IMPROVE- MENTS IN EVAPORATING AND BOILING APPARATUS EMPLOYED IN THE MANUFACTURE OF SUGAR, AND IN THE APPLICATION OF MEGASSE AS FUEL, PART OF WHICH APPARATUS IS ALSO APPLICABLE FOR EVAPORATING AND BOILING OTHER SUBSTANCES
Year: 1880

page_text: LETTERS PATENT to Charles Denton Abel, of No. 28, Southampton Buildings,
Chancery Lane, in the County of Middlesex, for an Invention of "IMPROVE-
MENTS IN EVAPORATING AND BOILING APPARATUS EMPLOYED IN THE
MANUFACTURE OF SUGAR, AND IN THE APPLICATION OF MEGASSE AS FUEL,
PART OF WHICH APPARATUS IS ALSO APPLICABLE FOR EVAPORATING AND
BOILING OTHER SUBSTANCES." A communication from abroad by Norbert
Rillieux, of Paris, France.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 17th December 1880.
"
CHARLES DENTON ABEL, of No. 28, Southampton Buildings, Chancery Lane,
in the County of Middlesex. IMPROVEMENTS IN EVAPORATING AND BOILING
APPARATUS EMPLOYED IN THE MANUFACTURE OF SUGAR, AND IN THE APPLICATION
OF MEGASSE AS FUEL, PART OF WHICH APPARATUS IS ALSO APPLICABLE FOR
EVAPORATING AND BOILING OTHER SUBSTANCES." [A communication from abroad
by Norbert Rillieux, of Paris, France.]
i
This Invention has reference to improvements in apparatus for evaporating in
vacuo in boiling pans and in triple action apparatus, such as are used more
particularly in the manufacture of sugar and other evaporating processes, the main
object being to obtain a maximum useful effect from the said apparatus..
In the evaporating apparatus with multiple action direct steam is necessary. This
is led into a recipient from which the first evaporating pan is fed through a valve.
If too much steam is introduced the action of the apparatus is retarded or stopped.
In order to avoid this I provide either the steam supply pipe leading to the
recipient, or that leading from the recipient to the boiling pan, with an equilibrium
valve, whose stem is loaded by a weighted lever, the play of which is limited by a
screw stop, so that by adjusting the stop the lift of the valve, and consequently
the passage of steam through it, may be regulated to the exact extent required.
The weight on the lever is such that the valve can only be lifted when the pressure

page_text: in the steam generator exceeds the limit adopted for insuring the effective action
of the machines.
The first evaporating pan being the steam generator of the entire apparatus, and
being beated by the discharge steam from the said apparatus, I also connect it
with the discharge of liquid from the steam coils of the boiling pan as follows:-
The said coils being provided with check valves are connected to one end of a
common collecting pipe, the other end of which is connected to the tubular part of
the first pan. By this means the small quantity of steam that passes away with
the liquid from the worms assists in heating the first pan, while the combined
waters of condensation from the coils and from the first pan flow off by a pipe
provided with a check valve into the supply reservoir of the feed pump to the
steam generators. When the boiling pan is used without triple action the passage
of the said steam and water of condensation is cut off from the first pan by means
of a three-way cock on the said conducting pipe, so arranged as either to connect
the steam coils directly with the said feed pump reservoir or to establish the
communication with the first pan. The waters of condensation from the first pan,
as also from the first above mentioned steam recipient, may also be conducted
directly into the said reservoir by separate pipes provided with check valves. All
the above named check valves are provided with regulating screws in order to
regulate the escape of steam and water to the exact degree required for the proper
action of the apparatus. The boiling pan is also heated by the steam from the
before mentioned steam recipient, conveyed thereto by a pipe leading to a
distributing passage, the admission being regulated by a valve. From the distri-
buting passage it passes into one or other of the several steam coils of the boiling
pan. The steam from the first evaporating pan may however also be used for this
purpose, the distributing passage being for this purpose provided with a branch
having a cock, and communicating with the pipe connecting the first evaporating
pan with its condensing column.
The boiling pans with steam coils have only a small heating surface, and contain
a large quantity of saccharine charge. In order to effect the boiling with double
action with these boiling pans a considerable pressure is required in the first pan,
namely, from to atmosphere, and even more, according to the size of the
coils. Under these conditions the vacuum is very small or even nothing in the
the second pan. Experiment has shewn that no deterioration of the sugar takes
place at this temperature. The pressure is regulated by introducing into the feed
vessel for the triple action a sufficient quantity of direct steam, such that it does not
interfere with the action of the apparatus. The pressure in this vessel may be one
atmosphere or more. Up to the present time the operations have never been
conducted under these conditions; the use of direct steam therefore has in this
case quite a different object from that which ordinarily regulates its employment.
In order to maintain in the first pan the normal pressure it is necessary in
large machines to regulate the pressure by means of a special apparatus. For this
purpose there is provided in the steam exhaust pipe of the first evaporating pan a
throttle valve, which is automatically regulated so as to intercept the passage of
the steam to the second pan as long as the pressure is not equal to that which it
is desired to maintain. For this purpose the axis of the throttle valve is provided
with an external lever connected to a piston in a small cylinder, on one side of
which the steam pressure in the first evaporating pan acts, while the other side is
open to the atmosphere. The piston is loaded so that it only rises when the
pressure in the first pan is equal to that desired to be maintained; thus when the
pressure is low the piston closes the throttle valve, while when the pressure rises
so as to be equal to that desired to be maintained the throttle valve is full open,
and at any intermediate pressure the valve is held in a corresponding intermediate
position. The regulating apparatus may either be a cylinder and piston, or
plunger, or a flexible diaphragm. For loading the piston lead discs may be used,
which may be added or removed as may be required; or a lever with adjustable
weight may be employed.

page_text: If the boiling pan is heated by direct steam at high pressure, the discharge
(condensed water and steam) is conveyed to the first evaporating pan. If steam
from the expansion chamber be used, or the escape steam from the machines, the
discharge from the boiling pan will be conveyed to the second evaporating pan.
If steain from the first evaporating pan be used for boiling, the discharge passes
from the third evaporating pan to the condenser. A pipe passes for this purpose
along the evaporating apparatus, and a branch provided with a valve or cock
extends from this pipe to the tubular part of each pan.
In triple action apparatus the first evaporating pan is according to the present
Invention provided with two small auxiliary pans, one serving to evaporate the
syrups that have been subjected to the osmose action, and the other for evaporating
the saline liquors.
For drawing off the water of condensation from the second and third evaporating
pans, a double acting pump is generally employed, each suction valve of which is
in communication with only one of the pans. In order to enable these pumps,
which are generally too small for the work, to be employed with more effect, the
following arrangement is, according to the present Invention, employed :-The
waters of condensation from the second and third pans pass into a small receptacle
having two compartments; one of these, which receives the water from the second
pan, has a float actuating a throttle valve, which opens or closes a communication
between the first and second compartment, of which the latter receives the water
from the third pap, while at bottom it is connected to the suction of the exhaust
pump. The first compartment also communicates by a pipe with the safety valve
of the second pan, and the second compartment communicates with the condenser,
The admission of water
both communications being regulated by check valves.
into the compartments is also regulated by check valves. When the water level in
the first compartment has sunk to a certain depth, the float closes the communi-
cation with the second one, and only opens it again when the water has accumulated
to a certain extent. As the float is so arranged as not to allow the water level to
uncover the communicating opening of the two compartments, no steam can pass
from the one to the other, although a single pump is employed for drawing off the
the water from both compartments. The back of the receptacle is removeable, and
can be made of glass for inspection.
In order to obtain a maximum effect from the apparatus modified as above
described, it is necessary to maintain a considerable vacuum in the last pan. As it
is much more difficult to obtain an effective vacuum by condensation of the steam
by means of a water jet in the above described apparatus, than it is to obtain this
in the condenser of an ordinary steam engine (probably on account of the presence
of a large quantity of air and other uncondensible gases in the steam in the former
case), the condensation is according to the present Invention effected by bringing
the steam in contact with very extended surfaces over which the water flows in
thin films, thus obtaining a very extended contact of the steam with the particles
of water. The steam from the safety chamber is as usual subjected to a water jet.
In order to render the air pumps for the exhaust more effective, the water is
removed from the bottom of the condensers by separate pumps, so that the air
pumps in only pumping air or gases can work much more rapidly than in the
present arrangement, where they have to pump both air and water. The pumps
that draw off the water deliver it to the refrigerating apparatus. In this apparatus
instead of causing the water to trickle over layers of faggots as at present, a series
of vertical canvas screens placed close together are employed, which descend to a
certain distance above the water level in a trough below; these are surrounded by
walls of any suitable material, and a strong current of air is directed by a fan into
the bottom of the enclosure, so as to ascend in the narrow spaces between the
canvas screens, while the water discharged by the before mentioned pump is made
to flow down them from perforated pipes or channels above. The air currents
may be further accelerated by forming a ventilating shaft extending some height
above the screens, so as to produce additional draught. The lower part of the

page_text: apparatus may be enclosed by moveable doors, which would be opened on that side
whence the wind proceeds. The water descending from the refrigerator is collected
in a tank where the excess of air passes off from it, and whence it is then led by a
pipe to the tops of the condensers.
According to another part of the Invention the "megasse" or "sugar cane trash,"
instead of being dried in the open air as heretofore, is delivered by travelling
buckets in a moist state into a hopper leading at bottom into a chamber com-
municating with the furnace of the steam boiler employed for the before described
evaporating and boiling pans. In the hopper is a hinged horizontal flap, on to
which the megasse falls, and which is kept in the horizontal position by a balance
weight, until the accumulated load upon it overbalances the weight, whereupon the
megasse is discharged down into the chamber, and passes thence to the furnace to
be burnt as fuel. While the megasse is retained in the hopper and descends in the
chamber, it is subjected to currents of hot gases from the furnace, so as to becomė
dry before passing into the fire. The hot currents may be accelerated by connecting
the hopper by a pipe with the chimney of the boiler, the draught being regulated
by a throttle valve, and if required a blowing fan may also be provided in such
pipe for accelerating the draught.
Although I have described the above improved apparatus as applied to the
manufacture of sugar, yet it will be evident that it is also applicable to other
manufactures, where substances undergo the same evaporating and boiling
processes to which sugar is subjected, such as saline solutions.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Denton Abel in the Great Seal Patent Office on the
15th June 1881.
CHARLES DENTON ABEL, of No. 28, Southampton Buildings, Chancery Lane,
in the County of Middlesex. "IMPROVEMENTS IN EVAPORATING AND BOILING
APPARATUS EMPLOYED IN THE MANUFACTURE OF SUGAR, AND IN THE APPLICATION
OF MEGASSE AS FUEL, PART OF WHICH APPARATUS IS ALSO APPLICABLE FOR
EVAPORATING AND BOILING OTHER SUBSTANCES." A communication from abroad
by Norbert Rillieux, of Paris, France.
This Invention has reference to improvements in apparatus for evaporating in
vacuo in boiling pans, and in triple action apparatus, such as are used more
particularly in the manufacture of sugar and other evaporating processes, the main
object being to obtain a maximum useful effect from the said apparatus, which
maximum has not been attained heretofore on account of the defective methods of
arranging and constructing the various apparatus.
The various improvements whereby these defects have been overcome, and which
by their combined operation tend to produce the maximum useful effect of the
apparatus, will be readily understood on reference to the accompanying Drawing,
in which Fig. 1 shews a general elevation of the combined apparatus, while Figs.
2 to 8 shew, separate details thereof.
In multiple action apparatus direct steam is required which is introduced into
the recipient K for discharge steam, Fig. 1, from which the first evaporating pan
is fed through the valve I'. If too much steam is introduced the action of the
apparatus is retarded or stopped. In order to prevent this the recipient K is
provided with an equilibrium valve A. (shewn in enlarged detail at Fig. 2) which
regulates the maximum quantity of steam that can be used. It prevents the
difference between the pressure upon the one face of the piston of the engines and
the counterpressure on the other side from sinking below a certain point. For this
purpose the valve is arranged as follows:-The valve a has a stem b passing
through a stuffing box, and connected to a loaded lever c; this lever cannot be
raised until the pressure in the generators exceeds the limit adopted for the proper
working of the apparatus. It works inside a loop d, in the top of which is a
screw which is screwed down to such an extent as to allow of only a small
amount of motion to the lever and its valve, so that by means of this screw the
supply of steam is regulated. Instead of arranging. this valve A to the left of the
recipient K, as shewn at Fig. 1, it may be placed at I' on the pipe leading to
the first evaporating pan. The first recipient being the steam generator of the
entire apparatus, and being heated by the discharge steam of all the engines, I
also connect therewith the discharge water from the coils of the boiling pan as
follows: The steam coils being provided at their extremities with check valves B,
are connected to a common collecting pipe C, of which the other end D is connected
to a branch pipe at bottom of the tubular part of the first evaporating pan. By
this means the small excess of steam that escapes with the water from the coils is
made to assist in heating the first pan, while the combined water of condensation
from the coils and from the said pan pass off through another pipe E, E¹, provided
with a check valve F into the recipient H or reservoir for the feed pump to the
generators. When the boiling pan is employed without using the triple action, the
passage of the condensing water and steam from the worms to the first pan is
prevented by turning a three-way cock G into such a position that the steam
worms of the boiling pan communicate directly with the reservoir H of the feed.
pump. This cock is arranged in the length of the collecting pipe C, D, and allows

page_text: •
this to communicate either with the bottom of the first pan, or with the reservoir H.
The water of condensation from the first pan, as also the water contained in the
vessel K, also flow directly into the reservoir of the feed pump through pipes in
which are the check valves F already mentioned, and the valve I on the pipe leading
from the vessel K to the reservoir H. The several check valves B to the worms of
the boiling pan, as also those F and I of the first pan and recipient, have the extent
of their opening regulated by a screw passing through the top of the valve chamber,
so that they shall only allow the exact quantity of steam and water to pass that is
necessary for the proper action of the apparatus. The boiling pan X, Fig. 1, is also
heated by the steam from the discharge steam recipient K, which is conducted into
it through the pipe L and distributing pipe P, the admission being regulated by a
valve O. From the distributor P it is led into the one or the other of the three or
four coils of the pan. Steam could however also be taken from the first evaporating
pan. For this purpose the distributor P has a branch provided with a valve at Q
connected to a pipe R leading to the branch connecting the first evaporating pan
with its condensing column. The boiling pans with steam coils have only a
small amount of heating surface in proportion to the saccharine charge contained
therein.
In order to effect the boiling with double action with these boiling pans, a con-
siderable pressure is required in the first pan, namely, from 1/2 to 3/4 atmosphere,
and even more according to the size of the coils. Under these conditions the
vacuum is very small, or even nothing in the second pan. Experiment has shewn
that no deterioration of the sugar takes place at this temperature. The pressure is
regulated by introducing into the feed vessel for the triple action a sufficient
quantity of direct steam such that it does not interfere with the action of the
apparatus. The pressure in this vessel may be one atmosphere or more. Up to the
present time the operations have never been conducted under these conditions;
the use of direct steam therefore has in this case quite a different object from that
which ordinarily regulates its employment.
In order to maintain in the first pan the normal pressure, it is necessary in large
machines to regulate the pressure by means of a special apparatus. For this purpose
there is provided in the steam exhaust pipe of the first evaporating pan a throttle
or other valve v, which is automatically regulated so as to intercept the passage of
the steam to the second pan as long as the pressure is not equal to that which it is
desired to maintain. For this purpose the axis of the throttle valve v is provided
with an external lever connected to a piston in a small cylinder t, on one side of
which the steam pressure in the first evaporating pan acts, while the other side is
open to the atmosphere. The piston is loaded so that it only rises when the
pressure in the first pan is equal to that desired to be maintained. Thus, when
the pressure is low the piston closes the throttle valve, while when the pressure
rises so as to be equal to that desired to be maintained, the throttle valve is full
open, and at any intermediate pressure the valve is held in a corresponding inter-
mediate position, thus maintaining the pressure approximately constant. The
regulating apparatus may either be a cylinder and piston or plunger, or a flexible
diaphragm, provided it be sensitive. For loading the piston lead discs may be used,
which may be added or removed as may be required, or a lever with adjustable
weight or other equivalent means may be employed.
If the boiling pan is heated by direct steam at high pressure the discharge
(condensed water and steam) is conveyed to the first evaporating pan. If steam
from the expansion chamber be used, or the escape steam from the engines, the
discharge from the boiling pan will be conveyed to the second evaporating pan; if
steam from the first evaporating pan be used for boiling the discharge passes to
the third evaporating pan, and thence to the condenser. A pipe passes for this
purpose along the evaporating apparatus, and a branch provided with a valve or
cock extends from this pipe to the tubular part of each pan.
In triple-action apparatus the first evaporating pan is according to the present.
Invention provided with two small auxiliary pans, shewn at Z¹ in the diagram-

page_text: matic plan at Fig. 8, one serving to evaporate the syrups that have been
subjected to the osmose action, and the other for evaporating the saline liquors,
both being connected to the same condensing column.
For drawing off the water of condensation from the second and third evaporating
pans a double acting pump is generally employed, each suction valve of which is in
communication with only one of the pans. In order to enable these pumps, which
are generally too small for the work, to be employed with more effect the following
arrangement is according to the present arrangement employed. The waters of
condensation from the second and third pans pass into a small receptacle J, Fig. 3,
having two compartments; one of these a¹ which receives the water from the
second pan has a float b¹ actuating a throttle valve c' which opens or closes a
communication between the first and the second compartment d², of which the
latter receives the water from the third pan, while at bottom it is connected to
the suction e¹ of the exhaust pump. The first compartment a also communicates
by a pipe a with the safety valve of the second pan, and the second compartment ď¹
communicates with the condenser by the pipe B, both communications being
regulated by check valves f, g. The admission of water into the two compartments
is also regulated by check valves h, i. When the water level in the first
compartment a¹ has sunk to a certain depth the float closes the communication
with the second one, and only opens it again when the water has accumulated to a
certain extent. As the float is so arranged as not to allow the water level to
uncover the communicating opening of the two compartments no steam can pass
from the one to the other, although a single pump is employed for drawing off the
water from both pans. The back of the receptacle is removeable and can be made
of glass for inspection.
In order to obtain a maximum effect from the apparatus modified as above
described it is necessary to maintain a considerable vacuum in the last pan. As
it is much more difficult to obtain an effective vacuum by condensation of the steam
by means of a water jet in the above described apparatus than it is to obtain this
in the condenser of an ordinary steam engine (probably on account of the presence
of a large quantity of air and other uncondensible gases in the steam in the former
case), the condensation is, according to the present Invention, effected by bringing
the steam in contact with very extended surfaces, over which the water flows in
thin films, thus obtaining a very extended contact of the steam with the particles
of water. The steam from the safety chamber is, as usual, subjected to a water
jet. In order to render the air pumps for the exhaust more effective, the water is
removed from the bottom of the condensers M, N, by separate pumps L, Fig. 1, so
that the air pumps in only pumping air or gases can work much more rapidly
than in the present arrangement where they have to pump both air and water.
The pumps are however kept moistened to prevent heating. The pumps that
draw off the water from the condensers deliver it to the refrigerating apparatus.
In this apparatus instead of causing the water to trickle over layers of faggots P,
Fig. 1, as at present, a series of vertical canvas screens R placed close together are
employed which descend to a certain distance above the water level in a trough Q
below; these are surrounded by walls of any suitable material, such as tarpauling,
wood, bricks, &c., and a strong current of air is directed by a fan, as shewn at
Figs. 6 and 7, into the bottom of the enclosure so as to ascend in the narrow spaces
between the canvas screens, while the water discharged by the before mentioned
pump L is made to flow down them in a very divided state from perforated pipes
or channels O above in the reverse direction to the air currents, whereby the water
will be cooled several degrees below the atmosphere. The air currents may also be
produced by forming a ventilating shaft S₁ extending some height above the
screens, as indicated at Fig. 7. The lower part of the apparatus would in that case
be enclosed by moveable doors or panels which would be opened on that side
whence the wind proceeds. The water descending from the refrigerator is collected
in a tank T where the excess of air passes off from it, and whence it is then led by
a pipe to the tops of the condensers. The canvas screens may conveniently be

page_text: made out of old filter press cloths, sacks, &c., sewn together. The apparatus would
not require to have the large dimensions of the fagot apparatus, and this may
therefore readily be converted into the former.
According to another part of the Invention the "megasse" or
" sugar cane
trash" instead of being dried in the open air as heretofore is delivered by travelling
buckets A, Figs. 4 and 5, in a moist state into a hopper T leading at bottom into
a chamber communicating with the furnace F of the steam boiler employed for the
before described evaporating and boiling pans. In the hopper is a hinged horizontal
flap P, on to which the megasse falls, and which is kept in the horizontal position
by a balance weight until the accumulated load upon it overbalances the weight,
whereupon the megasse is discharged down into the chamber and passes thence to
the furnace to be burnt as fuel, the flap being closed by its weight again, or any
suitable arrangement of mechanism might be employed for periodically opening
and closing the flap for the above purpose. While the megasse is retained in the
hopper and descends in the chamber it is subjected to currents of hot gases from
the furnace so as to become dry before passing into the fire. The hot currents
may be accelerated by connecting the hopper by a pipe C with the chimney of
the boiler, the draught being regulated by a throttle valve, and if required a
blowing fan V may also be provided in such pipe for accelerating or regulating the
draught, in which case the throttle valve can be dispensed with, the speed of the
fan being regulated to the exact degree to produce the required degree of dessication
of the megasse.
Although I have described the above improved apparatus as applied to the
manufacture of sugar, yet it will be evident that it is also applicable to other
manufactures where substances undergo the same evaporating and boiling processes
to which sugar is subjected, such as saline solutions.
Having thus described the nature of this Invention, and in what manner the
same is to be performed, as communicated to me by my foreign correspondent, I
claim in respect of the above described improved means for obtaining a more
perfect and economical utilisation of the steam, the vacuum and the waters of
condensation in the evaporating pans of sugar mills and analogous works,-
First. The use of an equilibrium valve, such as herein described with reference
to Figs. 1 and 2 of the Drawings, either upon the supply pipe of the recipient for
discharge or exhaust steam for regulating the supply of steam thereto, or upon the
pipe leading from the said recipient to the first evaporating pan, substantially as
herein described.
Second. The herein described arrangements whereby the boiling process with
double action may be effected in pans with steam coils by means of the steam
pressure of one half or three quarters of an atmosphere, or even greater, obtained
in the first evaporating pan.
Third. The beating of the boiling pan by means of the steam from the recipients
of discharge or exhaust steam, or from the first evaporating pan, the steam pipes
from both the said vessels being connected to the distributing pipe of the steam
coils of the boiling pan.
Fourth. The method of maintaining the pressure in the first evaporating pan
either automatically by means of a valve actuated by a pressure regulator, or by
means of a valve worked by hand, substantially as herein described.
Fifth. The combined arrangement herein described for regulating the supply of
discharge steam from the boiling pan, either to the first pan of the triple action
apparatus when direct steam is used in the boiling pan, or to the second pan when
discharge steam is used for heating, or to the third pan or to the condenser when.
the steam from the first evaporating pan is used for heating.
Sixth. The use, in combination with the first evaporating pan, of two smaller
pans, of which the discharge steam passes to one and the same column, and which
serve respectively to evaporate the syrups from the osmose action and the saline
solutions, substantially as herein described.
Seventh. The use of the float discharge vessel herein described with reference to

page_text: Fig. 3 of the Drawings for withdrawing the water of condensation from two
vacuum chambers with different degrees of vacuum, and in particular from two
consecutive evaporating pans.
Eighth. The combined arrangement of pipes and apparatus herein described for
obtaining a more perfect action of the triple action process, and a more perfect
utilisation of the steam in the factories.
Ninth. The arrangement herein described with reference to Figs. 4 and 5 of the
Drawings, whereby the drying of the megasse is effected by the furnace heat of the
steam boilers in which it is to serve as fuel.
In witness whereof, I, the said Charles Denton Abel, have hereunto set my
hand and seal, this Fifteenth day of June, in the year of our Lord One
thousand eight hundred and eighty one.
CHAP. D. ABEL. (L.S.)