Improvements in Apparatus for Sterilizing Milk, Cream, and other Liquids, by Means of Steam.
Year: 1896

page_text: Date of Application, 13th Apr., 1896-Accepted, 13th June, 1896
COMPLETE SPECIFICATION.
Improvements in Apparatus for Sterilizing Milk, Cream, and other
Liquids, by Means of Steam.
I, ALEXANDER THEODOR PFEIFF, Baron, of 16 Vendersgade, Copenhagen, in
the Kingdom of Denmark, 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 relates to apparatus for the sterilization of milk, cream and other
liquids by means of steam in which the liquid may be heated to a high temperature
near its boiling point, without acquiring a boiled taste. My apparatus can sterilize
a considerable quantity of liquid in a short time.
In the accompanying drawing,-
Figure 1 is section of an apparatus made according to my invention :
Figure 2 is a detail.
a is a vessel inside which is arranged an annular vessel b, the inner wall of which
projects above the outer wall and is provided with a lid b. Above this lid is fixed
an inlet funnel d for the liquid to be sterilized. Near the bottom the funnel is
provided with small perforations or holes through which the liquid can pass.
Inside the vessel 6 is arranged another vesself also annular in form, and inside this
again an inverted U-shaped vessel or bell c. Above the vessel f is a close-fitting
lid l, to which the bell c is suspended.
Steam is admitted to the apparatus through the pipe k and first fills the interior
of the bell c. At the bottom of the vessel f the steam is divided into two streams,
of which the one passes underneath the outer edge of the bell c and up through the
outer space between the bell c and the vessel f. From this space the steam passes
through the bent pipes q and an annular channel o into the outer space between the
vessels a and b, then underneath the bottom of the vessel b into the interior of the
vessel a whence it escapes through the pipe r. The other portion of the steam
passes underneath the inner edge of the bell c and up through the inner space
between the bell c and the vesself from which the waste steam passes away through
the pipe n. The outlet of this pipe may be regulated by means of a cock.
As shewn in dotted lines in Figure 1, steam may be introduced into the apparatus
at several points through pipes and provided with cocks. A more effective
operation is thus obtained. If steam is admitted through the pipe k, the bent
tube g must be closed up as shewn at q' in dotted lines.
The liquid which is to be sterilized is, as above mentioned, admitted into the
funnel d and passes through the perforations or holes in the bottom of this funnel
radially over the lid 6 to the space between the vessels band f. The liquid then
passes underneath the bottom of the vesself and up through the outer space between
the vessels band f to the annular channel e, from which it issues through a pipe h,
in which is inserted a thermometer g, by means of which the temperature of the
liquid may be ascertained.
in
In the bottom of the vessels a and f are arranged outlet pipes and y
convenient positions for the escape of the water arising from the condensed steam,
the said pipes x and y being so arranged that they do not prevent the steam from
passing freely up through the narrow spaces between the walls of the vessels. In
Figure 2 a somewhat modified construction of this arrangement is shewn.
My apparatus possesses great advantages above those used hitherto and combines
sure action with efficiency.
In apparatus of a similar kind, water has hitherto been used as a heating agent.

page_text: The water flowed in a single stream through the apparatus, and as it was not
subjected to any pressure the hottest liquid, as a rule, remained at the top. During
this operation the water became little by little so much cooled that it had no effect
on the liquid to be sterilized.
As a rule the liquid was collected in channels, but these were not capable of
receiving all the liquid. By reason of this defect, the efficiency of the apparatus
was low as a part of the cold liquid remained in the apparatus and did not circulate.
The liquid, was, moreover, led away from the centre of the apparatus and, in order
to obtain the necessary pressure, the lid on the inner central part of the vessel a had
to be placed below the outer edge of the same vessel. As a result of this arrangement
the liquid to be sterilized formed a thick layer upon the said lid and the cold liquid,
that always flowed into the apparatus at the centre, passed directly into. the
apparatus whilst the part already heated remained still and exposed to deterioration,
especially when the liquid was milk or cream. The liquid composing the layer
upon the lid of the vessel acquired a temperature that was considerably higher than
the temperature acquired by the liquid flowing into the apparatus so that, the latter
liquid being colder and consequently heavier, the circulation of the already heated
liquid was retarded.
In the present apparatus these drawbacks are completely avoided. The steam
passes, as already mentioned, in two streams through the apparatus and will affect
the liquid on both sides during the whole of the circulation of the liquid through
the apparatus. This result is obtained by means of the inverted U-shaped bell c
and the close-fitting lid which compel the steam to pass through the apparatus
under pressure and divide itself in the aforesaid manner. The outer and inner
spaces through which the liquid passes are furthermore connected by means of the
annular space e, thereby allowing a free passage. As the liquid is admitted through
the funnel d and passes in a thin layer over the lid b', it will be heated immediately
it flows into the apparatus which, in the case of milk and cream, causes the animal
smell to be removed and prevents the liquid from remaining still. The opening of
the exhaust pipe r is arranged just underneath the convex or upwardly bulged
part of the lid b' which causes a perfect and efficient circulation of the steam at this
point.
The steam in the interior of the bell c will not directly influence the liquid, but
its influence will be felt in the spaces between the bell c and the vessel, where the
temperature has already dropped slightly. By this means the burning of the milk
is avoided, and the inside of the bell c will form a heat reservoir for the steam
passing through the inner space, which steam will thus not be cooled too much by
meeting the liquid flowing into the apparatus.
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. In apparatus for sterilizing milk or other liquids wherein several annular
vessels are arranged inside one another, the combination of a close-fitting lid on
the innermost vessel and a U-shaped bell attached to the said lid, whereby the
steam which is admitted under pressure into the apparatus through several pipes is
caused to fill the apparatus and pass through the same in two streams in such a
manner, that the liquid to be sterilized, throughout its passage through the
apparatus, will receive heat on both sides, and will acquire the necessary
temperature during its passage from the funnel to the bottom of the vessel,
and will retain this temperature during the further passage of the liquid through
the apparatus.
2. In apparatus of the kind described in Claim 1, the arrangement of an exhaust
pipe the opening of which is close underneath the upwardly bulged portion of the
lid covering the inner part of the apparatus, and above which lid the liquid to be
sterilized flows in a thin layer substantially as, and for the purposes, hereinbefore
.described.

page_text: 3. In apparatus of the kind described in Claim 1, the arrangement of pipes in
the bottoms of the vessels (f) and (a) for the purpose of running off the water
formed when the steam first meets the cold liquid flowing into the apparatus, which
water would otherwise prevent the steam from passing through the apparatus,
substantially as described.
4. In apparatus of the kind described in Claim 1, the arrangement whereby the
vessels (a) and (f) are connected by means of one or more bent pipes (9), so that
the steam is led through these bent pipes from the vessel (f) into the vessel (a)
which is connected to the vessel (b) by means of a channel (o).
5. The improved apparatus for sterilizing milk, cream and other liquids berein-
before described and illustrated in the accompanying drawing.
Dated this 13th day of April 1896.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.