Improved Process for Destroying Infectious Germs in Milk, and Apparatus therefor.
Year: 1893

page_text: Date of Application, 1st Apr., 1893-Accepted, 2nd June, 1893
UOMI LUI DI MUIFICATION.
Improved Process for Destroying Infectious Germs in Milk, and
Apparatus therefor.
We, GUSTAV HERMANN NEUHAUSS, Councillor of Agricultural Economy,
JOHANN FRANZ HUGO GRONWALD, Apothecary, and EMIL HEINRICH CONRAD
OEHLMANN, Engineer, all of Alexandrinenstrasse 109, Berlin in the 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 :-
Our invention relates to the destruction of infectious gerins in milk and consists
in an improved process for said destruction and apparatus therefor, by means of
which the milk can be heated to more than 100° C. for destroying the infectious
germs contained therein while preserving most of the qualities of fresh milk and
the use and delivery of milk even from dairies and districts infected by disease is
rendered possible.
While in milk boiled in the usual way for this purpose a change of the milk is
produced, which renders a further utilisation of the same for making butter by
natural creaming or centrifugal separation impossible, the milk treated according
to our improved process retains almost completely the qualities of fresh milk, so
that notwithstanding its previous heating, butter or cream can be obtained from it.
The improved process consists in keeping the milk in open vessels in a closed
apparatus under steam pressure and raising it by steam to the desired temperature.
When the milk is drawn off, after it has been heated, while hot it must be kept
under the same pressure as in the apparatus; when the milk is heated in the vessels
in which it is to be dispatched, the pressure in the heating apparatus must be
reduced correspondingly with the gradual cooling of the vessels. The vessels
containing the milk may be quite open, or may be partly covered for preventing
the condensed water from entering the same, the special characteristic of the
improved process being that the pressure existing in the apparatus acts directly
upon the milk treated therein, for the prevention of ebullition during the heating.
The drawings appended hereunto show the apparatus required for carrying out
this process either for large quantities of milk on extensive dairy farms, or for
smaller dairies and household use.
Figs. 1 and
show a longitudinal and cross section of the apparatus arranged
suitably for treatment of large quantities. Into a closed vessel or steamer A
provided with safety valve or equivalent appliance is inserted a milk pan or
receptacle B formed in a special manner as shewn so as to separate the milk into
thin columns or divisions. Steam is supplied through pipe a, the condensed water
drawn off through pipe b. The pipe c (Fig. 2) starting from the bottom of the
milk pan B serves to discharge or draw off the milk after treatment.
Figs. 3 and 4 show a similar apparatus, in which the milk pan B is arranged so
that a thin horizontal layer of milk is formed instead of vertical layers. In both
cases comparatively large surfaces are exposed to the action of the steam, so that
the heating of the milk to the desired degree is effected with rapidity and
certainty.
In both these apparatus the steam for heating the milk is admitted through a
pipe a and generated in a separate boiler, which is practicable or profitable only in
Large establishments. For small dairies and household purposes the apparatus is
modified as shewn by Figs. 5 to 8. The vessel or boiler A is formed in its lower
part as a pan containing water and with a suitable furnace below the same, the
milk vessel or pan being contained in the upper part. In using this modified
apparatus the boiler A is filled to a certain height with water through a lateral
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page_text: cock d provided with a funnel e at the top. The cock d, e, may be placed at such
a height that it indicates when the boiler A has been filled sufficiently. The milk
pan B, Figs. 5, and 6, which similarly to that shewn on Figs. 1 to 4 is provided
with a discharge pipe r, is arranged above the water level. If the milk is to be
heated in vessels capable of removal a bottle carrier or rack C, Figs. 7 and 8 made
of perforated sheet or wire netting is conveniently used, in which the bottles D are
held while being heated. When the apparatus A has been filled with water and
in the case of that shewn by Figs. 5 and 6 milk has been filled into the pan B
through the cock g, the water contained in A is made to boil and the milk heated
thereby. As the steam generated cannot at first escape, it will soon acquire the
requisite pressure, which is regulated by means of the safety valve h.
Fig. 5 shows a modification that may be used in some cases, of the arrangement
shewn by Figs. 5 and 6. The funnel of the cock g for filling in the milk is
provided with a spout f¹, so that when the cock g is opened the steam pressure
in the vessel A will force out the milk and empty it into a receptacle through the
spout, the milk being thus discharged without opening the vessel. The discharge
pipe c from the bottom of the milk pan shewn on Figs. 5 and 6 is thereby done
away with. The water evaporated for heating the milk is replaced through the
cock d. In order to prevent the water filled in through the cock from entering the
milk pan, the latter may be covered with a loose cover, or the cock may be so
placed on the top of the steamer A that the water inlet is above the openings b₁
made through the pan B (Fig. 6) and the water falls directly through them into
the lower part of the steamer A. In a similar way the water lost by evaporation
in the apparatus shewn by Figs. 5 to 8 is replaced through the lateral cock d.
When the milk has been for a sufficient time subjected to the action of steam
under pressure, and heated thereby to 100 or more than 100° C., all the infectious
germs contained therein have been killed or destroyed and milk coming from
infected districts has been rendered available for use. The milk treated in the
manner hereinbefore described retains in so far its natural properties, that even
after this treatment, by heating, it can like fresh milk be churned for butter,
creamed after standing, or the cream separated by centrifugals, because, by being
heated under steam pressure the ebullition or boiling of the milk is prevented. If
it is drawn off hot from the apparatus shewn by Figs. 1 to 6, it must be kept under
pressure in order to prevent sudden ebullition in consequence of the reduction of
pressure. This may be done in any convenient manner, for instance by letting it
flow into vessels also under steam pressure and placed at a lower level than the
apparatus A, which after being filled are disconnected from the pipe c, and the
steam pipes, and allowed to cool. If the milk is treated in the vessels in which it
is to be dispatched as shewn by Figs. 7 and 8, or drawn off into open vessels, the
pressure in the boiler A must be gradually reduced correspondingly with the
gradual cooling of the milk and the milk drawn off when sufficiently cooled so that
sudden ebullition can no longer occur.
The process and apparatus hereinbefore described are intended as stated above
only for killing or destroying the infectious germs while preserving as much as
possible the qualities possessed by fresh milk. They are not intended to prepare
milk so as to remain permanently durable, but to enable even small farmers to
render milk suitable for carriage and use while depriving it as little as possible of
the qualities of fresh milk.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that
what we claim is.
1. A process for killing or destroying infectious germs in milk by heating the
milk in an open pan or vessel enclosed in another vessel or steamer, under pressure,
and discharging it either under pressure or after having been gradually cooled
under a gradually reduced pressure, substantially as and for the purposes herein á
before set forth.

page_text: 2. For carrying out the process claimed in the first claim, the use and arrange-
ment of an apparatus consisting of a closed vessel or steamer A provided with
safety valve h or its equivalent and steam supply pipe a, in which steamer is
arranged an open pan B dividing the milk into thin layers or columns and provided
with a discharge pipe c for the purpose of heating and discharging the milk under
pressure, substantially as herein before described with reference to Figures 1 to 4
of the drawings..
B
3. For carrying out the process claimed in the first claim the use and arrange-
ment of a closed boiler A provided with safety valve h or its equivalent, the
lower part of which boiler contains water and the upper part an open milk pan
provided with discharge pipe c, the boiler being provided with cocks or equivalent
devices e d and fg for supplying water and milk to the same while closed, substan-
tially as herein before described with reference to Figures 5, 6, and 54 of the
drawings.
4. For carrying out the process claimed in the first claim, a closed boiler A
provided with safety valve h or its equivalent, in the upper part of which boiler a
bottle carrier C of perforated sheet or wire netting is arranged for holding open
bottles filled with milk, substantially as hereinbefore described with reference to
Figs. 7 and 8 of the drawings.
Dated this 20th dor of March 1902
R. J. URQUHART,
57, Barton Arcade, Manchester, and 5, Clayton Square, Liverpool,
Consulting Engineer and Patent Agent.