Improvements in Apparatus for Distilling, Evaporating, or Concentrating Liquids.
Year: 1889

page_text: Date of Application, 2nd Jan., 1889
Complete Specification Left, 2nd Oct., 1889-Accepted, 23rd Nov., 1889
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Distilling, Evaporating, or
Concentrating Liquids.
We WILLIAM LAWRENCE of 22 St. Mary Axe in the City of London, Brewers'
Engineer, and RICHARD CHARLES GARTON and CHARLES HENRY GARTON, both of
Southampton Wharf, Battersea in the County of Surrey, Brewers, do hereby declare
the nature of this invention to be as follows:-
This invention consists of a set of vessels arranged in such fashion that the liquid
to be distilled or evaporated is intended to pass from vessel to vessel, either continu-
ously or intermittently, but by preference continuously. The form of the vessels is
preferably cylindrical and each vessel jacketted, so that steam passing between the
lining or jacket and the vessel inay act as the heating medium and become condensed
on transmitting its heat. The internal vessels are also intended to be fluted, waved or
corrugated laterally or otherwise curved at a right or other angle to the axis of the
cylinder. These cylindrical vessels are placed vertically and conveniently supported
in proper relation to each other according to the required differences of temperature
between them in succession. They are also connected with pipes or tubes for steam
and liquid, the steam pipe passing from near the top of one vessel to the jacket of the
next, so that the steam arising from the one vessel may act as the evaporating medium
for the next.
The pipe for the liquid passes from the bottom of one vessel to the top of the next,
and is connected with a distributing circular trough made so as to cause the liquid to
spread evenly inside all round the top or other wave or corrugation of the vessel.
The vessels are each furnished with flanges or unions for disconnecting the steam and
liquid pipes; also with manholes and sight-holes as in an ordinary vacuum pan when
they are large enough and require so fitting; also with pet cocks and steam traps to
allow the condensed water to escape from the jackets; and also with valves weighted
to regulate the pressure between the vessels, or in the usual way with stand-pipes con-
structed to maintain the pressure due to the column of liquid. Said stand-pipes may
be constructed with an inner or relief tube to prevent ebullition and any velocity
interfering with the columnar pressure. They are worked by either high or low
pressure steam, in which latter case a vacuum pump or other suitable apparatus for
producing a vacuum is employed. The cylinders may be of any suitable size and
metal, and may consist of tubes jacketted, which may have corrugations rolled in
them, or may be spirally twisted tubes placed inside other tubes forming the
jacket.
The liquor tubes may be made to pass from the bottom of the twisted tubes inter-
nally, and pass through the removable cap or flange, and thence to the top of the next
jacketted tube. The operation of the apparatus is as follows: The first vessel is
supplied with steam derived from any convenient generator, which, on condensing.
may return to it.
Whilst this steam is acting on the heating surface the liquid is delivered from the.
top of the twisted or corrugated internal part and flowing down becomes partly dis-
tilled as it condenses the steam in the jacket. The steam arising and the heat of the
liquid act in the next vessel, the steam passing into the jacketted portion and the
liquid into the interior to flow over the corrugations or waved or spiral convolutions
spirally or partly vertically. Thus the liquid may pass in succession from vessel to
vessel as many times as the columns of liquid in the pipes may, added together,
amount to the pressure of the initial steam and liquid in the first vessel. In this
manner it is calculated that a difference of a few degrees in each vessel, corresponding

page_text: to the varying pressures in each will successively condense and redistil many distilla--
tions which may be effected with the original amount of heat and condensing liquor,
as much only being required as will be needed to cause the first evaporation in the
first vessel and the condensation in the last. The construction of the vessels must
obviously be modified to suit the purpose for which it is intended, whether for water,
fresh or salt, or for syrups or ammoniacal liquors, in which latter case they would
require to be of iron. The jackets may either be rivetted on and cover the top and
bottom of the vessel as well as the sides, or the inner and outer tubes may be run into
one ring, disc or plate of metal and form the receiving cup, top and bottom and the
flanges for the liquor connections.
Dated the 2nd January 1889
Improvements in Apparatus for Distilling, Evaporating, or
Concentrating Liquids.
We WILLIAM LAWRENCE of 22 St. Mary Axe in the City of London, Brewers
Engineer and RICHARD CHARLES GARTON and CHARLES HENRY GARTON, both of
Southampton Wharf, Battersea in the County of Surrey, Brewers, do hereby
declare the nature of this invention and in what manner the same is to be
perfornied, to be particularly described and ascertained in and by the following
statement:
This invention has reference to apparatus for distilling evaporating or concentrating
liquids, and the improved apparatus comprises a set of vessels arranged in such manner
that the liquid which is being distilled or evaporated passes from vessel to vessel, the
apparatus working on the multiple effect principle. These vessels will generally be of
cylindrical form, and they constitute jackets to inner tubes or cylinders so that steam
or vapor passing or admitted to the space between the jackets and the inner tubes or
cylinders may act as the heating medium to the liquid which is flowing through the
interior of the tubes or cylinders, as in other multiple effect apparatus, the heating
vapor becoming condensed on transmitting its heat. The inner tubes or cylinders are
not plain tubes or cylinders; we make them waved or corrugated at right angles to
the plane of their axes, or we spirally twist or corrugate them. The liquid supply to
each tube or cylinder comprises a distributing trough made so as to cause the liquid
to spread evenly over the internal surface of the tube or cylinder down which it then
flows in a film. The vessels are placed vertically and are conveniently supported in
proper relation to each other according to the required differences of temperature
between them in succession. They are connected together by means of pipes or tubes
for steam and 'liquid, the steam pipe passing from near the top of one vessel to the
jacket of the next, or so that the steam arising from the one vessel may act as the
evaporating medium for the next, while the pipe for the liquid passes from the bottom
of one vessel to the top of the next, and is connected with the distributing trough
already referred to. The vessels are each furnished with flanges or unions for dis-
connecting the steam and liquid pipes, also with manholes and sight holes as in an
ordinary vacuum pan when they are large enough, and require so fitting; also with
pet-cocks and steain traps or other suitable devices to allow the condensed water to
escape from the jackets; and also with steam traps or with valves weighted to regulate
the pressure between the vessels, or with stand pipes constructed to maintain the
pressure due to the column liquid, or other suitable arrangement such as liniited
orifices or regulating valves to allow of the flow of the residual liquid between one
vessel and another without permitting the escape of steam. They are worked by either
high or low pressure steam, in which latter case a vacuum pump or other suitable
apparatus for producing a vacuum is employed. When our apparatus is used for the

page_text: purpose of evaporating or concentrating liquids,or solutions that act upon metals we
use glazed or enamelled metal or other tubes,upon which the liquids will not act.
a is the
Figure 1 of the annexed drawings represents an apparatus constructed according
to our invention in which the inner cylinders down the interior of which the liquid
flows are waved or corrugated at right angles to the plane of their axes. Two vessels
are shown but of course more may be used according to the number of evaporations
ог "effects" to be obtained. The first vessel (which is seen in elevation) is at a higher
level than the second (which is shown in vertical section). are the outer vessels.
gy their steam inlet pipes and g¹ g' the steam outlet pipes leading to the next vessel,
or in the case of the last vessel to a condenser. are the inlet pipes for the liquid
and the outlet pipes for same, the outlet pipe of the one vessel being connected
with the inlet pipe 6 of the next. are outlets for condensation water.
inner cylinder waved or corrugated as already described. is an annular distributing
trough above the cylinder a into which trough the liquid supplied by the pipe b empties.
d d are orifices around the trough through which the liquid flows so as to enter the
uppermost corrugation of the cylinder a in films; the liquid passes down the inside
of the cylinder a in contact with the corrugated wall of same. During its passage
it is heated by the steam in the jacket between the cylinder and the outer vessel i.
The vapor or steam evolved from the liquid rises in the cylinder a and passes off by
the pipe to the jacket of the next vessel, or (in the case of the last vessel of the
series) to a condenser. A represents a manhole with a cover which allows of the
apparatus being got at for cleaning when required. When the liquid to be evaporated
or concentrated is viscous, or has a tendency to adhere to the sides of the cylinder,
this corrugated form of cylinder of comparatively large diameter will be found par-
ticularly suitable, because it permits of the use of a revolving brush or stirrer for
cleaning the wall of the cylinder. A brush suitable for the purpose is shown at t; it
is operated by a shaft u and an external wheel or handle v.
Figures 2 and 3 are respectively an elevation and a plan both partly in section, of
an apparatus constructed according to.our invention, in which the inner tubes, down
the interior of which the liquid flows are spirally twisted. ii are the outer vessels ;
their steam inlet pipes and g'g their steam outlet pipes leading to the next vessel
(or to a condenser); bare the inlet pipes for the liquid and the outlet pipes for
same. hh are outlets for condensation water. aa are the inner spirally twisted
tubes connected to top and bottom tube plates &. is a pipe for conducting to the
upper part of the vessel such portion of the steam or vapor as issues from the bottom
of the tubes a. m is a perforated cylinder open top and bottom; na baffle dome for
directing the steam or vapor downwards so as to enter the annular space between the
Homes j and n. P is a perforated annular plate between the cylinder m and the wall
of the vessel. The arrangement of the perforated cylinder m, baffle domen and per-
forated plate p is intended to de-globulate the vapor, that is, to prevent any liquid
which the vapor may contain from passing into the dome and thence to the next
vessel; this liquid is intercepted and returns through the perforated plate p. Figure 4
shows on a larger scale the upper part of some of the twisted tubes a and the means
of feeding them with liquid in a film. The heads of the tubes above; the plate & have
movable or fixed tubular continuations open at top, and having feed slits d d
punched or cut in them so as to leave projecting baffle or guide pieces, see the
Sectional view Figure 5; the liquid which is supplied by the pipe Figure 2,
surrounds these continuations 1 and flows through the slits d so as to enter the
tubes a.
If the excess of pressure in the first vessel i, Figures 2 and 3, is
insufficient to force the liquid from the bottom thereof to the tops of the tubes a
of the next vessel, the first vessel may be placed on a higher level than the next.
The apparatus shown in Figures 2 and 3 is particularly adapted for evaporating
liquids of a viscous nature, and from which the vapors during ebullition do not
escape readily without forming bubbles or bladders. For some viscous fluids it
may be desirable to draw off the vapors from the bottom part e of the outer
vessel by means of the pipe 1; in such case this pipe may be continued into the
cylinder m, which may have a perforated bottom fitted to it, but with only a

page_text: limited number of perforations to return any liquid, that may be drawn over, to
the beating surfaces, and any small quantity of vapor that may have risen to the
top of the tubes.
1 Figures 6 and 7 represent in elevation and plan respectively an apparatus con-
structed according to our invention particularly adapted for distilling or evaporating
liquids which are not viscous, such for example as sea water, and in which a large
percentage of the liquid has to be evaporated. In such cases it is desirable to supply:
the outer vessels with liquid in groups, or to allow the liquid to flow from one group
of vessels to another. The great number of transmissions of heat that can be
obtained in evaporating. by means of our apparatus renders the feeding in groups
very desirable, because the salt water would become too much concentrated if fed con-
tinuously from vessel to vessel, In the evaporation of fresh water, however, where
the residual liquid forms only a very small proportion of the original liquid, the whole
may in certain cases pass in succession from vessel to vessel, that is to say where
only ten or fifteen transmissions of heat are required. But as the apparatus is
capable of effecting the condensation of vapor in one vessel and of reproducing it in
the next with a difference of about 3° Fahrenheit between the one vessel and the
other, and it may be constructed to be capable of resisting a steam pressure of many
hundreds of pounds per inch, the number of possible transmissions may exceed 100.
Therefore the question of supplying singly or in groups must be determined by the
general considerations and the number of transmissions desired. So also must the
number of inner tubes or cylinders, whether one or more in each vessel. The letters
of reference in Figures 6 and 7, which are the same as those in the figures previously
described, indicate corresponding parts. 66 are the liquid supply mains feeding
the various liquid pipes . ' is a main for condensation water into which all the
condensation water outlets discharge; this main has cocks h² to regulate the
passage of the condensation water; and because the pressures in the various vessels
gradually decrease, steam will arise from the condensation water from each vessel,
and pass up through the pipe into the next succeeding vessel. The liquid dis-
charged from each vessel through the outlet enters a main, and in the
arrangement shown the main f" that receives the unevaporated liquid from the
first five vessels supplies the liquid main that feeds the next five vessels, but
the number of vessels in a group will be regulated as may he thought best. accord-
ing to the particular circumstances of each case... The main is connected with
the boiler, and the steam thereto is regulated by a valve. Thus fresh steam can
be admitted to supply the heat absorbed by the expansion of the vapor as .the
pressures decrease. Or a separate main to supply the steam for this purpose can
be added, this main being connected with the main at as many points as may
be thought desirable.
An alternative form of tube is shown in Figure 8 in which, instead of the tube
itself being spirally twisted it is plain, but has metal pieces attached to its .inner
surface so as to form a spiral way for the flow of the liquid film. is the outer
vessel or jacket; a the inner tube and a' the- spiral formed of metal pieces attached
to the inner surface of the tube a¹. is the pipe for the outlet of the liquid to
the next vessel of the series; this pipe is shown as passing up the centre of the
tube a, and serves to illustrate this method of arranging it; with this arrange÷
ment the steam can be carried off from either the top or the bottom as thought best.
Figure 9 shows a form in which the outer vessel or jacket and the inner
twisted tube a are run into or connected to one cap or casting at top and bottom.
is the top casting with annular feed c having a screw threaded end or nozzle,
and with a screw-threaded steam outlet, gl. c is a ring in the casting constituting
the inner wall of the annular feed trough, and also carrying a directing pipe d
for the liquid film to the top of the tube a, which liquid passes through slots, c
in the casting. m is a perforated pipe for collecting the steam. is the bottom
casting receiving the lower ends of the tube a and vessel or jacket i; this casting is
threaded to receive the bottom cap s¹.
+
S
For the purpose of distilling sea water on board ship where the rolling motion

page_text: interferes with evenness of flow down. the heating surfaces a sharper twist of tube
than is necessary in some cases is required to compensate for the angle of the ship's
inclination.
It will of course be understood that our apparatus will be provided according to
the particular purpose for which it is intended with suitable valves, steam traps or
their equivalents, sight holes, manholes, circulating pumps &c., as will be well under-
stood. We have not thought it necessary to show all these appliances in the
drawings. The diameter and the kind of channelling or grooving of the evaporating
tubes can be varied as thought best according to the purpose for which the
apparatus is required and the special form of the apparatus. A convenient diameter
when the tube is a twisted or spirally grooved tube is from about one and a quarter
to four inches; if the tube be corrugated spirally a convenient diameter is from
about four to six inches.
An important feature of novelty in our invention is the use of twisted tubes
down the interior of which the liquid to be distilled, evaporated or concentrated
flows in a film, in contradistinction to the plain tubes which have hitherto been
employed. Liquid may be evaporated upon the thin film principle more readily
than when treated in the bulk, because aqueous liquids are bad conductors of heat.
Therefore however good a conducting heating metallic surface may be employed,
the aqueous liquid being acted upon, if not instantly and continuously removed
from the heating surface, will obstruct and interfere with the conductive power of
the metal. If the act of ebullition is to be made the motive power for removing
the heated liquid, then the liquid must become violently agitated by ebullition before
the conductive action can be fully set up. But when the lescent of the fluid by
gravitation is employed as the agent for removing the heated liquid, then the trans-
Dission of heat no longer depends for acceleration upon the action of ebullition,
and it becomes possible to transmit the heat from one side of the metallic surface
to the other as fast as the heat will traverse the metal. But such result cannot be
satisfactorily brought about by an ordinary plain tubular surface, even with film
evaporation, which we are aware has already been attempted. Other than a plaiu
surface must be necessary to fulfil the conditions required. In the first place in no
case is it practicable to secure evenness of flow down a plain surface. A twisted or
spirally grooved tube on the other hand meets the difficulty, even in the extreme
case of an apparatus working on board ship in a rolling sea. In addition to this
the spiral surface gives a greater distance of traverse for the liquid, and therefore a
greater mobility upon the heating surfaces, thereby rendering them more effective.
Beyond these advantages there are others of great importance in the evaporation of
viscous liquids which overcome the difficulty arising from bubbles forming upon and
throwing out of use, the heating surface when evaporation is being conducted upon
-the thin film principle.
It will be at once understood that wherever bubbles form upon the heating
surface, such surface becomes for the moment inoperative, and not only so, but
the high temperature of the heating medium will instantaneously affect the liquid,
a fine film of which will remain upon the surface and be left adhering to it,
and, in the case of liquids such as saccharine solutions, become charred more or
less.
In the employment of plain surfaces this difficulty arises for the reason that the
liquid in descending in a film becomes evenly heated and commences to boil at a
short distance from the top of the tubes, and a point is soon reached where the
bubbles or bladders that form upon the surface prevent the descending liquid from
touching the heating surface, a considerable portion of which is thereby thrown out
of use.
Now by the substitution of spirally twisted tubes for plain tubes the act of
ebullition does not throw the surface out of use, because the whole of their heating
surfaces are fed with liquid which flows down the channels in a liquid form and
small bubbles only form upon the edges of the channels; thereby a perfect ebullition
is set up from one end of the tubes to the other (or from top to bottom of the tubes).
We are aware that apparatus very similar in arrangement to that shown in Figure 2,

page_text: but having plain tubes for the heating surface has been manufactured in this
country and used abroad for several years past, but with results that have mot
proved so satisfactory as where liquid has been fed to tubes placed horizontally.
With the employment of the twisted tubes, however, the results have exceeded
anything yet known, and a new phase in redistillation has been made practicable
by rendering the operation possible with a difference of temperature of about
3° Fahrenheit between vessel and vessel; therefore effecting a great saving of heat
in bringing the expansion of the gases down to the minimum. This will be com-
prehended on reference to the tables of the estimated expansion of aqueous vapor
according to Molesworth. At about 1,000 pounds pressure (atmosphere included) the
volume of vapor is 31 times that of water, but at a vacuum corresponding with
about 28 inches of mercury the volume.is about. 20,000. The heat absorbed in the
expansion of the vapor between these volumes would result in a cold temperature
if no liquid were present, or if the vapors acted upon did not become condensed.
But in the evaporation of liquids the vapor arising robs the liquid of its heat to
make up the deficiency. This forms a great source of loss of heat, under certain
conditions, in the use of the vacuum pan where the differences of temperature are
very considerable between the heating medium and the evaporating liquid. For
instance the steam inside the coils of the vacuum pan may sometimes equal about
1,000 volumes, whereas the vapor in the pan, at a vacuum corresponding with
about 28 inches of mercury would equal 20,000. In this case the loss of heat
owing to the great expansion of the gases would be very considerable. It is for
this reason that this invention is of great importance in reducing to the fullest
extent the differences of temperatures necessary for evaporation between the one
side of the conducting surface and the other. To make this more evident it
should be borne in mind that for every transmission of heat or conversion of liquid
into vapor and vice versa the equivalent of the latent heat units, or 966 degrees,
have to be absorbed from the vapor on the one side and given off to vapor on the
.other side. When this is accomplished with a difference of say 3° of temperature
between vessel and vessel, the loss by the expansion of the vapor amounts to but a
very small percentage; but when, as is the case in an ordinary vacuum pan, the
difference equals about 120 degrees between the steam in the coils and the in
the pan arising in vacuo, the loss is equal to the heat absorbed in the expansion of
the
gases between about 1,000 and 20,000 times. When it is borne in mind that
in every form of multiple effect apparatus there must happen the loss.due to absorp-
tion of heat from the expansion of the vapors. it will be seen that where the trans-
.mission requires.many degrees of difference the loss by absorption will be,such that
a large percentage of steam must be added from the generator, or else there will be
evolved an insufficiency of steam in the one vessel to supply the increase of volume
required in the next. But when the transmission of the 966 units of heat is con-
ducted with but a few degrees of difference between one vessel and another,
the volume of steam necessary to be added will be very small between each
vessel.
vapor
The general conclusion is, therefore, that when evaporation is conducted upon the
multiple effect principle, the loss of heat between vessel and vessel resulting from the
expansion of the vapors must depend upon the difference of temperature between
the vessels. And as the gain by means of the multiple effect is in each transmission
ithe 966 units, or the equivalent of the latent heat of steam, so the loss arising
from the expansion of the vapor is as the temperature increases between vessel and
⚫vessel.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim.is -
1. In apparatus for distilling, evaporating or concentrating liquids and working on
the multiple effect system, the combination with outer vessels.or jackets supplied
with steam or vapor, of inner tubes or cylinders which are waved or corrugated at

page_text: right angles to the plane of their axes, and of means whereby the liquid under treat-
ment is made to flow down in films against the inner walls of the inner tubes or
cylinders, substantially as set forth.
O'E
2. In apparatus for distilling, evaporating or concentrating liquids, and working
the multiple effect system, the combination with outer vessels or jackots supplic.l
with steam or vapor, of inner tubes or cylinders which are spirally twisted or are
formed with spiral ways against their inner walls, and of means whereby the liquid
under treatment is made to flow down in films against the inner walls of the inner
tubes or cylinders, substantially as set forth.
3. The several arrangements or modifications substantially as hereinbefore described
and represented in the annexed drawings respectively constituting improved apparatus
for distilling, evaporating or concentrating liquids.
Dated this 1st day of Antalian 1884
J. C. MEWBURN,
55 & 56, Chancery Lane, London, Patent Agent.