Year: 1887

page_text: Date of Application, 31st Dec., 1887
Specification Accepted, 3rd Feb., 1888
We, GUSTAV JANTZEN and ROBERT LUTZ Manufacturers of Dresden in the
Kingdom of Saxony and German Empire do hereby declare the nature of this
invention and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement:—
The improvements hereinafter described are intended to have such an effect on the
runners and understones of cocoa grinding apparatus by external heating or cooling
means that they assume a fixed temperature and are either warmed or artificially
cooled so that the cocoa does not adhere to the stone and is not injuriously heated even
when the two mill stones rub together.
And in order that our invention may be easily understood and readily carried into
practice we will proceed to describe the same with reference to the accompanying
drawings.
Figures 1 to 3 show the new appliance when only the under stone is to be heated
or cooled, Figures 1 and 3 being sections and Figure 2 a plan.
Figures 4 to 7 show an altered appliance by which the understone and the runner
can be kept at a fixed temperature.
This appliance can also be used for each of the stones separately. Figure 4 is a
longitudinal section of the mill stones. Figure 5 a plan of the casing for the understone.
Figure 6 the siphon apparatus especially the siphon tube with its two valves for
regulating the influx and efflux of the heating or cooling fluid. Figure 7 is a section
through Figure 6 on section lines I II.
In order to cool the understone alone the casing G (Figures 1 to 3) is arranged
which fits air-tightly against the understone and forms with it a hollow space in which
the fluids or gases used to heat or cool the understone circulate. These fluids or gases
enter through the tap H into the space between the casing and the understone and
are let off again through the tap h (in the bottom of the casing G). The tap h at the
same time serves to let off the condensation or other water when steam is used. The
tap H can be made a three passage tap two of its passages being connected by pipes
with vessels which contain heated fluid (or steam) and cooled fluid. The pipe K in
Figures 2 and 3 serves to bring in heated or cooled air.

page_text: The casing G is provided with ice funnels E so that the space between the casing G
and the understone may also be cooled with ice. The melted water is as already
mentioned let off by opening the tap h.
The formation of the said hollow space between the understone and the casing G is
effected by ribs or feet », r.
The manipulation of this new appliance (Figures 1 to 3) is as follows:—
When by opening the tap H or through the pipe K heated fluids gases air or steam
have been let into the casing and the understone has thus been warmed for a very
short time the cocoa which lies between the grinding surfaces of the set of stones and
was coagulated becomes fluid and the apparatus is then ready to work.
It is well known that in ordinary mills in which the understone is not heated before
beginning to grind when the runner stands still the cocoa coagulates and this
coagulation is only removed by heat being generated by the friction of the stones
when the mill is set to work again which heat is communicated to the coagulated
cocoa. Not until then does the mill begin to grind again. This loss of time which
cannot be avoided in the ordinary mills is prevented by the heating of the
understone.
When the grinding bodies are sufficiently heated in the manner described (Figures 1
to 3) and in order to prevent them getting warmer than is just necessary for the
cocoa, cool fluid or cooled air or gas is let in by the tap H or through the pipe K into
the space between the under stone and the casing G.
In a similar way the ice funnels E can here be used. Thus the heat which is
generated by the friction in grinding can be drawn out of the understone so that
it can be brought to any desired low temperature and the temperature can be
regulated.
The above described apparatus possesses the following advantages over the ordinary
ones, viz. -
(1) The grinding surfaces in order to avoid sticking together do not require to be
placed apart i.e. to be at a distance from each other. On the contrary they remain in
their working position which prevents the grinding surfaces from getting too far apart
or too close together thus avoiding unnecessary friction.
(2) By the heating of the grinding bodies the apparatus is rendered ready to work
directly it is set in motion.
(3) By the artificial cooling applied in the 2nd period of the grinding the cocoa
retains its natural fine aroma morcover the working capacity of the whole apparatus is
thereby considerably increased.
In order to be able to use one and the same fluid for both heating and cooling the
understone and at the same time to prevent the coagulation of the cocoa we arrange
the modifications shewn in Figures 4 to 7. In this arrangement the understone is
enclosed by a casing G₁ (Figures 4 and 5) this casing has on its inner wall which
comes against the periphery of the understone B' a certain number of protuberances 1
to 8 which in conjunction with the periphery of the understone B¹ forin screw shaped
pipes.
The casing also has on its floor ribs upon which the understone rests and which
together with the understone B₁ form spiral shaped passages 9 to 17. In addition
there is a space W left between the understone and the axle tube L which contains
the stone bush and is made in one piece with the casing, in this space fluids can collect.
The axle tube L is shut off at the top i.e. towards the eye of the upper stone by a
plate L' which is set in a water tight manner on the understone by which means a
space is provided between the axle tube L and the opening of the understone. If
fluid is allowed to enter through a tap a to the casing G it circulates first in the screw
shaped pipes or passages 1 to 8 and thus by contact with the understone B' draws out
the superfluous heat of the latter. Now as in grinding the understone gets hot chiefly
at its grinding surface only while its bottom retains a uniform temperature the heating
fluid circulating out of the pipes or passages 1 to 8 to the bottom and into the
passages 9 to 17 will be partially cooled again against the cooling bottom of the under-
The fluid then comes up out of the passage No. 17 into the space W between
stone.

page_text: the axle tube L and the bottom stone. Thus that fluid which has a somewhat higher
temperature will collect up in the space W while the cooler fluid will remain down at
the bottom of the casing G. In order now to prevent the coagulation of the cocoa
lying on the plate K and also to prevent its being heated more than is just necessary
an appliance is used which enables the heating fluid to be drawn off at will from the
bottom of the casing or from the upper part of the space W. This appliance is shewn
on a large scale in Figures 6 and 7. It consists of two tubes QQ¹ joined by a bent
knee, of which is screwed into the bottom of the casing G and is connected with a
tap while Q has its mouth near the bottom of the casing. The tube Q' has at its
lower end and above the junction with the knee piece two funnels 7' 7" which are set,
opposite to each other. In the funnels there are two valves which are
connected together by a rods they are so arranged that one valve is open while
the other is closed and vice versa. The tube is in the space W between the
axle tube L and the understone B'. The funnel 7' has its mouth at the bottom of the
casing, the funnel q" at the upper end of W.
If now the cocoa on the plate K is to be further heated the rod s is so moved down
that the valve is shut while the valve is open. The cool fluid at the bottom of
the casing G then flows direct through the funnel q¹ tubes Q¹ Q and the tap ¹ into
the open air without any of the warmer fluid (warmed by the understone through the
working of the mill) being drawn off from the space W. If on the other hand the
cocoa being ground is not to receive any further heat the valve is shut and " is
opened so that the fluid is drawn off from the upper part of the space W and in
consequence of the rapid circulation setting in to the space W the fluid has no time
to give off its heat to the plate L'.
By partially opening both the valves one can exactly regulate the temperature
of the cocoa on the plate K.
In order also to bring and keep the runner at a fixed temperature or to cool it we
place on the circumference of the runner L" and let in to the latter a ring shaped
vessel M of somewhat U-shaped section, which is filled with fluid through a tube n
which latter can be closed by a tap N and terminates in a rose. In order to produce
circulation of this fluid in the runner the superfluous fluid is drawn off by a siphon
tube m.
Having now particularly described and ascertained the nature of our inven-
tion and in what manner the same is to be performed we declare that what we
claim is:
1. In cocoa grinding mills the casing G fitted air tightly against the understone.
and forming with the latter a hollow space which serves to heat or cool the under-
stone by means of fluids air steam gases or ice substantially as set forth.
2. The casing G with the understone enclosing a hollow space in connection with
the tap H for letting in fluids or steam and in connection with the tap 4 for letting off
same substantially as set forth.
3. The casing G forming a hollow space with the under stone in connection with
the pipe K to moderate the temperature of the understone substantially as set
forth.
4. The ice funnels E on the understone for cooling the latter by means of ice
substantially as set forth.
5. The casing G¹ with a number of screw shaped pipes or passages 1 to 8 at the
side and a number of spiral shaped passages 9 to 17 at the bottom for cooling the
grinding surface of the understone and at the same time partially to cool the fluid
heated by the grinding substantially as set forth.
6. The casing G¹ with screw shaped pipes at the side and spiral shaped passages at the
bottom in connection with the plate L on the eye of the understone substantially as
set forth.
7. The tubes QQ in the space W between the casing G' and the axle tube L in
connection with the tap h¹ to be able to regulate and draw off cold and warm fluid

page_text: at will from the bottom of the casing G¹ and the space W substantially as set
forth.
8. The ring shaped vessel M on the runner L" to cool or heat same substantially as
set forth.
9. The ring shaped vessel M to cool the runner L" in connection with the siphon
tube m to circulate fluids to heat or cool the understone substantially as set forth.
Dated this 31st day of December 1887.
TONGUE & BIRKBECK,
34, Southampton Buildings, London, W.C.,
Agents for the Applicants.
TONGUE & BIRKBECK,
34, Southampton Buildings, London, W.C.,
Agents for the Applicants.