Improvements in Evaporators or Apparatus for the Treatment of Cane Juice.
Year: 1889

page_text: Date of Application, 10th July, 1889
Complete Specification Left, 10th Apr., 1890-Accepted, 5th July, 1890
PROVISIONAL SPECIFICATION.
Improvements in Evaporators or Apparatus for the Treatment of
Cane Juice.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, do hereby declare
the nature of this invention (which has been communicated to me from abroad by
Lewis W. Tracy of New York City, New York, United States of America,
Mechanical Engineer) to be as follows:-
This invention relates to that class of apparatus in which cane juice or other liquor
to be treated is successively passed through a series of evaporators and in transit is
evaporated under a vacuum to the desired density. The first evaporator may be heated
by exhaust steam from the mill engine and each succeeding evaporator is heated by
the vapor of evaporation developed in the preceding evaporator, the vacuum in each
succeeding evaporator being greater than that in the preceding one: and the juice
may if desired be turned back to the evaporator from which it has been drawn to be
again treated therein and further condensed.
In general construction the apparatus comprises an evaporating pan or chamber
within the main chamber of which a bank or series of evaporating tubes preferably
arranged horizontally is contained, a supply main for the heating agent with connecting
conduits leading to the interiors of the evaporating tube, feed devices for distributing
liquid in a spray, rain, film-like, or divided condition over the evaporating tubes, a
second evaporator or pan of like construction, a vapor conduit and connections leading
from the tubes containing chamber of the first pan to the evaporating tubes of the
second pan, and a liquid conducting pipe leading from the bottom of the tube con-
taining chamber of one pan to the liquid feed devices of the other pan. There may be
two, three or more such pans according to the density to which the liquid is to be
evaporated.
Pumps may be connected with each evaporator and suitable valve and pipe-connec-
tions may be provided so that the liquor may be turned back through the same
evaporator if desired.
The invention may be carried out by constructing each evaporator substantially as
follows:-
Two end chambers are provided and they are connected by the bank of heating
tubes enclosed by the main casing or shell of the evaporator. The heating agent is
admitted to one of these chambers passes through the heating tubes to the other chamber
from whence it may be drawn, in the second and succeeding evaporators, by a vacuum
pump or pumps. In the case of the first evaporator the exit chamber may open into
the atmosphere or into a trap for returning the condensed steam to the boiler.
The evaporating or tube containing chamber of each evaporator is connected with
the inlet chamber leading to the heating tubes of the next evaporator. And the
tube containing chamber of the last evaporator is connected with the vacuum
pump. Liquor is led into the tube containing or vacuum chamber of the first
effect through feed devices which finely divide it and let it fall or descend upon
the heating tubes. The vapors of evaporation being carried to the heating tubes
of the next evaporator while the liquor at the bottom is carried to the feed devices
of the next evaporator. The vacuum in each evaporator is less than that in the
succeeding evaporator and the differences in vacuum may be sufficient to carry
the liquor from one evaporator to the other, or the pumps may be used for this
purpose, or the evaporators may be placed on different levels to assist the travel
of the liquor.
It is preferred to make the evaporators oblong in horizontal section and to connect
both ends of the juice evaporating chamber of one evaporator with both heating

page_text: chambers of the next evaporator, a suitable partition being placed in one of the heating
chambers to ensure the circulation of the vapor through the pipes connected
therewith.
The feed devices are preferably horizontal troughs or pipes slit along their upper
surfaces, the liquor overflowing and falling upon the heating tubes below.
The casing of each evaporator is preferably made in sections as follows: The top
and bottom are each composed of two sections, the sides of four sections each and the
ends of one section each. The sections are all flanged and bolted together. The tube
sheets at each end of the evaporator in which the heating tubes are mounted may be
clamped between the end sections and the top, bottom and side sections so as to leave
the inlet and outlet chambers for the heating agent.
Dated this 10th day of July 1889
COMPLETE SPECIFICATION.
Improvements in Evaporators or Apparatus for the Treatment of
Cane Juice.
I, SYDNEY PITT, of Sutton, in the County of Surrey, Gentleman, (a communication
to me from abroad by Lewis W. Tracy, of New York City, New York, United States
of America, Mechanical 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 that class of apparatus in which the cane juice is successively
passed through a series of evaporators and in transit is evaporated under a vacuum to
the desired density. The first evaporator may be heated by exhaust steam from the
mill engine and each succeeding one by the vapour of evaporation developed in the
preceding evaporator the vacuum in each succeeding evaporator being greater than
that in the preceding one; and the juice may if desired be turned back to the
evaporator from which it has been drawn to be again treated therein and further
condensed.
This general operation is well known and several forms of apparatus have been devised
for practising it.
The purpose of this invention is to provide an improved apparatus; to render it
lighter and consequently cheaper to manufacture, handle and erect than that hereto-
fore used; and to economically improve the results obtained.
The features of the invention will be understood from the accompanying drawings
in which they have been embodied in one practical and efficient form, and in
which-
Figure 1 shows in plan three of the improved evaporators connected for
operation ;
Figure 2 is an end view of the same;
Figure 3 a transverse section of an evaporator (A) on the line 3, 3 of Figure 4;
Figure 4 is a view of the same partly in elevation and partly in section on the
line 4, 4 of Figure 2, and-
Figure 5 is a vertical longitudinal section of the last evaporator (C) on the
line 5, 5 of Figure 2.
In the apparatus the heating medium, either exhaust steam from the engine in
the first evaporator or the vapours of evaporation in the succeeding ones, circulated
through pipes or passages over the outside of which the cane juice is caused to fall
or drip in thin films or spray. This is believed to be new in apparatus of this class
and is deemed a desirable and important feature.
Three evaporators A B C are shown. They are sufficient to illustrate the inven-
tion and are all that are required for use in most cases. They are preferably
relatively narrow, long and high, as illustrated, and are in general construction alike:
that is, the sides are each formed of four rectangular sections D of wrought or cast

page_text: metal, flanged at all four edges, and their contiguous vertical and horizontal edges
are bolted together. Correspondingly flanged cap and bottom sections EF and
end sections & are bolted to the sides, as appears plainly in the drawings. The top
and bottom sections may be formed, as illustrated, of two parts flanged and
bolted together. Between the end sections and the sides, cap, and bottom, and
held by the same bolts, are perforated plates H preferably of wrought iron;
and a like transverse plate H which may be of cast brass is similarly bolted between
the vertical edges of the sections of the sides. Open ended tubes of copper or
other suitable material are mounted in the perforated plates and expanded in the end
plates to form close joints. This construction provides end chambers I I¹ connected
by the tubes for the circulation of the heating steam or vapours as presently
described. In each evaporator the cane juice to be treated is introduced through the
cap to the chamber El and distributed over the bank of heated pipes in the following
manner: A nozzle K delivers the juice to a tank K¹, supported in the chamber E
by lugs or cleats on the side sections D, and the tank has a transverse well K² in
the bottom from each side of which a series-preferably four or more-of channel
pipes k, slit or open along their tops (Figure 3) extend, being supported in perforated
plates k, also carried by lugs on the side sections D. I also form in the bottom of
the well K², a line of apertures k², Figures 3 and 5, through which the juice also is
delivered. These apertures are made larger at the bottom than at the top to render
them less liable to become choked by deposits from the juice. The juice after
passing over the heated pipes falls into a chamber F1 formed by the bottom section
of the evaporator and having two outlets, one F2 through which the juice passes
out, and another F³ which serves as a tap or blow off to be used in cleansing the
apparatus.
The first evaporator A, shown in detail in Figure 4 has near the bottom of one
end section an inlet A' through which the exhaust steam passes to the chambers I I¹³¸
and tubes h, and at the bottom of the opposite end section an outlet A2 for the escape
of the steam and water of condensation to any suitable trap if desired.
The cane juice which has been introduced as described through a pipe K³ from
any suitable source descends over and through the bank of heated pipes h, and is
thereby evaporated or increased in density. From the chamber F the juice may
pass by pipe f, threeway cock f¹, pipe f², threeway cock f³, and pipe f* into the top
of the next evaporator B, through which it pursues a similar course. The heated
vapours driven off from the juice in evaporator A rise to the chamber E¹, and pass
out at each end through openings a and large pipes a¹ to the ends of the next
evaporator B which are each formed with taps or openings with which the pipes a¹
connect. These vapours circulate in the chambers I' and pipes of evaporator B
and pass out by a pipe B' to the condenser C d. The effect of this is to maintain a
vacuum say of 3 or 4 inches-in the chamber E¹, of the first evaporator A. The
vacuum is small because the juice contains an excess of water and the amount of
steam or vapour liberated is large. The juice from the chamber E¹ of evaporator B
may pass to evaporator C by pipe f, three-way cock f³, pipe, three-way cock f³ and
pipe ; and the vapours in chamber E¹ of B pass by outlets b, and pipes to the
chambers I and pipes of evaporator C, from which they are drawn through
pipe C to the condenser Cd. The juice in B, being however denser than that in A
less vapour will be liberated, and consequently a higher vacuum is maintained-say
from 15 to 18 inches-in the chamber E¹ of evaporator B. From the last
evaporator (the juice passes by pipe f to a pump, from whence it may be
delivered as desired. The vapours developed in C are drawn from the chamber E¹
through pipes C2, C3, to the condenser, and the juice having been further increased
in density gives off less vapour and consequently a greater vacuum-say of 26 or
27 inches is maintained in the chamber E¹ of C.
When working with sufficient difference in vacuum in the several evaporators the
juice will pass automatically in the manner described from one to another. But
otherwise the lower three-way cocks f¹ are turned so as to pass juice from the
chamber F¹ of A and B to pumps through pipes p, and from the opposite sides of

page_text: the pumps the juice is delivered through pipes p', to pipes f and to next evaporator
through the upper three-way cock f³. If upon testing, as presently described the
juice entering the last evaporator is found not to be of proper density either upper
three-way cock f³ may be turned so that the juice from the pump will be returned
through pipe and nozzle f' to the evaporator from which it has just been
taken.
On the last pipe 2 leading to the evaporator C a test cup L is placed. It may be
connected with the pipe at two points through valves i and has a removable or hinged
cap. Juice may thus be drawn from the pipe and tested as usual.
The cap or top section of each evaporator is provided with hand holes m two.
being shown on each side; and also with glass covered peep holes n arranged
opposite each other two on each side, through which the condition of the apparatus
and juice may be examined. Similar pairs of peep holes may be placed in the
bottom section F or in the side sections, as shown at n' near the lower edges of the
side sections.
The heating vapours in the second and third evaporators being introduced at both
ends, to ensure their proper circulation I form a transverse bridge or flange x on the
inner faces of the end pieces of B and C in which the outlets B₁ C¹ are formed
preferably about one third the way from the top. This compels the vapours introduced
at that end of the evaporator to pass through the tubes and prevents their being
drawn directly down through the end chamber.
Each vapor pipe a', b', is provided with an adjustable valve a², 62, by which A, or
A and B may be disconnected from C in the event of its being desired to use only
B and C or C alone. Inlets in B and C corresponding with the steam inlet A¹ of A
are therefore provided, but are closed as shown when the three evaporators are being
operated as described.
As is usual in apparatus of this class the temperature is reduced as the vacuum is
increased, the vapor from A which heats B being of a lower temperature than the
steam in A, and the vapor from B which heats C being of still lower temperature.
In the improved apparatus the arrangement of channel pipes for discharging the
juice in spray or finely divided condition upon the heated pipes or passages is
important not only because of the manner in which the juice is delivered upon the
pipes but because any lime or other foreign matter likely to deposit will settle in the
bottoms of the channel pipes and not in any way interfere with the free, even and
continuous discharge of the juice. The juice falling upon the bank of pipes h, flows
over and around them, is thoroughly broken up, and is during its passage to the
bottom fully exposed in the most advantageous manner to the heat and has the
greatest amount of moisture driven off for a given amount of heat. Further since
the juice in being evaporated can pass in any direction along, between and around
the pipes, its free passage cannot be choked or interfered with in any manner, as
is frequently the case where the juice is conveyed through pipes and the heat applied
outside.
Heretofore apparatus of this kind has been heavy, bulky, difficult to handle, and
expensive. The evaporators are constructed of detachable sections or parts each
relatively light and easily handled. They may therefore be easily shipped to the
point of use and there readily assembled for operation without the use of special
skilled labor. The space occupied is relatively small since the apparatus is compactly
built and is of such design as to occupy a minimum of space for the results
accomplished.
Having now particularly described and ascertained the nature of the said Inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
:-
1. The combination with the heating pipes or surfaces of a horizontal channel or
juice discharging pipe slit or open along its upper face, and arranged above the
heating surfaces and disconnected from them, substantially as set forth.
2. The combination with a bank of heating pipes of a series of horizontal channel

page_text: or juice discharging pipes arranged above the heating surfaces and disconnected from
them and slit or opeu along their upper faces and connecting with a common tank or
distributing vessel, substantially as set forth.
3. The combination of the bank of heating pipes, the juice tank arranged above
them, the tank having in its bottom a narrow transverse well or depression and the
open top channel pipes for discharging the juice in a divided or spray-like condition
upon the heating pipes, substantially as set forth.
4. In an apparatus for evaporating cane juice, an evaporator, having vertical end
chambers I, and horizontal tubes or passages for the circulation of the heating
steam or vapor from one end chamber to the other, an upper chamber from which
the juice is delivered in a spray-like or divided condition upon said horizontal tubes
or passages, and a lower chamber having a closed bottom for the collection of the
juice as it falls from the tubes substantially as set forth.
5. An evaporator of a width relatively narrow compared to its length and height,
and having heating tubes or passages occupying the main part of the interior of the
evaporator and communicating with chambers I, I, at each end thereof through
which chambers and tubes or passages the heating steam or vapors circulates, an
upper chamber E' into which the juice to be treated is delivered and discharged upon
the heating tubes and in which the vapors developed from said juice rise to be
conveyed to the next evaporator, and a lower chamber F1 in which the juice is
collected to be conveyed to the next evaporator, substantially as and for the purpose
set forth.
6. In an evaporator the combination of the flanged sections forming the sides,
the flanged cap E and flanged bottom F, the flanged end sections, the perforated tube-
plates bolted, between the end sections and the sides, top and bottom sections, the
bank of heating-tubes h mounted in said plates, juice delivery devices for discharging
the juice upon the top of the bank of tubes, an outlet for the withdrawal of the
juice after its descent over and around the tubes, and steam or vapor inlet and outlet
openings in the end sections.
7. In an evaporator the combination of the flanged rectangular sections forming
the sides, flanged top and bottom sections, flanged end sections, a perforated tube
supporting plate bolted between the contiguous vertical edges of the sections
forming the sides, similar tube-plates bolted between the end sections and the sides
and top and bottom sections, and heating tubes mounted in said tube plates and
communicating with steam or vapor chambers I, II, at the ends of the evaporator,
substantially as set forth.
8. The combination of two or more evaporators of oblong horizontal section
arranged side by side and having both ends of the juice evaporating chamber of one
evaporator connected with corresponding ends of the heating chamber of the next
evaporator, substantially as and for the purpose set forth.
9. The combination of two or more evaporators, each having end chambers I, I'
connected by heating tubes h, and having inlet and outlet openings for the entrance
and exit of the heating steam or vapor, and a central juice evaporating chamber
occupied by said heating tubes and having a juice inlet at the top and outlet at the
bottom, the juice outlet of the first evaporator communicating with the juice inlet
of the second evaporator, and the upper part of the evaporating chamber of the
first evaporator communicating with the heating chamber (I, I', h) of the second.
10. The evaporator having end chambers I, I', and connecting heating tubes, a
steam or vapor inlet for each chamber I, I, an outlet for one of them and a
bridge (x) across the latter chamber between the inlet and outlet, substantially as
set forth.
11. The combination of two or more evaporators having opposite sides of the
juice evaporating chamber of one evaporator directly connected with opposite
sides of the heating chamber of the next evaporator, substantially as set forth.
12. The combination of the bank of heating pipes, the tank having a transverse
well in its bottom, apertures 2 in the bottom of said tank and the open-top channel

page_text: pipes connected with the sides of the well, substantially as and for the purpose
set forth.
13. In a multiple effect evaporating apparatus, the combination with an evaporating
pan having a main chamber and evaporating tubes contained therein, a supply main
for the heating agent with connecting conduits leading to the interiors of the
evaporating tubes, feed devices for distributing liquid over the evaporating tubes, a
second pan of like construction, a vapor conduit and connections leading from the
tube containing chamber of the first pan to the evaporating tubes of the second pan
and liquid conducting pipe leading from the bottom of the tube containing chamber
of one pan to the liquid feed devices of the other.
Dated this 10th dow of Anril 1890
CARPMAEL & Co.,
Agents for the Applicant.