Improvements in Apparatus for Evaporating Liquids, Generating Steam, and the like.
Year: 1895

page_text: Date of Application, 29th Oct., 1895
Complete Specification Left, 12th June, 1896-Accepted, 18th July, 1896
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Evaporating Liquids, Generating
Steam, and the like.
1, PETER COOPER HEWITT, of 11, Lexington Avenue, New York City, in the
County and State of New York, United States of America, Manufacturer, do
hereby declare the nature of this invention to be as follows:-
In the evaporation of liquids for the purpose of concentrating them, or in the
generation of steam for motive power or heat, the circulation of the liquid is
commonly secured by taking advantage of the difference in specific gravity due to
different temperatures of different portions of the liquid. As the difference in
density is slight, permitting bubbles of vapour to adhere to the walls of the
chamber or of the tube in which they are formed and to hinder the rapid
transmission of heat from the said walls to the body of the liquid, and the liquid
itself not being a good conductor of heat except by convection, the amount of
liquil evaporated in a given time by a given amount of surface is limited by the
amount of heat the liquid will take up from the walls.
The object of my invention is to facilitate the evaporation of liquids by
accelerating their circulation, and by securing a more effective contact of the
liquid and heating surface by bringing more liquid in contact with the heating
surface, and also the rapid circulation of the vapour formed from the liquid.
My invention comprises an apparatus for rapidly evaporating liquids, which
consists of a separating chamber formed, in the present example, of a single
casting furnished with a cylindrical cavity and with passages which are tangential
to said cavity and curved inwardly in the casting. The lower part of the
cylindrical cavity is conical and in the casting is formed a central opening towards
which the conical sides of the cavity incline. In the chamber, above the conical
bottom thereof and a short distance below the openings of the passages, is arranged
a horizontal partition and in the said partition adjoining the wall of the cavity are
formed segmental ports and to the under side of the horizontal partition are
attached wings which are located between the curved ports and project downwardly,
the wings serving to check the rotary motion of the liquid passing through the
ports. Above the openings of the tangential passages the chamber is contracted
and furnished with an inwardly projecting flange forming an annular groove which
communicates with and forms part of the liquid discharge opening at one side of
the chamber. The inner edge of the inwardly projecting flange is arranged in a
position intermediate between perpendicular lines drawn from the walls of a
discharge opening and perpendicular lines drawn through the inner portions of
the ports, so that the inner wall of the revolving liquid will lie between the
perpendicular lines passing through the inner portions of the ports and thus be
withdrawn from the inner wall of said discharge opening, which is concentric with
the chamber and serves for the escape of vapour. The chamber is provided with
a flange at the top for receiving the vapour pipe and also with a Hange at the
bottom to which latter, and in contact with the bottom of the chamber, is secured
a plate provided with a central opening coinciding with the opening of the cavity
and with openings coinciding with the passages of the chamber. In the central
opening of the plate is screwed a pipe and in the openings in said plate which
coincide with the passages of the chamber are screwed a series of pipes, said pipes
being fitted with perforated plates which are each provided with a flange and
oppositely arranged with respect to each other and provided with glands on their

page_text: outer surfaces which permit of the movement of either or both of the plates or of
the pipes in the plates, without causing leakage or straining of the parts.
Surrounding the pipes, and between the plates, is placed a cylindrical shell
provided at its ends with flanges which are bolted to the flanges of the plates. To
one side of the shell, preferably above the centre thereof, is screwed a steam
supply pipe and to the opposite side of the shell is screwed a discharge pipe which
passes through the shell. A jacket surrounds the portion of the central pipe
enclosed by the shell, leaving an intervening space which prevents sail pipe from
being heated to the same degree as the circle of pipes. The central pipe is
screwed into a hollow base so as to communicate with a space in the said base
with which also the circle of pipes are caused to communicate the said pipes being
surrounded by glands. A supply pipe communicates with the interior of the
hollow base.
The operation of my improved evaporator is as follows:-The liquid to be
evaporated is introduced into the apparatus through the supply pipe in the base,
and in the present case the heat necessary to drive off the vapour is supplied by
steam introduced into the shell, the central pipe which is protected by the jacket
being not heated to the same degree as the circle of pipes The liquid contained
in the series of pipes gives off bubbles of vapour, thus rendering the columns
contained by the pipes non-homogeneous, that is to say the said columns are
composed partly of liquid and partly of vapour, while vapourization is partly or
wholly prevented in the central tube. In consequence of the difference in density
in the columns contained by the pipes the column contained in the central pipe
descends, forcing upwards the columns contained by the pipes and causing the said
pipes to discharge through the tangential passages into the separating chamber.
The jets which are thus made to enter the chamber impinge upon its walls and
thus produce a rapid rotary motion in the liquid contained by the chamber which
carries: the heavier portions of the liquid towards the wall of the chamber while
the vapour goes to the centre. As the capacity of the chamber is limited when
liquid is supplied one portion of the liquid is discharged over the inwardly
projecting flange the main portion being continuously discharged independently of
the feed, through the ports into the lower part of the chamber, thence into the
central pipe which returns it to the hollow base whence it again rises through the
ring of pipes. This operation is made continuous and the concentrated liquid,
which is discharged over the flange and through the discharge pipe, is replaced by
fresh liquid introduced into the hollow base. The rapid upward movement of the
liquid through the series of pipes frees their walls from all adhering bubbles of
vapour, thereby maintaining a perfect contact of the constantly changing liquid
with the walls of the pipes, thus ensuring the rapid transmission of heat and great
rapidity of action. Moreover, the portion of liquid which is returned to the
central tube possesses a downward velocity due to the ascending velocity of the
column in the series of pipes and its transformation into centrifugal force in
the chamber and this downward velocity increases the effect of the weight of the
liquid in the central pipe and adds to the rapidity of the circulation.
In a modification, the pipes in which the liquid is heated communicate with a
hollow base, as in the other case, and discharge into a receiver which is furnished
with an outlet pipe terminating in a multiple discharge nozzle placed within the
sej arating chamber, the said multiple discharge nozzle being provided with an
enlarged annular opening in which are placed oblique wings which cause the jets
of liquid to issue in a practically tangential direction so as to produce a rotary
motion of the liquid in the chamber. The separation of the liquid from the vapour
is effected in the manner before described and the vapour escapes through an
opening at top while the concentrated liquid escapes through a pipe at one side.
The liquid is returned to the hollow base through external return pipes.
In another modification, the construction is altered sufficiently to adapt the
device for evaporating water. In this case the hollow base is made annular and
the series of pipes enter the separating chamber tangentially as in the arrangement
.

page_text: just described, and the return pipes return the liquid to the annular base, as in the
first modification. The steam is taken from the generator through a pipe at the
top of the chamber and feed water is introduced into the annular base or one of
the return pipes. To economize the heat of the furnace which passes through the
annular base and cause it to surround the pipes to their fullest extent, baffle plates
are disposed in a suitable way in the heating chamber to deflect the flame and
products of combustion so as to cause them to surround the pipes. In the
present case a plate is placed above the hollow base and extends to the outer row
of pipes while above the space outside of the said plate is arranged an annular
plate.
My apparatus can be used for separating a mixed liquid or solution by the
removal of one portion in the form of vapour, leaving another portion which is not
vapourized. The absolute pressure, whether more or less than the atmospheric
pressure under which my apparatus may be operated, does not affect the working
of my invention which is applicable to a wide range of pressures.
I wish to be
understood as including in my invention, under the term "evaporator" as used in
the foregoing specification, such apparatus as steam generators, vacuum pans, etc.,
used to vapourize liquids wholly or partly for any purpose whatever.
Dated this 29th dov of Outabo 1805
A. M. & WM. CLARK,
53 Chancery Lane, London, Chartered Patent Agents.
Improvements in Apparatus for Evaporating Liquids, Generating
Steam, and the like.
I, PETER COOPER HEWITT of 11, Lexington Avenue, New York City, in the
County and State of New York, United States of America, Manufacturer, 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:-
In the evaporation of liquids for the purpose of concentrating them, or in the
generation of steam for motive power or heat, the circulation of the liquid is
commonly secured by taking advantage of the difference in specific gravity due to
different temperatures of different portions of the liquid. As the difference in
density is slight, permitting bubbles of vapour to adhere to the walls of the
chamber or of the tube in which they are formed and to hinder the rapid
transmission of heat from the said walls to the body of the liquid, and the liquid
itself not being a good conductor of heat except by convection, the amount of
liquid evaporated in a given time by a given amount of surface is limited by the
amount of heat the liquid will take up from the walls.
The object of my invention is to facilitate the evaporation of liquids by
accelerating their circulation and by securing a more effective contact of the
liquid and heating surface by bringing more liquid in contact with the heating
surface and also the rapid circulation of the vapour formed from the liquid.
My invention comprises an apparatus for rapidly evaporating liquids as will be
hereinafter fully described and pointed out in the claims.
Reference is to be had to the accompanying drawings forming part of this
specification in which
Figure 1 is a vertical section of my improved evaporator taken on line æ-æ in
Figure 2.
Figure 2 is a horizontal section taken on line y-y in Figure 1.
Figure 3 is a vertical transverse section of a modified form.
Figure 4 is a horizontal section taken on line 2-2 in Figure 3 and

page_text: Figure 5 is a vertical section of my improved evaporator adapted to the
evaporation of water.
Similar letters of reference indicate corresponding parts in all the views.
The separating chamber A in the present case consists of a single casting
furnished with a cylindrical cavity a and with passages 6 which are tangential to
said cavity a. The passages b are curved inwardly in the casting as shewn in
Figure 2. The lower part of the cylindrical cavity a is conical and in the casting
is formed a central opening c towards which the conical sides of the cavity incline.
In the chamber A above the conical bottom thereof and a short distance below
the openings of the passages is arranged a horizontal partition d and in the said
partition adjoining the wall of the cavity are formed segmental ports e and to the
under side of said partition are attached wings e¹ which are located between the
curved ports and project downwardly, the wings serving to check the rotary
motion of the liquid passing through the ports.
Above the openings of the passages the chamber A is contracted and furnished
with an inwardly-projecting flange f forming an annular groove g which
communicates with and forms part of the liquid discharge opening hat one side
of the chamber. The inner edge of the inwardly-projecting flange f is arranged
in a position intermediate between perpendicular lines drawn from the walls of the
discharge opening i, and perpendicular lines drawn through the inner portions of
the ports e, so that the inner wall of the revolving liquid will lie between the
perpendicular lines passing through the inner portions of the ports e, and thus be
withdrawn from the inner wall of the discharge opening. The discharge opening i
is concentric with the chamber and is for the escape of vapour.
The chamber A is provided with a flange j at the top for receiving the vapour
pipe, and with a perforated flange k at the bottom, to which latter and in contact
with the bottom of the chamber A, is secured a plate B, provided with a central
opening e', coinciding with the opening .e of the cavity a, and with openings 61
coinciding with the passages b of the chamber A. In the central opening c¹ of the
plate B, is screwed a pipe C, and in the openings 61 of the said plate B, are
screwed the pipes D. To the pipes C, D, are fitted the perforated plates E, E,
which are each provided with a flange l. The said plates E, E', are oppositely
arranged with respect to each other, and provided with glands m, n, m, n', on
their outer surfaces, which permit of the inovement of either or both of the
plates E, E, or of the pipes D, C, in the plates, without causing leakage or
straining of the parts.
Surrounding the pipes C, D, and between the plates E, E', is placed a cylindrical
shell F, provided at its ends with flanges o, which are secured to the flanges of
the plates E, E', by means of bolts or otherwise. To one side of the shell F,
preferably above the centre thereof, is secured a collar p, into which is screwed a
steam supply pipe G, and to the opposite side of the shell, or in any convenient
position, is secured a collar g, into which is screwed the discharge pipe H, which
passes through the shell F. A jacket I, surrounds, the portion of the pipe C
enclosed by the shell F, leaving an intervening space, which prevents the pipe C
from being heated to the same degree as the pipes D. The pipe C is screwed into
a hollow base J, communicating with the space S in the said base, and the pipes D
enter the hollow base J, and communicate with said space S, the said pipes D
being surrounded by glands n². A supply pipe K communicates with the interior S
of the hollow base J.
The operation of my improved evaporator is as follows:
The liquid to be evaporated is introduced into the apparatus through the pipe K,
and in the present case the heat necessary to drive off the vapour is supplied by
steam introduced into the shell F through the pipe G. The pipe C, being
proiected by the jacket D, is not heated to the same degree as the pipes D. The
fiquid contained in the pipes D gives off bubbles of vapour, thus rendering the
columus contained by the pipes D nou-homogeneous, that is to say, the said
columns are composed partly of liquid and partly of vapour, while vaporization is

page_text: partly or wholly prevented in the central tube C. In consequence of the difference
in density in the columns contained by the pipes C, D, the column contained in the
pipe C descends, forcing upward the columns contained by the pipes D, and
causing the said pipes to discharge through the tangential passages b into the
separating chamber A. The jets which are thus made to enter the chamber
impinge upon its walls, and thus produce a rapid rotary motion in the liquid
contained by the chamber, which carries the heavier portions of the liquid toward
the wall of the chamber, while the vapour goes to the centre of said chamber. As
the capacity of the chamber is limited, when liquid is supplied, one portion of the
liquid is discharged over the inwardly-projecting flange f, the main portion being
continuously discharged, independently of the feed, through the ports e, into the
lower part of the chamber A, thence into the pipe C, which returns it to the
hollow base J, whence it again rises through the pipes D. This operation is made
continuous, and the concentrated liquid which is discharged over the flange.f and
through the discharge pipe h, is replaced by fresh liquid introduced into the hollow
base through the pipe K. The rapid upward movement of the liquid through the
pipes D, frees their walls from all adhering bubbles of vapour, thereby maintaining
a perfect contact of the constantly changing liquid with the walls of the pipes,
thus insuring the rapid transmission of heat and great rapidity of action.
Moreover, the portion of liquid which is returned to the central tube C possesses
a downward velocity due to the ascending velocity of the column in the pipes D, D,
and its transformation into centrifugal force in the chamber A, and this downward
velocity increases the effect of the weight of the liquid in the pipe C, and adds to
the rapidity of the circulation.
In the modification shown in Figures 3 and 4, the pipes D', in which the liquid
is heated, communicate with a hollow base as in the other case, and discharge into
a receiver t, which is furnished with an outlet pipe u, terminating in a multiple
discharge nozzle L, placed within the separating chamber A¹, the said multiple
discharge nozzle being provided with an enlarged anuular opening v, in which are
placed oblique wings w, which cause the jets of liquid to issue in a practically
tangential direction, so as to produce a rotary motion of the liquid in the chamber A¹.
The separation of the liquid from the vapour is effected in the manner before
described, and the vapour escapes through the opening, while the concentrated
liquid escapes through the pipe h. The liquid is returned to the hollow base
through the external return pipes C¹.
In the form shown in Figure 5, the construction is altered sufficiently to adapt
the device for evaporating water. In this case, the hollow base J¹ is made annular;
the pipes D enter the separating chamber A2 tangentially as in the case just
described, and the return pipes C₁ return the liquid to the annular base as in the
first modification. The steam is taken from the generator through the pipe; ³,
and feed water is introduced into the annular base J', or one of the pipes C¹.
To economize the heat of the furnace which passes through the annular base J¹,
and cause it to surround the pipes D³ to their fullest extent, baffle plates are
disposed in a suitable way in the heating chamber, to deflect the flame and products
of combustion so as to cause them to surround the pipes D³. In the present case, a
plate M is placed above the hollow base J', and extends to the outer row of pipes,
while above the space outside of the said plate is arranged an annular plate N.
My apparatus can be used for separating á mixed liquid or solution by the
removal of one portion in the form of vapour, leaving another portion which is not
vaporized. The absolute pressure, whether more or less than the atmospheric
pressure under which my apparatus may be operated does not affect the working of
my invention, which is applicable to a wide range of pressures. I wish to
be understood as including in my invention, under the term "evaporator,” as used
in the foregoing specification and the following claims, such apparatus as steam
generators, vacuum pans, etc., used to vaporize liquids wholly or partly, for any
purpose whatever.
By the term "tangential jet or nozzle as used in my specification and claims,

page_text: I mean a nozzle arranged with reference to the separating chamber so that the jet
-discharged from the nozzle into the separating chamber will strike the wall of the
chamber at such an angle as to impart a rotary motion to the liquid discharged, and
to maintain rotary motion in the liquid in the separating chamber.
My apparatus will work successfully whether the liquid is discharged into the,
separating chamber from without inward, as would be the case in the form, shown
in Figure 1 and 2, or from the central portion of the separator toward the walls
thereof, as would be the case in the apparatus illustrated in Figure 3, as either
In the
method will produce the required rotary motion in the separating chamber.
first instance, the particles of vapour would be forced inward toward the centre of
the chamber by the pressure of the liquid; in the second case the liquid would be
projected through and beyond the vapour by virtue of its superior weight and
density.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is,―
1. In an evaporator or steam boiler, provided with heating tubes and one or more
return tubes, a separating chamber provided with a series of stationary tangential
nozzles communicating with the heating tubes, substantially as specified.
2. In an evaporator, wherein the separation of the vapour and the concentrated
liquid is effected by the motion of the liquid, a separating chamber, the said
separating chamber being furnished with a vapour outlet, one or more liquor outlets
at the bottom thereof, and a liquor overflow arranged between lines passing through
the vapour outlet and return liquor outlet, for the purpose of maintaining the inner
or free surface of the body of liquor between the vapour outlet and the return
liquor outlet, substantially as specified.
3. In an evaporator, the combination with the heating and return tubes, of
a separating chamber provided with tangential nozzles, and having one or more
discharge ports each, for vapour, liquor, and the return liquor, the said discharge
ports being arranged in different planes, substantially as specified.
4. An evaporator, comprising a separating chamber a series of heating tubes
communicating with the separating chamber through tangential nozzles, a heating
drum enclosing the tubes, and one or more protected return pipes insulated from
the heat, for conveying the liquid from the separating chamber to the lower end of
the heating tubes, substantially as described.
5. In an evaporator, the combination with the heating and return tubes,, of
a separating chamber provided with tangential nozzles, and having one or more
discharge ports each, for vapour, for the liquid and for the return liquid,
substantially as specified.
6. In an evaporator, a series of evaporating tubes, and an enclosing shell provided
with heads through which the tubes pass, the said heads being separated from the
joints of the evaporating tubes with the separating chamber and hollow base,
leaving portions of each tube exposed between the separating chamber and beating
drum, and hollow base and heating drum, to avoid leakage of steam into the
vacuum space, substantially as specified.
7. An evaporator, comprising a separating chamber, a series of heating tubes
communicating with the separating chamber through tangential nozzles, a heating
drum enclosing the tubes, and one or more return pipes for conveying the liquid
from the separating chamber to the lower end of the heating tubes, substantially as
specified.
Dated this 12th day of June 1896.
A. M. & WM. CLARK,
53 Chancery Lane, London, Chartered Patent Agents.