IMPROVEMENTS IN APPARATUS FOR CONCENTRATING CANE JUICES AND OTHER SACCHARINE SOLUTIONS, AND IN THE TREATMENT OF SUCH FLUIDS."ATION
Year: 1852

page_text: Pancras Road, in the County of Middlesex, for the Invention of
"IMPROVEMENTS IN APPARATUS FOR CONCENTRATING CANE JUICES AND
OTHER SACCHARINE SOLUTIONS, AND IN THE TREATMENT OF SUCH FLUIDS."
PROVISIONAL SPECIFICATION.:left by the said Henry Bessemer
at the Office of the Commissioners of Patents, with his Petition,
on the 19th November 1852.
I, HENRY BESSEMER, of Baxter House, Old St. Pancras Road, in
the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN APPARATUS FOR CONCENTRATING CANE
JUICES AND OTHER SACCHARINE SOLUTIONS, AND IN THE TREATMENT OF SUCH
FLUIDS," to be as follows:-
My improvements consist, Firstly, in certain modifications of ap-
paratus for evaporating saccharine fluids for which Letters Patent
were granted to me for England, bearing date the
day of
185, wherein is described a mode of concentrating saccharine
fluids by bringing heated air in contact with the wet surface of a re-
volving screw or discs, the warm air in that case being forced between

page_text: the blades of such screw or discs from a central hollow axis, or from
a perforated pipe placed on one side and parallel with the axis; my
present improvements on this apparatus consist in constructing a
large hollow axis, closed at both ends and having trunnions formed
at each end for it to revolve upon. I prefer to make this axis of
about half the diameter of the screw or discs, so as to come in con-
tact with the fluid in the pan, and thus form an air-tight division
from end to end of the pan. An opening is made to extend all
along one side of the pan a few inches above the level of the fluid
contained therein. From this opening the warm air is forced in
between the blades of screw or discs which are enclosed in a case
which fits nearly close to it; in this case there is another opening
extending from end to end on the opposite side to that by which
the air enters the pan; the air, therefore, has to circulate round the
large hollow axis, and finally escapes by the opening in the case, and
will thus be kept much longer in contact with the wet surfaces than
when allowed to escape radially from the hollow axis. In the im-
proved pan, the large size of the axis causes it to come in contact
with the fluid, and thus prevents the air from passing direct across
it to the escape opening. The pan is to be placed over an opening
in the floor into which the warm air is conducted by a suitable
channel from the heating apparatus, so that the air may act on the
bottom of the pan and render a water bath unnecessary.
Another improvement in the construction of the screw or discks
consists in making them of much thinner metal, and giving them
the requisite degree of rigidity of stay rods, which are to pass
through each plate near to its outer edge, and thereby retain cach
plate in its proper position. A further improvement in these eva-
porating pans consist in causing the heated air, after it has passed
over the wet surfaces of. the screw or discs and escapes from the
case which encloses it, to pass through passages or between pipės
through which fresh portions of air is drawn by the blowing appa-
ratus, so that the heated air, after operating on the fluid, may give
off part of its heat again to other portions of air that are after-
wards to be used to promote evaporation, and thus much of

page_text: the heat will be saved and a great economy of fuel will result.
In pans for evaporating cane juice up to a density of about 30
degrees Beaume, it will be found that, unless the defecation has
been very perfect, a scum will arise, which will be moved by the
screw to one end of the pan, from which a channel is made to com-
municate with an open gutter which extends the whole length of
the pan, and in which may be placed a suitable wire strainer
through which the fluid will pass, and leave the scum behind to be
removed by hand from time to time as may be required; the gutter
communicates with the other end of the pan, and thus keeps up a
rapid circulation of the fluid.
Secondly. My Invention consists in a mode of concentrating
syrups after they have attained a density of 27 or 30 degrees
Beaume; for which purpose I let it down into another concentrating
pan, where, in lieu of the screw which causes a circulation of the
fluid, I prefer to use plain circular discs also mounted on a large
hollow axis, at such a distance apart as will admit of the syrup gra-
nulating without clogging up the spaces between them. To regulate
the thickness of the coating taken up upon plates I use a sort of
comb or scraper with a projecting piece between each plate; this
scraper is so arranged as to slide a short distance endwise, in order
to enable it to scrape one side of the plates when pushed forward,
and to scrape the opposite side of them when drawn back in the
reverse direction, and thus at any time during or at the end of the
operation the plates can all be rapidly cleansed; this comb or scraper
will be placed with each tooth of it midway between the plates, so
as not to allow a coating to be taken up upon the plates of greater
thickness than the clear space between the teeth of the comb and
the plates, and thus prevent the formation of too much concrete
sugar upon the plates. The circulating gutter will not be required
in this form of pan, but I prefer forming all along the bottom of it
a hollow channel deepening at one end to facilitate the drawing off
of its contents when required.
Thirdly. My improvements consist in the mode of applying
gaseous matters alone or mixed with atmospheric air, and bringing

page_text: the same in contact with the wet surfaces of the screw or discs in
the evaporating pan, for the purpose of chemically acting on the
saccharine solution under operation. For the purpose of decoloring
or bleaching and for preventing fermentation, I use the vapour
arising from the combustion of sulphur, which I force into and
among the discs, mixed with the air from the blowing-fan during
the process of concentration, for the purpose of facilitating the se-
paration of lime from such solutions. Carbonic acid gas may be
used in a similar manner; and for solutions of sugar containing
acetate of lead, sulphuric acid gas may be thus applied to the thin
films of fluid on the screw or discs, in lieu of being forced through
the fluid in the manner already practised.
SPECIFICATION in pursuance of the conditions of the Letters
Patent, filed by the said Henry Bessemer in the Great Seal
Patent Office on the 19th May 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
HENRY BESSEMER, of Baxter House, Old Saint Pancras Road, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of November, in
the year of our Lord One thousand eight hundred and fifty two, in
the sixteenth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Henry Bessemer, Her
special licence that I, the said Henry Bessemer, my executors, ad-
ministrators, and assigns, or such others as I, the said Henry
Bessemer, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and
Isle of Man, an Invention for "IMPROVEMENTS IN APPARATUS FOR CON-
CENTRATING CANE JUICE AND OTHER SACCHARINE SOLUTIONS, AND IN THE
TREATMENT OF SUCH FLUIDS," upon the condition (amongst others)

page_text: that I, the said Henry Bessemer, by an instrument in writing
under iny hand and seal, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same
was to be performed, and cause the same to be filed in the Great
Scal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Henry Bessemer, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascer-
tained in and by the following statement thereof (that is to say):
My improvements consist, Firstly, in certain modifications of an
apparatus for evaporating saccharine fluids, for which Letters
Patent were granted to me for England, bearing date the day
of
One thousand eight hundred and fifty
,
in which
is Patent described a mode of concentrating saccharine fluids by
bringing heated air in contact with the wet surface of a revolving
screw or a series of circular discs, the warm air in that case being
forced between the blades of such screw or discs from a central
hollow axis or from a perforated pipe placed on one side parallel
with the axis; when the air is thus inade to pass outwards from
perforations in the hollow axis, the distance it has to pass over the
wet surface of the disc is so small that much of it escapes at the
periphery of the disc without becoming perfectly saturated with
moisture, whereby a loss of heat is sustained. It may also be ob-
served that the air which issues from the small perforations in the
axis must pass partly across the discs before it expands sufficiently
to impinge upon them, and hence the entire surface of the discs is
not equally exposed to the action of the air. It has further been
found that the tendency which the fluid matter has to run down the
discs and accumulate upon or near the axis, is productive of some
inconvenience by clogging up the air passages, if not removed from
time to time. Now, the object of the present Invention is to pro-
vide a remedy for these defects, and thereby render the apparatus
inore economical and effective. For this purpose I construct an eva-
porating pan, as represented in the annexed Drawings, where Figure

page_text: 1, is an end clevation; Figure 2, a side elevation; Figure 3, a ver-
tical cross-section on the line A. B, of Figure 2; and Figure 4, is a
longitudinal section on the line C D, of Figure 1.
The saccharine fluid is contained in a cast-iron pan a, which is of
semi-cylindrical form with flat ends a'; the lower part of the pan has
a hollow or gutter a², formed in it, which is made deeper at one end
than the other for the purpose of facilitating the outflow of the con-
centrated syrup; below this gutter there is formed a rib of metal a³,
extending vertically downwards, which unites with the large flanges
a, at each end of the pan. There are also longitudinal flanges a,
extending from end to end and also uniting with the flanges a"; b, b,
are curved plates of iron having a flange b₁, on each of their four
sides, by which the plates b, are bolted to the upper flange a³, to
the lower one a³, and to the end flanges at, and thus forming a
chamber or jacket beneath the pan, for the purpose of containing hot
water or other heating media; the pan a, is strengthened by ribs a,
cast upon it, which are enclosed within the jacket; c, c, are two stout
cast iron frame plates bolted at c', to the flat ends of the pan, they
are also held together by iron plates d, d, which are curved outwards
at d'; within this part is fitted a curved plate e, which is mounted
on an axis e', which passes through the end plates c; the exterior
surface and ends of the plate e, are turned true, the ends fitting
closely up to the plate c, and the curved part fitting closely to a bar
of wood f, which is screwed down to the part d', and is covered
with a piece of soft leather on that side which is in contact with the
cylindrical surface of the curved plate e, whereby a nearly air tight
joint is made; the axes e', of the plate e, has a vertical lever g, keyed
upon it, and also an arm h, to which a wire rope is attached; the
rope passes between small antifriction pulleys i, and has a counter-
balance weight at its lower end, in order to balance the weight of
the plate e, and allow it to be moved by applying a small amount
of force to the handle g; on the upper side of the curved plate e,
there is screwed a bar of wood j, with a piece of soft leather on that
side which fits up against the iron bar k, and thus forms an air
tight joint; the bar k, has flanges at ', by which it is bolted to the

page_text: end plates c; a thin sheet iron cover l, is fitted on the upper part of
the apparatus, having angle iron ribs externally to strengthen it and
secured by angle flanges to the top of the plates c, c, and to the iron
bars k, k; the end frame plate c, c, have brasses n, fitted into them
for the purpose of supporting the main axis p, of the drum r; this
drum is hollow and has large end covers r, bolted to it, in the
centre of which the wrought iron axles p, are secured; the exterior
surface of the drum is turned true and has a series of discs or flat
annular rings of metals, put on it at a distance of from half to one
inch apart from each other; at one end of the apparatus the axis is
clongated and carries the spur wheel t, which gears with a spur
pinion u, keyed on to the drawing shaft v, on which there is a loose
druin W, and fast driving drum X, by which a slow and steady
motion is transmitted to the large drum r, from any first mover.
The apparatus rests upon a brick foundation A, in which there are
left two openings B, and C, for the passage of air, a central wall D,
separating them from each other.
The action of the apparatus is as follows the jacket of the pan is
filled with hot water or other heating inedia, which I prefer to main-
tain at a temperature of about one hundred and forty degrees
fahrenheit; this jacket may either have a steam pipe passing through
it for the purpose of heating the water therein contained, or it may
be kept at the desired temperature by any of the ordinary modes of
heating by hot water generally practised. I have therefore not
shewn in the Drawings annexed any pipes for that purpose; as the
precise mode of heating is unimportant provided the temperature
be kept sufficiently low to prevent any injurious action upon the
saccharine solution; or instead of using the jacket, the heated air
may be made to come in contact with the under side of the pan,
either before or after it is brought in contact with the saccharine
solution on the screw or discs; the pan a, is then to be filled up to
the height shewn at a Figure 3, with the fluid to be concentrated;
a current of warm dry air is then to be forced up through the
passage B, in the direction shewn by arrows, and passing round the
interior of the curved plate e, it will enter the pan throughout its

page_text: pan
entire length, and thence circulate around the large central drum 1,
as shewn by arrows, and thus it will be brought in contact with
both sides of the discs for a much greater length of time than it
would have done had it been allowed to escape from perforations in
the drum 7, in a radical direction. At the opposite side of the
from that at which the air enters there is provided an outlet con-
structed in the same manner as the inlet whereby the air finds its
passage through the opening C, in the foundation, and thence by an
underground tunnel into the open air. When it is desired to ascer-
tain in what state the syrup is in, the handle, g, is pulled down,
when the plate e, will assume the position shewn in Figure 5; the
lower edge of the curved plate coming in contact with the stop y,
will prevent the hot air from escaping and being troublesome to
the workman, while the position of the upper edge of the plate will
be such as to afford access to the pan from end to end, either for
purposes of examination or for cleansing the pan or discs with a
scraper; the same contrivance is provided on each side of the appa-
ratus. The stop y, is a piece of wood held in its place by screws, and
so shaped as to form a shield to the flanges of the pan, and offer a
smooth passage for the air to sweep over the curved lip of the pan;
it is also provided with a padding of leather for the purpose of
forming a good joint with the lower part of the curved plate e. By
reference to figure 3, it will be observed that the drum r, is im-
mersed a little way into the fluid, which effectually prevents the air
from passing directly across the pan from the inlet to the outlet, as
it would do if the drum was not large enough to dip into the fluid
and thus form a water joint and cause the air to take the more
circuitous passage over the upper part of it; this slight immersion
in the fluid also serves another most important purpose, for it en-
tirely prevents that accumulation of concrete sugar, that never fails
more or less to accumulate near the axis in every case where the
axis is above and not in contact with the fluid. The pan is to be
supplied from time to time with fresh portions of syrup to keep up
the level nearly the same throughout the process; and when it is
found that the syrup is sufficiently concentrated, it is to be drawn

page_text: off by a large sluice of any convenient form attached to the opening
z, at the lower end of the inclined gutter a².
When it is desired to concentrate cane juice or other weak sac-
charine solutions and bring them from eight to ten degrees Beaumé
to twenty eight or thirty degrees, it is unnecessary to place the
discs so far apart as they are required to be in pans which are used
to granulate more dense syrups, and consequently a much greater
amount of evaporative surface may be obtained in an apparatus in
which the discs or screw thread are thus placed nearer together; but
the weight of the apparatus is thus greatly increased, as well as the
cost, while a slight warping of the plates which takes place is apt
to bring them in contact at some places and prevent the free cir-
culation of the fluid. To avoid this extra weight and cost, and
insure the truc parallelism of the plates, I make eight or other
suitable number of holes in each plate, each hole being equidistant
from the other, and all of them equidistant from the centre, -as
shewn at G, Figures 6, and 7, which represents a disc or annular
plate with eight holes drilled through it; eight slender iron rods,
tapped with a screw and nut at each end, are inserted in these
holes, as shewn in Figure 7, which represents part of a drum and
discs with stays passing through them. A piece of tubing which
loosely fits the iron rods is cut into lengths equal to the space
intended to be preserved between the plates; these pieces form a
sort of washer, or collar, and by inserting them between every plate
and passing the rods through them and through the discs, whereby
the whole will be held rigidly and firmly together, admitting the
use of sheet metal of less than half the thickness that would be re-
quired if the plates were not held together by stays in the manner
described. It will be observed that plates so stayed are not equally
applicable for the concentration of very dense syrups, as there is no
means of scraping their surfaces as they revolve, owing to the rods
which pass through them.
In all cases where currents of heated air are brought in contact
with saccharine fluids for the purpose of carrying off the aqueous
portions of such fluids, a large quantity of the heat that has been

page_text: given to the air passes off and is lost. To prevent this waste of
heat, I conduct the escaping air from the evaporating apparatus
through a chamber in which a great number of small thin metal
pipes are placed, and through which pipes the fan or other air-
forcing apparatus takes in its supply, so that the moist hot air
escaping from the apparatus may impart its heat through the pipes
to the fresh supply of dry air which is passing through them in the
opposite direction, whereby the heat which is afterwards to be
applied to the fresh portions of air will be much less than if cold
air was supplied to the heating apparatus, and hence a considerable
economy of fuel will result. As the mode of carrying into effect this
portion of my Invention will be readily understood by engineers,
and as the same may be carried out by a variety of forms of appa-
ratus, I have not considered it necessary to give any Drawing
thereof.
.
When cane juice is to be evaporated in pans containing a screw
or series of discs, it will be found that, unless the defication has been
very perfect, a scum will arise, which should be removed from the
syrup if possible as soon as it is thrown up. I therefore construct
pans for this purpose in such a way that the circular blades form a
screw, as specified in my former patent, which screw causes the
juice to be carried to one end of the pan where an outlet or open
gutter is provided, which communicates with the opposite end of
the pan, so that a constant flow of juice is always passing along it
in an opposite direction to that which isimpelled by the screw; in
this gutter a strainer is placed to intercept the scum and allow it
to be removed from time to time. In order that the way in which
this gutter is formed may be fully understood, I have shewn a sec-
tion of a pan and gutter at Figure 8, of the annexed Drawing, and
a plan of the same at Figure 9. K, is the pan; L, the gutter; M, a
short channel at each end by which the gutter and the pan are
united; N, is a wire gauze strainer to intercept the scum; P, is the
screw for moving the syrup along the pan and at the same time
exposing it to the air, the details of which have already been given
in my former Patent.

page_text: Another improvement in the construction of pans used to con-
centrate or granulate saccharine fluids consists in a mode of
rapidly scraping the surfaces of the discs or annular plates. For this
purpose an iron bar is made with a number of projecting teeth or
scrapers somewhat resembling a comb; the width of these teeth are
such as to occupy about half the space between each disc or ring;
this scraping bar or comb is made to slide endwise, so that the teeth
of it can be made to bear against one side of all the discs at one
time, by which means they will all become scraped by revolving in
contact with it; the scraper may then be forced in opposite direc-
tion so as to cause the teeth of it to bear against the other side of
all the discs, which will thus in turn become cleansed by revolving
in contact with it; so that whatever number of discs may be used,
a few revolutions in contact with the scraper will be sufficient to
remove any accumulation of crystals that may have formed therein;
when this instrument is not required to act as a scraper, it should
be placed with its teeth midway between the discs, in which position
it will not prevent their surfaces from becoming properly coated
with syrup, but will nevertheless prevent any clogging up of the
space between the discs, as no accumulation can take place on their
surfaces of a greater thickness than is equal to the clear space
between the discs and the teeth of the scraper. At Figure 10, of the
annexed Drawings I have shewn an elevation of a scraper con-
structed in the manner described. Figure 11, is a cross section
thereof; R, is the scraper; and S, S, are the discs, which are drawn
to a larger scale than the rest of the figures.
Lastly, my improvements consists in a mode of applying gaseous
matters alone or mixed with atmospheric air, and bringing the same
in contact with, the wet surface of the screw or discs in the evapo
rating pan, for the purpose of chemically acting on the saccharine
solutions under operation. For the purpose of decoloring or
bleaching, and for preventing fermentation, of the saccharine
fluid, I use the vapours arising from the combustion of sulphur,
which vapour I force between the discs or threads of the screw, in
combination with the air from the blowing fan the process of con-

page_text: centration. The action of these vapours on the saccharine solution
will discharge the vegetable coloring matter of cane juice or of
syrups formed of dissolved sugar; it will also be found that the
tendency which such fluids have of undergoing fermentation will
be greatly reduced.
For the purpose of facilitating the separation of lime from sac-
charine solutions, carbonic acid gas may in like manner be forced
in with the air, and thus brought in contact with the great extent
of wet surface presented by the revolving discs; and also the sepa-
ration of subacitate or other solutions of lead may be effected by
forcing in with the air sulphurous acid gas; and so likewise the
treatment of saccharine fluids with other gaseous matters may
be effected with great facility, in consequence of the large extent of
surface of fluid presented to their action, while no extra apparatus
or separate process is rendered necessary.
Having thus described my said Invention and the manner in
which the same is to be performed, I desire it to be understood
that I do not confine myself to the precise details herein specified
so long as the peculiar character of any part of my Invention is
retained; but what I do clain is,.
Firstly, The formation of a gutter or channel at the bottom of
the pan when working with discs or screws as herein explained, for
the purpose of facilitating the outflow of the concentrated syrups.
Secondly, I claim the arrangement or combination of apparatus
for, and the mode of, applying currents of air partly round the
hollow axis carrying discs or screws, and the bringing the axis of
the discs or screw in contact with the fluid, for the purpose of pre-
venting a direct communication between the inlet and outlet air
passages.
Thirdly, I claim preventing the formation of dry concrete sugar
on or near the axis of the screw or discs, by causing the axis to be
partly immersed in the fluid.
Fourthly, I claim heating the bottom of the pan with the same
air which is used to evaporate the syrups carried up by the discs
or screw, whether such air be applied to the bottom of the pan

page_text: before or after its use in the pan; and also the mode herein de-
scribed of conveying the air to and from the pan by means of
channels below the pan, as herein described.
Fifthly, I claim the mode of preventing the bending or warping
of discs or screw blades by staying or connecting them together.
Sixthly, I claim in reference to pans in which saccharine fluids
are evaporated by contact with currents of air, and also the mode
herein described of obtaining access to a covered pan having
therein revolving discs or screws, by the use of moveable curved
plates covering an opening made on one side of the pan a few
inches above the level of the fluid, and also the absorption of a
portion of the heat from the air which escapes from the pan and
has acted on the fluid raised by the discs or screw by other portions
of air which are afterwards to be used therein to promote evapo-
ration.
Seventhly, I claim the use of a circulating channel and strainers
on the side of the pan, as herein described.
Eighthly, I claim the use of a toothed scraper or comb in eva-
porating pans, as described.
Ninthly, I claim the bleaching or decoloring of saccharine
solutions by bringing them in contact with the vapours arising from
the combustion of sulphur.
Tenthly, I claim the use of revolving discs or surfaces for the
purpose of exposing saccharine solutions to the action of any gases
or vapours (other than atmospheric air), for the purpose of effect-
ing chemical changes in such solutions.
In witness whereof, I, the said Henry Bessemer, have hereunto
set my hand and seal, this Nineteenth day of May, in the
vear of our Lord One thousand eight hundred and fifty three.
Witness,
FRANCIS HARRIS.
HENRY BESSEMER. (L.S.)