Improvements in Concentrating Alimentary or Pharmaceutical Liquids or other Substances, and in Apparatus therefor.
Year: 1895

page_text: Date of Application, 12th Sept., 1895
Complete Specification Left, 9th June, 1896-Accepted, 29th Aug., 1396
PROVISIONAL SPECIFICATION.
Improvements in Concentrating Alimentary or Pharmaceutical
Liquids or other Substances, and in Apparatus therefor.
1, SYDNEY DOMVILLE ROWLAND, of Toynbee Hall, Commercial Street,
Whitechapel, in the County of London, Student in Medicine, do hereby declare.
the nature of this invention to be as follows :-
The object of my invention is to free alimentary or pharmaceutical liquids or
other substances from some part of the water, alcohol or other readily procurable
liquid which they may contain, in such a way as to leave a concentrate which by
mixture with a fresh quantity of the abstracted liquid will yield substantially the
original liquid or substance.
In previous attempts to the same end the concentration has been effected
entirely or in part by raising the temperature of the liquids or substances to be
concentrated; and in the case of many such liquids or substances chemical or
physical changes occur in the process of heating, and the concentrate or residue
when again mixed with the separated liquid differs in chemical character and
physiological or therapeutic properties from the original liquid or substance. On
the other hand, concentration solely by the use of a vacuum is liable to the
objection of causing partial or complete congelation of the liquid or substance
treated.
I attain my object without these disadvantages by evaporating the surplus liquid
in a high vacuum, and continuously supplying to the liquid or substance under
treatment such a quantity of heat as is sufficient only to make up for that which is
abstracted by the evaporation of the liquid vaporised.
My process is specially applicable to milk which is known to suffer important
changes when its temperature is raised.
According to my invention propose to employ in the case of liquids an
arrangement of apparatus hereinafter described for conducting the following
process:-
The concentration takes place in a closed vacuum chamber which is provided
with external heating jacket, or internal hot-water circulation coils, or with both,
or with other suitable arrangements for providing surfaces heated to a definite
extent. This vacuum chamber communicates by means of an exhaust pipe
perforated at its lower end with a second closed chamber containing a suitable
absorbent of that part of the liquid which is to be vaporised. From this second or
absorbing chamber a pipe leads to an air-pump capable of producing a high vacuum.
The liquid to be treated is led from a trough or cistern placed above the vacuum
chamber, through a pipe extending downwards from its underside on to a perforated
tray arranged within the upper part of the vacuum chamber, whence it traverses
the heated surfaces of coils provided within the said chamber, the temperature of
which coils is so adjusted as to continuously replace enough of the leat lost by
evaporation to prevent freezing while not supplying enough heat to raise the
residual product to a temperature at which the changes which I wish to avoid may
occur.
In this way the liquid gradually loses its superfluous water or other diluent, and
when the process of concentration has gone sufficiently far, air is readmitted
through a valve or cock provided for the purpose, and the product drawn off from
a convenient tap or outlet at the bottom of the vacuum chamber, the air being

page_text: sterilised when necessary before readmission, by being caused to pass through one
or more layers of cotton wool, or by other suitable means.
Or I may arrange for the process to be carried on continuously, in which case I
connect the lower portion of the vacuum chamber with a supplementary chamber
below it by a down pipe the communication being controlled by a suitable valve or
stopcock. From this supplementary chamber the concentrate is drawn off through
a cock provided at the lower part thereof, air being admitted by an aircock and
sterilized as above described, the cock on the communication pipe between the
vacuum chamber and supplementary chamber being kept closed during the
operation of drawing off. The concentrate thus obtained may be preserved in any
suitable way, and by readmixture with the same amount of liquid which was
previously evaporated will yield substantially the original liquid.
I
I may allow the liquid under treatment to trickle down the heating surfaces, or
1 may determine a circulation up and down in any suitable way. Where desirable
may before drawing off the concentrate from the supplementary chamber, cause
it to re-enter the vacuum chamber through an ascension pipe by opening a cock
provided thereon and the aircock already referred to, the cock communicating
between the two chambers and the regulating cock from the cistern being kept
closed, in this way retaining the vacuum in the vacuum chamber and causing the
concentrate to flow down the heated surfaces of the coils as in the previous
operation. In order to restore the vacuum in the supplementary chamber I may
connect the said chamber after this operation to the exhaust pipe by an air pipe
controlled by a suitable cock or valve. The sterilization of the air may be effected
by causing it to pass through layers of cotton wool before entering the vacuum
chamber or the supplementary chamber, and the exhaust pipe may be connected
to the vacuum chamber by means of a suitably arranged mercurial scaled joint in
order to facilitate the removal of the cover of the chamber when desired, the
depth or height of the seal of mercury under the vacuum being in excess of that of
the barometer.
In some cases I may prefer to separate the liquid into two parts and apply the
process of concentration to them separately or to one of them alone, remixing them
for preservation after the concentrating process. Such cases are those in which
one constituent of the liquid may during the process of concentration be injuriously
affected by it, or injuriously affect the remainder, and in which it is possible
mechanically or otherwise to separate such constituent. Thus in the case of milk
I prefer to separate the cream and treat the remaining milk, subsequently mixing
the residue with the cream, as in this way I find that the fat globules are
prevented from being broken up.
For the absorption of water I prefer, but do not necessarily restrict myself
to strong sulphuric acid suitably agitated by arms arranged within the absorbing
chamber.
In the case of solid substances containing liquids which it is desired to remove
for the purpose of concentration, as for instance-vegetables, I finely divide
them with a mineing machine, or a pulper of ordinary construction or otherwise
before applying my invention, so that for the purposes of the process they may
act substantially as a liquid does, and I then treat them in a manner similar to that
described in regard to liquids.
I may if necessary apply means for cooling the sulphuric acid, as for instance-
by causing it to circulate within refrigerating coils; and I may also or alterna-
tively substitute for, or combine with, or apply in succession to the process of
exhaustion and absorption which I have described above, an exhaustion and
simultaneous absorption by means of a sulphuric acid pump arranged on the
Geissler, Sprengel or equivalent system.
Or, in lieu of absorbing the vapours I may arrange to condense or freeze them
by any suitable apparatus.
I am aware that concentrates of alimentary or pharmaceutical products have
been obtained by the combined action of a vacuum and of heat, but in such cases

page_text: some part of the evaporation is obtained by the direct absorption of heat com-
municated to the liquid.
My invention consists in the process and apparatus described for obtaining the
concentration at ordinary temperatures by means of the vacuum aloue, the heat
communicated serving not to convert the liquid into vapour, but to prevent its
partial or complete solidification.
Improvements in Concentrating Alimentary or Pharmaceutical
Liquids or other Substances, and in Apparatus therefor.
1. SYDNEY DOMVILLE ROWLAND, of Toynbee Hall, Commercial Street,
Whitechapel, in the County of London, Student in Medicine 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:-
The object of my invention is to freefalimentary or pharmaceutical liquids or
other substances from some part of the water, alcohol or other readily procurable
liquid which they may contain, in such a way as to leave a concentrate or residue
which, by mixture with a fresh quantity of the abstracted liquid, will yield
substantially the original liquid or other substance.
In previous attempts to the same end the concentration has been effected entirely
or in part by raising the temperature of the liquids or substances to be con-
centrated; and in the case of many such liquids or substances chemical or physical
changes occur in the process of heating, and the concentrate or resi lue when again
mixed with the separated liquid differs in chemical character and physiological or
therapeutic properties from the original liquid or other substance. On the other
hand concentration solely by the use of a vacuum is liable to the objection
of causing partial or complete congelation of the liquid or other substance
treated.
I attain my object without these disadvantages by evaporating the surplus
liquid in a high vacuum, and continuously supplying to the liquid or other
substance under treatment such a quantity of heat as is sufficient only to make
up for that which is abstracted by the evaporation of the liquid vaporised.
My process is specially applicable to milk which is known to suffer important
changes when its temperature is raised.
Upon the accompanying drawings which illustrate an arrangement of apparatus
for carrying out my invention in the case of liquids,
Figure 1 represents a general view of the apparatus, and
Figure
2 is an enlarged view of a suitable air inlet.
A is the vacuum chamber B heating coils, C exhaust pipe, D absorbing
chamber, E pipe leading to air pump, Fliquid to be concentrated, G trough or
cistern, H pipe leading from cistern to vacuum chamber A, I perforated trays,
Kair inlet, L draw-off, M lower chamber, N pipe from chamber A to chamber M,
O stop-cock, P draw-off, Q air-inlet, R ascension pipe, S stop-cock, T regulating
valve, U cotton wool, V cocks for controlling flow through coils, W agitator,
X gauge glass, Z air-pipe leading to exhaust pipe C, z stop-cock thereon.
The concentration takes place in the closed vacuum chamber A which is
provided with external heating jacket, or internal hot-water circulation coils B or
with both, or with other suitable arrangements for providing surfaces heated to a
definite extent.

page_text: This chamber A communicates by means of the pipe C perforated at its lower
end, with a second closed chamber D containing a suitable absorbent of that
part of the liquid which is to be vaporised; or I may continue the pipe C
downwards within the chamber A and perforate the extended portion at intervals,
as shewn.
From this second chamber Da pipe E leads to an air-pump capable of producing
a high vacuum. The liquid to be treated, F, is led from the trough or cistern G
placed above the vacuum chamber-through the pipe H-extending downwards
from its underside on to the perforated tray I, arranged within the vacuum
chamber A. whence it traverses the heated surfaces of the coils B, of which the
temperature is so adjusted as to continuously replace enough of the heat lost by
evaporation to prevent freezing, while not supplying enough heat to raise the
residual product to a temperature at which the changes which I wish to avoid may
occur.
In this way the liquid gradually loses its superfluous water or other diluent, and
when the process of concentration has gone sufficiently far, air is re-admitted
through the valve or cock K and the product drawn off at L, the air being
sterilised when necessary before readmission by being caused to pass through one
or more layers of cotton wool U or by any other suitable means.
Or may
arrange for the process to be carried on continuously, in which case I connect the
lower portion of the vacuum chamber A with a supplementary chamber M by
pipe N, the communication being controlled by means of a valve or stop-cock 0.
From this chanıber the concentrate is drawn off through the cock P, air being
admitted by the cock Q and sterilised as above described, the cock O being kept
closed during the operation of drawing off. The concentrate thus obtained may
be preserved in any suitable way, and by readmixture with the same amount
of liquid which was previously evaporated will yield substantially the original
liquid.
I may allow the liquid under treatment to trickle down the heating surfaces, or
I may determine a circulation up and down in any suitable way. When desirable
I may, before drawing off the concentrate from the chamber M, cause it to re-enter
the vacuum chamber A through the pipe R by opening the cocks Q and S, the
cocks O and T being kept closed, in this way retaining the vacuum in the chamber A
and causing the concentrate to flow down the heated surfaces of the coils B as in
the previous operation.
In order to restore the vacuum in the chamber M after this operation, I may
connect the chamber M to the exhaust pipe C by the pipe Z controlled by a
suitable cock or valve z. The sterilisation of the air may be effected by causing it
to pass through the layers of cotton wool U, shewn in Figure 2, before entering
the chamber A or M, and the exhaust pipe C may be connected to the chamber A
by means of a mercurial seal joint, in order to facilitate the removal of the cover
of the chamber when desired. In this case the upper portion of the pipe C which
is made detachable is of larger diameter than the projecting end of the perforated
portion, over which it is capable of sliding, the projecting end being furnished with
an outer shell which encloses the end of the pipe C so as to form a seal or trap,
the depth or height of the seal of mercury under the vacuum being in excess of
that of the harometer.
In some cases I may prefer to separate the liquid into two parts and apply the
process of concentration to them separately or to one of them alone, remixing them
for preservation after the concentrating process. Such cases are those in which
one constituent of the liquid may during the process of concentration be injuriously
affected by it, or injuriously affect the remainder, and in which it is possible
mechanically or otherwise to separate such constituent. Thus in the case of milk
I may prefer to separate the cream and treat the remaining milk, subsequently
mixing the residue with the cream, as in this way I find that the fat globules are
prevented from being broken up.
For the absorption of water I prefer, but do not necessarily restrict myself to

page_text: strong sulphuric acid, (sp.g.: 1.84) suitably agitated by arms W. In the case of
solid substances containing liquids which it is desired to remove for the purpose
of concentration, as for instance vegetables, I finely divide them with a mincing
machine, or a pulper of ordinary construction or otherwise before applying my
invention, so that for the purposes of the process they act substantially as a liquid
does, and I then treat them in a manner similar to that described in regard to
liquids.
I may if necessary apply means for cooling the sulphuric acid, as for instance by
causing it to circulate within refrigerating coils; and I may also or alternatively
substitute for or combine with, or apply in succession to the process of exhaustion
and absorption which I have described above, an exhaustion and simultaneous
absorption by means of a sulphuric acid pump arranged on the Geissler Sprengel
or equivalent system. Or in lieu of absorbing the vapours I may arrange to
condense or freeze them by any suitable apparatus.
I am aware that concentrates of alimentary or pharmaceutical products have
been obtained by the combined action of a vacuum and of heat, but in such cases
some part of the evaporation is obtained by the direct absorption of heat com-
municated to the liquid. My invention consists in the process and apparatus
described for obtaining the concentration at ordinary temperatures by means of the
vacuum alone, the heat communicated serving not to convert the liquid into vapor,
but to prevent its partial or complete solidification; and accordingly
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. The apparatus described and illustrated, Figures 1 and 2, for intermittent
or continuous concentration of alimentary or pharmaceutical liquids or other
substances.
2. The herein described process of concentrating alimentary or pharmaceutical
liquids or other substances in a high vacuum with the continuous addition of heat
not exceeding in amount that absorbed in evaporation so as to prevent deleterious
change of temperature or congelation in the substance operated upon.
Dated this Ninth day of June 1890.
Dased this I men day or une LORD.
For the Applicant,
GEDGE & FEENY,
60 Queen Victoria Street, London, E.C., Chartered Patent Agents.