A NEW METHOD OF COMPRESSING AND PRESERVING GROUND COFFEE AND MACHINE THEREFOR
Year: 1881

page_text: LETTERS PATENT to Carl Pieper, Civil Engineer and Patent Agent, of
109/110, Gneisenaustrasse, Berlin, S.W., Prussia, for an Invention of
"A NEW METHOD OF COMPRESSING AND PRESERVING GROUND COFFEE AND
MACHINE THEREFOR." A communication from Captain Adalbert von Hofmann,
of Augsburg, Bavaria.
PROVISIONAL SPECIFICATION left by the said Carl Pieper at the Office
of the Commissioners of Patents on the 20th January 1881.
CARL PIEPER, Civil Engineer and Patent Agent, of 109/110, Gneisenaustrasse,
Berlin, S.W., Prussia. "A NEW METHOD OF COMPRESSING AND PRESERVING
GROUND COFFEE AND MACHINE THEREFOR." (A communication from Captain
Adalbert von Hofmann, of Augsburg, Bavaria.)
This Invention consists in an improved method of treating ground coffee and of
compressing the same into tablets or blocks, so that it will preserve its full flavour
and other original qualities for a considerable length of time.
The coffee after having been roasted, and while yet warm, is mixed with a small
quantity of a very pure, inodorous, and tasteless fat or oil, and is thereupon ground.
Subsequently, a certain quantity of potash or of bicarbonate of soda is added.
The coffee-powder thus prepared is compressed into blocks or tablets by means of a
suitable apparatus.
The machine which the inventor prefers using for this purpose, consists of a
hollow slide, moved to and fro by means of a cam, and having at the top an aperture
which at a certain position of the slide communicates with the receptacle in which
the coffee is contained, or with a pipe leading to such receptacle. Within the slide
a piston works, which is actuated by a crank. Opposite to this piston there is a
fixed piston, over which the said slide is pushed at every stroke, and against which
the movable piston acts.
The operation of the machine is as follows:-The movable piston having closed
from below the aperture in the top of the slide, this aperture is made to communicate
with the coffee-receptacle, and is thereby filled. The slide is then pushed forward
and over the fixed piston, and recloses the receptacle, whereas the movable piston
recedes and allows the coffee to drop from the said aperture into the space within
the slide between the two pistons. The movable piston thereupon advances and
compresses the coffee-powder between it and the fixed piston. Finally, the slide
and the movable piston recede, but the former at a greater speed than the latter,
in consequence whereof the compressed tablet of coffee-powder is pushed out of the
slide.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Carl Pieper in the Great Seal Patent Office on the 12th July
1881.
CARL PIEPER, Civil Engineer and Patent Agent, of 109/110, Gneisenau Strasse,
.Berlin, S.W., Prussia. "A NEW METHOD OF COMPRESSING AND PRESERVING
GROUND COFFEE AND MACHINE THEREFOR." (A communication from Captain
Adalbert von Hofmann, of Augsburg, Bavaria.)
This Invention consists in a special method of treating ground coffee, and of
compressing the same into tablets or blocks, so that it will preserve its full flavour
and other original qualities for a considerable length of time.
The raw coffee after having been roasted is allowed to cool to a certain degree,
but while yet warm it is mixed uniformly with an oil or fat which is perfectly
inodorous, tasteless, and free from acid; subsequently the coffee is ground.
The oil or fat, of which about 6 ounces on 100 lbs. of coffee is to be used, causes
the particles of the powder to adhere together, and besides it produces a protecting
covering on the surface of the tablets or blocks into which the coffee-powder is
compressed in the manner to be described hereafter.
The coffee having been ground, bicarbonate of soda or potash or any other
equivalent alkaline carbonate is added to the same in the proportion of about 1 lb.
on 100 lbs. of coffee. By the mixture with such salts (some of which have s
heretofore already been applied for the better extraction of the coffee) the powder
is prevented from becoming sour. If it should be desired sugar may finally be
added.
The coffee-powder thus prepared is hereupon compressed into blocks or tablets
by means of a suitable apparatus. The machine which the inventor prefers using
this purpose is represented on the annexed Sheet of Drawings, Fig. 1 being a
longitudinal section, Fig. 2 a transverse section, and Fig. 3 a plan.
The main operating parts of this machine are a hollow slide g and a movable
piston c, working within the former and against a fixed piston h. The piston c_is
conneeted by the rod k with the crank d, the shaft of which is operated from the
shafts by means of a worm-wheel-gearing j, and two pairs of bevel-wheels t¹ and t.
The said shafts may be rotated by hand or by engine-power. To the slide g
motion is imparted by a cam-disk / keyed on the crank-shaft, and acting on the
slide through the medium of a lever m, of the two levers n, n, and the rods o, o.
The lever m is provided at the end with a roller, which is kept in contact with the
cam by means of a weighted lever p keyed on the same shaft r to which the
levers m and n, n, are fixed. In the top of the slide there is an aperture w
serving to receive coffee-powder from the funnel x connected with a receptacle
(not shown in the Drawing) in which the coffee is contained, or with a pipe
leading thereto. The aperture w is of the proper size for taking up the quantity
of coffee to be compressed into a tablet.
The form of the cam-disk and its position relatively to the crank d are such
that the piston c closes the aperture w from below, while the latter is in communi-
cation with the funnel x so that coffee may drop into the same. After having been
filled the slide moves towards and over the fixed piston h, and recloses the funnel x.
The piston c being meanwhile drawn towards the crank-shaft uncovers the aperture w
and allows the coffee to fall from w into the space left within the slide between
the two pistons c and h. The cam-disk now keeps the slide at rest, while the
piston c moves forward again and compresses the coffee-powder between it and the
piston h. The pressing-process being completed the slide g récedes, the piston c
soon after follows in the same direction, but at a smaller speed, so that the tablet

page_text: of coffee-powder is pushed out of the slide so that it falls on the travelling band z,
which conveys the same forward and into a suitable receptacle. The said band
runs over two rollers, one of which is actuated from the shaft r' by means of a
worm-wheel-gearing a¹.
For the purpose of altering the size of the tablets to be manufactured the
aperture w may be fitted with removable plates at the sides, while the piston h is
made adjustable lengthwise. When the machine is driven by engine-power the
driving pulley is preferably keyed on the shaft s.
On account of the oil or fat added to the coffee, and from the pressure to which
the coffee-powder is exposed, the blocks or tablets prepared according to this
process are on the outside almost impervious to air. It is mainly this imper-
viousness which ensures the preservation of the coffee, and which prevents the
volatilization of the aromatic substance contained in the same.
The tablets are with advantage packed in parchment-paper or other similar
material.
It may finally be mentioned that the described machine may also be used for
dividing into equal portions and compressing other mealy, powdered, or granular
substances into blocks or tablets.
Having thus described the nature and object of this Invention and the manner
in which it is to be carried out in practice, as communicated to me by the inventor,
I hereby claim as new and important features of the same,-
1. The method of preserving ground coffee by mixing the roasted coffee, while
yet warm, with an inodorous and tasteless oil or fat which is free from acid;
moreover, by adding to the coffee bicarbonate of soda or potash or other equivalent
alkaline carbonate, and, finally, by compressing the prepared coffee-powder into
blocks or tablets by means of a suitable press, substantially as and for the purpose
described.
2. In a machine for dividing into equal portions and compressing ground coffee
a hollow slide g provided with an aperture w, a movable piston c working in the
slide, a fixed piston h, and a fixed funnel or pipe x, all combined together, and with
a suitable operating mechanism, substantially as described and for the purpose
specified.
In witness whereof, I, the said Carl Pieper, have hereunto set my hand and
seal, this Twenty fourth day of June, in the year of our Lord One
thousand eight hundred and eighty one.
-
CARL PIEPER. (L.S.)