Improvements in Apparatus for Heating and Pasteurizing Liquids.
Year: 1899

page_text: Date of Application, 6th Dec., 1899-Accepted, 20th Jan., 1900
0
COMPLETE SPECIFICATION.
Improvements in Apparatus for Heating and Pasteurizing Liquids.
A Communication to me from LARS CHRISTIAN NIELSEN, of Kong Georgsvej 12
Copenhagen, in the Kingdom of Denmark, Engineer, and PETER VALDEMAR
FREDERIK PETERSEN, of Falkonerallé 41, Copenhagen, aforesaid, Accountant.
I, EDMUND EDWARDS, of the Firm of Edwards and Co., Chartered Patent Agents
Engineers, of 65 & 66, Chancery Lane, in the County of Middlesex, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following state-
ment, and accompanying drawing, that is to say:-
This invention relates to improvements in heating apparatus of the kind in
which fluid (milk and cream especially) are led into a metal reservoir, the wall of
which forms a heating surface surrounded by a steam chamber into which steam
is introduced. The steam striking the heating surface is condensed and transmits
its heat to the heating surface, through which it penetrates and heats the fluid.
The condensed water escapes through a waste-pipe fixed in or near the bottom of
the steam mantle. This waste-pipe is bent, and thus forms a drain-trap excluding
the outside air from the steam chamber. During the heating process the fluid is
stirred by means of a revolving stirrer fixed in the reservoir, and the fluid
gradually leaves the apparatus through the outlet-spout.
Such apparatus, however, has been proved to be deficient in several respects, the
working capacity being disproportionally low and the apparatus not being able
to answer to the ever growing requirements. A thorough investigation of the
matter has proved the following circumstances to be the causes;
29
1. The thermal conductivity of the heating-surface (and consequently the work-
ing capacity of the apparatus) is lowered to a marked degree by the water pro-
duced by the condensation of the steam, gathering in a layer outside the heating-
surface. This layer increases in thickness, towards the bottom, and, as water
is a bad conductor of heat, the consequence is obvious.
not able to bring about a sufficient renewal of
2. It appears that the "stirrer
fluid on the inside of the heating-surface, the temperature consequently being
too high everywhere (about the same as the temperature of the fluid at the outlet).
The difference in temperature of the two sides of the heating-surface is consequently
too small and the current of heat (and therefore the working capacity of the
apparatus) too small.
3. It also appears that air accumulates in the steam-chamber (the air being
carried along by the steam and disengaged by the condensation of the steam).
The air accumulates especially near the heating-surface, thus hindering the steam
from coming in so direct a contact with the heating surface as would be the case
if no air interfered, and thus partly lowering the working capacity of the
apparatus and partly making it inconstant.
The present invention relates to improvements to the apparatus, by which the
above named defects are remedied, in such a manner that the working capacity of
the apparatus is several times greater than before.
The following are the new contrivances by which these objects are effected.

page_text: 1. "Drip-rings" fixed on the outside of the heating surface (i.c. in the steam
chamber). These rings lead the condensed water from narrow zones of the
heating-surface, while otherwise this water has to pass down the heating-surface
in a layer growing thicker towards the bottom.
2. Plates" fixed on the "stirrer" by which the fluid is forced to pass through
the apparatus in such a manner, that mixing of the parts of the fluid in a direction
parallel with the stirrer" axis, is virtually hindered, while mixing of the parts
in a direction perpendicular to the axis, is considerably furthered, and this causes
the temperature of the innerside of the heating-surface in the layers formed by
the plates, to differ much. This lowers the average-temperature on the innerside
of the heating-surface considerably and causes a greater difference in the tem-
perature outside and inside of the heating-surface, thus promoting the passage
of heat and consequently increasing the working capacity of the apparatus.
"
3. Vent-cock, fixed on the waste-pipe, for the escape of the air disengaged
in the steam-chamber.
Numerous experiments have proved that the working capacity of the apparatus,
by means of these improvements, has been increased from 3 to 9 times, according
to the heating process taking place at temperatures, lying between 85° and 95° C.
(185 and 2030 F.)
The annexed drawings illustrate the invention.
Fig. 1 shows a heating-apparatus. The left half is a vertical section through
the centre, the right half is an outside view, a part of the steam-mantle being
omitted in order to show the "drip-rings."
Fig. 2 is a horizontal section on line 2-2 in Fig. 1.
a is the cylindrical (parabolic or conical) reservoir made from copper or other
metal, the steam-mantle surrounding the reservoir. The steam is led into b
through the opening c. while the condensed-water is carried away through the
outlet connected with a waste-pipe e, which is bent so as to form a drain-trap
and thus separating the outside air from the steam-chamber. On the outside of
the reservoir are fixed a number of roof-shaped "drip-rings" f made from sheet-
metal. These "drip-rings" lead, as stated above-the condensed water from the
heating-surface, so as not to allow it to accumulate on this surface, but make
the water drip from the lower edges of the " drip rings to the bottom of the
steam-chamber. The "drip-rings" are in the drawing shown with a toothed edge,
but may be smooth edged as those (f) which are fixed at the bottom of the heating-
surface.
"
The fluid to be heated is led into the reservoir a through a feed-pipe g in the
bottom of a and escapes after sufficient heating through the spout h. In the
reservoir is a stirrer k, on which are fixed the plates m, the diameter of which is
of such a size that it leaves small ring-shaped passages between the plates and the
innerside of the reservoir; through these passages the fluid-particles must pass
successively on their way through the apparatus, and during this passage every
single particle comes successively in direct touch with the heating surface.
In the connection inserted between the outlet d and the waste, pipe e forming the
chamber is fixed a vent-cock o through which is led the air carried along by
the steam and disengaged in the steam-chamber.
In order to ensure this air a free passage down along the heating-furnace, if this
is cylindrical, the "drip-rings" must-as stated above-have toothed edges so as to
let the air pass freely through the incisions, while the condense-water is gathering
at the points and drips from these. If the heating-surface is perpendicular,
toothed"
drip-rings are to be preferred.
2
The air disengaged in the steam-chamber, and gathering at the bottom of the
latter, is carried with the condensed-water down through the passage d and collects
in the chamber above the water standing in the waste-pipe e. Above this air
is now a low pressure of steam and below is a pressure of water, consequently the
air will gradually be forced out of the vent-cock o, if only the opening in this
is so small, that the resistance to the outflow of air is sufficient to keep steam and

page_text: water in the chamber separated. How much the vent-cock has to be opened
must be ascertained by trials.
The apparatus constructed as described above and used for heating ("pasteuriz-
ing") skim-milk or cream, also operates as a foam-remover or foam-preventer.
The fact is that the foam formed in the separators follows the milk or cream into
the heating-apparatus. When now the foaming milk or cream passes between the
plates m and the inner side of the reservoir, the foam-bubbles are broken and dis-
solve into fluid and air. The centrifugal power forces the air to the centre of the
apparatus and from there it passes through the holes in the plates m (see Fig. 2)
and leaves the apparatus by this way, and thus the milk or cream leaves the
apparatus practically free from foam.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is:-
*
In heating or "pasteurizing" apparatus consisting of a reservoir supplied with a
stirrer," and surrounded by a steam-mantle into which steam is introduced
so as to heat the reservoir, through which the fluid to be heated continually flows,
while the water accumulated through condensation of the steam, is continually led
away.
1. The arrangement of " drip-rings" on the outside of the reservoir (i.e. in
the steam-chamber) for the purpose of leading the condensed-water from narrow
zones of the heating surface.
66
"
stirrer across its axis,-these plates
2. The arrangement of plates on the
extending almost to the side of the reservoir and serving to separate the fluid
in layers, so that mixing of the fluid-particles in a direction parallel with the
stirrer-axis is virtually hindered.
3. The arrangement of holes in the plates stated in Claim 2,-these holes serving
as outlets for the air disengaged during the foam-removing process.
4. The arrangement of a vent-cock on the waste-pipe or in the bottom of the
steam-chamber through which the air carried along by the steam and disengaged
by the condensation of the steam, is forced.
Dated this 5th day of December 1800.
EDWARDS & Co.,
Chartered Patent Agents, 65 and 66, Chancery Lane, London,
Agents for the Applicant.