Improvements in and relating to Multiple-effect Evaporating Apparatus.
Year: 1888

page_text: Improvements in and relating to Multiple-effect Evaporating
Apparatus.
I, SAMUEL MORRIS LILLIE, of Philadelphia, State of Pennsylvania, U.S.A.,
Engineer and Chemist, do hereby declare the nature of my invention for "IMPROVE
MENTS IN AND RELATING TO MULTIPLE-EFFECT EVAPORATING APPARATUS" and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement:—
This invention consists in combining a series of evaporating pans having a peculiar
construction to form a multiple effect evaporating apparatus, and it consists further
in a series of surface heaters arranged in connection with the pans of the multiple
effect, and operating to use a portion of the vapors from the several pans for heating
either a single liquid passed in succession through the several heaters in the direction
from the coolest to the hottest, or for heating different liquids in the several heaters
respectively.
Referring to the drawings
Fig. 1 is an elevation of a triple effect, and connected surface heaters, illustrative
of my invention, one of the pans, viz.: 1, being shown in vertical section and one of
the heaters viz.: N¹ having a portion of its shell broken away to expose its interior
construction to view.
Fig. 2 is a view of a detached part showing on an enlarged scale tubes c and 6 with
the annular passages n between them, which passages do not distinctly appear in
figure 1, on account of the greater number of tubes in the latter and of the smallness
of the scale to which it is drawn.
The modus operandi of the individual evaporator is briefly, as follows: The liquid
to be evaporated is delivered continuously from the supply pipe f (or v¹) upon the
inner surfaces of the evaporating tubes b, through connections consisting of the
passages among the tubes c, in the chamber G, and the annular passages n, see
figure 2, between the tubes c and b, down which surfaces it flows into the collecting
chamber P, suffering an evaporation in its course due to a heating agent, such as

page_text: steam supplied to the case E, by the main S. The liquid which falls into the chamber P
is drawn continuously from the latter by a pump Ċ which delivers it, either through
the pipe, back into the chamber G to pass again through the tubes b, or by a main v³,
to some other destination, which in the case of a multiple effect, is into the evaporating
tubes b, of the next pan.
The vapors resulting from the evaporation escape from the tubes from their upper
extremities through the tubes c into the dome D, and from their lower extremities
into the collecting chamber P, and lastly pass from the dome D, and chamber P,
through the conduits V and Y. Any liquid that may be projected from the tubes c,
into the dome D, falls upon the tube plate p, and flows back through the tubes c¹,
and into the chamber P.
%
In the drawings, three pans numbered 1, 2 and 3 respectively each having the
construction and method of operation above described, are connected together to work
as a multiple effect. The collecting chamber P of each pan is connected through the
pipe d, pump C, pipe ' and passages among the tubes c, in the chamber G, of the
next pan of the series, with the feed ends of the evaporating tubes, 6 of the latter,
excepting that of the last pan which communicates through its pump C, and pipes d,
and with the receptacle for the evaporated liquid. The dome D and the chamber P,
of each pan communicate through the connections V and Y, respectively, and in tho
particular construction shown, through the case of a surface heater N, with the
heating chamber E of the next pan of the series, excepting in the case of the last pan,
viz. pan 3, whose vapors pass from the case of its surface heater N³, to a condenser M',
provided with the usual vacuum pumps, not shown, in which they are condensed by
cold water passing through the same. Each pipe, has a branch v, leading into the
feeding chamber G, of the pan from whose pump C it leads, so that each pump may
deliver from the chamber P of its own pan, back into the evaporating tubes 6 of the
same or into the tubes 6 of the next pan or into both.
Each pipe vis fitted with a valve, h, whose stem bears two levers, one of which
inclines from the stem below the horizontal and carries a weight w, which tends to
revolve the stem to close the valve, while the other, which stands horizontal while
the valve is closed, supports by the suspending rod or cord x, the hollow globe F
whose interior communicates at the top and bottom through the flexible tubes e e¹
with the collecting chamber P, at different levels, respectively above and below the
globe, and whose weight tends to revolve the stem of valve h, so as to open the valve.
The effort of the weight w, acting on its lever, is sufficient to overbalance that of the
empty globe F, and its lever and to close the valve h, and to keep it closed as long as
the globe remains empty. As, in the operation of the apparatus to be hereinafter
described, liquid rises in the collecting chamber P, above the level of the bottom of
the globe, the latter becomes weighted by the rising liquid, (which maintains the
same level in the globe as in the chamber ) more and more until finally the combined
weight of the globe and its contained liquid will slightly overbalance the weight w,
and will cause the stem of the valve to revolve to open the valve, until the leverage of
the weight w is increased by the motion of its lever t, towards the horizontal,
sufficiently to enable it to counterbalance the increased weight of the partially filled
globe F. As the liquid continues to rise in the chamber P, and globe F, the valve
will be more and more opened by the increasing weight of the globe, until finally it
will be wide open when the liquid has risen in the chamber and globe, so as to say,
two thirds fill the latter. It is apparent that, by this device, the flow of liquid away
from a pan by the main v', will be regulated automatically by the height of the liquid
in P, and that as the globe F is above the connection leading from the piped, to the
pump C the valve h will be closed before the surface of the liquid in the chamber P,
and pipe d, sinks to the said outlet to the pump C, and so nothing but liquid i.e.—
vapors can ever pass from the pan by the pipe v.
011-
The surface heaters used in connection with the several pans of the multiple effect
may be of any of the common and suitable constructions, those shown in the drawings
being each in the form of a vertical cylinder having induction and eduction chambers s
at its two ends, respectively, for the liquid to be heated which communicate with each

page_text: other by a battery of tubes g which extend through a heating chamber N forming the
middle section of the cylinder.
The dome D and chamber P of each pan of the multiple effect, communicate with
the heating chamber of its surface heater N by means of the conduits V and Y,
respectively and the said heating chamber of the surface heater has a connection
through B with the heating chamber E of the next coolest pan, excepting in the case of
the surface heater of the last pan of the series which connects with a condenser M' in
which cold water is used as the condensing agent. The several surface heaters N of
the multiple effect are connected together by means of the pipes r³ r² so that a liquid
may be passed through them in succession.
Each surface heater N is provided with a pipe u for conducting away its water of
condensation and the heating chamber E of each of the pans is provided with similar
condensed water pipes z¹ all of which pipes u and are fitted with the usual steam
traps although they 'do not appear in the drawings. The collecting chambers P of
each pan is provided with a guage glass for indicating the level of the liquid in the
chamber. The pans are fitted with the usual fittings, vacuum guages, thermometers
and the like, although they do not appear in the drawings. The vapor spaces of all
the pans are connected together by the main H, having valved branches m, one to the
dome D of each pan.
The method of using this apparatus for the evaporation of a liquid is as follows.
The valves in the branches m of the main H are opened the vacuum pumps of the
condenser M started, and the cold condensing water turned into the condenser M², in
virtue of which the air is exhausted from all the elements of the apparatus. The
valves in m, are then closed, and steam is allowed to flow into the chamber E of
pan 1
from the main S and the liquid to be evaporated is delivered continuously into the
evaporating tubes b, from the supply pipe, through the connecting passages in the
chamber G, and between the walls of the tubes c and 6 (see Fig. 2) and is allowed to
flow down the inner surfaces of the evaporating tube into the collecting chamber P.
When the level of the liquid in P has risen sufficiently to weigh down the globe F, and
open the valve in the pipe ' to a degree the pump C draws the liquid from the
chamber P and delivers it continuously into the feeding chamber G of pan 2, whence
it flows down the inner surfaces of the tubes 6 of the same into the collecting chamber P,
whence having attained a sufficient level in the latter to act through its globe F, to open
the valve in its pipe v¹, the liquid is delivered into the feeding chamber G of pan
thence to flow down the inner surfaces of the tubes b, of the latter into its collecting
chamber P whence having attained a sufficient altitude to operate the valve of the 3rd
pan, it is delivered by the pump U of the same, through its pipe v to any destination
desired.
pan
3
As long as the liquid is continued running into the feeding chamber G of the first
pan, and the pumps are continued moving the liquid will continue running from the
discharge pipe v of the 3rd pan (or of the last pan, whatever may be the number of
pans in the series) and the liquid will be maintained at certain levels in the chambers P,
through the automatic operation of the valves h by the liquid in the said chamber as
herein before described. The steam supplied to the heating chamber E of 1
causes evaporation from the liquid running down the interior surfaces of its tubes b,
the resulting vapors escaping from the tubes into the dome D, and collecting
chamber P of the pan and thence pass into the case of the surface heater N¹,
whence the portion not condensed in the latter as presently to be described, passes
by B into the heating chamber E of pan 2, and causes evaporation from the liquid
flowing down the interior surfaces of its tubes b, the vapors from which pass into
the dome D, and chamber P, of the pan and from them into the case of surface
heater N, and the portion uncondensed in the latter passes to the chamber E of
pan and in this case the last pan of the series, and effects evaporation from the
liquid flowing down the interior surfaces of its tubes, the vapors from which pass
through the dome D, chamber P' of the pan and through the case of the heater N³
to the condenser M' in which they are condensed.
The temperatures and pressures in the several pans will vary with the pressure of

page_text: "steam in the case E of the first pan, and with the degree of vacuum, or pressure,
maintained in the vapor spaces D and P, of the last pan by the condenser M³ and its
pumps.
By the above described operation of pans, pumps C and automatically regulated
valves, the dilute liquid entering pan 1 continuously from the supply pipe fis
made to flow as continuously but in diminished quantity and concentrated form from
the pipe of pan 3 the last pan of the series.
The density of the liquid flowing from the last pan will, other things being equal,
vary with the rate of flow of the dilute liquid into the first pan, and may be varied to
suit by opening or closing the valve in the supply pipe f to the proper degree.
If at any time the liquid passing into any feed chamber G is insufficient to keep
the surfaces of the evaporating tubes b, below it, properly covered with the liquid, the
valve in the pipe leading into that chamber is opened to a degree, and the want is
met by liquid returned from the collecting chamber P of the same pan by its pump C,
and pipes vv. This return is maintained constantly or as long as needed.
This circulation of liquid from the chamber P of a pan, into the chamber G and
back again by the tubes 6 into P does not affect the level of the liquid in the latter
and so does not influence at all the workings of valve h, and its regulating devices,
their operations being influenced entirely by the rate of flow of the dilute liquid from
the supply pipe f into the first pan. If this flow be diminished, the valves h will be
in succession automatically closed to a degree; if the rate be increased the valves will
be in succession opened wider to a degree.
If the feed chamber G of each pan had an independent supply connection, (as
indicated by the dotted lines leading to the pipe v¹ in the case of pans 2 and 3) it
could be supplied with its own liquid to the exclusion of any from the preceding pan
of the series and concentrate it to any degree, the concentrated liquid may be drawn
by the pump C from the collecting chamber P and delivered by a separate pipe, not
shown to any destination desired.
The surface heaters N used in combination with the pans are intended for using a
portion of the vapors from each pan for heating the liquid to be evaporated prior to
its passing into the feed chamber G of the first pan. The course of this liquid
through the combination of surface heaters and pans is indicated by the arrows, the
arrows having but one barb showing its course through the surface heaters, and those
having two barbs indicating its course through the pans. The cool liquid enters the
heater N³ at the bottom by the pipe i, flows from the top of the same by the pipe ³,
into the top of the heater N2, from the bottom of N2, by the pipe r², into the bottom
of heater N¹ and from the top of latter by the connecting pipes and f, into the
feed chamber G of pan 1 whence it flows through the series of pans, and away
concentrated from the last of the latter, as hereinbefore described. In its passage
through the heating tubes of the surface heater it is heated in N3, to a degree by the
vapors from pan 3 during its passage through N2, it is further heated by the hotter
vapors from pan 2, and finally in passing through N₁, it is still further heated by the
still hotter vapors from pan 1, and if the condensers are of sufficient size, it will
leave N heated nearly to the temperature at which it will be evaporated in pan 1.
The heated liquid may flow from the heater N', of the first pan directly into the
feeding chamber G, of the latter via the pipes and f, or it may pass by the
pipe o, to apparatus in which it suffers a preliminary treatment, such as a defecation
or filtration, as is the case in the treatment of cane or beet juice, in which event the
heating in the heaters N1 would be preparatory to the said preliminary treatment;
in either case, the heating is very economically done by heat which has been used
from one to three times in the pans of the multiple effect.
It is apparent that any liquid other than that to be evaporated may be heated by
being passed through the heaters N and that by having proper connections to the
several heaters, a different liquid may be heated in each and also that when the
dilution of the liquid to be heated is no objection the heaters may be of the jet or
spray pattern, instead of being surface condensers as shown. The vapors which pass
from a pan uncondensed through its heater N, to the next pan of the series, play no

page_text: part in the heater, and so it is not necessary that they should pass through it, they
might therefore be led directly from one pan to the other by a separate conduit
between the two, as for example by that, indicated by dotted lines, joining the dome D
of pan 1, with the chamber E of pan 2, or by that connecting the chamber P of the
former with the chamber E of the latter also as indicated by dotted lines, the heater N
in that case, being connected only with the pan furnishing steam or vapors to it.
As the evaporators are shown in the drawings, the vapors escape from the tubes of
each pan to the next one in the series via both the dome D and the collecting
chamber P.
Should the conduit Y leading from the chamber P, be closed the vapors would all
pass from the tubes of the pan by the dome D, and conduit V; should the conduit V
be closed, the vapors would all pass from the tubes of the pan to the next one in the
series by the collecting chamber and its conduit Y, and I consider the construction
to be included within the scope of my invention, whether the vapors escape from the
tubes via both D and P, or from either alone to the next pan of the series.
I consider it advantageous in some respects to have the vapors escape from both
ends of the evaporating tubes b, but without departing from my invention the dome D
and tubes c, may be dispensed with and all the vapors be made to escape from the
opposite ends of the tubes into the common collecting chamber P, and from thence by
the conduit Y, the liquid to be evaporated being delivered into the feed ends of the
tubes by suitably arranged channels.
The distribution of the liquid to be evaporated from the feed pipe (for v¹) of each
pan to the different tubes of the pan may be accomplished by various means.
In many instances the difference in pressure between consecutive pans would be
sufficient to cause a suitable flow of liquid from the chamber P of one pan into
the evaporating tubes 6 of the next pan and in such cases a separate pipe con-
nection might be made, for this purpose between the two pans, the pump C, and
connections only being employed to return liquid from the collecting chamber of
the pan to the chamber G, of the same.
When however the difference in pressure
between consecutive pans is small, the power of a pump, or equivalent device is
desirable for forcing the liquid through the restricted feed passages into the
evaporating tubes.
I do not limit myself either to any particular number, size, shape or disposition
of tubes in the individual pans, or to any special form of feeding devices for the
evaporating tubes, or of other details connected with the same, or to any particular
number of pans in the series, the principle of the operation of the apparatus being
that the liquid to be evaporated is delivered in the case of each pan from a
supply pipe such as f, in limited quantities into the tubes of the pan at one end,
through which tubes the liquid flows into a collecting chamber common to all
the tubes (such as P) suffering evaporation during its passage by contact with
the heated walls of the tubes, that the vapors are allowed to escape from one or
both ends of the tubes and are led to the heating chamber (E) of the next pan,
while the unevaporated liquid is delivered as a rule from the collecting chamber P,
to the feeding device for the evaporating tubes of the next pan.
Having now particularly described and ascertained the nature of my invention,
and in what manner the same is to be performed, I declare that what I claim is :-
1st. The combination with an evaporating pan having the dome D, collecting
chamber P, heating chamber E, pipes b, and feeding devices for said pipes, of a
second evaporating pan having the same construction, vapor conduits between the
dome D and chamber P of the first pan, and the heating chamber E of the
second pan, and a liquid conducting main connecting the chamber P of the first
pan with the feeding devices of the tubes b of the second pan.
2nd. The combination of two or more evaporating pans to form a multiple-
effect apparatus, each pan being provided with a heating chamber E, containing
evaporating tubes b, which tubes communicate at one end with the dome D and
with a feeding device G, having restricted connections to the several tubes, and
at the other end with the collecting chamber P, a vapor conduit for each pan,

page_text: excepting the last one of the series, leading from the dome of the same to the heating
chamber of the next cooler pan, and a liquid-conducting pipe leading from the
collecting chamber of the former pan to the feeding device of the evaporating tubes
of the latter pan.
3rd. The combination of the battery of evaporating tubes their surrounding heating
chamber E, and collecting chamber P, common to the said tubes, of an evaporating
pan, operating substantially as described; the heating chamber and its contained
evaporating tubes of a second similarly operating pan; a vapor conduit leading from
the collecting chamber P of the first pan to the heating chamber E of the second
pan; and a liquid conducting pipe and connections leading from the chamber P of
the former to the feed ends of the evaporating tubes of the latter.
4th. The combination of the battery of evaporating tubes b, their surrounding
heating chamber E and collecting chamber P, common to the said tubes, of an
evaporating pan, operating substantially as described; the heating chamber E and
tubes B of a second similarly operating pan and a vapor conduit leading from the
collecting chamber P of the first pan to the heating chamber E of the second pan.
5th. The combination with two consecutive pans of a multiple effect evaporating
apparatus, each pan being provided with the evaporating tubes b and collecting
chamber P of a pump C, having its suction pipe connected with the chamber P of
the first of the two pans, and its eduction pipe ¹v, with the feed ends of the
evaporating tubes of cach pan, the pump and its connections operating to draw
liquid from the chamber P of the first pan and to deliver it to the evaporating tubes
of the same pan, or to the tubes of the second pan, or to both.
6th. The combination with two consecutive pans of the multiple-effect evaporating
apparatus, each pan being provided with evaporating tubes and collecting chamber 1
of a pump C, having its suction pipe connected with the chamber P of the first of
the two pans and its eduction pipe ¹, with the feed ends of the evaporating tubes of
the second pan, the pump and its connections operating to draw liquid from the
chamber P of the first pan and to deliver it to the evaporating tubes of the
second pan.
7th. The combination with an evaporating pan of a surface heater adapted to
heating a liquid and a second evaporating pan, each connected with the first pan by
a suitable vapor conduit, the surface heater operating to utilize a portion of the vapors
generated in the first pan for heating a liquid passing through the said heater, and
the second pan operating to utilize another portion of the vapors for evaporating
a liquid.
8th. The combination with an evaporating pan constructed and operating sub-
stantially as set forth, of a surface heater and a second evaporating pan, the collecting
chamber of the first pan being connected by suitable vapor conduits with the surface
heater and with the heating chamber of the second pan.
9th. The combination with an evaporating pan, constructed and operating sub-
stantially as set forth, of a surface heater and a second evaporating pan, the dome of
the first pan being connected by suitable vapor conduits with the surface heater and
with the heating chamber of the second pan.
10th. The combination with an evaporating pan, constructed and operating sub-
stantially as set forth, of a surface heater and a second evaporating pan, the dome
and the collecting chamber of the first pan each being connected by suitable vapor
conduits with the surface heater and with the heating chamber of the second pan.
BASE
CHATS QUILTY του.
SAMUEL MORRIS LILLIE.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.