by means of a
cylindrical air-tight enclosure, by preference of leather, fixed with its
upper end to the top of the casing, while its lower end is fixed to a metal
ring fitting loosely, but in an air-tight manner, into a V groove in a
second metal ring fixed on the running millstone concentric with the
eye thereof, and revolving with the same.
An exhaust pipe communicates with the interior of the casing through
an aperture in the top of the latter, through which the air is exhausted
from the casing by a fan or other suitable exhauster. The external air
is thus caused to enter through the eye of the running stone and
between the grinding surfaces of the millstones in order to pass into the
casing, any other entrance of air being prevented, firstly, by the before-
mentioned enclosure round the funnel, and, secondly, by forming the
meal spout at the bottom of the casing with a bend, and by introducing
into the spout above such bend a screw blade on a shaft, rotated by
means of an external pulley in such manner as to force the meal. down
into the bend of the spout, whereby the spout will be effectually closed
against the entrance of air.
The millstones will act all the more efficiently the more powerful the
exhaust from the casing is made, and in order therefore to allow of such
powerful exhaust being applied, I entirely prevent the escape of particles
of flour, together with the exhausted air, by introducing into the upper
part of the casing a screening surface, through which the whole of the
air and moist vapour exhausted from the casing has to pass before

page_text: escaping through the exhaust aperture, which screening surface inter-
cepts all particles of flour that the air would otherwise carry away with
it. This screen is constructed of a framing suspended by chains from
the top of the casing, which framing is covered by a cloth of a woolly
nature, presenting a considerable area of screening surface by being
mado of a zig-zag form, the cloth being fastened in an air-tight manner
to the top of the casing. A rod attached to the framing of this screen
passes through the millstone casing, in order that by imparting slight
blows occasionally to the outer end of this rod the flour that accumulates
on the screen may from time to time be shaken off.
The exhaust pipo is protected from the cooling influence of the
external air at the part nearest the millstone casing by means of a
covering of felt and slicet iron, in order to provent the moist vapour
that passes away with the air from condensing in that part of the pipe
until it has passed the vertical bend which is there formed in the pipe. 1
After passing this bend tho moisture is allowed to condense and to flow
downwards in the pipe to the outside of the building if required.
The degree of exhaust in the casing can be regulated by a throttle
valve in the exhaust pipe, and a double vacuum gauge is fixed on the
top of the casing for observing the degree of exhaust existing both in 2
the lower part of the casing and in the space above the screening
surface.
By the above-described arrangements a very powerful exhaust may
be applied to the millstone casing, producing a strong current of air
through the millstones, whereby, as also by the absence of any con-
densed moisture on the grinding surfaces, a greatly increased yield is
obtained, while the grinding surfaces are at the same time kept perfectly
Figure 1 represents a sectional elevation, and Figure 2 a plan partly 30
sectional of a pair of millstones and casing to which my Invention is
applied.
A is the lower millstone, and B is the upper millstone. C is the
wooden casing enclosing the millstones, which is lined with felt or other
suitable non-conducting material D and metal plating E, so as to be 35
air-tight, and to protect the interior of the casing from the influence of

page_text: 0
external temperature. F is an air tubo concentrically surrounding the
eye tube by which the corn is supplied to be ground. I is a metal
ring let into and fixed in the upper stone B, and J is another ring fitting
into a recess with sloping sides formed in the ring H. The ring J is
prevented from revolving by chains K attached to the ring J and to
brackets projecting down from the top of the casing O. The ring J is
also connected to the casing O by a flexible enclosure L, by preference
of leather. Thus while the upper stone B and the ring I revolve, the
ring J with the enclosure L form an air-tight separation between the
cyc of the stone and the interior of the casing, the chains K, which
hold the ring J and the flexible enclosure L, allowing the ring J to
accomodate itself to any eccentricity in the movement of the stone B.
G is an air tube connecting the upper part of the casing C with a fan
or other exhauster. The bend of the tube G is lined like the casing C
with felt and metal plating to prevent condensation of moisture within
the tube until the air flowing through it shall have passed the bend. The
tube G is also furnished with a throttle valve U for regulating the
draught of air through it. M is the outlet for the flour; it is made
with a bend M', above which is a screw N, caused to revolve by a strap
working a pulley O¹ on the screw shaft from a pulley O on the stone
spindle. The effect of the screw N is to compress the flour on the
inclined part of the bend below it, and thus to render it sufficiently
compact to prevent ingress of air to the interior of the casing through
the flour passage M. P is a cylindrical grating hung by chains from
the cover of the casing C, and Q is a porous wool or hair fabric attached
to the upper rim of the grating P, and arranged in zig-zag wise so as to
form a series of radiating ridges and furrows, exposing a large surface
for the passage of air through it, the fabric being sufficiently porous for
the passage of air but not for the passage of the fine or dust flour. R is.
an arm attached to the grating P, and projecting through the casing C;
this arm R is caused to oscillate in the direction of its length by a cam,
wiper, or other convenient means, so as to give a jigging movement to
the grating P and fabric Q for the purpose of shaking the dust from the
under surface of Q; or the arm R may for this purpose simply be struck
slightly from time to time with a hammer. S is a double vacuum gauge
(shewn detached at Fig. 3) fixed on the casing, and communicating
by one pipe with the space in the casing outside of the grating P, and
by another pipo with the space above the fabric Q, so that it indicates
the pressure within these spaces respectively. The arrows in Fig. 1

page_text: :
indicate the course of the air drawn by the action of the exhauster down
the tube between the working faces of the millstones; thence tlirough
the pores of the fabric Q, and by the pipe G to tlie exhauster.
. J.
By the above-described. arrangements it will be seen that a powerful
exhaust can be applied to the casing C through the tube G, G', whereby 5
a strong current of air will enter between the millstones from the
air tube F, resulting in a greatly increased yield of flour for a given
motive power, any entrance of air into the casing except through the
eye of the millstone being prevented by the enclosure L and by the.
combined action of the bend M and screw blade N in the meal spout. 1
The air on issuing from the circumference of the stones has first to pass
through the screening surface Q before it can enter the tube G, G₁,"
whereby all particles of: flour carried with it will be retained in the
casing, thus preventing any loss through the formation of stive, and
doing away with the use of the usual stive room; at the same time any 1
condensation of moisture, either between tlie millstones or in the casing
and in the bend of the tube G, G³, is prevented by the before-described
non-conducting lining to the casing and bend of the tube, whereby the
formation of paste between the millstones and the consequent clogging of
the grinding surfaces is obviated. After passing the bend of the tube G¹ 2
the moisture contained in the exhausted air is allowed to condense
on the surfaces of the tube G', and to flow along the same, in order
eventually to be discharged at the outside of the mill.
Having thus described the nature of my Invention, and in what
manner it is to be performed, I would have it understood that I do not 2
claim generally the use of exhaust in-connection-with millstones for. the
purpose of drawing air through between the stones, but I do claim in
connection with millstones worked with exhaust,—
First. The use of a flexible enclosure, such as Ļ, with its fitting to
the revolving millstone, so as to make an air-tight separation between 3
'the eye of the stone and the space in the casing, substantially as herein
described.
Secondly. The use of a screw, such as N, in connection with a bend,
such as M', for preventing ingress of air to the casing by the flour spout,
substantially as herein described.
Thirdly. The use of a grating and screen, such as P and Q, for sifting
-the air on its way to the exhaust pipe, substantially as herein described.

page_text: Fourthly. The lining of the casing and exhaust bend with non-
conducting material and metal plating, so as to render them air-tight
and to prevent the cooling influence of the external atmosphere, sub-
stantially as herein described.
Fifthly. The combination of any two or more of the improvements
claimed above.
In witness whereof, I, the said Gustav. Ludwig Behins have here-
unto set my hand and seal, this Sixteenth day of February, in the
year of our Lord One thousand eight hundred and seventy-two.
GUSTAV LUDWIG BĚHRNS. (L.S.)