IMPROVEMENTS IN OPERATIONS AND APPARATUS FOR DRYING DOWN ALKALINE SOLUTIONS OF EXTRACTIVE MATTER OBTAINED IN PREPARING VEGETABLE FIBROUS MATERIALS FOR USE IN THE MANUFACTURE OF PAPER, AND IN RECOVERING ALKALI THEREFROM FOR RE- EMPLOYMENT
Year: 1868

page_text: ETTERS PATENT to Frederick Oldfield Ward, of 6; Hertford Street,
Mayfair, London, William Ibotson, of 3, New Inn, London; and
Anthony Gapper Southby, of Bulford, in the County of Wilts,
Gentlemen, for the Invention of "IMPROVEMENTS IN OPERATIONS AND
APPARATUS FOR DRYING DOWN ALKALINE SOLUTIONS OF EXTRACTIVE MATTER
OBTAINED IN PREPARING VEGETABLE FIBROUS MATERIALS FOR USE IN THE
MANUFACTURE OF PAPER, AND IN RECOVERING ALKALI THEREFROM FOR RE-
EMPLOYMENT."
Sealed the 11th May 1869, and dated the 18th November-1868.
PROVISIONAL SPECIFICATION left by the said Frederick Oldfield
Ward, William Ibotson, and Anthony Gapper Soutliby at the
Office of the Commissioners of Patents, with their Petition, on the
18th November 1868.
We, FREDERICK OLDFIELD WARD; of 6, Hertford Street, Mayfair,
London, WILLIAM IBOTSON, of 3, New Inn, London, and ANTHONY
GAPPER SOUTHBY, of Bulford, in the County of Wilts; Gentlemen, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
OPERATIONS AND APPARATUS FOR DRYING DOWN ALKALINE SOLUTIONS OF EXTRACTIVE

page_text: MATTER OBTAINED IN PREPARING VEGETABLE FIBROUS MATERIALS FOR USE IN THE
MANUFACTURE OF PAPER, AND IN RECOVERING ALKALI THEREFROM FOR RE-
EMPLOYMENT," to be as follows:-
These improvements relate to operations and apparatus for drying
down alkaline solutions of extractive matter, obtained in preparing
vegetable fibrous materials for use in the manufacture of paper, and in
recovering alkali therefrom for re-employment; and the said improve-
ments consist,-
Firstly. In evaporating such liquor by means of the heat afforded by
the regulated supply to, and combustion in a suitable sole or fire-place,
of the hydro-carbonaceous matters which such liquors hold in solution,
the effect being to supersede, partly or wholly according to the greater
or less dilution of the liquor, the necessity of coal or other extraneous
fuel for its desiccation.
Secondly. In separating from the liquor, under treatment to that end,
either continuously or at frequent intervals, its said self-contained fuel,
so fast as this solidifies to a crust or deposit coherent enough for.
removal.
Thirdly. In applying this liquor derived fuel in one or other of the
following ways, namely, (a), to feed a fire so disposed as to heat a
series of shallow liquor trays or receptacles superposed in a chamber
in such manner that the heat may pass over and under them in succes-
sion, the first of such receptacles being fed by a regulated influx of the
liquor for treatment, the second by a regulated supply from the first,
and so on, each receiving a more concentrated supply till solidification
commences, when the solid matter is removed from the liquid to a
succeeding receptacle, where it undergoes further desiccation, and is
finally advanced to the sole or fire-place in which it takes fire and is
incinerated: This operation may be facilitated (1), by forming the recep-
tacles with an inclined lip or border, adapted to retain the liquor whilst
facilitating the separation therefrom of floating crust; (2), by forming
the receptacles of fire-tiles covered with iron, wrought or cast, for the
readier removal or scraping off of adherent deposit; (3), by employing
for the said separating of solidified matters from the liquor power-
driven apparatus, of the nature of rakes, scrapers, or archimedean screws.
(b), as an alternative mode, the heat produced by the said liquor derived
fuel may be applied to the accomplishment of the end in view by
employing it to raise steam and thereby to work a fan or other suitable

page_text: apparatus to create a draft of air, which may be either cold or preferably
heated by the self-supplied fuel or otherwise, and conveyed over or
through or amidst the liquor in such manner as to dry it down, pre-
ferably using a series of shallow superposed receptacles, similar to the
above described, but which in this case need not be fireproof, the
solidified material being in 'this mode of working conveyed for its final
desiccation and combustion to the furnace of the steam generator. (c),
as a still more economical alternative mode to the same end in localities
where water power is cheap and abundant, this may be employed to
produce air currents for the preliminary concentration of the liquor,
its self-supplied fuel being burnt only to complete the desiccation, thus
Leaving an excess of fuel available for other heating purposes.
Fourthly. In obviating the diffusion of odour from the liquor during
its evaporation and incineration by condensing the fumes with water
or passing them through fire, the former of which objects may pre-
ferably be accomplished by a water-fed tower, as is well understood;
while the latter may be attained as regards the emanations of the solidi-
fied matter, by raking this into a receptacle with a vent to some fire-
place preferably the fire-place of the apparatus, wherein such emanations
may be consumed.
Fifthly. In obviating the progressive contamination of the recovered
ash, through the accumulation therein of extraneous neutral salts, by
dissolving the said ash in water, and "salting out" the said extraneous
ingredients from the solution in any of the ways in use among chemists
for that purpose.
Sixthly. In utilising waste heat, such as, for instance, waste chimney
heat, to further economise the self-supplied fuel of the liquor by effecting
a preliminary concentration, more or less considerable, thereof, the waste
heat being applied to this end either by passing it over and under shallow
receptacles of the liquor, in the manner above described, or through
tubes traversing the liquor as is well understood, or in any other suitable
manner, the draft to effect this being obtained in any usual way, as, for
instance, by the draft of the hot gases themselves, or by a fan or
ventilator.
Seventhly. In further economising artificial heat of all kinds by
employing spontaneous evaporation under the influence of the sun and
the atmosphere to remove vapour from surfaces of the liquor, exposed

page_text: fo: that purpose during the day time, but kept covered from the counter-
vailing deposit of dew between sundown and sunrise of successive
days.
Eighthly. In combining together such of these modes, two or more,
as local and other circumstances may indicate, in each special case as
forming the most economical and suitable group or series of operations
available in that case to the end in view.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frederick Oldfield Ward, William Ibotson, and
Anthony Gapper Southby in the Great Seal Patent Office on the
18th May 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, FREDERICK
OLDFIELD WARD, of 6, Hertford Street, Mayfair, London, WILLIAM
IBOTSON, of 3, New Inn, London, and ANTHONY GAPPER SOUTHBY, of
Bulford, in the County of Wilts, Gentlemen, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of November, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said Frederick Oldfield Ward, William
Ibotson, and Anthony Gapper Southby, Her special licence that we, the
said Frederick Oldfield Ward, William Ibotson, and Anthony Gapper
Southby, our executors, administrators, and assigns, or such others as
we, the said Frederick Oldfield Ward, William Ibotson, and Anthony
Gapper Southby, our executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Inven-
tion for "IMPROVEMENTS IN OPERATIONS AND APPARATUS FOR DRYING DOWN
ALKALINE SOLUTIONS OF EXTRACTIVE MATTER OBTAINED IN PREPARING VEGETABLE
FIBROUS MATERIALS FOR USE IN THE MANUFACTURE OF PAPER, AND IN RECOVER-
ING ALKALI THEREPROM FOR RE-EMPLOYMENT," upon the condition (amongst
others) that we, the said Frederick Oldfield Ward, William Ibotson, and

page_text: Anthony Gapper Southby, our executors or administrators, by an instru-
ment in writing under our, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said In-
vention, and in what manner the same was to be performed, and.
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that we, the said Frederick Oldfield Ward, William
Ibotson, and Anthony Gapper Southby, do hereby declare the nature of
our said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following
statement, that is to say:-
These improvements relate to operations and apparatus employed in
drying down alkaline solutions of extractive matter obtained in pre-
paring vegetable fibrous materials for use in the manufacture of paper,
and in recovering alkali therefrom for re-employment; and the said
improvements consist,-
Firstly. In evaporating such liquor by means of the heat afforded
by the regulated supply to, and combustion in a suitable sole or fire-
place of the hydro-carbonaceous matter which such liquors hold in
solution, the effect being to supersede in a greater or less degree, partly
or wholly according to the less or greater dilution of the liquor, the
necessity of coal or other extraneous fuel for its desiccation.
Secondly. In separating from the liquor under treatment to this end,
either continuously or at intervals, as frequent as conveniently may be,
its said self-contained fuel, so fast as this solidifies to a crust or deposit
coherent enough for removal.
Thirdly. In applying this liquor derived fuel in one or other of the
following ways, viz., (a), to feed a fire so disposed as to heat a series of
three or more shallow liquor trays or receptacles superposed in a
chamber in such manner that the heat may pass over and under them
in succession, the first of such receptacles being fed by a regulated
influx of the liquor for treatment, the second by a regulated supply from
the first, and so on, each receiving a more concentrated supply till
solidification commences, when the solid matter is removed from the
liquid to a succeeding receptacle, where it undergoes further desiccation,
and is finally advanced to the sole or fire-place, in which it takes fire,
and is incinerated. This operation is facilitated (1) by forming the.

page_text: receptacles with an inclined lip or border adapted to retain the liquor
whilst facilitating the separation therefrom of floating crust; (2), by
forming the receptacle of fire-tiles, covered with iron, wrought' or cast,
for the readier removal or scraping off of adherent deposit; (3), by
employing for the said separating of solidified matters from the liquor
power-driven apparatus of the nature of rakes, scrapers, or archimedean
screws. (b), as an alternative mode the heat produced by the said self-
supplied fuel may be applied to the accomplishment of the end in view
by employing it to raise steam, and thereby work a fan or other suitable
apparatus to create a draft of air which may be either cold or preferably
heated by the self-supplied fuel or otherwise, and conveyed over, or
through, or amidst the liquor in such manner as to dry it down,
preferably using a series of shallow superposed receptacles similar to
the above-described, but which in this case need not be fireproof, the
solidified material being in this mode of working conveyed for its final
desiccation and combustion to the furnace of the steam generator.
(c), as a still more economical mode in localities where water power is
cheap and abundant this may be employed to produce air currents for
the preliminary concentration of the liquor, its self-supplied fuel being
burnt only to complete the desiccation, thus leaving an excess of fuel
available for other heating purposes.
Fourthly. In obviating the diffusion of odour from the liquor during
its evaporation and incineration by condensing the fumes with water or
passing them through fire, the former of which objects may preferably
be accomplished by a water-fed tower, as is well understood, while the
latter may be attained as regards the emanations of the solidified matter
by raking this into a receptacle with a vent to some fire, preferably the
fire-place of the apparatus, wherein such emanations may be consumed.
Fifthly. In obviating the progressive contamination of the recovered
ash, through the accumulation therein of extraneous neutral salts,
by dissolving the said ash in water and "salting out," the said
extraneous ingredients from the solution in any of the ways in use
among chemists for that purpose.
Sixthly. In utilising waste heat, such as, for instance, waste chimney
heat, to further economise the self-supplied fuel of the liquor, by
effecting a preliminary concentration, more or less considerable, thereof,
the waste heat being applied to this end either by passing it over and
under shallow receptacles, in the manner above described, or through

page_text: tubes traversing the liquor, as is well understood, or in any other
suitable manner, the draft to effect this being obtained in
any usual way,
as, for instance, the draft of the hot gasses themselves, or by a fan or
ventilator.
Seventhly. In further economising artificial heat of all kinds by em-
ploying spontaneous evaporation, under the influence of the sun and
the atmosphere, to remove vapour from surfaces of the liquor exposed
for that purpose during the day time, but kept covered from the counter-
vailing deposit of dew between sundown and sunrise of successive
days.
Eightly. In combining together such of these modes, two or more,
as local and other circumstances may indicate in each special case
as forming the most economical and suitable group or series of operations
available in that case to the end in view.
Interpretation. Having recited above the words of our Provisional
Specification, we notify all whom it may concern that we desire those
words to be interpretated with due restrictions, and not construed as
general claaims purporting to appropriate any matters already in the
public domain, or already rightfully claimed and appropriated under
patents of prior date to our own. As the best means of thus restrict-
ing their scope we will here enumerate all the matters we are aware of
which our said language might be construed to include, but which, on
the contrary, it is our wish and intention expressly to disclaim.
These matters fall for the most part under the first, second, third,
sixth, and seventh heads of our above-recited Provisional Specification.
The first head relates to the better regulated utilisation of the com-
bustible matter derived from the waste liquor in order to supersede more
or less completely the consumption of coal for boiling down the said
liquors. The second head relates to the separation of the said com-
bustible matter from the liquors to this end, either continuously or
at intervals, as nearly by their frequency approximating to continuity as
can in practice be conveniently accomplished. The third head includes
three sub-heads (a), (b), and (c), each relating to a particular mode of
utilising the heat of the said liquor-derived combustible, and the sub-
head (a) is further ramified into three minor sub-divisions (a), (B), and (7),
respectively relating to means of facilitating the application (a) in
question. As to the sixth and seventh heads, they relate to the two.

page_text: modes thereunder respectively set forth of effecting preliminary concen-
tration of the liquor for the purpose of economising fuel.
With a view to the due limitation of the scope of these parts of our
Provisional Specification we have to state as follows :—
1. We are aware that in the Patent of Chadwick and Clench,
No. 3168, 1863, it is suggested to employ a double-arched furnace,
with pendent bars, and therein to consume the viscous product of the
evaporation of papermakers' waste leys, by means of coal burnt in a
fire-grate placed at one end of the furnace, and with the waste heat
of the said double-arched furnace to boil down the solution obtained by
lixiviating the black granular ash" described by the patentees as being
the result of the said furnace operation; and this apparatus and mode of
procedure we entirely exclude from our claims.
2. We are also aware that in T. Routledge's Patent, No. 297, 1865, it
is proposed to employ for the "preliminary concentration" of the waste
leys a tower fitted up with a series of sloping shelves for the liquor to
flow or trickle along, and with a force pump or analagous apparatus
to raise again to the top of the tower the liquor that has trickled down,
and so on again and again till the concentration is deemed sufficient,
when the liquor so concentrated is run into another furnace, namely, an
ordinary reverbatory or boiling-down furnace, and there evaporated to
dryness and ignited, and its gaseous products utilized as a source of
heat. This apparatus of inclined beds and trickling liquor films and
pump and mode of operating in an ordinary furnace for the utilization
of the hydro-carbonaceous ingredients of the black liquor we expressly
exclude from our claims, as having nothing in common with our own
herein-described system.
3. We are also aware of the mode set forth in Routledge and Richard-
son's Patent, No. 532, 1865, consisting in the addition of waste leys to
the alkali makers' black balls, so that the hydro-carbonaceous matter
of the leys may replace in those balls part of the small coal usually
employed and thus be useful as a source of heat; and this mode of
utilization we also expressly disclaim as forming no part of our
method,
4. We are also acquainted with the proposal in Routledge and
Richardson's Patent, No. 812, 1866, namely, to work with a furnace
having two beds separated by bridges, as well from each other as from a

page_text: fire-grate for coal at one end and from a brick-built liquor pan heated
by top heat at the other end, above which brick-built liquor pan are two
iron pans, viz., an upper one heated by bottom heat only and an inter-
mediate one heated both by top and bottom heat, these three pans being
all heated by the heat from the fire-grate and by that from the two
furnace beds, on the first of which beds a mixture of dry ash and lime
is fired, while on the second bed the pasty product of evaporation is
burned; and we entirely disclaim this apparatus and this operation,
which, with all those above mentioned, we believe to be far less
effectual than our own herein-claimed apparatus and procedure for
utilizing, in lieu of coal, the hydro-carbonaceous matter, or as we term it
the "autopyric fuel" of the liquor itself.
5. We have moroover found in Palser's Patent, No. 2729, 1862,
antecedent to all those above-recited Patents, a proposal for first
concentrating waste exparto liquor by pouring it in from superposed
vats on to rotating steam heated exparto boilers and for then pushing
the viscous product thus obtained along an incline down to a hearth,
where its ignition may help to heat the aforesaid rotating esparto
boilers, which apparatus and method of operating we also expressly
disclaim as none of ours.
6. Furthermore, we are aware of the more recent proposal put forth
in Hooks's Patent, No. 1171, 1867, to draw heat by a fan from the
chimney of a waste ley evaporator and to apply the said heat so obtained
to evaporate thin films of liquor on rotating discs or on sheets of metal
alternately dipped in the liquor and lifted out of it, which apparatus
and modus operandi we also disclaim as having nothing in common
with our system.
7. We have also before us Swan's Provisional Specification, No. 2327,
1867, for raising steam in a boiler by the heat from the incombustible
product of the waste liquor and employing the steam from this boiler,
(a), to heat a series of close vessels, wholly or partly submerged in the
waste liquor to be evaporated and either fixed or made to rotate therein; or
(6), to heat an open evaporating pan formed around the upper part of the
boiler, and having for its bottom the upper part of the shell of the
boiler itself, and these applications of the heat of the liquor-derived
fuel we disclaim as wholly outside the meaning of our present
Specification.
8. With reference to the use of a fan as mentioned in subhead (b) of

page_text: head 3 of our Provisional Specification, we are aware of the special use
of a fan claimed in the Patent No. 297, 1865 (already above cited), to
force a current of heated air through a tower with sloping shelves,
having liquor truckling down them, and we expressly exclude from
our claim this application of a fan, confining our claim in this respect
to the particular use we specify, and by no means wishing to be
understood as claiming the use of a fan generally in relation to waste
liquor evaporation. On the other hand we would by no means have it
understood that we hold ourselves precluded from using a fan for any
other purpose relating to waste liquor evaporation.
Thus much premised by way of interpretation, and to do away with
any apparent interferences between our own and antecedent systems,
we proceed to describe by aid of the Drawings annexed the forms in
which and the means whereby according to our experience thus far
we prefer practically to carry out our own system.
Fig. 1 is a longitudinal sectional view of a very simple form of our
said apparatus, which we can recommend as answering well in actual
practice; Figure 2 is a plan of the same; and the letters imply like
parts in each Figure.
A, A, A, A, are the furnace walls in section; B, a fire-grate with
ash-pit C and fire-door D; E is a fire-bridge separating the grate from a
hearth or sole P, P, beneath which may be formed a cavity G, G, com-
municating by an aperture H with the exterior air, and by an aperture I
with the interior of the furnace, which may thus be supplied with
abundance of atmospheric oxygen. Above the hearth P, P, is a series of
shallow liquor trays or receptacles J, J, J, J, J, J, &c., access to which from
without is afforded by apertures in the furnace wall K, K, K, K, K, K,
K, K, K, K; L, L, is the top of the apparatus through which may be made
the aperture L bis leading to the chimney or flue by which air is drawn
through the apparatus. On the top L may advantageously be placed
one or more cisterns M, preferably of light iron, to hold the liquor and
to supply it to the apparatus through a valve N which may be
advantageously formed so as to enable the operator to nicely regulate
the supply by any of the well understood means to that end. It will
be observed that these trays are shallow, that each is turned up slightly
and as we prefer shelvingly at the end, so as to be retentive of liquor
to the depth of the upturn, which depth we prefer to make about three
inches. We find great advantage in forming these trays of fire-clay

page_text: tiles or blocks, long enough to extend from wall to wall and as wide
as they can be manufactured consistently with soundness and
durability. Those we have in use and find to answer are two feet long
by one foot wide, and by four inches thick for the lower and bottom
beds, three inches thick for the cooler ones above. This thickness we
consider sufficient, but we believe the other dimensions may in many
cases be advantageously increased, even to the extent of making an
entire bed with two or three blocks, possibly even with a single block.
These tiles or blocks may either be built in to the wall, as shewn in the
Drawing, or may have a ledge set out from the wall to support them, or
may be both thus supported and built in as preferred. They should be
made of the choicest fire-clay, we recommend the lunt clay for the
purpose as being strong, hard, and well adapted to endure contact with
alkaline liquors at furnace temperatures. The turnup at the ends of
the beds may be formed with a tile or block like the rest, the inclination
being given either by chipping the edge of the tile or by moulding it
to the requisite form before it is burnt. Great care should be taken to
have these tiles of regular form, thickness, and contour that they may
fit well together so as to form smoothly joined bottoms to the trays, and
they should be well jointed with fire-clay to make them as staunch as
may be. They may be flat or arched in either sense, at the constructor's
choice, but for hand working we find the flat form preferable. What-
ever may be their form it will be understood that the liquor under
treatment stands in these trays with a horizontal water line, instead of
sloping several inches from end to end, as the flowing water films do on
Routledge's inclined shelves in his evaporating tower. This horizontality
of the liquor surface in these trays, coupled with a small but adequate
depth of liquor in them, enables them to act as canals, that is, to carry
the crust afloat as it forms on the surface of the liquor under the
influence of heat. By this arrangement the operator is enabled easily
to float the crust along by pushing or drawing it with a light tool like
a hoe, instead of having to detach it laboriously as happens when the
crust is left behind as a pitchy adhesive deposit on sloping beds trickled
over by mere films of liquor incapable of carrying it afloat. In
operating with our canal trays the crust can, moreover, be advanced
with a gliding motion over the liquor so as to leave this latter behind
to undergo further evaporation, and thus to form more crust to be floated
forward in its turn, whereas in Routledge's tower it is the liquor which
flows on down the sloping beds, leaving any crust that may form to

page_text: settle as an adhesive deposit behind. The upturned liquor retaining
extremities of our trays facilitate by their shelving form the pushing or
drawing over of the crust from a tray to the next below it, or to the
hearth, and liquor also or any bottom deposit that may form in our
trays can in this way be easily pushed or drawn over the shelving lip
from either tray to its successor or to the hearth. The apertures
K, K, K, &c. admit the tool to perform these operations and may at
other times be kept closed by suitable doors or obturators (see Drawing).
The air supply may be in like manner regulated at the ash-pit and at the
aperture (H) below the hearth by hinged or sliding doors or otherwise
as is well understood. Here we may remark that in lieu of the
aperture for air at (I) one or more apertures may be made in one or
more of the furnace walls to supply the hearth with oxygen, suitable
obturators or dampers being employed to regulate the
admitted at the operator's will.
quantity
In constructing this evaporator we take pains to secure compactness,
preferring for example to avoid the waste of ground space and the
needless radiation of heat incurred by the patentees of Patent No. 812,
1866, who recommend a brick pan and two iron ones over it to be built
on the ground beyond their hearth, which is a double one and which
together with the grate erected at the opposite end to heat it stands on
ground of its own apart from the ground space of the three superposed
pans; other things being equal we evidently save half the ground space
by placing as we prefer to do our superposed trays above our grate and
hearth, and thus besides saving rent we also economise all the fuel
expended on the other plan in making good the heat lost through the
reverbatory arch built over the double bed and fire-grate. This advantage
of our improved construction is particularly valuable in localities where
ground space is precious and fuel expensive.
The fire-tile construction of our trays, as mentioned in our Provisional
Specification and further alluded to above, is another great source of
economy, as iron pans, owing to the deposit that takes place in them,
involve much labor to keep them scraped, and notwithstanding the
serious cost thus incurred soon burn away by reason of the overheating
occasioned by incrustation. Our fire-tile structure is found particularly
advantageous in the tray immediately over the hearth and grate, and it
is there too that the thickness of fire-tile, say three to four inches and
upwards, which we also claim, proves especially valuable in moderating

page_text: bottom heat, and so diminishing bottom deposit and promoting the
formation of floating crust. The same structure is also of marked
value in the tray next above (i.e. the second one from the hearth) and
when working at a high temperature its value is felt in the third tray
also; indeed it is our practice to continue the use of the refractory
material throughout the whole series of trays, even to the topmost one,
though here the temperature becomes so mild that it would not under
ordinary circumstances burn out even an iron pan, but besides that the
tilework is cheaper than iron, the upper trays like the lower ones may
accidentally take fire if left full of highly dried combustible deposit, and
such an accident, harmless to fire-ware, would be very injurious to iron,
whether wrought or cast.
The iron suggested in our Provisional Specification for covering the
fire-tiles to facilitate scraping off deposit takes comparatively little
harm by the strong heat because it is submerged in the liquor, but
we find that the use of this iron covering may be, in most cases
dispensed with, so hard and strong are the refractory tiles we have
latterly succeeded in obtaining for use. Moreover, with reference to
deposit, though strongly adhesive and hard to chisel off when it is
first formed, it is speedily reduced by the furnace heat to a pulverulent
deposit which takes but light raking to clear it off. The interior of
the furnace should of course be lined with fire-brick of good refractory
quality, preferably the lunt clay, especially in the hotter parts about
the grate, fire-bridge, and hearth, and the tray next above them. The
upper trays are exposed to temperatures in comparison so mild that but
as a safeguard against accidental overheating they and their surrounding
walls might be made with common non-refractory clay ware.
prefer, however, to use best fire-ware, especially as the additional
expence is not important save where very rigid economy is a paramount
consideration.
We
In working this apparatus we turn on a suitable supply of liquor
from the cistern to the top bed, and so on to the others, keeping them
all filled each with a more concentrated liquor, and preferring so to
regulate the supply that the crusting over may take place chiefly in
5 the lowest tray of the six, which number we usually employ. Instead
of leaving the solid matter thus formed to accumulate for a long time,
often for six or eight hours, as has been customary with our predecessors,
in order to save the labor of the reiterated chiselling and scraping off

page_text: to
of the adherent bottom deposit produced by their arrangements, we
prefer to advance our floating crust by a few light strokes of the hoe
or rake every few minutes, say every five or ten minutes on an average,
but the oftener the better consistently with practical convenience, a
continuous feed being theoretically the best of all, though its mainte-
nance when working by hand power involves too much assiduity to be
conveniently available in ordinary day by day use. Stokers will under-
stand our rule on this point when we recommend our autopyric fire, as
we term it, to be fed as often as an ordinary fire in cases requiring
considerable uniformity of heat supply. The economy thus attained is
very notable, and inter alia has enabled us to reduce our coal consump-
tion below the minimum attainable under any of the arrangements
previously in use. The crust when pushed over so as to fall on the
hearth may still be damp, and usually is so, but the higher temperature
of the hearth aided by agitation soon dries it and fits it for inflammation,
when it may be pushed forward to the more central part of the hearth,
there to burn with a bright flame, contributing largely to the heating of
the apparatus. It should be well stirred during its combustion, so as
expose the interior parts of the clots and make the mass blaze anew.
So soon as its flaming products are burnt off or nearly so it may be
again pushed forward to incinerate at the other end of the hearth, where
it may be still kept stirred and exhibits a glowing incandescence. We do
not find it necessary to separate by bridges, such as T. Routledge recom-
mends, the several parts of the hearth and its contents. The three masses
are easily kept apart while being stirred, and any casual mixing of them at
the edges matters not. As these masses are moved forward on the hearth
fresh crust may be fed down from above to be dried, burned, and in-
cinerated in its turn, and so on continuously. When the incineration is
deemed sufficient the glowing product may be withdrawn from the
hearth, either through its end door, or through a side door, or through
an aperture in the hearth itself, kept covered with a lid when not in use,
or through the aerating aperture (I). Such removal through whichever
aperture accomplished may be effected by raking, or by any other usual
or convenient means. The removed ash may be then thrown on to a
paved floor, walled round and roofed over, to shelter it from rain and
from the cooling influence of too much air; and its heat being thus
kept up the heap may be allowed to smoulder on for several days, and
will thus gradually burn itself white. At least three such heaps should
be formed in three separate ash bins; of these heaps, one burnt off and

page_text: cool may be drawn from for use while another is in course of replenishment
and while the third lics quiescent, undergoing the smouldering process.
This rotation or "methodical smouldering," though of our own inde-
pendent contrivance, is said to have been practised more or less perfectly
by antecedent operators, wherefore we refrain from claiming it. Here
we would remark that in some cases we vary the mode of working off
the damp crust on the hearth, not dropping it, as above described, on the
end remotest from the fire, and advancing it as it dries to inflame nearer
the fire, and again after inflammation advancing it still nearer to the
fire to incinerate, but, on the contrary, conveying it first along an
incline, or in any other convenient way to the hottest place next the fire,
and thence drawing it forward further from the fire, and again further
away still to incinerate.
The object of this modification is to bring the strongest heat to bear
upon the material in its dampest state. Much difficulty having been
experienced by our predecessors in avoiding noisome stench while
evaporating waste leys, we have paid particular attention to this point,
and find that by using the waste leys fresh and fresh, as produced, also
by working with a moderate temperature and regulating the feed of
crust in the manner above described, so as never to overcrowd the
hearth, also by supplying oxygen enough in the draft, and diligently
stirring the materials under treatment on the hearth, so as to keep them
all well aerated, objectionable stench may be entirely avoided. While
therefore the water tower for condensing fumes and the passage of the
fumes through fire to consume them, as suggested in our Provisional
Specification, may, if the operator sees fit, be employed as precautionary
measures against such stench as may occasionally result from neglect or
error on the operator's part, we do not now, in the light of our recent
experience, attach so much importance as formerly to these expedients
so far at least as regards the working of our apparatus and process by
skilled and careful hands. The recovered ash, after undergoing the
smouldering process above described, is found for the most part to be
burnt white, and to be as fit for use in the mill as bought soda ash.
Such portions of the ash product as may remaih black after the smoulder-
ing process may be transferred to the smoulder heap of the bin in course
of replenishment, there to ignite again and burn white with the rest.
Should the ash be found to become by dint of oft-repeated recovery and
reuse too much contaminated with neutral salts, such as sulphates,
chlorides, and silicious compounds, or should it be wanted of higher

page_text: sodic strength than its ordinary per-centage for sale in the market, it
may in such cases be dissolved and purified in a considerable degree by
settlement and decantation; sulphates may be then thrown down by
concentrating the decanted solution. Chlorides may be salted out by
boiling the solution down after caustification by lime; and the again
decanted solution after these successive purifications may be boiled down
to an excellent marketable sodic hydrate, or caustic soda as it is
termed in commerce. If a soda ash be desired for package in casks for
sale the solution left after settlement, decantation, and the salting out of
the sulphates may be boiled down without previous caustification and
finally ground and packed in casks in the alkali makers' customary way.
We note that it has been attempted by a preceding patentee to build a
claim upon some supposed difference between liquor pressed out and
liquor drained out of boiled fibre for evaporation. We deny the
existence of any such difference and the validity of any such claim, our
experience having proved our system to be as applicable to expressed as
to drained or washed out leys, and our claims accordingly extending
equally to all three cases. It is in the greater or less diluteness of waste
liquors, whether obtained by drainage, pressure, or washing, that we
find their chief difference to consist; and it is mainly to meet cases of
more than usual diluteness, as for instance when it is desired to
evaporate the ordinary washings of boiled esparto, that we have proposed
the ancillary methods described under heads 6 and 7 of our above-recited
Provisional Specification.
As regards the utilization of waste heat, whether obtained from the
chimney of the mill boilers or from the general stack of the mill, the
best mode we know of for doing this is to raise near the chimney in
question a new chimney about twenty feet high, and in plan of the same
shape and size as our evaporator as proposed to be built, say, for
instance, of about ten feet long by two feet wide (internal measurement)
if intended for a medium sized mill. To the lower end of this new
chimney may be conveyed the heat previously conveyed to the foot of
the old chimney. At the said height of twenty feet, or thereabouts,
our above-described apparatus may be constructed in continuation of the
said new chimney; and from the top of our apparatus, so placed, a flue
may be carried laterally to join the old chimney stack at about thirty-two
or thirty-three feet from the ground, more or less. This arrangement
secures a good draft, not only to the factory boilers, &c. by reason of the
extended sectional arca given to the new chimney, but also to our

page_text: II
apparatus itself, which profits by all. the suction power of the upper part-
of the old chimney above the point of junction of the flue. A working
stage may of course be formed around our apparatus at the aforesaid
height for the attendants' accommodation; and our said apparatus may,
be worked either as a preliminary evaporator to supply concentrated.
stuff for finishing in the hearth of an evaporator below; or preferably-
the said chimney apparatus itself may be constructed with sole, &c..
complete, so as to turn out the ash fully incinerated ready for the
smouldering bins.
The indications already given will enable a competent engineer to
construct this apparatus in either of the forms herein indicated."
Evaporation thus done will be unquestionably of a very economical
kind, and it is by this employment of waste chimney heat to concentrate
the waste leys free of coal cost that we expect to bring the thickened
solution within the scope of its own autopyric fuel to dry it down
without any consumption at all of coal bought expressly for that
purpose.
We have indicated in our Provisional Specification the use of a fan or
ventilator as an alternative mode of creating a draft of waste chimney
heat for this purpose; and this may be advantageously employed in
some cases, but we recommend as a very much preferable form of suction
power the draft of the hot chimney-gas current itself, obtained as above.
pointed out.
Spontaneous evaporation referred to under head No. 7 of our Provisional
Specification may be conducted in shallow trays conveniently arranged for
exposure to the sun and air by day and for being covered, as for instance by.
a canvass curtain drawn down over a light roof above or in any other con-.
venient way, from dewfall at evening, and from rain at any time. The.
successful practice of the common salt works, where much water is got.
rid of by processes of spontaneous evaporation, promises considerable
advantage from this part of our system, especially during favorable;
seasons, and in localities where there is space enough at disposal to carry,
it out. We do not, of course, recommend this method for general adoption
or otherwise than in conjunction with the above indicated conditions of
success.
Reverting to our principal apparatus, viz., the evaporator shown in the:
Drawing, Figs. 1 and 2, we may here mention a few additional details of
construction and management which we have found advantageous in

page_text: practice. The regulation of the liquor supply to the top tray may be
readily effected, as for instance, by an ordinary screw down valve, the
passage of which should be large, say three inches in diameter, and
easily accessible for cleansing as it is apt to collect the filamentous
matters usually floating in waste leys. The supply cistern or cisterns
may with advantage be clothed with brick, wood, felt, or other non-
conductor to obviate waste of heat by radiation. One cistern may suffice,
but two receptacles are preferrable as allowing of alternate cleansing and
repairs without stoppage. The capacity of the cistern or cisterns should
be about ten times that of a liquor tray. Stale deposits in the cisterns
and elsewhere in the apparatus are to be avoided as tending to cause
fermentation and smell. A float carrying a graduated rod, long enough
to protrude above the top of the cistern, is useful to shew the depth of
the liquor still remaining to evaporate. Roofs preferably of corrugated
iron may be provided at each end of the apparatus to shelter it
attendant at his work. Three square feet of grate surface we find to
suffice amply for twelve square feet of hearth, and eighty to one hundred
of tray surface. These proportions are not obligatory, but we find them
useful. Such an apparatus continuously and carefully worked suffices to
boil down and incinerate the drainage liquor from about three tons of
esparto boiled per day. One man per shift can easily manage two such,
and with a boy's help three. If aided by mechanical scummers as sug-
gested under subhead (y) of head 3 of our Provisional Specification the
labour is still further lightened, and one man may so assisted attend on a
series of evaporators.
Mechanical scraping and scumming may be carried out either by a
continuous or reciprocating motion. In our evaporator constructed as
shown at Figs. 1 & 2 the continuous scumming of the two lower trays
may be effected by an arrangement of the character illustrated at Figs. 3
and 4, the former being a lateral view, the latter a plan, in which like
letters denote like parts. A, A, and A', A', are drums or grooved chain
wheels placed in recesses formed for them in the end walls B, B, B', B¹,
of the apparatus, C, C, and C', C', being the two trays to be scammed';
D, D, and D, D¹, are endless chains carried by the drums or wheels;
E and E' are two scummers so carried by the chains at suitable intervals
and so shaped that by their upper part they may push forward the floating
crust whenever motion is given to the endless chains by rotating one
of the drums or wheels. This motion may be communicated from any
source of power by suitable gearing as is well understood. The gearing

page_text: may be adapted to enable the motion to be regulated to the speed found
best, and to be made continuous or intermittent as desired. So also as to
the scummers, such shape and weight may be given to them as
experience in each particular case may show best adapted to carry
forward surface crust. The course of the motion above and below as
shown by the arrows a and a¹ is in opposite directions, so that the
scummings of each tray may be respectively discharged to the tray or
bed next below it in the series. The scummers may if desired be made
to scrape as well as to scum, and they may be made with suitable
apertures to give passage to the liquor, so that they may not carry it
bodily before them along with the solidified matter. The recess E, E,
formed in the end wall to receive the drums may be made accessible from
without on removing the lid or obturator F, F', thus rendering it
easy to clean the chains and their appurtenants, seeing that all parts of
their length pass around the drums or wheels and can thus be got at
from without. Care should be taken to leave as little gangway as may
be for draft around the drum A, as any heat passing here is withdrawn
from its useful course between the trays. As many of these revolving
scummers may be fitted up as there are pairs of trays to discharge of
crust, but we find it only in the two lower trays that such assistance is
practically required.
Figs. 5 & 6 sbow in side view and plan respectively a form of
reciprocating scummer intended to drop into the position for scumming
when pushed forward for that purpose, and to rise out of the liquor when
drawn back in preparation for the succeeding stroke. A, A, and B, B, show
respectively the end wall of the apparatus and the tray to be
scummed; C, C, is a central bar of angle iron, carrying blades D, D, D, D,
intended to scum the tray; E, E', is the prolongations of the
angle iron C, C, moved to and fro by power and jointed at G to the con-
necting rod F, F; K is an eccentric roller on which E, E', runs, the
adjustments being such that while the tool is making its working stroke
the short radius of the eccentric roller is uppermost, being arrested by
the stop (a), and the scummers are consequently dropped into the liquor,
whereas, while the tool recedes its friction causes the eccentric to turn
round, so that its long radius assumes the uppermost position, thus lifting
the central bar and so raising out of the liquor the scummers it carries.
Four strokes of this tool, assuming the strokes to be two feet six inches.
long, will suffice to clear our eight foot long tray of scum from end to
end. It will be observed that a joint is requisite at H to allow the

page_text: The methods
Scraper to travel up the inclined end of the tray.
causing a power driven scummer to drop during its working stroke and
to lift out of the liquor during its alternate receding motion may be
greatly multiplied.
Fig. 9, 10, and 11 show respectively in end and side view and plan
another mode of doing this, like letters representing like parts in both
Figures.
:
A, A, is a frame of light bar or angle iron moving horizontally on
rollers B, B, over the lowest tray in our evaporator, Figure (1), and of
like form with the tray, but two feet shorter to allow of its moving to
and fro; C, C, C, C, are round iron rods formed as shown and swinging
freely by their ears (C, C,) in holes in the frame and carrying below
floats or skimmers D, D, which swing freely by loops (d, d.); the bar C
joins the swingers D, D, to each other; G, G, is a rod which when pulled
draws up the swingers so that the floats or skimmers hang out of the
liquor. The pull upon G being continued the frame is drawn back on the
rollers and thus recedes preparatory to its forward stroke. This may
be given by pushing the rod G, when the swingers descend, and are
stopped at the vertical line by stops such as the one shewn at H.
The push upon G being still continued the frame now advances the
floats pushing before them the floating crust. The repetition of this
action keeps the floating crust constantly pushed over the inclined lip
of the tray to the hearth. The alternate motion may be given at each
end either by power as shown or automatically, by means of a bucket at
each end alternately filled with water, each bucket when full in its descent
drawing the frame horizontally after it by means of a chain working over
a pulley. Each bucket may have a valve arranged to open and let out the
water when the bucket is down, but to close again when the bucket is
raised up, as it is by the weight of its companion bucket, when in its turn
descending full. Once set going this action continues at work for an
indefinite time, the intervals of the strokes being regulated at will by the
rate at which the buckets are alternately filled, which again can be de-
termined by the turning of a tap more or less. The water flow is
directed to this and that bucket alternately by simple and well known
arrangements. Should this apparatus get clogged it suffices to let the
adherent matter dry to pulverulence, when a little rattling of the rough
and simple swingers soon shakes the floats free of encumbrance. The
coupling of the to-and-fro_ horizontal motion with the alternate lifting

page_text: and letting down of the swingers is here the essential point; the mode
of doing it may be varied in many ways without deviating from this
main feature.
When it is desired to adapt our apparatus to rotary scumming and
scraping, a circular form may be adopted with arrangements of the
character illustrated in plan and section at Figs. 7 and 8. Here A, A,
is the wall of a cylindrical furnace whereof the beds B, B, B', B', are
formed of circular tiles about three or four feet diameter, and about four
inches thick, set sloping as shown, each having a central hole C about
one foot in diameter so that the bed is retentive of liquor. A vertical
shaft E, E, carried by a bearing above, descends through these holes
carrying horizontal cast-iron circular plates O, O, about three feet in
diameter, and each equidistant between the beds above and below it,
which may be about two feet apart. These plates rotate when the
axis E, E, is turned by suitable gearing actuated by steam, water, or
other power, and in rotating their surfaces are kept clean by scrapers
fixed horizontally, as shown at F, F, and curved so as to discharge their
scrapings on to the annular bed below. These beds on the other hand
are cleansed by revolving scrapers G, G, attached to the under side of
the plates O, O, and so shaped as to fit and scrape not only their upper
surfaces, but the interier of their central holes as shewn. These
revolving scrapers have morcover a suitable curve so disposed as to
give a centripetal direction to their scrapings, which are thus discharged
through the central hole on to the iron plate underneath. Fire being
kindled in a suitable grate J below, and a hearth K being also provided
there, on which the solidified deposit takes fire, as also a chimney to
afford draught, the products of combustion flow up through the apparatus,
and dry down its contents, while a cistern keeps the trays replenished
from above. Apertures as at I give access to the interior parts, but
should be kept closed during the operation. This furnace, though more
expensive to fit up than our other form, would we believe be very
saving of fuel by reason of its compactness and of labor by reason of
its automaticity. The trays and discs may of course be superposed in
any reasonable number till the evaporating surface requisite is in each
case attained. The feed of the liquor derived fuel to the hearth would
on this plan be strictly continuous.
Referring, lastly, to head eighth of our Provisional Specification ahove
recited, we wish that paragraph to be understood and construed not only

page_text: with reference to the special cases therein alluded to, but generally as
limiting our claims throughout these presents to the novel combinations
of means by which our improved results are obtained, our desire being to
guard ourselves against being supposed to claim severally any of the
herein mentioned matters and things which taken separately may be old,
and which therefore have to be grouped in new and useful combinations
in order to afford ground for valid claims. Should anything herein-before
written appear to carry a meaning contrary to this interpretation, we
desire that it may be thus understood and construed, any such apparently
contrary purport notwithstanding.
We have now endeavored to set forth clearly the nature of our
Invention and the means of carrying it out in its various parts, so that
any competent engineer may readily execute it, and any competent
manager or foreman work the process according to our improvements.
We have mentioned the restrictions with which we wish the language
of our Provisional Specification to be interpreted and we have further
illustrated this limitation by quoting claims of our predecessors which
we desire our said language to be understood as excluding. In contrast
with those antecedent claims the peculiarities of our own apparatus and
procedure, which are next described, stand out in very salient relief,
and their essential characteristics are prominently shown, in contra-
distinction to the mere details of execution, which details in the per-
formance of our own as of all other Inventions may be almost
indefinitely varied without on that account departing from the sub-
stantial features of the system.
Those substantial features as herein-before shown by the said con-
trasted descriptions we claim irrespectively of all inessential modifications.
Thus for instance we claim the construction and procedure by which
the liquor, at once pooled back, yet free to overflow, thickens at surface
to crust, but carries that crust afloat, thus at once preserving it from
the adhesion, which would make its removal laborious, and supplying
it with a level water-way or canal along which it may be easily floated
at frequent intervals or continuously by hand labor or by power over
the sloping lip of the tray to feed the fire on the hearth, thus helping
to evaporate the liquor left behind on the trays, which liquor replenished
from above continues to yield fuel and water carriage for that fuel,
so as economically to keep up the supply of heat by which it is itself
boiled down.

page_text: In like manner as to our other points we desire to be understood as
claiming only what the contrasted descriptions above set forth show to
be clearly our own, and we as distinctly disclaim all matters shown
to be legitimately claimed by our predecessors, or to belong by previous
user to the public domain,
In witness whereof, I, the said Frederick Oldfield Ward, have
hereunto set my hand and seal, this Eighteenth day of May,
in the year of our Lord One thousand eight hundred and sixty-
nine.