Improvements in Apparatus for Evaporating Liquids.
Year: 1888

page_text: Improvements in Apparatus for Evaporating Liquids.
We, THOMAS GAUNT, residing at 115 Broadway in the City, County and State of
New York, Engineer, and EUGENE HOWARD CLAPP, residing at 50 India Street,
City of Boston, in the County of Suffolk and State of Massachusetts, Manufacturer,
United States of America, 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 apparatus for evaporating or distilling liquids, and is
especially adapted among other things, to be used for the concentration of sugar,
soda and other solutions, and also for the refining or the distillation of glycerine, oils,
and other analogous substances.
The invention has for its object to provide an apparatus in which the concentration,
refining or distillation of liquid substances may be effected on the surface of the
apparatus in a shorter time and at a less expense than heretofore, our improved
apparatus being simple in construction and as shown, being adapted to be readily
taken apart for repairs shipment, and other purposes.
Prior to our invention apparatus for evaporating, concentrating and distilling
liquids have been constructed wherein the evaporating surface is formed by a nest of
independent pipes separated from one another, and upon which the liquid to be
evaporated is discharged in a number of fine streams, through perforations in a pipe,
or in the bottom of a vat located above the said evaporating pipes.
With apparatus constructed as above described, the liquid discharged upon the
evaporating surface does not completely cover the said surface, but strikes upon the
same in different places or spots, thus leaving parts of the surface dry or uncovered
by the liquid to be evaporated; and so also when the liquid is discharged upon the
evaporating surface under pressure, the said liquid spatters, or is broken up or
sprayed, so that when the particles or globules of liquid thus formed, again come in
contact with the evaporating surface, the said particles or globules of liquid are
substantially instantaneously evaporated, thus leaving upon the evaporating surface a
deposition of solid matter normally held in suspension or solution by the liquid. This
deposition of solid matter is gradually built upon or increased by the continued
spattering or breaking up of the liquid, so that, after the apparatus has been in
operation for some time, an incrustation is formed upon the evaporating surface, the
said incrustation rapidly accumulating after it has once commenced to forni.
The incrustation referred to, in course of time practically covers the evaporating
surface and forms thereon a non-conductor of heat, thereby rendering the apparatus after
little use practically worthless for evaporating purposes,

page_text: In accordance with our invention, we have discovered that the formation of an
incrustation upon the evaporating surface may be obviated, and a practical apparatus
capable of effecting a maximum evaporation may be produced as follows:
1st, by constructing the evaporating surface so as to possess or present an undulatory
outline upon which the heating medium, which may be steam, caloric, water or other
liquid or gas (according to the nature of the substance to be treated) may act with
maximum evaporating effect.
2nd, by flowing or discharging the liquid to be treated upon or against the
evaporating surface in a continuous sheet, said evaporating surface being constructed
so as to possess or present a substantially continuous surface over which the liquid
flows, that is, the parts comprising the evaporating surface, when the said surface is
made of independent parts, will be connected together or arranged in such juxta-
position as to prevent the sheet of liquid being broken or disconnected as it flows
over the evaporating surface.
In accordance with our invention, the liquid or fluid substance to be treated is spread
over and upon the evaporating surface in a substantially continuous thin sheet so that
the heating medium, which may be steam, caloric water or other liquid or gas,
according to the nature of the substance to be treated, may act upon a large surface
of the material with a maximum result.
Our improved apparatus may be coupled or connected together, as will be described,
to produce a double, triple, or other multiple effect, that is, the products of evaporation
or distillation from one apparatus being employed as the heating agent or medium
for another or second apparatus.
Our invention therefore consists of an evaporating apparatus, including a liquid
feeder and a heated evaporating surface such as described, the liquid feeder having a
delivery or orifice from which the substance to be evaporated flows by a force due to
gravity the said liquid spreading over and enveloping or covering the said evaporating
surface with a liquid sheet, the evaporating surface being of such form as to maintain
the said liquid sheet continuous or unbroken in its passage over it, the evaporating
surface being acted directly upon by the heating medium whereby a maximum
evaporating effect is produced.
Other features of our invention will be described hereinafter and pointed out in
the claims at the end of this specification.
Referring to the Drawings:
Figure 1, is an elevation, partially broken out and partially in section in line, x, x,
Figure 3, of an apparatus embodying our invention.
Figure 2, a transverse section of Figure 1, between adjacent rows of pipes
or tubes.
Figure 3, a partial horizontal section of the same.
Figure 4, a side elevation of the evaporating apparatus and its pipe connections,
whereby a multiple effect" is produced.
66
Figure 5, a longitudinal section of a modified form of the apparatus shown in
Figure 6.
Figure 6, an end elevation partially broken out and partially in section of the
apparatus shown in Figure 5.
Figures 7 and 8, partial horizontal sections through the heads of said
apparatus; and
Figures 9 to 15, inclusive, detail views of various modifications in the construction
or arrangement of the evaporating tubes.
Our improved apparatus will preferably be composed of a number of independent
sections each constituting in itself a distinct apparatus.
Each section referred to consists, as herein shown in Figures 1, 2 and 3, of preferably
cast iron headers, B, to which the evaporating surface is secured, the said headers
having flanges, b, see Figure 3, against which are bolted or otherwise secured covers, c,
the latter forming with the said flanges at each side of the apparatus a chamber
which may be divided, as shown, into a number of smaller chambers or pockets, u,
by division plates, 6', preferably cast integral with the header.

page_text: The evaporating surface is preferably composed of a series of substantially
horizontal tubes or pipes, A, arranged as shown, in a substantially vertical plane to
form an evaporating surface having an undulatory outline, the said tubes having their
ends expanded or secured into holes in the headers, B, and being so connected with
the chambers or pockets, a, as shown in Figure 2, as to form a continuous passage
from a point, e, at or near the top of the apparatus to a point, f, at the bottom
thereof.
The evaporating surface of each section has co-operating with it, a liquid feed or
supply herein shown as a tube, G, communicating as shown, with chambers, i, in the
headers, B, and provided at its upper side with a slot, ½, see Figure 1, extended
substantially the length of the said tube, the said slot which constitutes the discharge
outlet of the feed or supply tube, permitting the liquid or fluid substance to be
discharged upon the evaporating surface in a continuous thin sheet.
Each header, B, is provided with side flanges, g, see Figure 3, which abut against
each other when two or more sections are used, the flanges, g, of adjacent or
abutting headers being in practice bolted or otherwise secured together in the usual
manner.
The space, F, thus formed surrounds the tubes, and as shown, is common to all the
apparatus or structure extending between the covers from end to end and from top
to bottom of the apparatus.
The delivery tube or pipe, G, of each section is supplied, as shown, through the
chambers, i, from pipes, H, connected to the source of supply and communicating
with the said chamber by manifolds, I, provided with cocks, k, and nozzles, j,
extended into said chambers.
The liquid, it will be noticed, enters both ends of the feed or supply, G, thereby
ensuring a uniform spread throughout the length of the evaporating surface.
The liquid may be fed from its source of supply to the tube, G, from beneath the
latter if desired so that it will gradually rise therein and overflow free from
pressure.
The flow of liquid over the evaporating surface may be controlled by the cocks, k,
and may be increased or decreased, as desired, or the said supply may be entirely cut
off from one or more of the series of evaporating surfaces, as desired.
In practice the cocks controlling the flow of liquid are first opened to cover the
evaporating surface with liquid before the heating medium is turned on or admitted
to the apparatus, so that when the heat is admitted to the apparatus the evaporating
surface will not become dry but will be covered by the sheet of liquid, thus preventing
the formation of an incrustation on the said evaporating surface, thereby maintaining
the said surface clean and in normal or proper condition to obtain a maximum
evaporating effect. By preventing the formation of the incrustation referred to, our
improved apparatus may be used a long time without necessitating cleansing of the
apparatus.
The tubes, or pipes, A, and tube, G, will preferably be connected together by
bridges, o, having their ends fitted into substantially vertical grooves, m, see Figure 3,
in the headers, B, the said bridges forming, with the said tubes a continuous
surface having an undulatory outline over which the liquid flows in an unbroken thin
sheet. It is not essential that the surfaces between the tubes or feeder should be
continuous or in actual contact with the tubes, but may be separated to a certain
extent, without breaking the sheet form of the liquid in its passage.
As the liquid or substance to be treated flows down over the evaporating surface,
its velocity increases according to the distance through which it passes, and the
tendency of part of the liquid as it passes over the curved or rounded portion
of the evaporating surface, is to leave or drop away from said surface on a tangent.
To catch any liquid which may thus leave the evaporating surface, we have
provided, as shown, a series of preferably removable shelves, n, located below the
widest portion of the evaporating surface, that is, below each tube, as herein shown,
the said shelves being preferably fitted into inclined grooves, b, in the headers, B, see
Figure 3, on opposite sides of the said tube, the said shelves as shown in Figure 1,

page_text: being inclined toward the bridges, o, and being separated from the said bridges and
tubes so as to permit the ready or free passage of the liquid from them back onto
the evaporating surface.
Access to the evaporating surface for cleansing or other purposes may be had by
removing the shelves, n.
The heating agent or medium, which may be steam, hot water, or other liquid or
gas, according to the nature of the substance to be concentrated, distilled or refined,
is supplied to the chamber or pocket, e, of each section of the apparatus, as shown by
a pipe, K, provided with a cock or valve, r, by which the said supply of heating
medium may be cut off to render the said section inoperative.
The heating medium is caused to circulate through the pipes or tubes in a direction
preferably at a right angle to the flow of the material over the evaporating surface,
the said tubes or pipes, as above stated, being preferably arranged and connected at
their ends to cause the heating medium to cross and re-cross the apparatus one or
more times, as desired.
The heating medium after circulating through the apparatus, may be removed
therefrom by the pipe, t.
Should it be found expedient to renew the heating agent at a point intermediate to
the down-flow of the liquid or substance being treated, the pipe, K, having the stop-
valve or cock, r, may be repeated, as will be understood by the representation in
dotted lines, Figure 2, a partition, s, being interposed, and the additional drain pipe, u,
being provided for the upper portion of the evaporating surface.
We prefer to construct the apparatus in sections, as shown in Figures 1, 2 and 3,
but if desired the said apparatus may be constructed as shown in Figures 5 to 8,
inclusive, wherein the tubes or pipes, A, comprising the evaporating surface are
arranged as shown in vertical rows in a cylindrical shell, the said tubes or pipes being
extended through and supported as shown, by a division plate or wall, A³.
The heads, B, of the cylindrical shell are divided as shown, by horizontal partitions, 61,
to form chambers or pockets, a, in a similar manner to that shown in Figures 1, 2
and 3, the said pockets or chambers being arranged with relation to the independent
rows of tubes or pipes constituting the evaporating surface, so as to form a continuous
passage for the heating medium as hereinbefore described, the heating medium being
admitted through nipple, e', to a single chamber, e, communicating with the upper-
most row of tubes, A, as shown in Figure 8, the drainage being effected by the
pipe, t¹.
a
Each vertical row of tubes or pipes, A, has co-operating with it, as shown,
connected slotted feed or supply pipe, G, the said feed or supply pipe communicating
with a common chamber or pocket, i, to which the liquid is supplied by the pipes, H.
The products of evaporation or distillation pass out of the shell by the pipe, J, and
the products of condensation by the pipe, l.
The construction of the evaporating surface is capable of various modifications and
yet be within the scope of our invention, as illustrated by Figures 9 to 15, inclusive, viz.:
as in Figure 9, the evaporating surface consists of tubes which are brought with their
adjacent surfaces so nearly in contact, as not to break the flow, omitting the bridges, o,
shown in Figure 1, thereby concentrating the coil.
In Figure 10, the evaporating surface consists of tubes of increasing diameter in
descending order, and herein the shelves, n, may be employed or dispensed with, in
the latter case, the increasing diameters of the tubes serving to catch any portion of
the descending liquid that may fall away from the surface of each preceding tube.
In Figure 11, the surface is composed of tubes arranged in zigzag series, connected
by bridges, o, and having the shelves, n, adapted, as shown, to cause the currents to
follow the irregular course which will serve to retard the rate of its flow.
In Figure 12, the surface consists of two sheet metal plates having horizontally
arranged semi-tubular projections stamped in them, the said plates being riveted
together.
In Figure 13, the surface consists of united corrugated metal sheets, the form there
shown affording gradual curvatures of exterior surface, whereby the liquid will the

page_text: more readily adhere to the same, the shelves, n, preferably being employed with these
two latter constructions, but omitted in the drawing.
In Figures 14 and 15, the surface is composed of tubes, A, cast in sections, which
are firmly secured to the headers, B, and are adapted by a pear-shaped or ovoid form to
a continuous flowing surface and maximum heating surface.
In the adaptation to a vacuum evaporating or distilling system, we have shown in
Figure 4, the preferred form of apparatus first described, connected for "multiple
effect of evaporation; that is to say, utilizing the heat of the vapor constituent,
developed from one evaporating surface, in heating the next succeeding evaporating
29
surface.
Herein steam or other heating medium from a suitable source is introduced to the
first evaporator, C2, through pipe, K, the vapors of evaporation or distillation. there-
from being conveyed by means of pipe, J, to heat the evaporating surface in the
apparatus, C³, and the pipe, J2, performing a like function between the apparatus, C³, C.
The vapor in the last apparatus is withdrawn by the condenser and exbaust pump, M,
which maintain the different degrees of vacuum in the successive apparatus necessary
to produce repeated vaporization or distillation from a single source of heat, as common
in practice.
The liquid products of concentration from each apparatus are delivered from pipes, 1.
to pipes, H, and by these pipes to the feed or supply tubes, G, Figure 1, of each
succeeding apparatus, by means of suitable pumps, N, and the final heavier non-
volatizable constituent, as for instance, a concentrated saccharine solution, delivered by
pump, O.
By control of the cocks, y, y, and, w, w, the hot condensed portions of the heating
agent are withdrawn from pipes, u, or,, through the discharge pipes, u¹, t¹, or
utilized in repetition by delivery through pipes, u², t2, to the manifolds, L, to be
reconverted into steam by the lower succeeding vacuum.
In Figure 4, the double use of the evaporating surface is represented, that is, the
said surface is divided as above described, the lower additional set of manifolds, L,
being employed.
The final condensation of steam is carried to the condenser, M, by pipes, u³, 13.
Our improved apparatus in practice may be employed for concentrating sugar and
like solutions containing water, and in this case steam or caloric, that is, the products
of combustion from a furnace or other source, may be used as the heating medium,
but it is equally well adapted to be used for distilling glycerine which requires a very
high temperature, and in this case, the heating medium may be oil having a high
boiling point.
So also, the said apparatus may be used for refining or distilling substances of a
low boiling or volatilizing point, in which case warm water or other liquid maintained
at a temperature below the boiling point of water may be used as to the heating
medium.
We are aware prior to our invention that a surface evaporation is not broadly new,
but we are not aware prior to our invention that a surface evaporation has been
effected, wherein the liquid or substance to be treated has been spread or distributed
upon or against the heated evaporating surface in an unbroken sheet, so as to cover
the said surface.
We have herein shown the tubes or pipes connected to a number of chambers or
pockets, a, and while we prefer this construction, we do not desire to limit ourselves
to the particular construction shown, as the said tubes may be connected in various
ways to one or more chambers or pockets at each side of the apparatus, the said tubes
when connected to a single chamber at each side of the apparatus forming a single
hollow case or shell into which the heating medium is admitted.
Furthermore we do not desire to limit ourselves to the particular construction and
form of the liquid feeder shown, nor to the location or size or form of its discharge
slot or orifice, as the latter may be located at its sides or bottom. In such instances
it is obvious that a double slot or orifice may be divided to flow the liquid upon
opposite sides of the depending bridge or the latter separated from contact with the

page_text: adjacent evaporating tube a sufficient distance to permit the liquid sheet to spread
over and upon its opposite sides, or the liquid may be spread from the feeder upon the
interior of a surrounding surface and discharged upon the evaporating surface
through a slot or orifice, the object of our invention as it relates to the feeder being
to so devise it as to permit of, and ensure a uniform delivery of the liquid upon the
evaporating surface in a thin sheet.
Instead of arranging the apparatus for a multiple effect, as shown in Figure 4, that
is, on substantially the same level, and having the liquid outlet of one evaporator as, C²,
connected to a pump as, N, which is itself joined to the supply for the next evaporator
as, C3, the said evaporators may be arranged in gradation, that is, on different levels,
so that the liquid from one evaporator as, C2, will flow into the next succeeding
evaporator in the series as, C³, etc., whereby a uniform and steady flow or supply of
liquid substance to be evaporated is furnished each evaporator, the apparatus in this
case, when once started and the flow regulated, requiring little if any attention.
With the evaporators arranged in gradation, the pumps, N, may, and in practice
will be dispensed with.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is —
1. An evaporating apparatus including a liquid feeder and a heated evaporating
surface, such as described the liquid feeder having a delivery or orifice from which the
substance to be evaporated flows by a force due to gravity, the said liquid spreading
over and enveloping or covering the said evaporating surface with a liquid sheet, the
evaporating surface being of such form as to maintain continuous or unbroken in its
passage over it the said liquid sheet, the evaporating surface being acted directly upon
by the heating medium whereby a maximum evaporating effect is produced, substantially
as described.
2. An evaporating apparatus, including a liquid feeder, and a heated evaporating
surface such as described, the liquid feeder having a delivery or orifice from which
the substance to be evaporated flows by a force due to gravity, the said liquid spreading
over and enveloping or covering the said evaporating surface with a liquid sheet, the
evaporating surface being of such form as to maintain continuous or unbroken in its
passage over it, the said liquid sheet, the evaporating surface being acted directly upon
by the heating medium whereby a maximum evaporating effect is produced, and co-
operating shelves to maintain the liquid sheet, substantially as described.
3. An apparatus for evaporating liquids and other substances, it including an
undulatory evaporating surface, a feeder or delivery for the liquid to be treated, and a
series of shelves co-operating with the said surface to receive and return the liquid
thereto, the said parts co-operating together to maintain a liquid sheet, substantially as
described.
4. An evaporating apparatus including a plurality of independent detachable
sections, each consisting of an evaporating surface, a liquid feeder or delivery for
each evaporating surface, and a supply pipe connected to and common to all of the
said sections, and a cock or valve for each section whereby a section of the apparatus
may be cut off, and rendered inoperative, substantially as described.
Dated this 14th day of August 1888.
THOMAS GAUNT.
EUGENE HOWARD CLAPP.
By Jensen & Son,
77, Chancery Lane, London, W.C.,
Patent Agents.