An Improved Process for Condensing Milk and other Fluids Containing Protein and Preserving the same in Glass or other Hermetically Closed Vessels.
Year: 1887

page_text: Date of Application, 29th Oct., 1887
Specification Accepted, 29th Nov., 1887
COMPLETE SPECIFICATION.
An Improved Process for Condensing Milk and other Fluids
Containing Protein and Preserving the same in Glass or other
Hermetically Closed Vessels.
We, EDUARD SCHERFF of the town of Wendish Buchholz, Prussia, Germany,
Manufacturer, and CARL DRENCKHAN of the town of Stendorf near Schönwalde,
Holstein, Germany, Engineer, do hereby declare the nature of our said 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 relates to a process for condensing milk and other fluids containing
protein and preserving the same in glass or other hermetically closed vessels. The
protein particles in milk and other Huids are decomposed and chemically changed
If milk is condensed in a
when heated to a temperature above 60° Centigrade.
vacuuin apparatus at a temperature under 60° and then heated for the destruction of
the micro-organisms, it coagulates to a gelatine like mass that does not mix with other
fluids as the milk would if not heated in the above manner. When milk is heated
above 75° Centigrade the protein particles coagulate and form a coating around the
casein.
By destroying the micro-organisms by heating, this said casein is so closely
surrounded by the coagulated protein particles that its power of swelling is entirely
lost, which, therefore, makes it hard to digest.
If the milk, however, is condensed at a temperature which ranges between 60 and
75 degrees Centigrade it retains its swelling and soluble properties after the process
of destroying the micro-organisms has been carried into effect.
The invention is based on the principle of condensing milk and other fluids at a
temperature ranging between 60 and 75 degrees Centigrade and in the application of
a vacuum for the purpose of equally distributing the heat to all parts of the fluid.
If milk in glass bottles is exposed to the above-mentioned temperature for the
purpose of destroying the micro-organisms, so much gas will be developed at a
temperature above 60 degrees and so large a percentage of breakage of the bottles
ensues that the process is shown to be impracticable. If, however, it is heated before

page_text: the bottling, in a vacuum at a temperature above 60° Centigrade and consequently the
volatile particles extracted, then the aforementioned development of gas in destroying
the micro-organisms does not take place.
Our invention for preserving milk and other analogous fluids, consists in heating
them to a temperature of 60 degrees to 75 degrees Centigrade for a certain period of
time that they can be heated in bottles for the purpose of destroying the micro-
organisms after the gases have been absorbed by the vacuum so that they cannot
exert a detrimental effect.
For both purposes, viz. that of condensing and that of preserving, we employ the
apparatus shown in longitudinal section in the accompanying drawing, which consists
essentially of the heating vessel A, the vacuum pan B, the condenser C and the
receiver D. The heating vessel A consists of the water reservoir and the milk
receiver or receptacle a, which said milk receptacle is formed of the inner cylinder g
and the outer cylindrical casing a. Both are dished at the bottom and provided with
a pipe in which the end of the heating coil or tube & enters for the purpose of
heating the inner cylinder. The cover and inner wall of the milk receiver can be
readily removed for cleaning by unscrewing the screws" and i and loosening the
lower connection by means of the wrench or spanner . The milk receiver is heated
in its entire height by hot water so as to cause the same to boil over and also to keep
up the boiling over even after the quantity of milk is decreased by a part of the same
passing over into the vacuum apparatus.
The necessary boiling temperature aforementioned is obtained by the rarefaction of
the air in the apparatus as well as in the vessel B located at a higher point than the
said apparatus. The vessel B contains the distributing plates n and is connected with
the milk receiver a by means of the feed pipo m and the return pipe o and by the
pipe with the condenser C from whence the condensing water is led into the
receiver D. When the milk in the receiver a, in the water bath, is heated by
the steam pipe K, the air is rarefied by means of a pump which is in connection with
the receiver or vessel D, until the milk with the prescribed temperature is sucked
over the distributing plates in the said receiver B, where it gives off its gases and
steam into the vacuum, whereas the cooled milk flows back through the return pipe o
and causes a circulation through the entire apparatus.
1'
The large heating surfaces of the milk receiver allow the difference of the heating
and boiling temperature to be limited in such a manner that the temperature of the
milk on the walls of the vessel a cannot, as is the case with the vacuum apparatus,
exceed the limits of temperature fixed for it. This and the circulation in the apparatus
give the required equal warming of the milk.
The evaporated water is replaced when the apparatus is not in use for condensing.
The vessel a is supplied with a fresh charge of milk by opening a cock in the tube x,
the end of the latter being immersed or dipped into the milk pail and through
which the said milk is sucked up when the vacuum apparatus is in operation. The
vessel a is in communication with a tube y partly of glass in order to show the level
at which the milk stands.
Having now particularly described our said invention and in what manner the same
is to be performed we declare that what we claim is :-
:-
1. The process for condensing milk and other fluids containing protein characterized
by the fact that the condensation takes place at temperatures ranging between 60 and
75 degrees Centigrade, so that the subsequent destruction of the micro-organisms, the
fluid does not lose its nutritive property, nor will its solubility be affected, substan-
tially as described in the foregoing specification.
2. The process for preserving milk and other fluids containing protein, characterized
by the fact that the gases are extracted from the fluid by heating the same to
temperatures ranging between 60 and 75 degrees Centigrade, whereupon the micro-
organisms are destroyed in the fluid by again heating it in hermetically closed bottles
or other vessels, substantially as described in the foregoing specification.

page_text: 3. The apparatus substantially as herein set forth for carrying out the process
scribed in claims 1 and 2, said apparatus being characterized by the following
rangements:
:-
a. The cylindrical milk heating receiver, suspended in boiler b and composed of
the two casings u and g, whereby the pipe or tube h, which passes through said
casings, causes a circulation of the hot water in the receiver b.
The connection of the vessel A with the vacuum pan B by means of the pipe m
and the connection of said vacuum pan B by the return pipe or tube o with
the heating vessel A to lead off the fluid freed from gas, substantially as
described in the foregoing specification.