AN IMPROVED METHOD OF PRODUCING FLOUR FROM GRAIN
Year: 1878

page_text: LETTERS PATENT to Carl Pieper, of Dresden and Berlin, for the Invention of
"AN IMPROVED METHOD OF PRODUCING FLOUR FROM GRAIN." A communi-
cation from August Nagel and Reinhold Kaemp, both of Hamburg, Germany.
Sealed the 9th August 1878, and dated the 16th February 1878.
COMPLETE SPECIFICATION filed by the said Carl Pieper at the Office of
the Commissioners of Patents on the 16th February 1878.
CARL PIEPER, of Dresden and Berlin. "AN IMPROVED METHOD OF PRODUCING
FLOUR FROM GRAIN." A communication from August Nagel and Reinhold Kaemp,
both of Hamburg, Germany.
This Invention relates to an improved method of producing flour from grain by
a new combination of machines, which insures a complete reduction of the interior
parts of the grain without injurious comminution of its shell, so that the former
may be completely and easily separated from the latter on suitable dressing cylin-
ders, either with or without the assistance of purifying machines.
The difficulty hitherto encountered in separating the interior parts of the grain
from its shell on the one hand, and the demand for a pure white flour of superior
baking qualities on the other, have engendered various methods for its production,
but none of them are free from certain objections.
It may be premised that all machines or appliances the object of which is to
reduce grain into flour, will and must comminute its shell more or less, as other-
wise a reduction of the interior parts of the grain would simply be impossible.
For the purpose of obtaining a pure flour, it is, however, requisite that this com-
minution of the shell should be moderate, so as to allow its complete separation from
the flour produced. If the reduction of the grain is very intense at the onset, a
comparatively large proportion of small particles of bran will be obtained, which
cannot be separated from the flour, but if the grain is submitted to several succes-
sive reducing operations of increasing intensity, with intervening sifting processes,
he bran will in all cases be obtained in larger scales, which can consequently be
eparated more perfectly.

page_text: The degree to which the bran is torn into small particles is perhaps the highest
with the ordinary process of manufacture of flour by millstones, the object of which
is to obtain the greatest possible quantity of flour at the first run. In case, however,
this inconvenience is sought to be avoided, as in the Austrian method of producing
flour, the process becomes extremely complicated and expensive. Moreover, mill-
stones require a great driving power and careful attendance.
The so-called Carr's" disintegrator, which is used in many mills, does not com-
minute the shell quite as much as millstones do under similar degress of comminu-
tion of the grain in general; but it, nevertheless, pulverises the bran to such an
extent as to prevent the production of flour of satisfactory quality if its action on
the grain is very intense. When, on the other hand, the grain is only partly
reduced at the first run, the semolina obtained cannot with advantage be converted
into flour by this machine.
As regards driving power, the total amount of the same required by disin-
tegrators for the complete reduction of grain from its integral state, is altogether
excessive.
The application of roller mills to the manufacture of flour has certainly been
a step towards improvement, but whenever the rollers, whether smooth or grooved,
or otherwise roughened on the surface, are driven at differential speeds, as is ordi-
narily the case, their tearing or cutting action on the shell of the grain is similar to
that of millstones. If, on the other hand, rollers with smooth surfaces are driven at
equal circumferential speeds, they crush the grain without materially tearing its
shell; but they convert it into lamina of flour, semolina, and bran, which cannot be
Such roller mills
completely separated from each other on dressing machines.
have, therefore, always been used in combination with millstones, whether as
preparatory apparatus, or for finishing the products obtained from the latter. This,
however, being but an imperfect mode of operating, my correspondents have endea-
voured to provide better means for realising the valuable properties of roller mills
with smooth rollers, and for this purpose they proceed as follows:-The grain is at
the onset crushed on a roller mill with smooth rollers, having equal circumferential
speeds. This requires comparatively but little power. The lamina of crushed grain
thus produced are then passed through a disintegrating machine for the purpose of
completely detaching the particles of the lamina from each other, and finally the
meal obtained is separated into flour and bran, or as the case may be, into flour
semolina, and bran by a dressing machine, either with or without the aid of a puri-
fying machine.
The degree to which the shell of the grain is torn into fragments by the said
rollers is necessarily dependent upon the intensity with which the crushing operation
is carried out, as has already been stated with regard to flour-producing machines
in general. In all cases of equal comminution of the grain, however, the bran is
obtained in much larger scales by these rollers than by any other machine. If the
rollers are placed very close to each other for the purpose of obtaining the greatest
possible quantity of flour at the first run, the bran will be comminuted to a com-
paratively greater extent, and its separation will be less perfect than if the grain is
crushed moderately at the beginning. In the latter case less flour and more semolina
is obtained, and the scales of bran are larger, consequently the separation of the
latter will be more perfect, and the flour produced at the same time will be purer
than in the first case.
By a subsequent reduction of the semolina obtained another quantity of flour is
produced which yet surpasses the former in quality. Thus the total, reduction of
the grain may either be carried out by a single crushing, disintegrating, and
separating process, or by repeating the same once, twice, or oftener with regard to
the unfinished products, including bran, which yet contains particles of flour.
The particular machines which my correspondents use by preference for this
process are, those of their own Invention, for which they have received Patents in
various states, and the main features of which are the following:―
Firstly, the Roller Mill.-The same consists of two rollers arranged horizontally

page_text: with regard to each other. The bearings of one roller are fixed, while the other
roller. rotates in bearings forming part of a strong forked lever, provided with
suitable adjusting gear, by which the rollers can be regulated at the desired distance
from each other, or completely pressed together during the process of crushing.
This adjustability is, necessary for adapting the rollers to the varying degree of
comminution required, or to the size and hardness of the grain, respectively of the
particles of the material to be crushed.
Secondly, the Dismembering Machine. This machine is based on the principle of
the known disintegrating mill, and consists of two disks having concentric rows of
pegs intervening between each other, one disk being fixed, the other rotating
rapidly. Both disks are enclosed in a casing, which is made air-tight, as far as
practically possible. The crushed and laminated grain being introduced by an
aperture in the centre of the fixed disk, its particles are detached from each other as
it passes between the rows of revolving and fixed pegs; but the action of the
machine being less intense than in case of the comminution of intact grain by the
disintegrating mill, it practically does not cause any further reduction of the scales
of bran delivered by the rollers.
Thirdly, the Centrifugal Dressing Machine. The same consists of a horizontal
dressing cylinder, in which a shaft provided with a number of blades revolves.
These are arranged in screw lines of long pitch, and, moreover, they are curved
transversely.
Between these blades inclined plates are fixed for assisting in propelling forward
the meal within the cylinder, and disks are fixed on the shaft for preventing an
undue current of air from passing through the cylinder.
The described machines are the most advantageous for the object in view, but it
is to be observed that other machines of a similar character may also be used for
the same purpose. So, for instance, the roller mill may have three or more rollers
combined, and the rollers may be placed vertically one above the other, or obliquely
with regard to each other; also the adjusting gear may be of any suitable design.
Instead of the special machine which we have termed dismembrating machine, a
disintegrating mill with two rotating peg disks, whether arranged horizontally or
vertically, or otherwise, may be used. Finally, for the purpose of separation any
sort of flour dressing cylinder will be more or less adapted.
As regards the purifying machine, wherever the same is applied any known
apparatus of this kind may be used in combination with the roller mill, the disin-
tegrater, and the dressing cylinder, the object of the purifyer being mainly to
separate the smaller particles of bran from the semolina produced.
If the described mode of manufacture of flour is applied in existing mills it may
be considered advantageous not to give up the use of the millstones at once. The
Inventors wish it therefore to be understood that they claim as a part of their
Invention the use of millstones, in combination with their special process.
The advantages resulting from the described method are the following
1. Far less power is required for the conversion of a certain quantity of grain
into flour, than with any other method.
2. The flour is completely separated from the bran, consequently the greatest
possible quantity of flour is obtained, and this flour is of pure white colour and of
the best quality, while the bran is practically free from flour.
3. The germs of the grain, which are pulverized, when exposed to the action of
millstones, so as to cause the flour to become spotted, are only crushed, and are
therefore separated from the flour, together with the bran.
4. The flour is not appreciably heated during the process, and is obtained, together
with the whole amount of gluten of the grain, consequently its baking qualities are
materially improved.
5. The machinery requires but little attendance, and, moreover, no sharpening
or dressing of any parts being required, as is the case with ordinary millstones; the
described method is cheaper with regard to labour.
6 The wear and tear of the working parts is very alight

page_text: 7. The space required for the machinery is but small, consequently the building
in which it is to be erected may be much smaller than a mill of the present day;
and, moreover, it may be constructed lighter, as all shocks frequently occurring
with millstones are avoided.
8. The safety against danger from fire is increased, as the millstones, which have
hitherto mainly been the causes of fires in mills, are or may be put fully out
of use.
Having thus described the nature and object of this Invention, and the manner
in which it is or may be put into practice, I claim as new and essential features
of the same, the method of producing flour from grain or partly reduced grain,-
1. By, firstly, crushing the grain or partly reduced grain between rollers having
practically smooth surfaces and equal circumferential speeds; secondly, treating the
products thus obtained by a dismembrating or disintegrating machine; and, thirdly,
separating the dismembrated products by means of a flour-dressing machine, sub-
stantially as and for the purpose specified.
2. By, firstly, crushing the grain or partly reduced grain between rollers having
practically smooth surfaces and equal circumferential speeds; secondly, treating the
products thus obtained by a dismembrating or disintegrating machine; and, thirdly,
separating the dismembrated products by means of a flour-dressing machine and a
purifying machine, substantially as and for the purpose described.
In witness whereof, I, the said Carl Pieper, have hereunto set my hand and
seal, this Twelfth day of February, in the year of our Lord One thousand
eight hundred and seventy-eight.
CARL PIEPER. (L.S.)