IMPROVEMENTS IN TREATING AND SEPARATING THE CONSTITUENTS OF MAIZE FOR THE PRODUCTION OF FLOUR
Year: 1874

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN TREATING AND SEPARATING THE CONSTITUENTS OF MAIZE
FOR THE PRODUCTION OF FLOUR."-A communication from abroad by
Louis Chinzzs of Paris France
Sealed the 24th July 1874, and dated the 5th February 1874.
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 5th February 1874.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN TREATING AND SEPARATING THE
CONSTITUENTS OF MAIZE FOR THE PRODUCTION OF FLOUR," to be as follows:-
This Invention relates to an improved process of separating the oily
from the farinaceous parts of maize, and to the manufacture from
various kinds of white maize of flour of perfect whiteness, which may
be kept a length of time without liability to become rancid,

page_text: The oily matters contained in the germ or embryo of maize, and the
hardness of the perisperm enclosing the same, has prevented the obtain-
ment by the ordinary modes of grinding of fine maize flour capable of
being kept any length of time, as owing to the contact of the oily
matters with the farinaceous portions of the grain the oil penetrates the
whole mass and the resulting flour is liable to become quickly rancid.
Moreover, the perisperm, which is composed of starch, gluten, and an
albuminous matter serving to bind the constituent particles, possesses
great hardness as well as a certain amount of elasticity which renders
it very difficult to be reduced to fine flour.
Many attempts have been made to separate the fatty and farinaceous
portions of maize, as also to soften the perisperm before grinding, but
none have succeeded in practice.
The means I employ for obtaining the above result consists in effec-
tually softening the maize by steeping it from 5 to 10 days in a weak
aqueous solution of sulphurous acid. This solution possesses the pro-
perty of completely dissolving the particular albuminous matter to which
maize owes its hardness, while it also prevents any alteration during the
immersion.
The degree of concentration of the solution of sulphurous acid and
the length of time will vary according to the temperature at which the
operation is effected. Thus during the cold season the steeping may be
continued for ten days or more with a solution containing from 4 to 5
volumes of sulphurous acid to one volume of water, but with a higher
atmospheric temperature a more concentrated solution may be employed
and the time of steeping be reduced to from 4 to 6 days.
It is impossible to fix precise rules in this respect, as besides the tem-
perature the time required for softening and the proper degree of
concentration of the sulphurous solution depends greatly on the quality
of the maize itself.
I would remark that an aqueous solution of sulphurous acid has been
already successfully applied to effect the disaggregation of maize to be
employed for the production of alcohol and other products, but it has
never hitherto been observed that the maize when thus treated and after
being well drained if passed between two cylinders placed in close
proximity to one another becomes converted into a flour which is soft to
the touch while still moist, and of great fineness and surpassing whiteness

page_text: (when white maize is so treated). The pellicle or coriaceous envelope of
the grain is broken up into coarse fragments, while the germ owing to
the elasticity it acquires passes intact or nearly so between the cylinders,
nearly the whole of the oily matter being thus retained. In this manner,
with the combined assistance of bolting and repeatedly passing it through
the cylinders, a flour is obtained containing all the gluten of the maize
of a particularly good quality for the purpose of panification, and which
may be kept with facility. This improved process is thus based on
the above property imparted to the maize by the sulphurous acid
treatment.
In practise it is convenient to have six receptacles placed either on
the ground floor or basement, each capable of containing the quantity
of maize it is proposed to treat each day, and also the solution of
sulphurous acid. An elevator conducts the maize when sufficiently
softened to an upper floor, where it is discharged on to a vibrating screen
to be drained, which operation may further be facilitated by a current of
hot air passed through the screen. This however is not indispensable,
although it has the advantage of freeing the maize at the commencement
of the operation of a portion of the sulphurous acid it contains.
maize is discharged from the vibrating screen into a hopper provided
with an arrangement for feeding it in a regular manner to the cylinders.
These latter should be a least 12 inches in diameter with slightly varying
surface speeds, for example, in the ratio of 5 to 6. If this variation
were more considerable the germ and pellicle would be too much
reduced.
The
The cylinders should be in sufficiently close proximity (say th of
an inch) to reduce the farinaceous portion of the maize to fine flour.
Assuming the cylinders to be of equal diameter, one should make about
50 revolutions to 60 of the other, and each is furnished with a metal
scraper or doctor for keeping their surfaces perfectly clean.
The product obtained consists as before mentioned of flour, which is
soft to the touch, and containing the broken germs and pellicle. It will
however be easily understood that a perfect separation of the different
matters of which the maize is composed cannot be obtained by once
passing it through a bolter, nor by the subsequent operations, but to
attain this result as nearly as possible it is necessary to dry the product
gradually during the subsequent treatment, but not to deprive it entirely
of water until the final operation.

page_text: In the preliminary operation, when the product contains a considerable
amount of water, it is indispensable that a dressing machine, consisting
of a stationary cylinder, through which passes a spindle carrying spiral
brushes, which facilitate the passage of the finer portion of the meal
through the meshes of the cloth lining of the cylinder, and also conduct
the refuse towards its end. If however the product is less moist the
ordinary revolving bolting mill may be employed.
One peculiarity of the farinaceous portion of the maize reduced to
meal by the improved process of this Invention is that it may contain as
much as 20 per cent. of water without binding when compressed or
choking the meshes of the screens, as would be the case with other kinds
of flour. It is in fact necessary as above mentioned that it should retain
a considerable amount of water until the final operation, as in this state
it is much easier to separate the particles of germs and pellicle, which
are tougher when moist, the contrary being the case with the farinaceous
portion.
In order to dry the product endless travelling webs placed one above
the other may be used stretched on wooden rollers and moving in
opposite directions. The matters being received on the top web and
transferred successively to those beneath it a current of hot air is caused
to pass between the webs in an opposite direction to that in which the
matters move.
The exact arrangements of the several apparatus for crushing the
maize after steeping and for separating and drying the products will be
easily understood with the assistance of the accompanying Drawing.
The maize falls from the vibrating screen before mentioned (which is
not shown in the Drawing) into the hopper above the first pair of
rollers a, and the product after being operated on by these falls into a
spout leading to a dressing machine having rotary brushes 1 and clothed
with brass or preferably silvered wire cloth, having a mesh of about
th of an inch.
That part of the product which does not pass throughthe meshes of the
cloth falls on to the series of the travelling webs e, where it is partially
dried and deprived of nearly all the sulphurous acid it contains. It is
then conducted by the elevator o into the hopper of cylinders b.
This latter portion of the product contains the germs and pellicles,
while the meal which has passed through the meshes of the cloth 1 falls

page_text: on to the series of travelling webs d, in traversing which it is con-
tinually exposed to a current of hot air to deprive it of the sulphurous
acid it may contain. The meal (which is already very white for the
slightly colored variety of maize from which it is obtained, and contains
5 but very little oily matters) falls into the spout of the dressing machine 4,
where it is more completely deprived of the fragments of the germ and
pellicle.
It is now sufficiently free from oily matters to be thoroughly dried on
the travelling webs 1, and passes thence into the inclined dressing
machine 6, 5, 4, placed beneath where the products are assorted
according to their degrees of fineness. This constitutes the principal
part of the product, and represents according to the quality of the maize
employed from 70 to 75 or even 78 per cent. of the weight in some
varieties.
This flour may be kept without turning rancid, and when mixed with
twice its weight of wheat flour will produce a very white bread of
excellent flavor and possessing the valuable property of remaining sweet
for a week and upwards.
The oily portion is discharged into the hopper, which conducts it to
cylinders b, whence it passes through the dressing machine 2, whereby
the coarse bran is separated and passes away at pipe W. This bran,
which is composed of germs and pellicles, may be utilized by extracting
the oil which it contains in considerable quantity. The matters which
pass through the meshes of the dressing machine No. 2 fall on to
travelling webs, where they are mixed with those passing through No. 3,
which are fed by a screw conveyor n on to webs f, where they are dried
and then passed to dressing machine No. 45. To the matters which do
not pass through the meshes of this machine are added by means of
screw conveyor m those eliminated by machine No. 4. The whole is
then carried by elevator p into the hopper-supplying cylinders c, whence
it passes to dressing machine No. 3. This latter machine eliminates
finer bran than that separated by machine No. 2, and which is very
useful for fattening live stock.
The coarse and finer brans represent from 8 to 18 per cent. of the
weight of the grain, according to the variety of maize employed.
I have already traced the course of the products which traverse the
meshes of machine 3, and it only remains to follow those passing through

page_text: the meshes of machine in 48, which fall upon travelling webs F, and
after being thoroughly dried are conducted to the dressing machine 6, 5, 4,
where they are assorted according to their different degrees of fineness
and discharged at spouts II. These latter products constitute in all
cases an infinitely superior quality of flour to that obtained from maize
by the ordinary processes, but they do not keep as well as the principal
product, of which they represent at least one-third of the weight.
The farinaceous varieties of maize supply but little of this second
flour, the only objection to which is its comparative want of keeping
qualities
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 4th August 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of February, in the year of our
Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Alexander Melville Clark, Her special
licence that I, the said Alexander Melville Clark, my executors, admi-
nistrators, and assigns, or such others as I, the said Alexander
Melville Clark, my executors, administrators, and assigns, should at any a
time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might

page_text: for the slightly colored varieties of maize from which it is obtained,
and contains but very little oily matters, falls to the spout of the
dressing machine 4, where it is more completely deprived of the frag-
ments of the germ and pellicle. It is now sufficiently free from oily
matters to be thoroughly dried on the travelling webs 1, and passes
thence into the inclined dressing machine 6, 5, 4, placed beneath where
the products are assorted according to their degree of fineness. This
constitutes the principal part of the product, and represents, according
to the quality of the maize employed, from 60 to 75, or even 78 per cent.
of the weight in some varities. This flour may be kept without
turning rancid, and when mixed with twice its weight of wheat flour
will produce a very white bread of excellent flavour and possessing
the valuable property of remaining sweet for a week and upwards.
The oily portion is discharged into the hopper, which conducts it to
cylinder 6, whence it passes through the dressing machine 2, whereby
the coarse bran is separated and passes away at spout IV. This bran,
which is composed of germ and pellicles, may be utilized by extracting
the oil, of which it contains a considerable quantity. The matters
which pass through the meshes of the dressing machine No. 2 falls on to
webs, where they are mixed with those passing through No. 3, which are
fed by a screw conveyor n on to webs, where they are dried, and then
passed to dressing machine No. 4 g. To the matters which do not pass
through the meshes of this machine are added by means of screw con-
veyor m those eliminated by machine No. 4. The whole is then carried
by elevator p into the hopper supplying cylinders c, whence it passes to
dressing machine No. 3. This latter machine eliminates finer bran than
that separated by machine No. 2, and which is very useful for fattening
live stock.
The coarse and finer brans represent from 8 to 18 per cent. of the
weight of the grain according to the variety of maize employed.
I have already traced the course of the products which traverse the
meshes of machine 3, and it only remains to follow those passing through
the meshes of machine No. 4 g, which fall upon webs 1, and after being
thoroughly dried are conducted to the dressing machines 6, 5, 4, where
they are assorted according to their different degrees of fineness, and.
discharged at spouts II. These latter products constitute in all cases an
infinitely superior quality of flour to that obtained from maize by the

page_text: eliminated by bolting or dressing in the condition of fine white flour not
liable to become rancid, all as herein-before described.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Fourth day of August, in
the year of our Lord One thousand eight hundred and seventy-
four.