Distilling Liquids.
Year: 1888

page_text: Distilling Liquids.
We, WILLIAM RENNY WATSON and ROBERT ANDREW ROBERTSON both of
45 Scotland Street, Glasgow, in the Counties of Lanark and Renfrew, North
Britain, Engineers do hereby declare the nature of this invention to be as
follows:-
This Invention relates to vacuum evaporating and distilling apparatus of the
tubular variety, wherein the evaporization is effected by causing a limited supply
of liquid to flow in a state of ebullition through a heated pipe or connected series
of such pipes, while undergoing the evaporizing and distilling operation, and in which
the vapour or steam is separated from the liquid in a chamber at the discharge end of
the pipe or series of pipes, and is conducted to the heating chamber surrounding the
evaporating pipes of the next division of the apparatus and so on from the first to
the last evaporator or directly from a single or any one evaporator of a series to the
condenser.
In apparatus of this kind as hitherto constructed it has been usual to employ
heating tubes having the same cross section or area throughout all the divisions of
the apparatus the result of which has been that whilst the tubes of the first division
are sufficiently supplied with liquid the tubes of the second, third or other succeeding
divisions of the apparatus are, owing to the volume diminishing under treatment less
and less sufficiently supplied with liquid which favors formation of scale in the tubes
and reduces the speed of flow through them below that necessary to ensure a scouring
action sufficient to remove the deposit.
The object of the present improvements is to as far as possible maintain a constant
and high speed of flow through the heating tubes of the different divisions of the
apparatus so as to prevent the formation or collection of scale and deposit in the
tubes and this object is effected by reducing the cross sectional area of the tubes
available for the passage of the liquid in approximately the same proportion as the
volume of the liquid diminishes during treatment.

page_text: In carrying out this Invention the area of the tubes available for the passage of
the liquid is reduced by placing in each tube either a tube or bar of any suitable
material of such dimensions as will produce the required effect, and such bar or tube
may be parallel, tapered or of any other form found most suitable to produce the
desired scouring action.
By means of this Invention the areas of the heating tubes in each division of
evaporating apparatus of the kind herein before referred to when worked in series or
multiple effect may be adjusted to the varying volume of liquid passing through them
and this Invention is equally applicable to the tubes of such apparatus when arranged
to work single effect.
Dated this 15th day of December 1888.
ST. JOHN V. DAY,
115, St. Vincent Street, Glasgow,
Petitioner's Agent.

page_text: Improvements in Apparatus for Evaporating, Concentrating, and
Distilling Liquids.
We, WILLIAM RENNY WATSON, and ROBERT ANDREW ROBERTSON, both of
45 Scotland Street, Glasgow, in the Counties of Lanark and Renfrew, North Britain,
Engineers 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 :-
Our Invention relates to vacuum, evaporating, concentrating and distilling apparatus
of the tubular variety constructed as hereinafter described wherein the evaporization,
concentration and distillation of liquids is effected by causing a limited supply of
liquid to flow in a state of ebullition through a heated pipe or connected series of
such pipes while undergoing the evaporating concentrating and distilling operation,
und in which the vapor or steam is separated from the liquid in a chamber at the
discharge end of the pipe or series of pipes, and is conducted to the heating chamber
surrounding the evaporating pipes of the next division of the apparatus, and so on
from the first to the last evaporator or directly from a single evaporator or any one
evaporator of a series to the condenser.
It is explained that the construction of the apparatus is not altered, whether used
as an apparatus for concentrating, that is to say, increasing the density of the liquid
passed through it, or where used as a distilling apparatus for either concentration or
distillation is effected by the process or operation of evaporation.
When used for concentrating a liquid, the object may be to effect concentration
only, or to both concentrate the liquid, as well as to collect the vapour given off, by
passing it into a condenser, or when such vapour is of no value, then the object may
he to concentrate the liquid without collecting the vapour, which in such cases may
be allowed to escape..
When used for distilling a liquid, the object may be to effect distillation only, with
or without collecting the concentrated portion of the liquid, accordingly as it is, or is
not, of commercial value. In either case the vapor given off is collected by being
passed into or through a condenser.
As an instance of using our apparatus for distilling, we may mention its
applicability for producing fresh water on board ship or elsewhere, from sea-
water.
In this case the object is to collect the water of condensation and to allow the
concentrated brine to pass off as a waste product. In such case, the fresh water is
collected in the condenser after the vapor from which it has been condensed has given
up heat in effecting the concentration of the sea water in the apparatus and the brine
is discharged as a waste product.
In apparatus of this kind as hitherto constructed it has been usual to employ heating
tubes either having the same cross section or area throughout all the divisions of

page_text: the apparatus or having a gradually increasing section, the result of which has been
that, whilst the tubes of the first division are sufficiently supplied with liquid, the
tubes of the second, third or other succeeding divisions under treatment, less and less
sufficiently supplied with liquid which favor formation of scale in the tubes and reduces
the speed of flow through them below that necessary to ensure a scouring action
sufficient to remove the deposit.
The speed of flow of the liquid under treatment in such apparatus can be increased
by diminishing the diameter of the tubes towards their outlet ends which however
necessitate a corresponding increase in the number of tubes in order to obtain the
heating surface required rendering the apparatus more costly to construct and very
considerably increasing the difficulties already experienced in equally distributing the
liquid amongst the tubes.
The object of the present invention is as far as possible to maintain under any
required conditions as to extent of heating surface a constant and high speed of flow
through the different heating tubes and different divisions of the apparatus and
thereby to provent the formation or collection of scale and deposit in the tubes.. This
is effected by reducing the cross sectional area of the tubes available for the passage
of the liquid in approximately the same proportion as the volume of the liquid
diminishes during treatment.
In carrying out this Invention the area of the tubes available for the passage of the
liquid is reduced as hereinafter described by placing in each tube a bar or rod of any
suitable material of such dimensions as will produce the desired effect and such bar or
rod may be hollow or solid, parallel, tapered or any other form found most suitable to
produce the desired scouring action.
By means of this Invention the areas of the heating tubes in each division of the
evaporating apparatus of the kind hereinbefore referred to when worked in series or
multiple effect may be adjusted to the varying volume of liquid passing through them
and this Invention is equally applicable to the tubes of such apparatus when arranged
to work in single effect.
In order that our Invention may be properly understood and readily carried into a
effect, we will now proceed to describe the drawings herounto annexed.
Figure 1, is a longitudinal section of a set of tubos numbered 1, 2, 3 and 4
respectively with the front tube plate A, removable cover piece B, and return-bend
end and the tube plates C, and C1, constructed in the same manner as that described
in and shewn on the drawings attached to the complete specification of the said a
William Renny Watson and Robert Andrew Roberston No. 11485 of 1888.
Figure 2, is an elevation of the front ends of such tubes carried in the tube
plate A, which is shewn broken off round its edges and representing the said
tube plate and ends of the tubes as they would be seen when the front cover B, is
removed.
The outer casing or cylinder within which the sets of tubes, tube plates and inner
return-bend ond plates are contained in the tubular vacuum apparatus of this kind is
not shown on the drawings but it is to be understood that it is of the same or
analogous construction to that described in the aforesaid specification of and shewn in
the drawings attached thereto No. 11485 of 1888. The regulator for admitting fluid
to the several rows of pipes or tubos 1, 2, 3, and 4, is of the same analogous
construction to that described in the aforesaid specification and therefore need not be
here further referred to.
4
The sets of tubes or pipes 1, 2, 3 and 4 shewn in Figures 1 and 2 may be the tubes
of a single effect tubular vacuum apparatus for evaporating, concentrating or distilling 5
liquids or those of any one division of a similar multiple effect apparatus and it will
be observed on reference to the drawings that the rods D, E, F, G, placed respectively
in each tube of the several rows of tubes numbered 1, 2, 3, and 4 progressively
increase in diameter so that whilst the tubes themselves are all of the same external
diameter the area of the annular space within them, that is to say, the space contained 5
between the rods and the internal diameter of each tube progressively decreases
downwards, that is to say towards the bottom tube of the apparatus or of each division

page_text: of it wherein the said rods D, E, F, G, are placed and thus the volume of the space
through which the liquid passes in each row of tubes progressively corresponds to
the diminishing volume of the liquid undergoing evaporation, concentration and
distillation.
The tubes or rods D, E, F, G, may be of any suitable material, metal, wood,
vulcanite or other substance which will not act upon or be acted upon by the liquid or
vapors thereof undergoing evaporation, concentration and distillation. In practice we
find that cylindrical rods of wood answers the purpose of our improvements and they
are preferably made in the form shewn at Figure 1, that is to say having cylindrical
bodies gradually tapered off at each end the longth of each end being preferably but
little shorter than the clear distance between the insides of the front and rear
covers B, and C, the tapering off of each rod D, E, F, and G. at both ends affords
sufficient free space for the easy passage of the liquid and vapor from one row of tubes
to another through the spaces in the front cover B, and the return bend end C. The
several rods D, E, F, and G, may be maintained in a central position in their
respective tubes by any convenient means. A single and efficient means which we
find to answer well in practice is shewn in the annexed drawings namely the insertion
radially of metallic pins or screws a, a, a, each projecting an equal distance outwards
from each bar or rod D, E, F, G.
Another method of securing the said bars or rods centrally in the heating tubes is
by means of plates or vanos attached to the bars at suitable distances apart and
projecting sufficiently to centre the bars in the tubes and so inclined as to impart a
rotary motion of the liquid passing through the tubes. Such distance plates or vanes
may also be carried spirally the whole length of each bar thus forming annular spiral
passages for the liquid.
In place of the rods D, E, F, G, being cylindrical and of one continuous diameter
as shown at Figures 1 and 2, they may be made of varying shapes of which an
example is given at Figure 3, G, being the lower rod of a series and which it will be
observed is not of a continuous or uniform diameter but is of varying diameters having
for its object to facilitate the agitation and breaking up of the flow of the liquid as it
passes through the tubes thus rendering the exposure of all the parts of the liquid to
the heating surface more complete than might be the case when using cylindrical rods
only.
In practice and with a multiple effect vacuum apparatus of the kind herein before
referred to it will generally not be necessary to employ the rods D, E, F, G, in the
first division or first effect part of the apparatus but in the second, third, fourth or
other number of multiple effects wherein the volume of the liquids under treatment
becomes much reduced in volume, the use of the said rods D, E, F, G, becomes of
considerable importance for, whilst ensuring as they do the exposure of the liquid to
the required area of heating surface they at same time cause the rate of flow of the
liquid and vapor through the tubes to go on at a more rapid rate than has been the
case hitherto in apparatus of this kind with which any large range of concentration
has been attempted wherein the tubes through which the liquor passes after the first
or second effects have been either of the same diameter or of a larger diameter than
the tubes used in the first or second effects.
In single effect apparatus also it may not be necessary to use the said rods D, E, F, G,
in the upper row or it may be in the two or three uppermost rows thereof but there
importance comes into operation when used in the lowest or it may be the two or
three lowest rows of tubes or pipes thereof.
Having now particularly described and ascertained the nature of our said Invention
and in what manner the same is to be performed, we declare that what we claim is :—
1. In tubular vacuum apparatus for evaporating, concentrating and in some cases
distilling liquids constructed as described the reduction of the cross sectional area or
space in the tubes or pipes thereof through which the liquid and vapor flows whilst
undergoing treatment by the placing of rods or bars therein so as to form an annular

page_text: space in each tube or pipe the gradual diminution of such space corresponding
approximately to the gradually diminishing volume of the liquid flowing therethrough,
substantially as hereinbefore described and shewn upon the annexed sheets of drawings.
2. The formation of vanes either continuous or in short sections on the bars or rods
inserted in the heating tubes of vacuum evaporating and distilling apparatus as
hereinbefore described for the purpose of securing the said bars or rods centrally
within the tubes and imparting to the liquid passing through them a rotary motion,
substantially as set forth.
1
JOHN LIDDLE,
154, St. Vincent Street, Glasgow,
Applicants' Agent.