IMPROVEMENTS IN APPARATUS FOR EVAPORATING SEA WATER, NITRATE OR OTHER SOLUTIONS OR LIQUIDS
Year: 1885

page_text: CER SOFT
I FREDERICK BERNARD DŒERING, of 17 York Street, in the City of Liverpool,
Civil Engineer do hereby declare the nature of my invention for "IMPROVEMENTS
IN APPARATUS FOR EVAPORATING SEA WATER, NITRATE OR OTHER SOLUTIONS OR
LIQUIDS" to be as follows:-
My invention has reference to evaporating apparatus of the kind in which the
solution or liquid to be evaporated is contained in an evaporating vessel, herein-
after called a pan, and is heated by means of steam supplied to a drum or
equivalent device within or below or surrounding the pan and the improvements
comprise the combination with the apparatus of an ejector or injector for extract-
ing a portion of the vapor or steam from the steam space of the pan and sending
it into the drum or its equivalent either directly or into and through the liquid in
a beater from which the pan is supplied a filter being in this case interposed
between the said heater and the pan; also the use in connection with the ejector of
a pocket or chamber to intercept or retain any air which may be drawn in by the
ejector and thus prevent such air being sent on with the steam or vapor to the
drum of the pan; also means whereby the steam and air or gases liberated together
from the liquid that is evaporated are allowed to separate in the steam space of the
pan; also the insertion of tubes into some or all of the vertical or approximately
vertical tubes that pass through the drum of the evaporating apparatus and form the
communication between the lower and upper parts of the pan; also the com-
bination with such inner and outer tubes of means whereby the deposit or
precipitation of crystals or insoluble matter evolved from the liquid is facilitated;
also in the case of evaporating apparatus which have not a lower compartment for
the liquid to be evaporated the employment of tubes within other tubes which
depend into the drum or steam heated compartment the lower ends of these outer
tubes being closed.
Having stated the nature of my improvements I will proceed to describe more
in detail the construction and action of an apparatus in which they are embodied.
From the upper part of the steam space of the pan is carried a pipe which is
connected with an ejector or injector worked by either direct or exhaust steam;
this ejector extracts vapor or steam from the said steam space and forces it'

page_text: through a pipe into the drum or equivalent device in the pan. Or instead of
sending the steam directly from the ejector into the drum it may be discharged
through a perforated pipe or otherwise into the liquid in a heater from which the
pan is supplied thereby heating this liquid to a temperature above that in the pan to
which it is to be supplied. This arrangement will be found advantageous when, sea
water is the liquid treated because the high temperature renders insoluble the lime
contained therein; this lime is then retained in a filter interposed between, the
heater and the pan. From the heater so much of the steam as has not been
condensed passes to the drum of the evaporating apparatus. Instead of the steam
from the ejector passing to the heater it may pass directly to the drum while other
steam from a boiler or other source may be applied to heat the water about to
enter the pan.
The steam that enters the drum vaporizes the liquid in the pan
and is itself condensed as usual. Some of the vapor is extracted from the pan by
the ejector as already described, while the remainder passes either to a condenser
or to the next pan if the apparatus is one of double or multiple effect.
When it is required that the evaporating pans or any of them shall be worked
below atmospheric pressure the last pan or condenser of the series of pans must
have an ejector or air pump applied to it to extract the air.
The steam and air
from this ejector may be discharged into the drum or air pocket of any pan in
which the pressure is above that of the atmosphere. When an air pump is used
the contents of the pump will be discharged into the atmosphere or otherwise, the
steam working the pump may be passed to any of the drums or condenser.
In order to intercept any air which may be drawn in by the ejector with the
steam that works it a pocket or chamber is provided, the ejector discharges the
steam into a first chamber in which the velocity becomes reduced; the air and
steam then pass quietly into another chamber through a hole at the lower part of
the first chamber and while the steam passes off at the upper part of the second
chamber the air owing to its greater specific gravity falls into a pocket forming
part of the second chamber. This pocket is fitted with a cock or other contrivance
for drawing off the air. This pocket may also be connected by means of a small
pipe with the drum of the evaporating apparatus to draw off any air contained
therein.
In order to allow the steam and air or other gases which are given off together
from the liquid that is evaporated to separate by gravity the steam space of the
pan is divided by a convex plate having an aperture in the centre covered by a
baffle plate. The intermingled steam and air or gases pass together through the
aperture and are diverted by the baffle plate towards the circumference of the pan.
The steam being of less specific gravity rises and is drawn off by the ejector free of
air or gas while the air or gases being denser fall into the lower portion of the
space above the convex plate and pass off to the condenser or other apparatus to
which the surplus steam is conducted.
Within some or all of the vertical or approximately vertical tubes that pass
through the drum of the evaporating apparatus and form the communication
between the upper and lower parts of the pan are inserted other tubes which are
open at both ends. Their lower ends may extend to or beyond the ends of the
outer tubes; the upper ends of the small tubes extend beyond the outer tubes and
are preferably trumpet-mouthed. They are supported on the upper edge of the
outer tubes by means of feathers or otherwise. Their area is preferably larger
than that of the annular space between the inner and outer tubes. These inner
tubes prevent priming of the apparatus, ensure efficient circulation through the
tubes, cause a greater evaporative effect to be obtained and in the case of solutions
such as sea water from which solid matters are liable to be deposited the deposit
takes place more readily upon the inner tubes than upon the outer and the former can
be readily removed for cleaning. When the apparatus is at work and vapor or steain
has freed itself from the water the dead water will flow down the inner tubes and up
the annular spaces between the inner and outer tubes carrying the vapor or steam
with it; or if some of the tubes are not fitted with inner tubes a portion of the water

page_text: will flow up them and the remainder up the annular spaces. Any opposition between
the water endeavoring to flow down the tubes and the steam-carrying water endea-
voring to flow up them is thus obviated. In cases where it is wished to deposit
crystals or insoluble matter in the lower part of the pan as, for example, in the
treatment of saline or nitrate solutions the inner tubes are made to extend some
distance beyond the lower ends of the outer tubes and the lower part of the pan is
proportionately elongated and is preferably increased in horizontal area and is
made conical below the level of the inner tubes. The circulation of the liquid
while rapid in passing down the inner tubes and up the annular spaces is very
much reduced in the lower part of the pan while passing from the inner tubes to
the annular spaces, whereby the crystals or insoluble matter evolved from the
liquid are enabled to deposit in the cone-shaped bottom of the pan from which
they can be extracted at intervals, by means of a cock or valve. In order further
to facilitate the deposit of the crystals or insoluble matter or to prevent their
passing up the annular spaces a filter or strainer may be placed across the pan
above the lower ends of the inner tubes which pass through it with more or less
tight joints and these may be supplemented by stuffing boxes. A brush may be
provided to clean the surface of the strainer, and apertures may be placed in the
strainer at those parts where the upward flow of water is least agitated and
consequently contains least sediment, so that the rising water may not be so much
impeded as to interfere with rapid circulation and hinder evaporation. It may in
some cases be preferable to substitute a solid plate for the strainer in the pan, and
pass the fluid through an opening in the side of the pan through a filter or
depositing-box, and return it through another opening above the plate to the
heating tubes for further evaporation. If the evaporating apparatus has not a
lower compartment for the liquid to be evaporated, tubes open at their upper ends
and closed at their lower ends are made to depend into the steam-heated compart-
ment or drum from the plate that divides this from the liquid compartment or pan
and within these tubes or some of them are fitted tubes open at both ends; the
liquid will thus flow down the inner tubes and up the annular spaces between the
inner and outer tubes carrying the vapor or steam with it.
Although I prefer to use my invention in its entirety it is evident. that a part
of the advantages to be derived therefrom would be obtained by the use of an
ejector in the manner described in connection with evaporating apparatus not
fitted with outer and inner tubes as described, while on the other hand a part of
the advantages would be obtained by constructing evaporating apparatus with
outer and inner tubes and with or without the means for causing crystals or
insoluble matter to deposit, as described without connecting an ejector with the
apparatus.

page_text: or other Solutions or Liquids.
I FREDERICK BERNARD DŒERING, of 5 Westminster Chambers, London, Civil
Engineer do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
My invention has reference to evaporating apparatus of the kind in which the
solution or liquid to be evaporated is contained in an evaporating vessel, herein-
after called a pan, and is heated by means of steam supplied to a drum or equivalent
device within or below or surrounding the pan and the improvements comprise the
combination with the apparatus of an ejector or injector for extracting a portion of
the vapor or steam from the steam space of the pan and sending it into the drum
or its equivalent either directly or into and through the liquid in a heater from
which the pan is supplied, a filter being in this case interposed between the said
heater and the pan; also the use in connection with the ejector of a pocket or
chamber to intercept or retain any air which may be drawn in by the ejector and
thus prevent such air being sent on with the steam or vapor to the drum of the
pan; also means whereby the steam and air or gases liberated together from the
liquid that is evaporated are allowed to separate in the steam space of the pan;
also the insertion of tubes into some or all of the vertical or approximately vertical
tubes that pass through the drum of the evaporating apparatus and form the com-
munication between the lower and upper parts of the pan and the combination.
with such inner and outer tubes of means whereby the deposit or precipitation of
crystals or insoluble matter evolved from the liquid is facilitated; also in the case
of evaporating apparatus which have not a lower compartment for the liquid to be
evaporated the employment of tubes within other tubes which depend into the
drum or steam heated compartment, the lower ends of these outer tubes being
closed.
Having stated the nature of my improvements I will proceed to describe more in
detail the construction and action of an apparatus in which they are embodied.
From the upper part of the steam space of the pan is carried a pipe which is con-
nected with an ejector or injector worked by either direct or exhaust steam; this
ejector extracts vapor or steam from the said steam space and forces it through a
pipe into the drum or equivalent device in the pan; thus both the steam or vapor
extracted from the pan and that which works the ejector become condensed in the
drum the heat liberated by the condensation serving to heat and evaporate the
liquid in the pan. Or, instead of sending the steam directly from the ejector into
the drum it may be discharged through a perforated pipe or otherwise into the
liquid in a heater from which the pan is supplied thereby heating this liquid to a
temperature above that in the pan to which it is to be supplied. This arrange-
ment will be found advantageous when sea water is the liquid treated because the
high temperature renders insoluble the lime contained therein; this lime is then
retained in a filter interposed between the heater and the pan. From the heater
so much of the steam as has not been condensed passes to the drum of the
evaporating apparatus. Instead of the steam from the ejector passing to the
heater it may pass directly to the drum while other steam from a boiler or
other source may be applied to heat the water about to enter the pan. The steam

page_text: that enters the drum vaporizes the liquid in the pan and is itself condensed as
usual. Some of the vapor is extracted from the pan by the ejector as already
described while the remainder passes either to a condenser or to the next pan if
the apparatus is one of double or multiple effect.
When it is required that the evaporating pans or any of them shall be worked
below atmospheric pressure the last pan or condenser of the series of pans must
have an ejector or air pump applied to it to extract the air. The steam and air
from this ejector may be discharged into the drum or air pocket of any pan in
which the pressure is above that of the pan from which it was drawn.
When an
air pump is used the contents of the pump will be discharged into the atmosphere
or otherwise; the steam working the pump may be passed to any of the drums or
condenser.
In order to intercept any air which may be drawn in by the ejector with the
steam that works it a pocket or chamber is provided; the ejector discharges the
steam into a first chamber in which the velocity becomes reduced; the air and steam
then pass quietly into another chamber through a hole at the lower part of the first
chamber and while the steam passes off at the upper part of the second chamber
the air owing to its greater specific gravity falls into a pocket forming part of the
second chamber. This pocket is fitted with a cock or other contrivance for drawing
off the air. This pocket may also be connected by means of a small pipe with the
lower part of the drum-of the evaporating apparatus to draw off any air contained
therein.
In order to allow the steam and air or other gases which are given off together
from the liquid that is evaporated, to separate by gravity, the steam space of the
pan is divided by a plate, preferably convex, having an aperture in the centre
covered by a baffle plate. The intermingled steam and air or gases pass together
through the aperture and are diverted by the baffle plate towards the circumference
of the pan. The steam being of less specific gravity rises and is drawn off by the
ejector free of air or gas while the air or gases being denser fall into the lower
portion of the space above the convex plate and pass off to the condenser or other
apparatus to which the surplus steam is conducted.
Within some or all of the vertical or approximately vertical tubes that pass
through the drum of the evaporating apparatus and form the communication
between the upper and lower parts of the pan are inserted other tubes which are
open at both ends. Their lower ends may extend to or beyond the ends of the
outer tubes; and their upper ends extend beyond the outer tubes and are preferably
trumpet-mouthed. They are supported on the upper edge of the outer tubes by
means of feathers or otherwise. Their area is preferably larger than that of the
annular space between the inner and outer tubes. These inner tubes prevent
priming of the apparatus, ensure efficient circulation through the tubes, cause a
greater evaporative effect to be obtained and in the case of solutions, such as sea
water from which solid matters are liable to be deposited, the deposit takes place
more readily upon the inner tubes than upon the outer and the former can be
readily removed for cleaning. When the apparatus is at work and vapor or steam
has freed itself from the water, the dead water will flow down the inner tubes and
then up the annular spaces between the inner and outer tubes, being carried by the
vapor or steam generated; or if some of the tubes are not fitted with inner tubes a
portion of the water will flow up them and the remainder up the annular spaces.
Any opposition between the water endeavoring to flow down the tubes and the
steam-carried water endeavoring to flow up them is thus obviated. In cases where
it is wished to deposit crystals or insoluble matter in the lower part of the pan,
as, for example, in the treatment of saline or nitrate solutions, the inner tubes are
made to extend some distance beyond the lower ends of the outer tubes and the
lower part of the pan is proportionately elongated and may be increased in horizontal
area and is made conical below the level of the inner tubes. The circulation of
the liquid while rapid in passing down the inner tubes and up the annular spaces
is very much reduced in the lower part of the pan while passing from the inner

page_text: tubes to the annular spaces, whereby the crystals or insoluble matter evolved from.
the liquid are enabled to deposit in the cone-shaped bottom of the pan from which
they can be extracted at intervals, by means of a cock or valve.
In order further to facilitate the deposit of the crystals or insoluble matter or
to prevent their passing up the annular spaces a filter or strainer may be placed
across the pan above the lower ends of the inner tubes which pass through it with
more or less tight joints and these may be supplemented by stuffing boxes. A
brush may be provided to clean the surface of the strainer, and apertures may be
placed in the strainer at those parts where the upward flow of water is least
agitated and consequently contains least sediment, so that the rising water may
not be so much impeded as to interfere with rapid circulation and hinder evapora-
tion. It may in some cases be preferable to substitute a solid plate for the strainer
in the pan, and pass the fluid through an opening in the side of the pan through a
filter or depositing box, and return it through another opening above the plate to
the heating tubes for further evaporation. If the evaporating apparatus has not a
lower compartment for the liquid to be evaporated, tubes, open at their upper ends
and closed at their lower ends, are made to depend into the steam heated compart-
ment or drum from the plate that divides this from the liquid compartment or pan
and within these tubes or some of them are fitted tubes open at both ends, the
combined inner and outer tubes being similar to what are known as "Field
boiler tubes; the liquid will thus flow down the inner tubes and up the
annular spaces between the inner and outer tubes carrying the vapor or steam
with it.
"
The annexed drawings represent evaporating apparatus in which most of my
improvements as hereinbefore described are embodied, the construction shown
being suitable for the evaporation of a nitrate or other solution from which crystals
or insoluble matter have to be deposited in the lower part of the pan. Figure 1
is an elevation of one form of the apparatus; Figure 2 a vertical section and
Figure 3 a sectional plan of the same. Figure is a part vertical section of
another form of the apparatus combining improvements that are not shown in
Figures 1, 2 and 3.
A is the pan containing the nitrate or other solution to be evaporated. D is the
drum or steam chamber wherein the steam used for evaporating the solution in the
pan is condensed, and in the act of condensing, heats up the said solution. From
the upper part of the steam space of the pan A is carried a pipe a which is con-
nected with an ejector E worked by steam admitted by the pipe b, such steam
coming either from the boiler or being exhaust steam. This ejector extracts vapor
or steam from the steam space of the pan and forces it through a pipe c either
directly into the drum D as shown in Figures 1 and 2, or into a heater as herein-
before described from which the pan is supplied, or into a pocket or chamber as
shown in Figure 4 (seen also in plan in Figure 5) for intercepting any air which
may be drawn in by the ejector with the steam that works it; in this last modi-
fication the steam from the pipe c is discharged into a first chamber d in which the
velocity becomes reduced; the air and steam then pass quietly into another
chamber e through a hole f at the lower part of the chamber d; the steam passes
off at the upper part of the chamber e while the air falls into the pocket g; this
pocket has a cock h for drawing off the air and is shown as connected by a pipe ¿
with the drum D so as to draw off any air contained therein.
The ejector E cannot draw off all the vapor or steam from the pan A and send it
on to the drum D; the remainder or surplus (if the apparatus is not one of double
or multiple effect in which case it will pass into the next pan) passes through a
pipe and cock at R to a condenser B. G is the inlet pipe for the circulating water
to this condenser and H the outlet pipe for the circulating water; this pipe H
supplies the pipe J which is the feed pipe supplying the liquid to be evaporated to
the pan A; N is a waste pipe for surplus circulating water not required for feed.
W, W are pipes for carrying off condensed water from the drum and condenser
respectively.

page_text: L is a convex plate or division in the upper part of the pan A with an aperture
in the centre covered by a baffle plate. This plate or division L allows the steam
and air or gases given off by the liquid that is being evaporated to separate by
gravity, the steam being of less specific gravity rises towards the ejector E while
the air and gases fall and pass off at R.
}
T, T are the tubes forming the communication between the upper and lower
parts of the pan A, they are securely fastened between the tube plates P and these
form the drum. Within the tubes T, T are suspended other tubes S, S. When
the apparatus is intended for getting a deposit at the bottom of the pan of crystals
or insoluble matter from the solution that is being evaporated the tubes S, S are
carried to a considerable distance below the outer tubes T, T as shown and the
lower part of the pan is proportionately elongated as seen at Y and below the ends
of the tubes S, S the pan is preferably made conical as shown at C. The space Y
constitutes a chamber in which the velocity of the upward current of the liquid
under treatment becomes very much reduced and therefore the crystals or insoluble
matter are enabled to deposit readily in the cone C; the velocity of the liquid is
comparatively quick in passing down the inner tubes S, it becomes very slow in
rising up the space Y and then very rapid in passing up the annular spaces
between the tubes S and T. The distance to which the inner tubes S are carried
below the tubes T will never be less than 9 inches, but in practice from 18 to 30
or more will be desirable; the distance should be regulated by the class of liquid
which is to be treated, those liquids in which the specific gravity of the solid
particles is great compared with that of the solution will not require so long a
projection of the tubes S as liquids in which the difference of the specific gravities
is small. The depth of the pan prolongation Y should not be less than 6 inches
below the tubes S. F is a cock or valve at the bottom of the cone C for drawing
off the precipitated or deposited matter at intervals. In order to further facilitate
the deposit of crystals or insoluble matter a strainer or filter (not shown) may be
placed across the space Y above the lower ends of the tubes S. In Figure 4 I show
a solid plate k which may be used instead of the strainer; in this case the liquid
flows through an opening into a depositing box m and returns to the pan through.
another opening n above the plate k. The provision for reducing the velocity of
the liquid under treatment to a very slow degree before passing up the tubes
means of the space or pan prolongation Y which allows the crystals or insoluble
matter to become deposited in a chamber or cone, such as C, is a characteristic
feature of my apparatus, and is not limited to the particular form of drum shown
in the figures, the essential point is that the liquid which flows quickly down
through the drum shall rise slowly up the space Y its velocity in passing up
through the drum being again quick.
by
Although I prefer to use my invention in its entirety it is evident that a part of
the advantages to be derived therefrom would be obtained by the use, for example,
of an ejector in the manner described in connection with evaporating apparatus
not fitted with outer and inner tubes as described or with the means for causing
crystals or insoluble matter to deposit and on the other hand by constructing
evaporating apparatus with the means for causing crystals or insoluble matter to
deposit, and with or without outer and inner tubes, as described, without con-
necting an ejector with the apparatus.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim, in respect of apparatus for evaporating sea water, nitrate or other solutions
or liquids, is:
1. Constructing apparatus substantially as herein before described in such manner
that some of the vapor or steam generated in the evaporating pan is drawn off
directly by an ejector and forced by it into the drum or its equivalent together
with the steam that works the ejector so that both the vapor thus drawn off from
the pan and the vapor which works the ejector are condensed in the drum and

page_text: serve to heat and evaporate the liquid in the pan, the surplus or remainder of the
vapor or steam in the pan, that is to say, the portion not drawn off by the ejector
passing to a condenser or to the drum of another pan if the apparatus is one of
double or multiple effect the vapor from the last pan passing to a condenser or
otherwise.
2. The interposition, as herein before described, between the evaporating apparatus
and an ejector employed for drawing off some of the vapor, as referred to in claim 1,
of a vessel or heater containing the liquid to be supplied to the pan the steam
from the ejector being discharged into the liquid in the said heater, so much of the
steam as is not condensed in the heater being passed on to the drum while the
water on its way from the heater to the pan passes through a filter, as set forth.
3. The modification herein before described in which steam for heating the liquid
in the heater, referred to in claim 2, comes from some other source than the
ejector.
4. The combination with an ejector used to extract steam or vapor from an
evaporating pan and pass it on to the drum, as referred to in claim 1, of a pocket
or chamber, substantially as described and shown, to intercept the air drawn in by
the ejector.
5. The fitting in the steam space of an evaporating pan of a dividing plate
having an aperture and a baffle plate, substantially as described and shown for the
purpose of enabling the steam and air or gases to separate.
6. In an evaporating apparatus having outer and inner tubes that pass through
the drum and form the communication between the upper and lower portions of
the pan, I claim the employment of inner tubes that extend to a considerable
distance (at least 9 inches) below the outer tubes in combination with a space or
pan prolongation (such as Y, extending 6 inches or more below the inner tubes)
and a depositing chamber or cone (such as C) whereby the velocity of the liquid
that flows down the inner tubes becomes very much reduced in the said space or
pan prolongation and allows the crystals or insoluble matters to precipitate or
deposit, the liquid again assuming a rapid velocity in passing up the annular
-spaces between the outer and inner tubes, all substantially as set forth.
7. In an evaporating apparatus having a pan with a compartment above and a
compartment below the heating drum or equivalent device, I claim the providing
of means, substantially as described, whereby the liquid under treatment and
which has passed down through the drum, or at the side thereof, is caused to
descend a considerable distance, say not less than 9 inches beyond the drum, and
to ascend this distance very slowly before again passing up into the drum so that
the crystals or insoluble matter are enabled to precipitate or deposit, as set forth.
8. In an apparatus constructed for the purpose of allowing of the precipitation
or deposit of crystals or insoluble matter as referred to in claims 6 and 7, I claim
a depositing box or filter, substantially as described and shown in Figure 4,
through which the liquid flows after passing down through the drum and before
returning to pass up through the drum.
9. The combination in an evaporating apparatus of an evaporating pan, a drum
fitted with inner and outer tubes through which the liquid to be evaporated flows,
an ejector for drawing off some of the steam or vapor from the pan and passing it
on to the drum, and an outlet leading to a condenser or otherwise for carrying off
the surplus or remaining steam or vapor, substantially as described.
10. Constructing evaporating apparatus as represented in the annexed drawings
and hereinbefore described.