Improvements in Evaporating Apparatus.
Year: 1892

page_text: Date of Application, 25th Oct., 1892-Accepted, 3rd Dec., 1892
COMPLETE SPECIFICATION.
[Communicated from abroad by OSCAR BISHOP STILLMAN, of South Natick,
County of Middlesex, and State of Massachusetts, United States of America,
Mechanical Engineer.
Improvements in Evaporating Apparatus.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake and Co., Patent
Agents, 45 Southampton Buildings, London, W.C., 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 an evaporating apparatus of the kind known as the
multiple effect apparatus in which a series of closed vessels is employed, and the
vapour given off from the liquid to be evaporated or concentrated in one vessel is
employed to heat the liquor in the next vessel, and so on.
The invention relates especially to the construction of the appliances used in
each vessel and is consequently independent of the number of vessels employed,
the apparatus being shown for the purposes of illustration as containing a series of
three vessels.
In apparatus of this kind as heretofore constructed the vessels have sometimes
been made in the form of vertical cylinders divided by transverse partitions near
the top and bottom so as to partition off an intermediate chamber, traversed by
vertical tubes that connect the spaces below and above the said intermediate
chamber.
The space around the tubes in the intermediate chamber receives the vapour, the
latent heat of which is employed to evaporate the liquid contained within and
passing through the tubes, the said liquid being introduced into the space below
the lower tube plate and passed up through the tubes to the space above the upper
tube sheet in which upper space the vapour given off by the said liquid is
collected and from which it is carried by a pipe to the vapour space of the next
vessel of the series and so on.
For convenience the intermediate chamber in which the liquid in the tubes is
subjected to the heat of the vapour, surrounding the tubes, will be hereinafter
called the heating chamber, and the present invention consists partly in partitioning
off from the said heating chamber by a longitudinal partition a separate chamber
extending lengthwise of the vessel through which the liquid (after passing through
the tubes of the heating chamber) is permitted to fall as will be hereinafter
described.
The partition that thus separates off a portion of the heating chamber forming
what will be called a collecting passage is shown as concentric with the walls of
the vessel, and the collecting passage is preferably at the middle of the vessel and
surrounded by the heating chamber which is thus in the form of an annulus, but
the relative arrangement might be modified, as for example by making the
collecting passage an annulus surrounding the heating chamber, or otherwise
forming the collecting passage inside the vessel.
The lower portion of the said collecting passage constitutes a collecting chamber
for the partially concentrated liquid said chamber extending below and outside of
the main body of the receptacle and communicating with the liquid receiving
space of the next vessel of the series, and means are provided for controlling the
flow of liquid from the lower portion of the collecting passage of one vessel into
the liquid receiving space of the next vessel.
The invention further consists in providing the tubes through which the liquid
passes with extensions above the upper tube plate so that the liquid passing up

page_text: through the said tubes and delivered from the upper end thereof, will descend on
to the upper surface of the tube plate where it will stand at a certain depth before
flowing over into the collecting passage the said depth, however, being less than
the upward extent of the tubes so that the ends of the latter will always be
uncovered by the liquid.
The invention consists further in a separating apparatus hereinafter described,
and shown as contained in the vapour space above the upper tube sheet, although
it might be located in the vapour pipe connecting the vapour chamber in the top of
one vessel with the vapour space in the heating chamber of the next vessel.
In the accompanying drawings ;-
Figure 1 is a side elevation of an evaporating apparatus embodying this
invention, one of the vessels being shown in longitudinal section.
Figure 2 a plan view thereof.
Figure 3 a transverse section on line x, Figure 1 of one of the vessels on a
larger scale.
Figure 4 an enlarged sectional detail showing the construction of the distributor.
Figure 5 is a sectional modification in the arrangement of the collecting
passage, and
Figure 6 a side elevation of the lower portion of one of the evaporating vessels
as seen from the opposite side to that represented in Figure 1 and on a larger
scale.
The general arrangement of the apparatus may be such as is usually employed
the said apparatus comprising a number of vessels, A, A', A³, arranged in series
and connected so that the vapour given off by the liquid being evaporated or
concentrated in one vessel, is employed to heat the liquid to be evaporated in the
next vessel, and so on.
Each of said vessels is provided with transverse partitions or tube plates a, b,
see Figure 1, the space between which is traversed by a number of tubes c which
thus connect the space or chamber d below the tube plate a with the space e above
the upper tube plate b.
The space between the plates a and that is traversed by the tubes.c
constitutes the heating chamber, the said space receiving steam or vapour, which in
condensing gives off its latent heat to the liquid in the tubes c heating them and
evaporating their contents.
Exhaust steam is usually employed in the heating chamber of the first vessel
of the series being introduced thereto through a pipe g. The space below the
upper tube plate b is divided by a longitudinal partition thus separating off a
space or collecting passage from the said chamber, said partition h being continued.
as shown at through the lower chamber d and below the bottom thereof, and
the passage thus formed being closed at its lower end preferably by a removablet
cap or bonnet, so that the lower end of the passage constitutes a collecting chamber
for the unevaporated portion of the liquid.
As shown in Figure the collecting passage i is contained within the heating
chamber which is usually the best arrangement, but if for any reason it is.
desirable, the collecting passage i might be made in the form of an annulus as
shown in Figure 5 surrounding the heating chamber for any other convenient or
desirable arrangement might be adopted.
Around the upper end of the collecting passage is a distributor shown as a rib
or flange k projecting upward from the tube plate b and provided with an inclined
flange overhanging the space in the collecting passage i and notched or corru-
gated, preferably at its upper and lower edges as shown in Figure 4; so that the
liquid on the tube plate b when rising above the upper edge of the rib & will flow down
over the flange k, and will be broken up and delivered in the form of a shower,
which will fall through the collecting passage i thus affording an opportunity for.
the vapour to part from the heated liquid.
The tubes care provided with upward extensious c² above the tube plates b and

page_text: above the level of the rib & so that the liquid rising from the said tubes and being
delivered from the upper end thereof in a state of ebullition or in partially vaporized
condition, will descend on to the plate and thence be delivered over the dis-
tributor k, k, into the collecting passage as described, the upper ends of the tubes
thus projecting above the level of the liquid on the tube plate band being
always uncovered.
The object of this construction of the tubes is as follows;-When the apparatus
is in operation the liquid which is introduced to the tubes at the lower end and
carried upward progressively therethrough, is brought to a state of ebullition in
the tubes, the lower portion only of which is thus filled with the liquid, while the
upper portion is filled with vapour, and spray resulting from the ebullition of the
liquid, which vapour and spray is delivered in jets from the upper ends of the tubes,
the more thoroughly vaporized parts rising while the unvaporized portion falls
back on to the tube plate b around the tubes.
If the tubes were flush with the tube plate, portions of the uncondensed liquid
would flow back into the tubes, thus raising the level of the liquid in the tubes,
increasing the pressure thereon, and diminishing the ebullition, but by having the
tubes extend above the level to which the liquid can accumulate on the tube plate b
as shown, such back flow of liquid into the tubes is prevented.
It is obvious that this feature of construction and operation does not depend upon
the form of collecting passage and the invention so far as this feature is concerned
is not limited to any specific construction of the means by which the liquid delivered
from the tubes on to the upper tube plate is removed therefrom to be conveyed to
the next vessel or otherwise disposed of.
The liquid to be evaporated or condensed is introduced into the chamber d in any
usual way through a suitable inlet passage indicated at d² and rises through the
tubes c in the heating chamber and is thereby heated by the surrounding hot vapour
in the vapour chamber and finally issues from the upper ends of the said tubes,
the unevaporated portion thereof descending on to the plate band being delivered
therefrom over the distributor kas has been described.
In order to prevent irregularity in the flow of the liquid over the distributor k, k²,
by the disturbance from the liquid issuing from the tubes a shield or apron k³ is
provided surrounding the rib k as shown and extending above, and below the
level at which the liquid would naturally stand on the sheet when flowing over
the distributor k, k³.
This portion of the invention is not limited to an apparatus in which the tubes
are upwardly extended, as before described, since it is obvious that the shield and
distributor would perform their functions in substantially the same way whatever
might be the construction or arrangement of the tubes by which the liquid is
delivered on to the tube plate, it being essential only that the said shield should be
interposed between the distributor and the delivery orifices of the tubes so as to
prevent the agitation or ebullition at the latter point from disturbing the even flow
of liquid over the distributor.
The liquid thus heated in the tube c and in its fall through the collecting
passage i gives off a large amount of vapour which passes into the chamber e and
thence through the pipe 92 into the vapour space of the heating chamber, of the
next vessel of the series, and in its passage from one vessel to the next the vapour
is subjected to the action of a separating apparatus shown in this instance as
contained in the vapour chamber è at the top of the vessel in which the said
vapour is generated. The said separator consists of a series of plates or transverse
partitions m, m2, m³, m, etc. each of which is provided with numerous perforations
containing short tubes m³ projecting some distance above the said plates, the tubes
in one plate being out of line with those in the next plate, so that the vapour
that passes through the tubes in one plate has to take a devious course in arriving
at the tubes of the next plate, through which it has to pass on its way to the
next vessel.
These plates cause the vapour to be sub-divided, and to impinge against the

page_text: succeeding plates in such a way as to throw down any liquid or matter other than
the vapour or entrained in the vapour, so that finally nothing but the vapour
arrives at and passes through the pipe q leading to the next vessel.
When the separator plates m, m2, m³, are arranged in the vapour chamber e as
shown they are somewhat inclined as shown downward from the outer walls towards
the axis of the vessel and at the lowest point are provided with return pipes n, n²,
n³, n, arranged so that each receives the liquid from the one above it so that the
entire liquid or material separated from the vapour is returned through the pipe n
to the bottom of the collecting passage i together with the liquid that overflows the
distributor k, k2, from the tubes c.
The said partially concentrated liquid which has been acted upon and evaporated
to a certain extent in the first vessel thus accumulates in the lower part of the
collecting passage i which is connected by a pipe d³ with the liquid receiving
chamber d of the next vessel of the series, so that the partially concentrated liquid
that has been acted upon in one vessel may be conveyed to the next vessel to be
acted upon therein by the vapour which has been evaporated from it in the first
vessel.
Suitable means are provided for controlling the flow of the liquid through the
pipe from one vessel to the next. As shown in this instance the said pipe is
provided with a butterfly valve o the operating crank o² (see Figure 6) of which
is connected by a link o³ with an arm o on a rock shaft or spindle o extending into
the collecting chamber at the lower part of the collecting passage, and provided at
the inside of said chamber with an arm of connected with a float o' which when the
liquid accumulates to a sufficient depth is raised and thus opens the valve o and
partially permits the liquid to flow through the pipe d³ to the next vessel, the said
How being due to the fact that each succeeding vessel is under lower pressure than
the preceding ones.
The collecting chamber at the lower part of the collecting passage, is shown as
provided with a gauge glass p to show the height at which the liquid stands in the
collecting passage, the upper portion of which constitutes substantially a part of
the vapour chamber of the vessel thus enabling the vapour chamber e to be reduced
in size.
The liquid receiving chamber d is formed between the lower tube sheet a and
removable annular bonnets connected with the side shell of the vessel and the side
wall of the lower part of the collecting passage as shown so that said bonnet may
be easily removed thus affording access to the tubes when necessary for cleaning or
repairing the apparatus, which is thus more easily kept in working order than in
the constructions. generally adopted in apparatus of this kind. Except as herein
before described, the several vessels may be of the usual construction and operated
in the usual manner being provided with the usual accessories for controlling the
passage of the liquid and vapour for determining the level of the liquid and for
testing the degree of condensation, etc., the vapour being taken from the last
chamber of the series by a condenser or air pump and the water of condensation
being removed from the several heating chambers by the usual means and in the
usual manner, the said parts themselves forming no part of the present invention.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is ;-
i
1. In a multiple effect evaporating apparatus, the main vessel containing the
heating chamber comprising à vapour space and tubes in which the liquid to be.
evaporated is exposed to the heating effect of said vapour, combined with a
collecting passage contained within the vessel and adjacent to said heating chamber,
through which collecting passage a portion of said liquid is caused to pass after
traversing the tubes of the heating chamber, and the collecting chamber at the
lower end of said collecting passage and extending through and below the bottom
of the main vessel, substantially as described.

page_text: 2. In a multiple effect evaporating apparatus, the vessel provided with a heating
chamber comprising a vapour space and tubes in which the liquid to be evaporated
is exposed to the heating effect of said vapour, combined with a collecting passage
extending from the space above the said heating chamber to the lower part of
the vessel, and a distributor by which the liquid above the heating chamber is
delivered into the said collecting passage in the form of a shower, substantially as
described.
3. In a multiple effect evaporating apparatus, the vessel provided with transverse
tube plates and tubes connecting the space below the lower with the space above the
upper tube plate said tubes being provided with extensions above the upper tube
plate and a collecting passage extending from the space above the upper tube plate
and communicating with the liquid receiving space of the next vessel, said collecting
passage having its mouth or inlet opening at a lower level than the orifices of the
extensions of the tubes above the upper tube plate substantially as described.
4. In a multiple effect evaporating apparatus the vessel provided with transverse
tube plates and tubes connecting the space below the lower with the space above
the upper tube plate a collecting passage extending from the space above the upper
tube plate to the lower part of the vessel, and a distributor at the upper end of said
collecting passage, the said tubes being provided with extensions above the upper
tube plate and above the level of the liquid flowing over the distributor, substantially
as described.
5. In a multiple effect evaporating apparatus the vessel provided with á heating
chamber comprising a vapour space, and tubes in which the liquid, to be evaporated
is exposed to the heating effect of said vapour; a collecting passage extending
from the space above the said heating chamber to the lower part of the vessel, and
a distributor at the upper end of said collecting passage, and a shield or apron
interposed between the said distributor, and the delivery ends of said tubes, sub-
stantially as described.
6. In a multiple effect evaporating apparatus the vessel provided with a heating
chamber comprising a vapour space and tubes in which the liquid to be evaporated
is exposed to the heating effect of said vapour, a collecting passage extending from
the space above the said heating chamber to the lower part of the vessel, and
a distributor at the upper end of the said collecting passage, the said tubes being
provided with extensions above the upper tube plate and above the level of the
liquid flowing over the distributor, and a shield or apron interposed between the
said distributor and the delivery ends of said tubes, substantially as described.
7. In a multiple effect evaporating apparatus the vessel provided with a heating
chamber comprising a vapour space and tubes in which the liquid to be evaporated
is exposed to the heating effect of said vapour, a collecting passage extending from
the space above the said chamber to the lower part of the vessel; and a duct con-
necting the lower part of the said collecting passage with the liquid receiving space
of the next vessel of the series, and means for controlling the flow of liquid through
the said duct, substantially as described.
8. In a multiple effect evaporating apparatus the vessel provided with a heating
chamber comprising a vapour space and tubes in which the liquid to be evaporated
is exposed to the heating effect of said vapour; and a duct connecting the space
above the said chamber with the space around the tubes in the heating chamber of
the next receptacle, forming the vapour passage from one vessel to the next, com-
bined with a series of perforated plates forming partitions through which the
vapour must pass, the perforation of said plates being provided with tubes and
said tubes. of one plate being out of line with the tubes of the next plate,
substantially as and for the purpose described.
9. The main vessel of a multiple effect evaporating apparatus provided with
transverse tube plates and tubes connecting the space below the lower with the
space above the upper tube plate, a collecting passage extending from the space
above the upper tube plate to the lower tube plate and a collecting chamber at
the lower end of said passage extending below the lower tube plate and a removable

page_text: annular hood or bonnet extending from the outer wall of said collecting chamber to
the outer wall of the main vessel and enclosing the liquid inlet chamber communi-
cating with the lower ends of the tubes substantially as described.
Dated this 25th day of October 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.