Year: 1887

page_text: Date of Application, 14th May, 1887
Complete Left, 8th Feb., 1888
Complete Accepted, 9th Mar., 1888
Used in Connection therewith.
I, WILLIAM RENNY WATSON of the firm of Mirrlees, Watson and Company of
Scotland Street Iron Works, Glasgow, in the Counties of Lanark and Renfrew,
North Britain, Engineer do hereby declare the nature of this invention to be as
follows:-
This Invention relates to certain improvements in the manufacture of sugar and in
the apparatus used in connection therewith.
The object of the Invention is to prevent or as much as possible diminish the
deterioration of sugar cane juice, syrup, and other saccharine liquids by inversion
which takes place during the cleaning of saccharine liquids by or during boiling.
The object of this Invention is attained by boiling saccharine liquids in vacuo
and through the application of varying degrees of heat in different parts of a vacuum
pan or equivalent vessel used for boiling the liquids in. This is effected by causing
the ebullition of the saccharine liquid to take place in a part of the vessel which is
depressed below the other parts thereof, such depression being either at the centre or
at the side or one end of the vacuum pan according to the shape and arrangement of
such vacuum pan.
Wherever such depression of the vacuum pan may be situated the
arrangement is such that the ebullition takes place in such depressed part only so
that the impurities are caused by the ebullition to be thrown up to the surface of the
liquid mass, whence they flow off or are removed to cooler parts of the vacuum pan
from which they are swept to other parts wherein they are collected by mechanically
actuated skimmers or sweepers; such parts to which these impurities are swept or
skimmed are so arranged that any portion of the saccharine liquid which may be
removed from the impurities may drain off or separate therefrom, and such saccharine

page_text: liquid is drawn off separate from the impurities and may be returned to that part of
the vessel wherein the ebullition takes place. Provision is made for drawing off the
separated impurities by a pump or otherwise.
The ebullition is effected by means of a coil of pipe or other heating surface placed
in the depressed or sunk part of the vacuum pan into which steam of the necessary
temperature is introduced.
The skimmers or sweepers are provided with reverse cones or equivalently suitable
driving gear regulating the rate of motion thereof.
Lastly, it is to be understood that the treatment or process herein before described
may be practised either as a continuous or a discontinuous process.
. H. JOHNSON, DAY & JOHNSON,
115, St. Vincent Street, Glasgow,
Petitioner's Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Sugar and in the Apparatus
Used in Connection therewith.
I, WILLIAM RENNY WATSON of the firm of Mirrlees Watson & Company of
Scotland Street Iron Works, Glasgow, in the Counties of Lanark and Renfrew, North
Britain, Engineer 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 :-
This Invention relates to certain improvements in the manufacture of sugar, and in
the apparatus used in connection therewith.
The object of the invention is to prevent or as much as possible diminish the
deterioration of sugar cane juice, syrup, and other saccharine liquids by "inversion"
which takes place during the cleaning of saccharine liquids by or during boiling.
The object of this Invention is attained by boiling saccharine liquids in vacuo and
through the application of varying degrees of heat in different parts of a vacuum pan
or equivalent vessel used for boiling the liquids in. This is effected by causing the
ebullition of the saccharine liquid to take place in a part of the vessel which is
depressed below the other parts thereof, such depression being either at the centre or
at the side or one end of the vacuum pan according to the shape and arrangement of
such vacuum pan.
Wherever such depression of the vacuum pan may be situated the
arrangement is such that the ebullition takes place in such depressed part only so
that the impurities are caused by the ebullition to be thrown up to the surface of the
liquid mass, whence they flow off or are removed to cooler parts of the vacuum pan
from which they are swept to other parts wherein they are collected by mechanically
actuated skimmers or sweepers; such parts to which these impurities are swept or
skimmed are so arranged that any portion of the saccharine liquid which may be
removed from the impurities may drain off or separate therefrom, and such saccharine
liquid is drawn off separate from the impurities and may be returned to that part of
the vessel wherein the ebullition takes place. Provision is made for drawing off the
soparated impurities by a pump or otherwise.
The ebullition is effected by means of a coil of pipe or other heating surface placed
in the depressed or sunk part of the vacuum pan into which steam of the necessary
temperature is introduced.
The skimmers or sweepers are provided with reverse cones or equivalently suitable
driving gear regulating the rate of motion thereof.
Lastly, it is to be understood that the treatment or process hereinbefore described
may be practised either as a continuous or a discontinuous process.
In order that my Invention may be properly understood and readily carried into
effect, I will now proceed to describe the drawings hereunto annexed.
Figure 1, is an elevation partly in vertical section, of a vacuum pan constructed
according to my Invention.
Figure 2, is a plan of the same.

page_text: Figure 3, is a horizontal section through the line W, W, Figure 1.
Figure 4, is a fragmentary side elevation and part section looking in the direction
of the arrow y, Figure 3.
Figure 5, is a longitudinal section on the line Z, Z, of an alternative method of
constructing a vacuum pan according to my Invention and Figure 6, is a transverse
section of the same on the line x, x, Figure 5.
The vacuum pan marked A, is constructed of three parts, namely the dome or upper
section marked D, an upright cylinder or middle section marked E, and the pan-
bottom or lower section marked F. The three portions marked D, E, F, are bolted
together in an air-tight manner and are sufficiently strong to withstand the pressure
of the external atmosphere.
The lower section marked F, is formed with a deeply depressed central portion or
boiling vessel G, with a conical raised rim H, and with a flat annular flange or
bottom I. The latter is bolted to the middle section E. The conical rim marked H,
forms an upward and outward continuation of the central vessel marked G, and
projects up within the cylindrical section E, extending outward of the cylindrical
section E, and near to the sides of the dome A, but leaving an annular interstice a,
between the two.
An annular gutter or channel J, is formed by means of the flat flange I, the conical
rim H, and the exterior cylindrical wall.
The depressed boiling vessel G, is provided with a coil of steam pipes L, L, and
with a central steam cone M. Steam is admitted to these by a pipe N, which extends
under and enters the bottom of the pan. If live steam is used to heat the coil, it is
admitted by the valve P. A drain-pipe marked Q, is provided by which the water of
condensation may be drawn off.
During the operation, the saccharine juice is boiled in the vessel G, by the heat
from the coil, and the scum arising from it flows outward on to the surface of the
inclined rim H, where there is less heat. From this rim it is swept or forced over
the upper edge of the rim, and into the annular channel J. This is accomplished by
means of a skimmer or sweeper K, which is mounted to move or slide over the
smooth upper surface of the rim E. This skimmer is mounted on or formed with a
radial arın k, which is fixed on a vertical shaft or spindle b, extending through the
centre of the vacuum pan A. The upper end of this shaft passes out through a
stuffing-box c, on the elbow of the vapor-pipe, and has fixed to it a bevil-gear d,
engaging with a pinion e, on a shaft f, which is rotated by a rope or belt passing over
a pulley g. This rope or belt is driven from another pulley (not shewn on the
accompanying drawings) through the medium of a pair of reversed coned pulleys or
drums and a belt, by which means the shaft b, may be driven with any desired
velocity or other convenient means may be employed.
The skimmer k, is driven in the direction indicated by the arrow y', Figure 3, so
that it sweeps around, over the coned flange or rim H. It is made of a finely
perforated plate or blade composed of brass or any other suitable material, so that as
it advances and pushes the scum before it, the juice will flow through the perforations
and run back down the rim H, while the scum, which is less fluid will be forced up
the inclined rim and will fall over through the interstice a, into the skimmings
channel or gutter J. The skimmer blade K, is made with a backward curve, so that
as it advances it is presented obliquely to the scum, which aids in thrusting the scum
outward.
The channel J, has its bottom slightly inclined, as shewn in Figure 4, and at the
lowest point an outlet pipe R, is connected, through which the skimmings are pumped
out. This pipe projects up above the bottom I, as shewn q, in Figure 4, so that in
case any juice settles under the skimmings, it need not be drawn off therewith. An
outlet-cock r, Figures 1 and 3, is provided to draw off the juice from the lowest
part of the channel J, and return it to the vessel G. The pipe R, is controlled by
cocks m, m.
The juice to be cleaned is drawn into the vacuum pan through a pipe S, controlled
by a valve T, which is within easy reach of the operator. The purified juice is drawn

page_text: out through a cock U, when the apparatus is oporated intermittently. If it is to be
operated continuously, an outlet pipe should be placed at the side of the pan, some
distance from the bottom.
Observation windows V are provided through which to see the skimmings or juice
in the channel J. The windows marked W, W, in the dome marked D, are provided
to light the interior of the fan and through which to see the process of cleaning.
A test cup is used for drawing off samples of the liquid for examination, so that
the attendant may properly regulate the inflow and drawing off of the juice.
The mode of operating this improved apparatus for the manufacture of sugar is as
follows:-
The apparatus having been placed in communication with an air pump or other
exhauster and the pressure within it reduced, the juice inlet T, is opened and a
quantity of the liquid to be cleaned is drawn into the pan.
Steam (exhaust steam is preferred) is turned on to the central cone M, and coil L,
which soon causes the liquid to boil rapidly at a very low temperature in the middle
of the depressed central vessel G. The violent ebullition causes the impurities to
float on the surface of the liquid and flow rapidly towards the circumference where
there is less heat and no ebullition and to form on the undisturbed surface a scum or
froth. The revolving skimmer K, is set in motion and this scum as fast as produced
is swept up the inclined rim, H, and falls over into the annular chamber J.
The speed of the revolving skimmers is regulated by the attendant according to
requirements as the cleaning progresses.
The skimmings are pumped off continuously and without being allowed time to
deteriorate are forced by the same pump through the mud presses without any
exposure to the atmosphere.
Any juice which may be swept over with the skimmings will settle to the bottom
of the channel J, under the thick skimmings and may be allowed to gravitate back
to the inner pan through the cock r. Through the side windows V, may be seen how
much scum and how much juice under the scum there is at any time.
By this Invention, the process of cleaning saccharine juices or liquids in vacuo
may be carried on either continuously, that is by constantly drawing and pumping
out the liquid, or the liquid may be treated in successive quantities or charges, and in
the manufacture of sugar the cleaning may be effected previous to concentration-
during concentration in vacuo, or after concentration and previous to treatment in
the strike pan.
When the cleaning is effected during centration the invention may
be applied to any one or all of the pans of single or multiple effect apparatus in
which the juices or liquids are concentrated in vacuo and in such an application the
process would be carried on under the reduction of pressure existing in the respective
pan or pans to which the Invention was applied.
In the alternative arrangement as represented by Figures 5 and 6, sheet 3. The
pan is shewn elongated resembling a steam boiler. The juice enters at the pipe S,
and after being cleaned is drawn off by the pipe U. It is boiled by the steam coil L,
which is arranged at one end of the vacuum pan. In the boiling, the impurities rise
to the surface and the froth or scum flows toward the opposite end of the pan, where
there is no ebullition. The skimming is performed by an endless apron K¹, of
perforated metal or other material, which is carried over revolving drums X, X. A
revolving brush Y, throws the scum from the apron over into the deep receptacle J,
from which it is pumped out through a pipe R. The heavy settlings collect in the
pocket Z, whence they are pumped out through a pipe t. This process is essentially
the same as that first hereinbefore described.
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
1. The improvement in purifying saccharine liquids consisting in boiling them in
vacuo and simultaneously separating the resulting froth or scum by skimming it from
the surface of the liquid substantially as hereinbefore described.

page_text: 2. The improvement in purifying saccharine liquids consisting in purifying the
same by separating the scum or froth resulting from boiling during the concentration
in vacuo substantially as herein before described.
3. The improved apparatus for purifying saccharine liquids consisting of a closed
pan or vessel within which a partial vacuum is maintained provided with a skimming
instrument for removing the froth or scum from the surface of the liquid under
treatment and a heating contrivance for boiling the liquid together with a receptacle
for the liquid to be treated and another receptacle for the skimmings remote from the
said heating contrivance the whole being combined and operating substantially as
hereinbefore described and shewn upon the annexed sheets of drawings.
4. In the apparatus for purifying saccharine liquids in vacuo the inclined surface
extending from the boiling receptacle towards and over the skimming receptacle and
over or around which a rotary skiminer moves or operates substantially as hereinbefore
described.
5. The apparatus for purifying saccharine liquids in vacuo with provision. for
removal of the scum by mechanical means as shewn at Figures 5 and 6 of the
annexed drawings and operating substantially as hereinbefore described.
Dated this 7th day of February 1888.
ST. JOHN V. DAY,
115, St. Vincent Street, Glasgow,
Applicant's Agent.
ST. JOHN V. DAY,
115, St. Vincent Street, Glasgow,
Applicant's Agent.