Improvements in Evaporating Apparatus.
Year: 1890

page_text: Date of Application (in United Kingdom), 25th July, 1890
Complete Specification Left, 25:h July, 1890-Accepted, 27th Sept., 1890
COMPLETE SPECIFICATION.
Improvements in Evaporating Apparatus.
I, SAMUEL MORRIS LILLIE, of Fourth and Chestnut Streets, in the City of
Philadelphia, Pennsylvania, United States of America, Chemist, 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 "Instransit Evaporating Apparatus." namely, apparatus in
which the evaporation is effected from a liquid while flowing in comparatively thin
films or sheets over the heated evaporating surfaces. It consists, as regards a single
pan, or
"effect," of a battery of horizontal evaporating tubes contained in an
evaporating chamber, which tubes are closed at their ends fronting one end of the
chainber, and at their other extremities connect with steam supply conduits from which
their interiors are supplied with steam. Above the evaporating tubes in the chamber
is arranged a spraying or distributing device, or devices, fed by suitable conduit, with
the liquid to be evaporated, and by which the liquid is distributed over the surfaces of
the evaporating tubes and then flows downwards over the same to the floor of the
evaporating chamber. The tubes are provided with means for the escape of air or
incondensible gases that may collect in them and tend to exclude the steam and so
lessen the efficiency of the apparatus, and the evaporating chamber is provided with
proper escapes for the vapours resulting from the evaporation and for the concentrated
liquid.
In the drawings is shown, in double effects, apparatus illustrative of my
invention.
Figure 1 being an end elevation of a double effect with the front end of the
evaporating chamber of one of the effects removed so as to expose the closed ends of
the evaporating tubes to view ;
Figure 2 is a side view of the double effect one of the pans shown in vertical
longitudinal section, i.e. parallel to the axis of the evaporating tubes ;
Figure 3, a plan of the double effect, and
Figure 4a view of a modified construction of portions of the apparatus.
Referring to the figures, ss are a battery of horizontal tubes contained in a
chamber E having arranged towards one end R of the chamber, tightly closed save for a
small perforation c, in each looking towards the end R of the chamber. The other ends of
the tubes open through the opposite end plate G, in which they are tightly expanded and
by which they are supported-into a steam fed chamber S, closed by a door D, and
having a steam or vapour supplying main B, and valve pipe h, which leads through
suitable connections to the vacuum pump used in connection with the apparatus. The
evaporating tubes are arranged in horizontal rows which break spaces with each other
vertically, and the two side walls have horizontal ribs e, e, &c., which break spaces between
the two side rows of the tubes and the said side walls. The liquid distributing device
above the tubes consists, in the construction shown, of a horizontal plate 6 located
immediately above the tube and pierced by lines of perforations, one directly over the
axis of each tube of the uppermost row. Above this plate 6, are one or more perforated
distributing plates a, above and upon the uppermost one of which the return feed

page_text: pipe A, delivers through the walls of the case. One of the side walls of the evaporating
chamber E, is formed with a passage in it, which communicates below through a
horizontal narrow opening y, with the interior of the chamber E, beneath the tubes,
and above through the nozzle J, to a catch all C, from which the vapour escape main H,
leads to a suitable condensing apparatus.
Below the lower row of evaporating tubes the chamber E contains a corrugated
false bottom n, which touches the hollow side wall above the narrow horizontal
opening g, and extends, slightly inclined downwards, to within a fow inches of the
opposite wall, the corrugations extending in the same direction. From below the false
bottom n, and from the side of the chamber E, opposite the vapour outlet, g, a dis-
charge conduit o, leads through suitable connections to a circulating pump P, whose
discharge pipo A, which I will term "the return pipe" delivers back into the space F,
above the upper perforated plate a. In the double effect shown in the drawings, and
hereinafter described, these connections of the discharge pipe, o, of the first pan, to
the circulating pump Paro through the second effect and its connections; and those
of the discharge opening o¹, of the second effect, are through the float chamber T
and the connecting pipe l. A conducting pipe N for the liquid to be evaporated
delivers into the return pipe A at a point, i, and a pipe L, for the thickened liquid
leaves the return pipe at a point between where the feed pipo Njoins the return
pipe A and the circulating pump-and leads to the tail pump I, which is provided for
drawing away the concentrated material. In the drawings two pans, constructed and
above described, are placed one above the other and connected so as to form a double
effect, the upper pan being the first effect and the lower pan the second effect. The
various parts hereinbefore referred to are indicated in the first effect by the letters
stated, and in the second effect by the same letters primed. The steam case S, of the
first effect is supplied with steam from an extraneous source by the main B, the vapour
main H, of the first effect lends into the steam chamber S' of the second effect and
the vapour main H' of the second effect leads to a condenser and vacuum pump by
which a proper vacuum is maintained in the evaporating chamber E¹ of the second
effect. The liquid discharge pipe o, of the first effect delivers through a steam trap
(that shown in the drawings consisting of a U tube with a valve u, in it) and upon the
distributing plates of the secon'! effect. The discharge for liquid from the evaporating
chamber of the second effect is by the opening o' through the floor of the latter into
the float box T from which a connection 1, leads to the suction port of the circulating
pump P. The float box T contains a float having a stem the end of which is koyed
on the arbor of a butterfly valve v located in the thin liquor supply pipe N which
stem extends through the side of the box into the interior of the same. The rising
and falling of the float respectively closes and opens the butterfly valve. The return
pipe A, in tho pump delivers into the feeding space, F, of the upper effect, and also
has a valved branch connection A¹ to the feed space of the second effect, permitting
liquor to be returned to both effects simultaneously if desired. The upper effect is
shown provided with a longitudinal opening through one of the side walls into the
feeding space F and closed by a plate by removing which the distributing
plates a, b, may be gotten at, and removed from the case for cleaning
purposes.
The operation of this double effect may be described as follows, it being first
supposed that all air has been exhausted from the apparatus by means of the vacuum
pump and connections, and that steam is being continuously supplied to the steam
chamber S of the first effect, and that the vacuum pump and condenser are at work
maintaining the proper vacuum in the case E of the last effect. The double effect
contains during normal working about, say, fifty gallons of liquid, which is con-
tinuously circulated through the two effects by the circulating pump P at a rate
sufficient to keep the surfaces of the tubes thoroughly covered with films of liquid.
The liquid passes through the circulating pump by the return pipe A up into the
feeding space F, of the first offect, falls through the perforated plates evenly distributed
upon the plate b, below, through whose longitudinal lines of perforations it flows upon
the upper surface of each surface of each of the tubes or the uppermost row, and

page_text: thence flows down over the battery of tubes, from tube to tube to the floor of the
evaporating chamber, whence, it passes through the pipe o, and trap upon the dis-
tributing feed plates of the second effect, au thence upon and down over the exterior
surfaces of the tuhes of the second effect on to the floor of the evaporating chamber
of the same, and thence through the float chamber T, to the circulating pump again.
The tubes in each vertical row serve as deflecting surfaces for the liquid which falls
from the adjacent vertical rows, throwing the liquid which does not adhere to and wet
themselves back into the tubes of the adjacent rows, and the ribs e, on the side walls
of the evaporating cases, serve to throw back upon the tubes the liquid which would
otherwise leave them and run down the surfaces of the walls. The thin liquid which
is to be thickened is continuously fed by the feed pipe N, into the return pipe A, and
mixed with and thins the ascending liquid which in flowing down over the evaporating
tubes in the two effects is thickened again. The concentrated circulating liquid is
constantly being drawn from through the discharge pipe L, at a rate regulated by the
valve p, in the said pipe. The stean affording original heat is fed to the steam
chamber S, of the first effect, and thence flows into the tubes of the samo. Tho
vapours resulting from evaporating in the first effect escape from its evaporating
chamber into the vapour passage, at one side, and thence through a catch all 0,
and pass from the latter by the vapour pipe H, into the steam chamber S¹ of the
second effect and thence into the tubes of the latter. During its passage through
the catch all, all particles of entrained liquid are separated from the vapour, and
remain in the catch all from which it flows by a drain pipe j, back into the chamber E.
The vapours resulting from the evaporation in the second effect escape through its
catch all C, and vapour pipe H', to the condenser and vacuum pumps, not shown in
the drawings. The regulation of the density of the concentrated material that is,
the flow of liquid through the double effect, is effected entirely by means of the
valve p in the discharge pipe L, the in-flow of thin liquid by the feed pipe N,
being maintained proportional to the out-flow through the discharge pipe L, by the
automatic action of the level of the liquid in the float chamber, and the float and the
butterfly valve in the feed pipe N. operated by the same. Opening the valve in the
discharge pipe L, permits the more rapid flow of the liquid through the apparatus,
and consequently diminished the density of the finished product, closing the valve,
lessens the flow of liquid through the double effect and increases the density of the
finished product. The rate of evaporation in the double effect is varied by increasing
or diminishing the pressure of steam in the chamber S of the first effect, supposing
the vacuum to remain constant. While in operation steam or vapour is constantly
flowing into and being condensed on the interior surfaces of the tubes, while evaporation
from the liquid takes place from the exteriors of the tubes. Any air which may leak
into the effects, which must be expected to occur to a greater or less extent in all
vacuum evaporating apparatus, will collect in the tubes at their closed ends, and if not
allowed to escape, or if not occasionally exhausted, would, in time, materially diminish
the efficiency of the apparatus. To permit this escape of air the closed end of each
tube has a perforation c, through it by which the air which reaches the ends of the
tubes continuously passes into the surrounding evaporating chamber, and thence
through the intermediate connections, to the vacuum pump. In the case of the tubes
of the first effect of a multiple effect evaporating apparatus, the tubes and evaporating
chambers of the pans between it and the vacuum pump, respectively form parts of the
said intermediate connections. In this manner, stagnant air and incondensable gases,
which are net and have to be overcome in every form of multiple effect apparatus are
easily and entirely avoided, and the entire surface of each evaporating tube made
efficient. The corrugated false bottom n in each effect, assists in separating the
thickened liquid and the vapours resulting from evaporation, first by delivering the
liquid as far as possible away from the vapour outlets g, and second, by collecting
the liquid into the depressions of the corrugations, from which it flows in solid streams
upon the floor of the chamber E, leaving free and intermediate spaces through which
the vapours may flow back under the plate towards the vapour outlet y. I omitted to

page_text: state in the preceding that the water of condensation, resulting during the working
of the apparatus, flows from the evaporating tubes s, back into the chamber S and
thence away by the drain pipe m.
There are many modifications which may be made in the construction of this apparatus
without departing from the essence of my invention. For example, I do not limit
myself to any particular means for drawing off the air and non-condensable gaseous
products of evaporation from the sealed evaporating tubes s. One way is by means
of the simple perforations c, shown in Figures 1 and 2; another way is illustrated in
Figure 4 which shows the sealed ends of the vertical rows of tubes each communicating
by a small pipe connection 1, with a vertical manifold pipe 2, which communicates
through pipe 3, and its connections with exhausting apparatus not shown. Again,
the tubes may be entirely closed at their ends, i.e. without openings there of any kind,
the accumulated air be exhausted from the tubes, and the chamber S, through the
exhaust pipes h, as often as may be found desirable, the evaporation being stopped
each time to allow of its being done. In supplying the steam to the tubes's a
different construction may also be used, for example the steam chamber S, common
to the tubes of an effect, may be replaced by a system of steam supply manifolds
having connecting branches to the interiors of the several tubes. Multiple effects
having a greater number of effects than two, may be formed by increasing the number
of effects in the column to three or more and connecting each effect with the next
effect beneath it in the same manner as the first effecs in the drawings is connected
with the second effect. In forming multiple effects. again, the several pans may be
placed side by side with a circulating pump for each pan, if preferred, as in the case
of the multiple effect shown in U.S. Patent No. 378,843 issued to me February 28th
1888, or, to form a multiple effect which is a multiple of two a number of double effects,
such as shown in the drawings, equal to that multiple, may be placed side by side with a
vapour main H¹ of each double effect (excepting the last whose vapour main H¹ would
lead to the condenser and vacuum pump of the system) with the steam chamber S, of
the next double effect, and its liquid discharge pipe L, with the feed pipe N, of the next,
the feed pipe N of the first pair being the original feed pipe of the series, and
the discharge pipe L of the last pair being the final discharge pipe for tho
thickened material. In constructing individual effects the plate D, forming the
cover of the steam case S, is bung by hinges, for convenience in opening. When
closed this door is caused to make air tight bearings against the flanges of the
steam case by any of the methods usually employed for the purpose in similar con-
structions. When practicablo the chamber E, is cast in one piece, the perforated
plates a, b, being supported in position on ledges formed on the interiors of the
walls of the chamber at the proper places. The plate G, forms at once one end of
the chamber E and also the tube plates and with it the side walls of the steam
chamber S, are formed in one piece all as shown in the drawings. A feature
of this construction is, that the tube sheet and the sealed evaporating tubes form
a distinct and separable element of the construction, and may be removed from
and replaced in position at will after loosening the fastenings which hold it in
place. In larger apparatus the tabe plate, might form but a portion of the end
of the body E of the pan, simply covering and closing an opening in the end wall
through which the battery of tubes supported in the tubo plate project into the
interior.
Having thus 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 :-
First. In an evaporating pan, the combination of a battery of horizontal evaporating
tubes ench closed at one end and contained in a chamber closed practically air
tight and connected at their other ends with a supply conduit or conduits for steam
or other condensable heating agents; means above the tubos for distributing the
liquid to be evaporated in thin films over the exterior surfaces of. the tubes means

page_text: for continuously removing from the said evaporating tubes closed at one end, the
incondensable gases which may flow into the same with the condensable heating
agents; and vapour and liquid escape conduits lending from the chamber containing
the tubes, substantially as specified.
Second. In an evaporating pan, the combination of an evaporating chamber con-
structed practically air tight but with vapour and liquid escape conduits leading
from the same, substantially as described; a steam chamber at one end of the
evaporating chamber; a battery of horizontal evaporating tubes contained for the
evaporating chamber each opening at one end into the steam chamber and having
the other end closed; a conduit for supplying steam or other condensable heating
agents to the steam chamber; means above the tubes for distributing the liquid to
be evaporated over the exterior or surfaces of the same in tbin films; and means for
continuously removing from the said steam chamber, and evaporating tubes, closed
at one end, the incondensable gases which may flow into the same with the condensuble
heating agent, substantially as specified.
Third. In an evaporating pan constructed and operated substantially as described
the evaporating tubes each closed at one end and supplied with steam from the other
end and having perforations through the wall of each at or near the closed end of
the same, the said perforations forming communication between the interiors of the
tubes and the surrounding chamber and permitting the escape of incondensable gases
from the former into the latter, substantially as specified.
Fourth. In a multiple effect evaporating apparatus, the combination of two con-
secutive pans of the same, each comprising an evaporating chamber and a battery of
steam fed evaporating tubes contained therein with means for delivering the liquid
to be evaporated upon the exterior surfaces of the tubes, means whereby the interiors
of the evaporating tules of the first pan are connected with evaporating chamber in
which they are contained, a vapour conduit and connections leading from the said
evaporating chamber of the first pan to the interiors of the evaporating tubes of
the second path, and connections leading from the interiors of the evaporating
tubes of the second pan to suitable exhausting apparatus, the combination affording
means for conducting air and incondensable gases which may collect in the tubes
of the first pan away from the same to the exhaust apparatus, substantially as
specified.
Fifth. In an evaporator operated substantially as described the combination of a
steam-chamber, horizontal evaporating tubes closed at one end and receiving steam from
the steam chamber at the other end, and exhausting apparatus and a valved pipe as h
connection between the steam chamber and exhausting apparatus the air may be
exhausted from the steam chamber, and tubes, substantially as specified.
Sixth. In an evaporator operating substantially as described, the combination of a
battery of horizontal steam fed evaporating tubes, their containing chamber, means
above the battery of tubes for distributing the liquid to be evaporated over their
exterior surfaces, a vapour escape conduit opening from the tube containing chamber
below the battery of tubes, and a liquid escape opening from the chamber near the
bottom of the same, substantially as specified.
72
Seventh. In the tube containing chamber of an evaporator constructed and operated
substantially as described and having a vapour escape conduit leading away near the
bottom thereof the partial false bottom n located below the battery of evaporating tubes,
and extending the length of the same, touching along one of its edges the wall through
which the vapour escape conduit opens along a line above the opening of the latter,
and extending nearly to the opposite wall, substantially as specified.
Eighth. In the tube containing chamber of an evaporator constructed and operated
substantially as described and having a vapour escape conduit leading out near the
bottom thereof, the corrugated partial false bottom n located below the battery of
evaporating tubes in the evaporating chamber and extending the length of the same,
and touching along one of its edges the wall of the evaporating chamber through
which the vapour escape conduit opens at a level above the opening of the latter and

page_text: extending nearly to the opposite wall, the corrugations of the false bottom having
the direction transverse to the length of the tubes, substantially as specifiel.
Ninth. In an evaporator operated substantially as described, the combination of a
horizontal evaporating chamber, containing a battery of horizontal steam fed
evaporating tubes a feed chamber above the evaporated chamber with a conduit for
the liquid to be evaporated opening into it, a horizontal distributing plate forming the
floor of the feed chamber and the roof of the evaporating chamber and extending from
side wall to side wall of the evaporating chamber, and operating to distribute the
liquid to be evaporated over the evaporating tubes, and a vapour escape conduit
through one of its vertical walls below the feed chamber and leading from the
evaporating chamber substantially as specified
Tenth. In an evaporating pan the combination of a horizontal evaporating chamber
containing a battery of horizontal steam fed tubes, a feed chamber above the
evaporating chainber, a horizontal distributing plate, as 6 separating the feed chamber
from the evaporating chamber, distributing plates a, in, the feed chamber above the
distributing plates a, in the feed chamber above the distributing plate b, a conduit
for the liquid to be evaporated opening into the feed chamber above the upper dis-
tributing, plate a, and a vapour escape conduit leading from the evaporating chamber
substantially as specified.
Eleventh. In an evaporating pan, the combination of a chamber containing a battery
of horizontal evaporating tubes, horizontal perforated distributing plates supported
above the tubes on ledges formed on the walls of the chamber, means for delivering
the liquid to be evaporated upon the distributing plates, and a removable plate closing
and opening into the chamber above the tubes through which the distributing plates
may be removed, or inspected, substantially as specified.
Twelfth. In an evaporating pan, the combination with a horizontal evaporating
chamber of a removable tube plate closing one end of the chamber and held in place
by suitable fastenings between it and the walls of the latter, a steam fed chamber
supported upon the outer surfaces of the tube plate independently of the fastenings
between the latter and the walls of the evaporating chamber, and a battery
of horizontal evaporating tubes extending from the steam chamber through (and
firmly supported in) the tube plate into the evaporating chamber and having their
ends in the latter closed, the tube plate steam chamber, and evaporating tubes forming
together an independent construction separable as an entirely from the horizontal
evaporating chamber after loosening the fastenings between the walls of the latter and
the tube plate substantially as specified.
1000
Dated this 25th day of July 1800.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.