Improvements in the Evaporation and Concentration of Sugar Cano Juice and other Liquids and Apparatus therefor.
Year: 1887

page_text: Improvements in the Evaporation and Concentration of Sugar Cano
Juice and other Liquids and Apparatus therefor.
I, GEORGE FLETCHER, of Masson Works, Litchurch, in the County of Derby,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to the evaporation and concentration of sugar cane juice and
other liquids by the aid of steam, air or fire, in either open or closed vessels, under
vacuum or pressure or ordinary atmospheric conditions; it relates however more
particularly to the working of vacuum pans and effets.
The object of the invention is to accelerate the circulation of the liquids treated in
the evaporators or concentrators and thus enable evaporation to take place under the
most favorable conditions. It is well known that the more complete the circulation
of boiling or heated liquids, the more readily does evaporation take place and con-
This is more
sequently the more effective is the working of the pan or vessel.
especially the case with the denser liquids such as cane juice and syrup, the reason
being that a good circulation enables the vapour or steam to separate more readily,
the working being thereby improved and the danger of priming proportionately
lessened.
Up to the present time the circulation of the contents of the vessels or pans has
depended entirely upon the tendency of the heated liquids to rise and the consequent
displacement of the cooler liquid. This is except under very favorable conditions—
necessarily uncertain and unsatisfactory.
By this invention a complete and rapid circulation is ensured, by employing
mechanical means to assist and accelerate the imperfect circulation produced by
reason of the difference in specific gravity of the more heated and the cooler
liquids.
In carrying out my invention I employ an effet vessel having a heating chamber
or drum with a large tube and a number of smaller tubes fixed in the tube plates.
The large tube is the circulation tube and the smaller ones are the heating tubes.
These tubes contain the liquid to be treated, the steam or vapour being on the outer

page_text: surface of the tubes. The bottom cover of the vessel carries a vertical revolving
spindle having a screw propeller fixed thereon, this screw as it revolves forces the
liquid contained in the large tube towards the lower end whence it passes out and
ascends through the heating tubes, the liquid displaced in the large tube being
replaced by liquid in the upper part of the tube. In this way a constant and regular
circulation of the liquor is ensured and an excellent effect obtained from the heating
surface in the vessel.
Bevel wheels can be used to drive the vertical spindle through a horizontal counter-
shaft carried by a bearing bracket. This countershaft may however be dispensed
with and the vertical spindle be driven direct.
In another arrangement the vertical spindle and screw can be driven by a hori-
zontal shaft inside the vessel and above the drum, the horizontal shaft being taken
through a stuffing box outside the vessel.
Or I can employ a horizontal screw placed outside and underneath the vessel, the
contents of the large tube being drawn through a connecting pipe and afterwards
forced through the heating tubes.
I sometimes employ a centrifugal pump the suction branch of which is connected
to the large or central tube, the liquid is drawn out of the said tube and delivered
underneath and forced through the heating tubes, the circulation maintained is con-
sequently regular and constant and may be varied at will by increasing or decreasing
the speed of the pump.
In another arrangement a central circulating tube provided with a screw propeller
is employed for maintaining a constant and effective circulation in a vacuum pan.
The tube is arranged in lengths so that the circulation may be maintained when the
level of the liquid is just above any one or all of the coils. The screw spindle
projects through the headbox of the pan and is made in lengths for convenience
when erecting and repairing the apparatus.
Or the central circulating tube can be so arranged that the height of the tube can
be adjusted to suit the level of the contents of the pan. To effect this the spindle
can be arranged with a sliding bush and a screw threaded hand wheel by means of
which the circulating tube may be raised or lowered as required.
The foregoing are simply examples of the practical application of my invention but
I would have it understood that other suitable types of pumps or propellers may be
used as well as other methods of fixing and driving the same.
Dated the 18th day of October 1887.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London,
Agents for the Applicant.

page_text: Juice, and other Liquids and Apparatus therefor.
I, GEORGE FLETCHER, of Masson Works, Litchurch, in the county of Derby,
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 :-
My invention relates to the evaporation and concentration of sugar cane juice and
other liquids by the aid of steam, air or fire, in either open or closed vessels, under
vacuum or pressure or ordinary atmospheric conditions; it relates however more par-
ticularly to the working of vacuum pans and effets.
The object of my said invention is to accelerate the circulation of the liquids treated
in the evaporators or concentrators, and thus enable evaporation to take place under
the most favorable conditions. It is well known that the more complete the circulation
of boiling or heated liquids, the more readily does evaporation take place and con-
sequently the more effective is the working of the pan or vessel.
This is more
especially the case with the denser liquids, such as cane juice and syrup, the reason
being that a good circulation enables the vapour or steam to separate more readily.
whereby the working is improved and the danger of priming proportionately
lessened.
Up to the present time the circulation of the contents of the vessels or pans has
depended entirely upon the tendency of the heated liquids to rise and the consequent
displacement of the cooler liquid. This is (except under very favorable conditions)
necessarily uncertain and unsatisfactory.
By this invention a complete and rapid circulation is ensured by employing
mechanical means to assist and accelerate the imperfect circulation produced by reason
of the difference in specific gravity of the more heated and the cooler liquids.
To enable my invention to be clearly understood I will describe some practical appli-
cations of the same by reference to the accompanying drawing, in which,
Figure 1 is a sectional elevation of vertical triple effet evaporating apparatus pro-
vided with my improvements; and,
Figure 2 is a plan of the same.
Figures 3 and 4 are views similar to Figures 1 and 2, respectively, illustrating a
modification of my invention.
Figures 5 and 6 are vertical sections illustrating other modifications; and,
Figures 7 and 8 are vertical longitudinal and transverse sections respectively,
illustrating still another modification.
Referring first to Figures 1 and 2, a, a, a are the three vessels, each of which
contains a heating drum b, the heating tubes c fixed in the drums and the circulating
tube d.
e, e are screw blades which are placed in these circulating tubes and f,fare the
spindles carrying the same, the said spindles revolving in bearings 9, 9 fixed in the
bottom covers of the vessels. These bearings are provided with packing glands h, h
and are arranged with troughs i for molasses or other liquids, to prevent leakage. The

page_text: outer ends of the spindles are produced through the bearings and are carried by
brackets j, j. the said spindles having fixed to them spur wheels k, k with diagonal
teeth. These wheels are driven by similar spur wheels fixed on a horizontal shaft
which is carried by swing bearings on the brackets j, j.
The rotation of this horizontal shaft causes the propellers to revolve in such a manner
as to cause the liquors in the circulating tubes d, d, d to descend. In this way a
constant current of the liquors is passing down through the circulating tubes and up
through the heating tubes, whereby a constant and complete circulation of the contents
of the vessels is maintained.
0,
In the modification of my invention shown in Figures 3 and 4 centrifugal pumps m, m
are substituted for the screw blades last described. The suction branches n, n of these
pumps are connected to the circulating tubes d, d, d, and the discharge branches
to the space immediately under the heating tubes. These pumps cause currents of
liquor to pass down the circulating tubes d, d, d and to ascend through the heating
tubes c, c, c.
In figure 5 I show a vacuum pan a provided with a central circulating tube d
formed in several sections and containing a revolving screw e. This central tube is so
arranged that the circulation of the contents of the pan commences directly the bottom
heating coil is covered with the liquor.
In the modification of my invention shown in Figure 6 a screw e arranged on a
horizontal axis is located in the bottom cover of the heating drum. This screw draws
the liquor down through the circulating tube d and impels the same up through the
heating tubes c.
In figures 7 and 81 illustrate the manner in which the invention may be used in
connection with a horizontal triple effet vessel.-a is the vessel in which are placed the
heating tubes c. The steam or vapour enters through the branch c¹ into the heating
tubes which are surrounded by the liquor under treatment. The heating tubes are so
arranged that they do not extend the extreme length of the vessel, the space thus left
at the back end of the tubes allowing the cooler liquids to gravitate to the bottom of
the vessel. To this part of the vessel is connected a passage p which leads to one end
of a tube 9. In this tube a screw e revolves and by so doing draws the liquor from
the space at the back end of the tubes and discharges it among the tubes at the front
end of the vessel. In this way a continuous current of liquor is maintained in the
tube 9, thus causing a complete circulation of the contents of the vessel. The screw e
is fixed upon a shaft f which passes through the front and back end covers of the cir-
culating tube, these covers being fitted with packing glands to maintain the vacuum
in the vessel. The covers for the heating tubes may be so arranged that the vapour
in the tubes must pass two or more times the full length of the tubes.
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. In apparatus for the evaporation or concentration of sugar-cane juice and other
liquids, the employment of mechanical means such as hereinbefore described for main-
taining the circulation of the liquid, substantially in the manner set forth.
2. The manufacture and use of the improved apparatus for evaporating or concen-
trating sugar-cane juice and other liquids hereinbefore described and illustrated in the
accompanying drawings.