CERTAIN IMPROVEMENTS IN THE PROCESS OF CONCENTRATING CERTAIN VEGETABLE JUICES AND SACCHARINE SOLUTIONS
Year: 1838

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MORTON
WILLIAM LAWRENCE, of Leman Street, Goodman's Fields, in the County of
Middlesex, Sugar Refiner, send greeting.
WHEREAS Her most Gracious Majesty Queen Victoria, by Her Letters
Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Eighth day of March, in the first year of Her reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said Morton
William Lawrence, my exors, admors, and assigns. Her especial licence, full
power, sole privilege and authority, that I, the Morton William Lawrence,
my exors, adiñors, and assigns, or such others as I, the said Morton
William Lawrence, my exors, admors, or assigns, should at any time agrée
with, and no others, from time to time and at all times thereafter during
the term of years therein expressed, should and lawfully might make, use,
exercise, and vend, within that part of Her said Majesty's United Kingdom
of Great Britain and Ireland called England, Her Dominion of Wales, and
Town of Berwick-upon-Tweed, and also in all Her said Majesty's Colonies
and Plantations abroad, in such manner as to me, the said Morton William*
Lawrence, my exors, admors, and assigns, or any of them, should in my or
their discretion seem meet, my Invention of "CERTAIN IMPROVEMENTS IN THE
PROCESS OF CONCENTRATING CERTAIN VEGETABLE JUICES AND SACCHARINE SOLUTIONS,"
to have, hold, exercise, and enjoy the said licence, powers, privileges, and
advantages therein-before granted unto me, the said Morton William Lawrence,

page_text: my exors, admors, and assigns, for and during and unto the full end and term
of fourteen years from the date of the said Letters Patent next. and imme-
diately ensuing; in which said Letters Patent is contained a proviso that
I, the said Morton William Lawrence, should particularly describe and
ascertain the nature of my said Invention, and in what manner the same
is to be performed, by an instrument in writing under my hand and seal,
and cause the same to be inrolled in Her said Majesty's High Court of
Chancery within four calendar months next and immediately after the date of
the said Letters Patent, as in and by the same, reference being thereunto had,
will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Morton William Lawrence, do hereby declare that the nature of my said
Invention, and the manner in which the same is to be performed, are as
follows:-
Firstly, I take any vegetable juice or saccharine solution capable of yielding
sugar on evaporation, and which is commonly used for that purpose by sugar
manufacturers; and I evaporate such juice or solution by boiling it in an
open vessel (by which expression I throughout this Specification mean a vessel
left open to the atmospheric pressure) to a point of concentration short of that
to which I intend ultimately to bring it, but as near thereto as I consider
attainable in such open vessel without risk of injuring the juice or solution.
The precise point of concentration to which it will be desirable thus to bring
the juice or solution in the open 'vessel must be determined in every particular
case by the judgement of the operator, who will be guided and governed therein
by the treatment he proposes, or the use he intends to make of the juice or
solution after concentration and by the quality and condition of the material
on which he is operating. But in general, as soon as the juice or solution
begins to come to proof, that is, to exhibit such degree of viscidity as allows
of a thread being drawn in it between the finger and thumb, the boiling in the
open vessel should be discontinued. I have in practice found that the requisite
degree of viscidity is obtained by the time the juice or solution is brought in
the open vessel to a temperature varying from 228° to 286° Fahrenheit. I
do not judge it advisable under any circumstances to exceed 236° Fahrenheit.
The other point, also, videlicet, that point of concentration to which the juice
or solution is ultimately to be brought, must depend upon the views of the
operator in reference to its subsequent treatment or intended use; but having
brought it in the open vessel to the degree of concentration above mentioned
and described as attainable at a temperature lying between 228° and 236°
Fahrenheit, he will have it in his power to bring it to a much higher degree

page_text: of concentration, and to such a degree as will be quite high enough for any
practical purpose by pursuing the treatment I am about to describe. Having
boiled the juice or solution in the open vessel to the point described, I transfer
it with as little loss of heat as possible into a close vessel, either of the same
kind as the vacuum vessels now used in the ordinary vacuum process of
sugar boiling, or into one, the improved construction of which and the mode
of using, which are hereafter described. A vacuum advancing as the process
proceeds to a degree supporting not more than three or four inches of mercury
(as indicated by a guage made to communicate with the exhausted space or
vacuum) being produced and maintained in the close vessel by the action of
an air pump, or other known means, the juice or solution, already heated to a
high degree, will undergo a further evaporation, and speedily reach a high
degree of concentration, while the vapour produced may be carried off and
condensed by any of the contrivances usually employed for such purposes.
This process of evaporation and concentration in vacuo may be carried on and
completed in the close vessell either with or without the supply of further heat
to it or to the juice or solution whilst it remains therein. I find that I can
thus without supply of further heat concentrate the juice or solution to a point
high enough for any practical purposes. But in many cases, and especially
where it is proposed that the concentrated juice or solution (or in other words,
the mass resulting from such concentration) should after quitting the close
vessel be transferred into moulds, I find it preferable to supply heat to the
close vessel (in any of the usual modes) during the evaporation of the juice or
solution in vacuo, and the consentrated juice or solution (or mass resulting
from the concentration) may by this method be sustained in the vacuum at a
temperature not lower than 180° Fahrenheit, or if it be deemed expedient to
let it fall below that temperature, it may be restored to such temperature, and
then transferred at once from the close vessel into the moulds without first
heating it up after it quits the close vessel. And it is to be observed, that
when heat is supplied to the close vessel during the process of evaporation or
less perfect vacuum will suffice, but the vacuum and the supply of heat ought
to be so regulated that the said juice or mass should not boil over. When
evaporation has taken place in the close vessel to the point at which the
operator wishes it to stop, the air may be admitted, and the operation of
concentration is finished. When I do not supply heat to the close vessel
during evaporation, I judge of the degree to which concentration has taken
place by observation of a thermometer fixed in the cover of the vessel, and
descending into the juice or solution, for I find in practice that the increase of
density in the juice or solution when no heat is applied during its evaporation in

page_text: And
the close vessel very nearly corresponds. with the fall of temperature as indicated
by the thermometer inserted therein, allowance being made for such circumstances
as readily present themselves to any experienced operator: Thus in general I
find that if the juice or solution be at a temperature of 284° or 235° Fahren-
heit or thereabouts when it is removed from the open vessel, and the process
of evaporation be forthwith carried on in the close vessel, without supply of
further heat, a sufficiently high point of concentration for any practical purpose
will have been attained by the time the thermometer so inserted as aforesaid
falls to a temperature varying from 140° to 150° Fahrenheit, and even when
heat is supplied to the close vessel during the process of evaporation therein,
the observation of the thermometer will still generally enable an experienced
workman to judge of the degree of concentration which the juice or solution has
attained in the close vessel, but in such case I provide myself with a proof stick,
such as is in use in the ordinary vacuum process of sugar boiling, by aid of which
I can draw out and inspect a portion of the juice or solution contained in the
close vessel without disturbing the vacuum, and I can also use the proof stick,
even when I do not apply heat to the close vessel, if for more complete satis-
faction I desire to do so. By the process thus described, I escape all necessity
of heating the juices or solutions in an open vessel to certain degrees known
to be injurious to such juices and solutions while in such open vessel.
I nevertheless obtain a considerable abridgement and simplification of the
vacuum process, as now practised, and I can either abstain altogether from the
use of heat applied during the evaporation in vacuo, or I can use it partially
and moderately, or continuously. And I do declare that my Invention, for
which the present Patent is obtained, in so far as regards this first part of my
improvements in the process of concentrating certain vegetable juices and sac-
charine solutions, does consist in first evaporating in an open vessel the juices
and solutions before described to a point of concentration as near that which
I desire them ultimately to attain as they can be safely made to attain in
such open vessel, and then completing the process of concentration by further
evaporating such juices and solutions in vacuo, either with or without the
application of heat during such evaporation in vacuo, and whether such last-
mentioned evaporation be carried on in any close vessel of the kinds now in
use, or in any close vessel of either of the kinds herein-after described, as
subservient to which operation I have pointed out methods (which I do not,
however, claim to have invented) of ascertaining from time to time the density
of the juices or solutions proposed to be so concentrated. And, secondly, I
do declare as one of my said improvements in the process of concentrating
certain vegetable juices and saccharine solutions, that I construct and use the

page_text: close vessel in which the juice or solution is to be evaporated in vacuo, in
one or other of the two manners hereafter described. The first manner of
construction is represented in the Drawings hereunto annexed Number 1,
and the mode of constructing and using it as follows:-The lower part of
the vessel may conveniently consist of a copper or iron pan, in size and form
resembling the vessel called a cooler in ordinary sugar houses, but the bottom
of it should be somewhat curved downwards for the better resisting atmo-
spheric pressure when the air from within comes to be exhausted (B, Number 1);
when it is not intended to apply heat to it during the process of evaporation in
vacuo, it is desirable to enclose the lower part of the vessel in a casing of wood
(C, No. 1) containing sawdust, charcoal, or other non-conducting substance,
with the view of checking the escape of heat through the metal. When it is
intended to apply heat to the close vessel, this casing of wood should not be
used, but another sort of casing, adapted to the purpose of administering heat
to vessels of a similar form, must be employed, and such sorts of casings and
modes of applying heat are too well known to require description. The
upper part or cover of the vessel (E, No. 1) may also be conveniently con-
structed of copper; and it should be made so as to drop into the lower part,
and to rest when down upon the interior surface of the bottom of such lower
part. How much of such interior surface shall be enclosed by the cover when
so dropped must of course depend upon the size of the cover relatively to the
size of the bottom. I recommend, however, the cover of the vessel to be so
constructed, that when let down upon the bottom it may enclose nearly the
whole thereof. This cover is made with a flanch (D, No. 1) about two inches
wide, running along the edge thereof, and to the lower side of the flanch a
packing of sail cloth or some similar compressible material of the same width as
the flanch, in folds or pieces, of which I have found eight to form a sufficient
thickness, is rivetted or attached by any other convenient fastening. The
cover is furnished with a neck (F, No. 1) in the manner of the head of a still,
and this neck being formed so as to turn downwards at its extremity, dips when:
let down into a pipe (G, No. 1) placed to receive it, and is furnished at such
extremity with a packing, which being occasionally moistened by a small
quantity of water, will have the effect of keeping the junction between the
pipe and the neck air-tight, permitting at the same time the neck to be raised
and lowered with the cover. This pipe must be firmly fixed and have a com-
munication (H, No. 1) with a condensing and exhausting apparatus, which may.
be of any of the known kinds, and need not therefore be particularly described.
It is convenient to have a small aperture, which may be stopped by a cork or
stopcock, in some part of the cover, for the purpose of admitting air without.

page_text: raising the cover. The mode of using the vessel so constructed is as follows:-
The juice or solution having in the open vessel been brought to the desired
temperature, as pointed out in the former part of this my Specification, the
close vessel is prepared for receiving it by dropping the cover into the lower
part till the flanch of the cover barely rests upon the interior surface of the
bottom of such lower part; the extremity of the neck at the same time
entering the pipe, and the juice or solution is then transferred into the
close vessel, flowing into that portion of it which is covered partly through
a small orifice made for the purpose in the cover close to and above the
flanch, and partly under the flanch, which in this stage of the process has
not been fixed down; the exhaustion of the air from within the cover is
then commenced by the action of the air pump or other known means, and
the flanch of the cover, with the packing attached, becomes firmly and closely
fixed down by the atmospheric pressure, so as to form an air-tight junction.
The juice or solution is rapidly sucked in through the orifice before described.
When it has nearly all entered, a plug with a handle is applied by band to
stop the orifice, and the juice or solution within the cover being then confined,
and the exhaustion of the air and condensation of the vapor proceeding by
means of the exhausting and condensing apparatus before alluding to, a rapid
evaporation takes place, till the requisite point of concentration is reached.
The speed of the operation may be retarded at the pleasure of the operator by
a moderated use of the air pump, or by a partial or occasional admission of air
through the aperture in the cover above mentioned, or by any of these means.
My second manner of constructing and using the close vessel is represented
in the Drawings hereunto annexed, No. 2 and No. 3, and the mode of con-
structing and using it is as follows:-The lower part may consist of a copper
or iron pan, of a hemispherical, eliptical, or some other convenient shape, for
the purpose of resisting atmospheric pressure, of the usual size of sugar pans,
(B, No. 2, and No. 3) cased in the mode or modes above mentioned, according
as the operator may wish to apply or not to apply heat during the process of
evaporation, and having a flanch of from three to five inches broad, running
along the edge thereof (A, No. 2 and No. 3), which flanch is provided
with rims at its external and internal circumference, so as to form a channel
between the rims of about an inch and an half in depth, and of sufficient width
to receive the edge of the cover intended to drop into it. The cover is con-
structed with a flanch (D, No. 2 and No. 3) of the width of about two inches
running along its edge, to be adapted to and fall into the channel above
described. A packing of sail cloth or some similar compressible material, but
somewhat thicker than heretofore described, must be laid in the channel

page_text: etween the rims of the flanch which runs along the edge of the lower part
in which case it is not necessary to fasten such packing), or else be rivetted on
o the flanch of the cover, or attached to it by some other convenient fastening.
I myself lay the packing as above described in the channel, between the rims of
he flanch which runs along the lower part, whether the packing be placed in
uch channel or attached to the flanch of the cover; it should be moistened
previous to use. The cover (E, No. 2) is furnished with a neck (F, No. 2) of
such form, and dropping into such pipe (G, No. 2), and having connection
(H, No. 2) with a condensing and exhausting apparatus, as above described;
or the neck may be altogether omitted in a vessel thus constructed, in which
case the air may be exhausted, and the vapour formed during evaporation
may be carried off by means of a lateral pipe fixed in the lower part of the
vessel (G, No. 3), and communicating with an ordinary exhausting and
condensing apparatus. But the latter mode of construction, viz', with a
lateral pipe, is not adviseable when a steam case is applied to the
close vessel, because the perforating of such case would be inconvenient. The
mode of using the vessel thus constructed is as follows:-It may be supplied
with juice or solution brought in the open vessel to the desired temperature
or consistency, as pointed out in the former part of this my Specification, either
by raising the cover, and pouring such juice or solution into the lower part of
the vessel, and then dropping the cover upon the lower part of the vessel, or it
may be supplied, as in the vacuum pan now in use, through a supply vessel
attached to the cover, and furnished with a valve, without raising the cover..
The cover when down rests upon the channel described above. The ex-
haustion of the air from within the cover is then commenced and carried on
by the action of the air pump or other known means, and the two parts of the
vessel becoming closely united by the atmospheric pressure, an air-tight
junction is formed, and the exhaustion of the air and condensation of the
vapour proceeding by means of the exhausting and condensing apparatus, a
rapid evaporation takes place, till (as in the former instance, the requisite
degree of concentration is attained. In case the junction does not appear
perfectly tight, I find it serviceable to pour a small quantity of the juice or
solution, or any saccharine syrup, upon the edges of the channel before
described, which may be done at any period of the operation, and without
raising the cover. The juice or solution admitted into the close vessel of any
or either of the forms above described, having thus been brought to the
requisite degree of concentration, may be removed, and a fresh quantity boiled
in the open vessel to the desired temperature may be admitted to be similarly
dealt with, or the first quantity having so been brought to the requisite degree

page_text: of concentration by evaporation in vacuo, 1, 2, 8, or more successive quantitie
may be admitted into the close vessel (without removing the first or forme
quantities), and the whole when brought to the requisite degree of con
centration be removed at the same time at the discretion of the operator, bu
in general I find it better to pursue the method of admitting successive
quantities, and removing the whole at the same time. Whichever of the two
modes of constructing the close vessel be resorted to, the cover may be raised
or lowered at pleasure by means of a crane (I, No. 1, 2, and 3); screw, or
other mechanical apparatus, and in either mode of construction both the lower
part of the vessel and the cover must be made of strength to resist the
pressure of the atmosphere upon a vacuum. By either of these modes
of constructing and using the close vessel, the process of concentration may
be conveniently and satisfactorily carried on therein, and an air-tight junction
is obtained, by which the cover and the lower part of the vessel may
be securely and conveniently united, and which admits of being easily and
conveniently separated, and of easy and convenient access being given to the
whole inside of the said vessel and its contents.
And I hereby declare that my Invention, for which this present Patent is
obtained, in so far as regards this second part of my improvements in the
process of concentrating certain vegetable juices and saccharine solutions
does consist in substituting for the usual mode of fastening the cover of close
vessels employed in the concentration of the juices and solutions comprehended
in this Patent by bolts and cement, or other fixed and permanent fastenings,
an air-tight junction effected in the manner herein-before described. And
although I have particularly described the period or stage of the process of
concentration at which I use my said close vessel, I nevertheless claim as
part of my Invention for which this present Patent is obtained the use of close
vessels so constructed, with such air-tight junctions as aforesaid, in the
process of concentrating the before-mentioned juices or solutions, at whatever
period or stage of such process the same may be made use of. And although
I have herein particularly described the manner in which a close vessel
having the cover and lower parts thereof united by such air-tight junction
as aforesaid may be conveniently used in the concentration of such juices and
solutions, by having a neck so contrived as aforesaid in the cover thereof, or
such lateral pipe so placed as aforesaid in the lower part thereof, I never-
theless do not claim to have invented the use of a neck so contrived, or
of a lateral pipe so placed in all cases of close vessels used in the con-
centration of such juices and solutions, but only the adaptation thereof to such
closo vessels so used as aforesaid as are united by such air-tight junctions.

page_text: And though I have herein pointed out as subservient to the use of such
air-tight junctions_means of raising and lowering the cover of such close
vessel, and of admitting the air and the juices or solutions aforesaid into such
close vessel, and of carrying off the vapour for condensation, and of supplying
heat to such close vessel where it is judged adviseable to do so, and of checking
the escape of heat where it is not judged right to supply heat, I nevertheless
declare that I do not claim to have invented such means or modes, but only
to have applied and adapted them in subserviency to the use in the process of
concentrating the juices and solutions aforesaid of such close vessels as are
united by such air-tight junctions.
In witness whereof, I have hereunto set my hand and seal, the Second
day of July, in the year_of_ our Lord One thousand eight hundred and
thirty-eight.
MORTON WILLIAM (L.S.) LAWRENCE.
Signed, sealed, and delivered, by
the within-named Morton William
Lawrence, in the presence of
J. M. TEESDALE,
JAS. LANGLEY,
Moss Tonsdale Sumos & Weston