An Improved Process and Apparatus for the Treatment of Milk, Bouillon, or the like to Produce an Entirely Germ-free and Transportable Alimentary Product.
Year: 1895

page_text: Date of Application, 28th Aug., 1895-Accepted, 26th Oct., 1805
COMPLETE SPECIFICATION.
An Improved Process and Apparatus for the Treatment of Milk,
Bouillon, or the like to Produce an Entirely Germ-free and
Transportable Alimentary Product.
A communication by EMIL HILBERG, of 54 Märkischestrasse, Essen-on-the-Ruhr,
in the Empire of Germany, Dr. of Chemistry.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E. of The Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool and 6 Bank Street,
Manchester both in the County of Lancaster, 118 New Street, Birmingham
in the County of Warwick and 31 High Holborn in the County of Middlesex,
Civil Engineer 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 :-
This invention has for its object an improved process and apparatus for the
treatment of milk, bouillon or the like to produce an entirely germ-free and
transportable alimentary product which undergoes no alteration as regards
digestibility, natural appearance, colour or taste as against fresh milk, bouillon or
the like.
A product entirely free from germs can only be obtained by fractional
sterilization in a current of steam, the vessel and the article to be sterilized
requiring to have the air entirely excluded.
It is thus a main condition that the sterilizing vessel or apparatus shall be
opened or closed at a suitable moment.
An absolutely transportable product can only be obtained by subjecting the
sterilized fluid to a pressure sufficiently great to fix the separate fat particles in the
serum in such a way that their rising and collecting on the surface (the so-called
buttering") does not take place even during a long transportation.
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In order that during the sterilization the product shall not lose the digestibility,
natural appearance, colour or taste of the unsterilized product, the limit of
temperature, that is to say a given maximum degree of heat must not be exceeded.
In any case by the first sterilization, and at this maximum degree of heat, the
destruction of all bacteria does not take place. This latter is attained by the
fractional sterilization. What has hitherto been described as fractional sterilization,
is only to be regarded as a preliminary and subsequent sterilization.
The sterilizing apparatuses hitherto employed have the drawback that they are
not applicable for transportation, because the shutting off or expulsion of the air
does not take place at the suitable moment.
The fractional sterilization is effected for the purpose of this invention in the
following manner.
is
The portable or transporting vessel, which is provided with a tight cover,
tightly connected with an overflow vessel, which again is provided with an
automatic stopper or closing device, such for instance as a ball valve of suitable
construction standing under the pressure of a spring. After the transporting
vessel has been entirely filled with the product which is to be sterilized, the filling
opening is closed and the overflow vessel also partially filled with the milk or the
like which is to be sterilized, and then the transporting vessel is heated in a current
of steam. The milk or the like then expands and rises in the overflow vessel which

page_text: is placed above. By the steam developed by the heating of the milk, the air in
the overflow vessel is compressed and a given excess pressure in the interior of the
sterilizing vessel is produced. If the temperature exceeds the admissible limit, the
pressure also of course increases in the vessel, the automatic joint of the latter
opens or expands, and the resulting gases escape. After the sterilization has been
carried on for a given time in a current of steam, the sterilizing vessel is
removed from the sterilizing chamber, cooled down and allowed to stand a certain
time.
Owing to a cooling and setting of the liquid taking place and to the condensation
of the vapour contained in the overflow vessel, a vacuum is produced in the over-
flow vessel, which causes any particles of air which may still be contained in the
liquid to rise up into it. As all the bacteria are not killed at the necessary
sterilization temperature of about 102° to 103° C. because a very much greater
temperature and one which burns milk, is necessary for killing the very resistant
spores of the potato bacillus, it results that the process must be carried out in
another way in order to kill or neutralize existing spores in such a way that any
germination of the same and deleterious action is entirely excluded. This is only
attainable in a current of steam alternating with sudden cooling, as by the cooling
the undeveloped spores are further developed and are then killed or rendered
harmless by the subsequent sterilization.
This process is repeated several times without atmospheric air entering the
apparatus itself. When the sterilization is completed, the apparatus is cooled
down to that temperature which produces the maximum density of the liquid, and
in case of milk amounts to about 4° C. according to the quantity of fat contained
in the milk. When a cooling down to this temperature has taken place the
transporting vessel is closed and the overflow vessel is removed therefrom.
When the sterilized cooled liquid has reached the normal temperature, such a
pressure is produced by the tension of the liquid in the interior of the vessel as is
necessary to allow of its being conveyed. In order that the vessel may not be
burst by the strong pressure, it is made preferably of an elliptical section, which
owing to the inner pressure tends to adopt a round section, in case the pressure
becomes too great.
The inner pressure may however be produced in another manner than by the
cooling down of the liquid to that temperature which produces the maximum
density, namely, by closing for instance the sterilizing vessel and screwing down
further into the interior of the vessel a screw inserted in the wall of the same,
and thus increasing the volume of the contents, and producing the requisite
pressure.
An apparatus is necessary for carrying out this improved process, which
apparatus is shown in the accompanying drawings:
Figure 1 being a longitudinal section;
Figure 2 a side view, and
Figure 3 a plan view of the apparatus.
The transporting vessel A is provided with a removable cover, in which a filling
orifice N is arranged. On the cover is a cock M on which an overflow vessel B is
airtightly placed. The overflow vessel itself is provided at its upper part with an
automatic closing device, which in the case shown in the drawing consists of a ball
valve a kept closed by the pressure of a spring. A cap c provided with openings b
is placed over the ball valve and this cap has ridges d in its interior for guiding
the ball valve.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is :-
1. A process for the treatment of milk, bouillon or the like to produce a
thoroughly germless and transportable alimentary product, consisting in sterilizing
under pressure the milk or the like in a current of steam, air being totally excluded

page_text: and the vessel automatically closed, and in then suddenly cooling and again
frequently repeating this process in a similar manner, and finally imparting to the
sterilised liquid a constant pressure by either cooling the sterilizing vessel down to
the temperature of the maximum density or increasing the density of the liquid by
screwing down tightly into the vessel a screw for instance, whereby all the bacteria
and more particularly the spores of the potato bacillus are killed or neutralized
and by the stiffness or solidity given to the serum any rising of the globules of fat
or the production of any "buttering" of the liquid is prevented, substantially as
described.
2. A sterilizing apparatus for carrying out the process described in Claim 1,
consisting in an overflow vessel with an automatic closing device, provided on a
transporting vessel and which by the action of outside influences such for instance
as atmospheric pressure or the pressure of weights or springs is automatically
closed at the requisite moment, substantially as described.
הלה .נית
100%
WM. P. THOMPSON & Co.,
Agents.