Process and Apparatus for Sterilising Liquids.
Year: 1891

page_text: Date of Application, 16th Feb., 1891
Complete Specification Left, 14th Nov., 1891-Accepted, 9th Jan., 1892
PROVISIONAL SPECIFICATION.
[Communicated from abroad by CALBERLA, FITZ UND CONSORTEN, of 101, 102,
Leipzigerstrasse, Berlin, Germany, Manufacturers.]
Process and Apparatus for Sterilising Liquids.
I, OLIVER IMRAY of No. 28 Southampton Buildings in the County of London,
Fellow of the Institute of Patent Agents do hereby declare the nature of this
invention to be as follows:-
This invention has reference to a process and apparatus for sterilising milk
and other liquids, in particular for the continuous production on a large scale.
The object of the invention is on the one hand, to effect the sterilisation on a
large scale, secondly to render the process continuous, and lastly to prevent the
possibility of re-infection during sterilisation.
In the following description it will be assumed throughout that the liquid to be
treated is milk, although it will be obvious that the new process is in its main
features also essentially applicable to other liquids.
Various methods for preventing deterioration of milk by alternate heating and
cooling thereof, with or without condensation, have been proposed. They have
however not hitherto attained any extended application for the milk supply of
towns, and they have not been able to improve the position of milk producers in
remote districts, firstly, because they only effected the sterilising in bottles or metal
cans, which method of supply is mostly too expensive for the general public;
secondly, because they were entirely wanting in the necessary conditions for a
continuous production on a large scale, with the attendant advantages of cheapness
and great uniformity in the product; thirdly, because the fractional sterilisation
was effected in separate vessels which were not connected together in an air-tight
manner under the exclusion of germs, so that it was always possible that a
re-infection of the milk took place between the separate stages of the fractional
sterilisation, and thus no satisfactory reliable result could be obtained.
By the present improved process all these defects are obviated in the following
manner.
After the milk has been brought to the works under observance of all possible
precautions against infection by germs, it is introduced, after the most careful
cleansing, into an apparatus, called "Pasteuriser" in which it is heated to the
degree and for the length of time necessary for effectually killing bacteria, &c.
already developed and in process of development, and where it is then cooled down
to the temperature necessary for the following germinating process.
From this pasteurising apparatus the milk is introduced into a system of
germinating vessels and is kept therein at a temperature and for a length of time
necessary for bringing most of those enduring germs that were not killed by the
pasteurising process from the latent to the germinating and therefore more readily
destructible condition. From these germinating apparatus the milk is again
brought into a second or after-pasteurising apparatus and is again treated in the
above described manner, if only for a short time. These processes of germinating
and pasteurising may if necessary be successively repeated several times.
If it be desired to produce concentrated milk, this is introduced from the
pasteuriser, or after-pasteuriser into a vacuum apparatus.
From this apparatus or from the last germinator the milk is brought into the
steriliser, in which it is, in suitable succession, subjected to those temperatures,
conditions of pressure, &c. which are necessary to effectually kill all living bacteria
or enduring germs capable of development.

page_text: With pasture feeding or particularly cleanly stall feeding the milk will generally
contain so few germs, that the perfect sterilisation will already have been effected
by repeated pasteurising, i.e. heating to about 70° to 80° C., in combination with
the said germinations. In this case the final heating to above 100° C. in the so
called steriliser can be avoided.
In this steriliser is an arrangement for cooling the milk to the temperature
suitable for transport.
From the steriliser the milk, perfectly germ-free, is led into collecting vessels
from which it is charged into vessels for transport or storage under precautions for
effectually preventing any re-infection from the outside.
All cocks, connections, and closing devices of the apparatus and conduits are
rendered secure against germs by surrounding those parts which might allow of the
passage of hurtful germs, with an antiseptic liquid or by wadding, carbon, or quartz
powder treated with antiseptic materials.
As essentially new in the present invention is considered :-
1. That all apparatus are closed securely against the entrance of germs, and are
connected together by germ-tight conduits and closing devices so as to constitute
practically a single complex apparatus.
2. That the movement of the liquid from one part of the apparatus into the
other, when not effected by gravity, is effected by germ-freed gases or mixtures of
gases under
pressure.
3. That when the flow of the liquid from one vessel to another is effected by
gravity only, air or gas freed from germs follows after it.
4. That the separate apparatus are provided and arranged in such number and
capacity and are so connected together, that the sterilising process can be carried
on continuously and uninterruptedly day and night.
5. As new is also considered an apparatus to be presently described for restoring
the good flavor of the milk after its sterilisation.
The accompanying drawings shew diagrammatically the several apparatus and
their connection with each other.
Figure 1 shews the pasteurising apparatus, in vertical section.
Figure 2 shews the generator of sterilised air.
Figure 3 is the after-pasteuriser ;
Figures 4 to 7 shew germinators;
Figures 8 to 11 shew the after-germinators;
Figure 12 is the vacuum apparatus ;
Figure 13 the steriliser;
Figure 14 the collecting vessel;
Figures 15 and 16 shew respectively a germ-tight cock and pipe joint.
It is to be observed generally as to the apparatus for treating the milk, that
they should be so constructed as to be cleansed with the greatest ease.
For this
purpose the larger apparatus are provided with removeable covers and the smaller
ones with man holes or arm holes, and each apparatus is provided with a steam and
water supply. All apparatus are provided with pressure gauges, glazed sight holes
and the like.
THE PASTEURISING APPARATUS. FIGURE 1.
This consists of a vessel A preferably of cylindrical form closed by the removeable
domed cover G. This cover carries the entire internal parts of the apparatus by
means of suspension plates H, so that when cleansing is required it is only required
to remove the cover.
"After completion of the treatment, the liquid is led off through the pipe 11
leading from the bottom F.
The internal arrangement of the apparatus consists of a closely wound steam
coil D, a stirring apparatus B driven by a shaft C, a supply pipe for cooling
water 8, and the guiding cone E.
On the cover G are fixed, a water supply 2, the supply pipe 1 for the liquid to

page_text: be treated, the steam supply pipe 4 connected by pipe 9 with the coil D, and the
pipe 3 for leading off the cooling water.
The pipe 5 enables cooling water to be introduced into the coil in place of
steam, while through the pipe the water of condensation from the steam is
led off.
Through the pipe 10 sterilized air pressure can be introduced while an air cock a
serves for regulating the pressures in the apparatus.
The pasteurising apparatus has to perform the duty of maintaining the milk for a
certain length of time at a certain temperature, and then to cool it down.
The milk is introduced into it through the pipe 2 and at the same time the
stirrer B is put in motion so that the milk is maintained in continuous circulation.
The arrows shew the direction of the circulation. The guiding cone E distributes
the descending central column of milk very uniformly to the periphery.
If cooling water is to be passed through the coil, it is introduced at 3, and flows off
at 5. As has been stated, sterilized air under pressure, can be introduced into the
apparatus through pipe 10, which is of the greatest importance for the proper
treatment of the milk.
.
From the pasteurising apparatus the milk is led through the pipes 11 and 12
to the
GERMINATOR (FIGURES 4 TO 7)
in which it remains for a certain extended time at a definite constant temperature.
The object of the germinator N is to bring into development those enduring
germs or spores that have resisted the action of the previous process, and thus to
neutralize their resistance to sterilisation at a moderate temperature and duration
of the heating.
Through pipe 22 and branches 13 steam or water for cleansing the germinations
is admitted. The requisite heating of the milk is in this case also effected by
means of a heating coil which is not shewn.
After completion of the treatment in the germinator N, the milk is forced by
sterilized air pressure entering through branches 16 connected to pipe 17 into the
after pasteurising apparatus.
The water, or water of condensation formed from the steam during the cleansing
operation can be led off through branch 18.

page_text: parts which are the same in both are indicated by the same letters of reference
and numerals.
It is advisable in this case to give the heating coil D a larger diameter than in
the pasteurising apparatus, and the height of the space in which the milk circulates
is also made greater.
The sterilising apparatus differs from the pasteurising apparatus in the use of
the rose-like device R for the introduction of cooled and compressed sterilised
air or gases into the milk. The object of this arrangement will be described
later on.
The milk passes into the apparatus through the pipe 25 and branch 2, if coming
from the vacuum apparatus, and through pipe 17 if from the final germinator. It
is subject in the same successively to such temperatures as to allow of the certain
assumption that not only all bacteria contained in the milk are killed, but also that
all enduring spores or germs are firstly germinated and then destroyed by the
subsequent heating.
After this treatment the milk may be considered as absolutely free from injurious
micro-organisms, that is to say, sterilised; at the same time it has lost none of its
liquidity, it creams well, and can be made into butter and cheese; it has however
the one disadvantage that it has received the unpleasant boiled flavour. But it
must be stated that milk treated as above described possesses this boiled flavour in
a much less degree than milk sterilised in any other manner.
The above described disadvantage is done away with in the present invention by
removing the boiled flavor by aeration.
For this purpose the rose-like air or gas supply device R Figure 15 is employed.
After the milk has been maintained for a certain length of time under a certain
pressure at so high a temperature in the sterilising apparatus, that the sterilisation
may be considered complete, sterilised air or gases, as cool as possible, are introduced
through the rose R in very fine streams.
These fine and cold streams, in mixing intimately with the milk, blow the said
boiled flavor away, as it were, and again impart to the milk its original good
flavor.
When this object has been completely fulfilled, the cooled milk can be conveyed
through pipe 21 into a collecting vessel Figure 14, from which it is filled into
vessels for storage or transport through pipes 33.
As to the preparation of the sterilised air, this can be effected in the air filter
Figure 2. This filter consists mainly of a vertical cylindrical vessel J in which
the air coming from a pipe 27. rises slowly while antiseptic liquid flows through
pipes L
and roses in a finely divided state in the contrary direction to the air.
Very suitable for this purpose are essential or volatile oils.
The vessel K is filled to a certain extent with a sealing liquid 28 in order, in
drawing off the collected oil from the vessel K through the bent pipe 29, to prevent
impure air from entering the filter through such pipe.
The purified air passes off through the pipe 23 and can be led directly into
these vessels from which the milk is discharged solely by gravity.
When sterilised air under pressure is required, the air coming from the above
described apparatus is compressed by any suitable known means.
The germ-proof cock or valve Figure 15 consists of a casing T which encloses
the cock S air tight and through a stuffing box t of which the plug or valve stem s
passes.
The interior of the casing is best filled with an antiseptic liquid, which can be
introduced through a funnel b provided with a cock. The liquid can be drawn off
through the cock c. Instead of filling the casing T. with antiseptic liquid it may
contain cotton wool, charcoal, quartz sand &c., saturated with antiseptic materials.
In certain cases it may be sufficient merely to surround the joints of the cock with
such materials, without the casing.
The germ proof pipe joint Figure 16, is arrangel similarly to the cock above
described.

page_text: The two pipe-ends U and V with the flanges and vare surrounded by a
casing W which is also filled with liquid &c. through a funnel with cock and
which has a discharge cock at bottom.
1001
ABEL & IMRAY,
Agents for the Applicant.
Process and Apparatus for Sterilising Liquids.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, in the County of London,
Chartered Patent Agent, 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 reference to a process and apparatus for sterilising milk and
other liquids, in particular for the continuous production on a large scale.
The object of the invention is, on the one hand, to effect the sterilisation on a
large scale, secondly to render the process continuous, and lastly to prevent the
possibility of re-infection during sterilisation.
In the following description it will be assumed throughout that the liquid to be
treated is milk, although it will be obvious that the new process is in its main
features also essentially applicable to other liquids.
Various methods for preventing deterioration of milk by alternate heating and
cooling thereof, with or without condensation, have been proposed.
They have however not hitherto attained any extended application for the milk
supply of towns, and they have not been able to improve the position of milk pro-
ducers in remote districts, firstly, because they only effected the sterilising in
bottles or metal cans, which method of supply is mostly too expensive for the
general public; secondly, because they were entirely wanting in the necessary
conditions for a continuous production on a large scale, with the attendant
advantages of cheapness and great uniformity in the product; thirdly, because the
fractional sterilisation was effected in separate vessels which were not connected
together in an air tight manner under the exclusion of germs, so that it was always
possible that a re-infection of the milk took place between the separate stages
of the fractional sterilisation, and thus no satisfactory reliable result could be
obtained.
By the present improved process all these defects are obviated in the following
manner.
After the milk has been brought to the works under observance of all possible
precautions against infection by germs, it is introduced, after the most careful
cleansing, into an apparatus, called "Pasteuriser" in which it is heated to the
degree and for the length of time necessary for effectually killing bacteria &c.
already developed and in process of development, and where it is then cooled down
to the temperature necessary for the foliowing germinating process.
From this pasteurising apparatus the milk is introduced into a system of
germinating vessels and is kept therein at a temperature and for a length of time
necessary for bringing most of those enduring gerins that were not killed by the
pasteurising process from the latent to the germinating and therefore more readily
destructible condition. From these germinating apparatus the milk is again
brought into a second or after-pasteurising apparatus, and is again treated in the
above described manner, if only for a short time. These processes of germinating
and pasteurising may if necessary be successively repeated several times.
If it be desired to produce concentrated milk, this is introduced from the
pasteuriser, or after-pasteuriser into a vacuum apparatus.
From this apparatus or from the last germinator the milk is brought into the
steriliser, in which it is, in suitable succession, subjected to those temperatures,

page_text: conditions of pressure &c. which are necessary to effectually kill all living bacteria
or enduring germs capable of development.
With pasture feeding or particularly cleanly stall feeding, the milk will
generally contain so few germs, that the perfect sterilisation will already have
been, effected by repeated pasteurising i.e. heating to about 70° to 80° C., in
combination with the said germinations. In this case the final heating to above
100° C. in the so called steriliser can be avoided.
In this steriliser is an arrangement for cooling the milk to the temperature
suitable for transport.
From the steriliser the milk, perfectly germ free, is led into collecting vessels
from which it is charged into vessels for transport or storage under precautions for
effectually preventing any re-infection from the outside.
All cocks, connectious, and closing devices of the apparatus and conduits are
rendered secure against germs by surrounding those parts which might allow of
the passage of hurtful germs, with an antiseptic liquid or by wadding, carbon, or
quartz powder treated with antiseptic materials.
As essentially new in the present invention is considered:
1. That all apparatus are closed securely against the entrance of germs, and are
connected together by germ tight conduits and closing devices so as to constitute
practically a single complex apparatus.
2. That the movement of the liquid from one part of the apparatus into the
other, when not effected by gravity, is effected by germ-freed gases or mixtures of
gases under pressure.
'
3. That when the flow of the liquid from one vessel to another is effected by
gravity only, air or gas freed from germs follows after it.
4. That the separate apparatus are provided and arranged in such number and
capacity and are so connected together, that the sterilising process can be carried
on continuously and uninterruptedly day and night.
5. As new is also considered an apparatus to be presently described for restoring
the good flavor of the milk after its sterilisation.
The drawings accompanying my Provisional Specification shew diagrammatically
the several apparatus and their connection with each other.
Fig. 1 shews the pasteurising apparatus, in vertical section.
Fig. 2 shews the generator of sterilised air.
Fig. 3 is the after pasteuriser.
Figures 4 to 7 shew germinators.
Figure 8 to 11 shew the after germinators;
Figure 12 is the vacuum apparatus;
Figure 13 the steriliser.
Figure 14 the collecting vessel.
Figures 15 and 16 shew respectively a germ tight cock and pipe joint.
For
It is to be observed generally as to the apparatus for treating the milk, that
they should be so constructed as to be cleansed with the greatest ease.
this purpose the larger apparatus are provided with removeable covers and the
smaller ones with man holes or arm holes, and each apparatus
a steam and water supply. All apparatus are provided with pressure gauges,
provided with
glazed sight holes and the like.
THE PASTEURISING APPARATUS. FIGURE 1.
This consists of a vessel A preferably of cylindrical form closed by the removeable
domed cover G. This cover carries the entire internal parts of the apparatus by
means of suspension plates H, so that when cleansing is required, it is only required
to remove the cover.
After completion of the treatment; the liquid is led off through the nine 11

page_text: This apparatus is similar in construction to the pasteurising apparatus. Those
parts which are the same in both are indicated by the same letters of reference and
numerals.
It is advisable in this case to give the heating coil D a larger diameter than in
the pasteurising apparatus, and the height of the space in which the milk circulates
is also made greater.
The sterilising apparatus differs from the pasteurising apparatus in the use of
the rose-like device R for the introduction of cooled and compressed sterilised air
or gases into the milk. The object of this arrangement will be described
later on..
The milk passes into the apparatus through the pipe 25 and branch 2, if coming
from the vacuum apparatus, and through pipe 17 if from the final germinator. It
is subject in the same successively to such temperatures as to allow of the certain
assumption that not only all bacteria contained in the milk are killed, but also
that all enduring spores or germs are firstly germinated and then destroyed by
the subsequent heating.
After this treatment the milk may be considered as absolutely free from injurious
micro-organisms, that is to say, sterilised; at the same time it has lost none of its
liquidity, it creams well, and can be made into butter and cheese; it has however
the one disadvantage that it, has received the unpleasant boiled flavour. But it
must be stated that milk treated as above described possesses this boiled flavour in
a much less degree than milk sterilised in any other manner.
The above described disadvantage is done away with in the present invention by
removing the boiled flavour by aeration.
For this purpose the rose-like air or gas supply device R Figure 15 is employed.
After the milk has been maintained for a certain length of time under a certain
pressure at so high a temperature in the sterilising apparatus that the sterilisation
may be considered complete, sterilized air or gases, as cool as possible, are introduced
through the rose R in very fine streams.
These fine and cold streams, in mixing intimately with the milk, blow the said
boiled flavor away, as it were, and again impart to the milk its original good
flavor.
When this object has been completely fulfilled, the cooled milk can be conveyed
through pipe 21 into a collecting vessel Figure 14, from which it is filled into
vessels for storage or transport through pipes 33.
As to the preparation of the sterilised air, this can be effected in the air filter
Figure 2. This filter consists mainly of a vertical cylindrical vessel J in which the
air coming from a pipe 27 rises slowly while antiseptic fluid flows through pipes L L
and roses in a finely divided state in the contrary direction to the air. Very
suitable for this purpose are essential or volatile oils.
The vessel K is filled to a certain extent with a sealing liquid 28 in order, in
drawing off the collected oil from the vessel K through the bent pipe 29 to prevent
impure air from entering the filter through such pipe.
The purified air passes off through the pipe 23 and can be led directly into these
vessels from which the milk is discharged solely by gravity.
When sterilised air under pressure is required, the air coming from the above
described apparatus is compressed by any suitable known means.
The germ-proof cock or valve Figure 15 consists of a casing T which encloses
the cock S air tight and through a stuffing box t of which the plug or valve stem s
passes.
The interior of the casing is best filled with an antiseptic liquid, which can be
introduced through a funnel 6 provided with a cock. The liquid can be drawn off
through the cock c. Instead of filling the casing T with antiseptic liquid it may
contain cotton wool, quartz, sand &c. saturated with antiseptic materials.
In

page_text: certain cases it may be Buthcient merely to surround the joints or the cock witn
such materials, without the casing.
The germ-proof pipe joint Figure 16, is arranged similarly to the cock above
described.
The two pipe ends U and V with the flanges u and are surrounded by a
casing W which is also filled with liquid &c. through a funnel with cock and which
has a discharge cock at bottom.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A process for sterilising milk and other liquids wherein the possibility of
reinfection during the several stages of fractional sterilisation is prevented by
treating the liquid in germ-free closed vessels, which are connected together by
germ-proof connections, the movement of the liquid through the several vessels
being effected either by gravity with a following supply of sterilised gas or mixture
of gases at atmospheric pressure, or by the employment of such sterilised gas or
mixture of gases under pressure, substantially as described.
2. A process for sterilising milk and other liquids in germ-proof closed vessels
connected by germ-proof connections, and in which the liquid to be treated can
only come in contact with sterilized air or with gases, such process consisting
of the treatment of the liquid first in a pasteurising apparatus, then effecting the
conversion of the enduring germs from the latent to the germinating condition in
special germinating apparatus, and lastly sterilising the liquid in sterilising apparatus,
the liquid being, if necessary, subject before or after sterilisation to an after-
pasteurisation and germination, and to a condensing process in a vacuum apparatus
substantially as described.
3. A process for removing the boiled flavor of sterilised liquids consisting in
passing compressed cold sterilised air or gases or mixtures of gases through the
sterilised liquid, substantially as described.
4. An apparatus for pasteurising liquids consisting in the combiration within
a closed vessel of a heating coil D, a stirring apparatus B and a guide cone E,
substantially as described.
5. An apparatus for pasteurising as also for sterilising liquids consisting of the
combination within a closed vessel of the heating coil D, stirring apparatus B,
guiding cone E, and the rose-like device R for the introduction of sterilised air or
gas, substantially as described.
6. A germ-proof cock or valve and pipe connection, consisting of a germ-proof
covering surrounding the cock or valve or pipe joint, and composed of antiseptic
material substantially as described.
Dated this 14th day of November. 1891.
ABEL & IMKAY,
Agents for the Applicant.