CERTAIN IMPROVEMENTS IN EVAPORATING SUGAR, WHICH IMPROVEMENTS ARE ALSO APPLI CABLE TO OTHER PURPOSES
Year: 1828

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
GODFREY KNELLER, of Pearl Street, Spital Fields, in the County of Middlesex,
Chemist, send greeting.
WHEREAS His present most Excellent Majesty King George the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Twenty-seventh day of November, in the ninth year
of His reign, did for Himself, His heirs and successors, give and grant
unto me, the said William Godfrey Kneller, His especial licence, that I,
the William Godfrey Kneller, my executors, administrators, and assigns, or
such others as I, the said William Godfrey Kneller, my executors, admi-
nistrators, or assigns, should at any time agree with, and no others, from
time to time and at all times during the term of years therein expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, my Invention of "CERTAIN
IMPROVEMENTS IN EVAPORATING SUGAR, WHICH IMPROVEMENTS ARE ALSO APPLI
CABLE TO OTHER PURPOSES;" in which said Letters Patent is contained a
proviso, obliging me, the said William Godfrey Kneller, by an instru-
ment in writing under my hand and seal, particularly to describe and
ascertain the nature of my said Invention, and in what manner the same
is to be performed, and to cause the same to be enrolled in His said Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said recited Letters Patent, as in and by the same,
reference being thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
William Godfrey Kneller, do hereby declare that my said Invention consists
in a method or process and certain apparatus as herein-after described, by
which I am enabled to evaporate liquids and solutions at a low temperature,
and thereby to avoid the injury to which certain substances, which require
a nice and delicate application of heat, such as sugar, for instance, are liable
to be by being exposed to too high a temperature.
And I do further declare, that my said Invention and improvements consist
in forcing, by means of bellows or any other blowing apparatus, atmospheric
or any other air in a hot or cold state through the liquid or solution subjected
to evaporation, and this I do by means of pipes whose extremities reach
nearly or within such distance as may be found most suitable, under peculiar
circumstances, to the upper or interior area of the bottom of the
pan or boiler
containing such liquid or solution, the other extremities of such pipes being
connected with larger pipes which communicate with the bellows or other
blowing apparatus which forces the air into them. The pan or boiler may be
of any shape or dimensions, but I prefer it with a flat level bottom; and
I introduce the liquid or solution to the depth of from about 4 to six inches.
The heat may be applied to the lower or exterior area of the bottom of such
pan or boiler by naked fire, steam, or hot air, in the usual manner and by means
well understood; the air then forced into the heated liquid or solution keeps it
in a constant agitation, abstracts its heat and carries off the steam or vapor
which is to be expelled. By raising the degree of heat under the pan or boiler
and increasing the quantity and velocity of the air injected into the liquid or
solution, or, on the contrary, by lowering the heat, and moderating the injection
of air, the evaporation is accelerated or retarded at the pleasure of the operator,
according to the nature of the substances or the effect desired.
And I do further declare, that in applying this my said Invention and
improvements to the evaporation of cane juice or syrrup for making refined
sugar, I can bring it to the proof or chrystallizing points by keeping the
temperature of such syrup or cane juice between one hundred and forty and
one hundred and seventy degrees of Fahrenheit's thermometer, although I
prefer to keep it between one hundred and sixty and one hundred and seventy
degrees. By this simple and cheap apparatus I obtain a great quantity of
large and shining chrystals, which hitherto were attainable only by evapo
rating in vacuo, a very troublesome and expensive process, while other
methods, by exposing the sugar to a high temperature, impair the quantity,
size, and brilliancy of the chrystals, and form a great quantity of molasses or
treacle.

page_text: And I further declare that this my Invention and improvements can be
applied to the evaporation of other liquids and solution as well as syrups and
cane juice or sugar, by varying the apparatus and the degree of temperature
according to their nature and the will of the operator.
And I further declare that this my Invention and improvements can also
be applied to distilling or rectifying spirits, provided that a vent be given to
the air arising with the spirit after the latter shall be condensed.
And I further declare that in order more quickly to remove the steam or
vapour from the surface of the liquid or solution, and thereby to favor the
evaporation, I sometimes, particularly when I use hot air for heating the pan
or boiler, conduct the hot air, after it has given out part of the heat to the
bottom of the boiler, to the surface of the liquor or solution; but I do not
consider this contrivance necessary in any nor adviseable in all cases. It is
hardly necessary to observe, that the evaporating power is augmented by
encreasing the diameter of the pipes and the quantity of air propelled by the
blowing apparatus through the liquid.
And I do further declare, that as it is desirable that the liquid to be evapo-
rated should be of equal depth in every part of the evaporator, the bottom of
which is recommended to be perfectly level, it will be found that the liquid,
when sufficiently evaporated and concentrated, does not readily flow out
through the spout opened for the purpose. To remedy this inconvenience, I
place a vertical sliding plate, four and an half to five inches in height, and
somewhat less in length than the breadth of the evaporator or pan,
such plate
being kept in its upright position by projections at right angles with its lower
edge, which must slide as nearly as possible in contact with the bottom of the
said pan. This plate is in the first instance put at that end of the pan or
evaporator which is opposite to where the spout is situated. When the
evaporation is effected to a sufficient degree, I damp the fire, or shut off the
steam or hot air, and open the spout to draw off the liquid, a great part of
which will immediately flow out. I then, by means of a winch or lever, raise
the pipes about six inches, and gently draw the said vertical plate by a thin
wire or chain towards the spout, and thus quickly clean the bottom of the
pan.
It is necessary to raise the pipes in order that the before-mentioned plate may
pass under them, and at the same time not interrupt the blast of air through
the small pipes, which might be obstructed if any of the evaporated liquid
should congeal or chrystalize in them by cooling. For effecting these objects,
the main pipe, arising from the bellows or blowing apparatus, is inserted
into the main pipe in the evaporator in an air-tight manner, but with a
joint or flexible tube sufficiently long to allow the system of blowing pipes

page_text: to slide upwards for about six inches. The form and construction of the
apparatus which I use to produce the above effect may be varied according to
circumstances and the form and position_of_the_pan_or_evaporating vessel to
which it is to be applied; but two things are essential in its construction; the
first of which is, that, however numerous the blowing pipes may be, that their
lower orifices should be distributed as evenly and equally over the whole
surface of the bottom of the pan as possible; and, secondly, that a stream of air
should issue from the lower end of every one of them at the samo time.
To insure this latter object it is immaterial whether the bottom of the pan
or boiler be perfectly level, but it is quite necessary that all the lower ends of
the blowing tubes should be on a level and parallel to the surface of the fluid
to be evaporated, in order that there may not be a higher column of fluid.in
one tube than in another. The mode of construction necessary to produce
these objects may be various; but in order the more distinctly to explain my
meaning and my mode of operating, I hereunto. subjoin a Drawing of the
apparatus which I have used, and find to answer the purpose, and, in which
A, A, A, A, Figure 1, is a plan or bird's eye view of an oblong pan or boiler;
B, B, B, the tinned copper or other large air pipes, which are closed at their
ends C, C, C, but open into each other, and likewise into the still larger
perpendicular pipe D, from which the air is supplied, by communicating, as
aforesaid to bellows or other blowing machinery. e, e, e, e, &c, are the small
lateral pipes which communicate with the large air pipes, and proceed down
wards through, the fluid to be evaporated to very near the bottom of the pan.
The lower ends c, e, &c. of these pipes are all very nearly equidistant from
each other, to produce the equal distribution of air before mentioned.
Figure 2 is a transverse section of the pan A, A, A, A, Figure 1, showing
the great air pipe D, the cross pipe and its continuations B, B, B, in section,
and the small descending pipes e, e, e, e, &c., as shewn in the last Figure,
likewise the pipes ffff, which likewise descend from the pipes B, B, but
in a more nearly vertical direction, which prevents their being seen in the
view, Figure 1, but by means of which the distances of the lower ends of
these blowing tubes are brought to the same distance asunder under the pipes
B, B, as in other parts of the pan. 9, 9, 9, are legs to support the above-
described system of pipes, by standing on the bottom of the pan, and are of
such length as will just prevent the lower ends of the said blowing pipes from
touching it. The whole of this system of pipes is to be raised at once, as
before mentioned, by any adequate machinery, in order to permit the scraping
or cleansing plate h, h to pass under the ends of the before mentioned small
blowing pipes.

page_text: Figure 3 is a longitudinal section of Figure 1, of which a particular
description will be unnecessary; as the same letters of reference denote the
same parts in this and the other Figures, the insertions of the small blowing
pipes into the pipes B, B being shewn by black dots. In all these Figures
I shows the situation near which the discharging valve or orifice should be
placed. K, K is the line near which the surface of the fluid should stand,
when first introduced to be evaporated. As before mentioned, the form of
this apparatus may be varied, provided its essential properties of the air
blowing through all the descending tubes, and this being so disposed as to
produce greatly divided and equally distributed currents of air over the whole
bottom of the vessel at once, are maintained, because my Invention consists in
producing rapid evaporation at lower temperatures than usual by the means
herein-before described.
In witness whereof, I, the said William Godfrey Kneller, have hereunto
set my hand and seal, this Twenty-seventh day of May, in the year