IMPROVED EVAPORATING OR RECOVERING FURNACE OR APPARATUS TO BE USED FOR EVAPORATING THE WATER IN SODA LYE OR LIQUIDS CONTAINING ANY VALUABLE SEDIMENT OP BODY SO THAT THE SAME MAY BE RENDERED FIT FOR BEING AGAIN USED FOR MANUFACTURING PURPOSES
Year: 1874

page_text: LETTERS PATENT to Charles Stevenson, of Milngavic, in the County
of Stirling, North Britain, for the Invention of "IMPROVED EVAPORATING
OR RECOVERING FURNACE OR APPARATUS TO BE USED FOR EVAPORATING THE
WATER IN SODA LYE OR LIQUIDS CONTAINING ANY VALUABLE SEDIMENT OP
BODY SO THAT THE SAME MAY BE RENDERED FIT FOR BEING AGAIN USED FOR
MANUFACTURING PURPOSES."
ealed the 23rd October 1874, and dated the 27th April 1874.
PROVISIONAL SPECIFICATION left by the said Charles Stevenson at
the Office of the Commissioners of Patents, with his Petition, on
the 27th April 1874.
I, CHARLES STEVENSON, of Milngavie, in the County of Stirling,
North Britain, do hereby declare the nature of the said Invention for
"IMPROVED EVAPORATING OR RECOVERING FURNACE OR APPARATUS TO BE USED FOR
EVAPORATING THE WATER IN SODA LYE OR LIQUIDS CONTAINING ANY VALUABLE
SEDIMENT OR BODY SO THAT THE SAME MAY BE RENDERED FIT FOR BEING AGAIN USED
FOR MANUFACTURING PURPOSES," to be as follows:-
This Invention relates to exposing and distributing to the action of
fire and heat the soda lyc or liquid by means of roasting beds, per-
forated trays, slits, rose pipes, or whatever may best distribute or break
up the said liquid into rain drops or spray, same to be placed in

page_text: position as found necessary, the soda lye being allowed to percolate the
said trays or slits or pipes by its own gravity, and also forcing the liquid
through said perforations by means of a force pump, reserving the right
to force in longitudinally by force pump a spray of soda lye or liquid
over the flame, all for the purpose of breaking up the liquid and
exposing it to the full action of the flame, as afterwards described.
Likewise this Invention relates to the use of agitators in the furnace
for the purpose of stirring up the sediment or ash which will fall from
the evaporated lye or liquid so as to expose more fully any moisture
which may still remain in the sediment whatever it may be, and at the
same time serving the purpose of a scraper in drawing forward to a
bench formed in the furnace the recovered ash or sediment.
As instancing means whereby I carry into effect my said Invention I
will describe a furnace in detail:-The furnace is built of fire-brick
sides, ends, and arches or beds, and consists of a fire-place or fire-places
placed as may be thought best to give the greatest heating power. The
length of furnace and beds and breadth of same will be determined by the
evaporating capacity required, the beds or flues are formed by arches
thrown from side to side of furnace, the number of same will also be
determined by the required evaporating capacity. At one end imme-
diately over the top bed is placed perpendicularly a pipe or retort with open
mouth looking downwards. On top of said pipe is placed the supply cistern
to contain the liquor to be evaporated, and under which will be placed
trays or perforations of the best description so as to break up the soda lye
flowing from the cistern, or it may be forced in by force pumps; it after-
wards is arranged so as to flow over all the beds, the flame at the same
time passing over it. In the bed described will be placed agitators or
mixers which in working back and forward will stir up the ash or
sediment and expose it fully to the flame so that any moisture it may
still retain will be completely evaporated, leaving a dry ash or sediment
which is brought forward to a bench and falls into a pit behind as it
accumulates.
The great advantages which will be derived from the above improve-
ments will be that the lye or liquid will be evaporated in half the time
that it is by the old system, thes aving of fuel and labour, as the agitators
will do the work which à man has to be in constant attendance to do.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles Stevenson in the Great Seal Patent Office
on the 26th October 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
STEVENSON, of Milngavie, in the County of Stirling, North Britain, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-seventh day of April, in the year of
our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Charles Stevenson, Her special licence,
that I, the said Charles Stevenson, my executors, administrators, and
assigns, or such others as I, the said Charles Stevenson, my 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 Invention for "IMPROVED EVAPORATING
OR RECOVERING FURNACE OR APPARATUS TO BE USED FOR EVAPORATING THE WATER
IN SODA LYE OR LIQUIDS CONTAINING ANY VALUABLE SEDIMENT OR BODY SO THAT
THE SAME MAY BE RENDERED FIT FOR BEING AGAIN USED FOR MANUFACTURING
PURPOSES," upon the condition (amongst others) that I, the said Charles
Stevenson, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, 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 I, the said Charles Stevenson, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement :-
This Invention relates to exposing and distributing to the action of
fire and heat the soda lye or liquid by means of roasting beds, perforated
trays, slits, rose pipes, or whatever may best distribute or break up the
said liquors into rain drops or spray, the said liquors before reaching the

page_text: main roasting bed of evaporating furnace. The soda lye or liquid is
allowed to percolate the said trays by its own gravity, and may also be
forced through same or any other part of the furnace by means of force
or other pumps, all for the purpose of breaking up and spreading out
the said liquid and exposing it in small particles in the shape of rain
drops or spray to the full action of flame and heat. Also distributing as
described the soda lye or waste liquids to heat or flame, thereby evapo-
rating the same in the most economical manner. Also the formation of
said evaporating furnace whereby the charges can be conveniently drawn
from roasting bed into a close chamber without the burning ash coming
in contact with the cold air, thus allowing it to burn off more uniformly
and more perfectly, at the same time the offensive fumes arising from
the burning ash being conveyed by a flue directly and naturally into the
flame issuing from the roasting fire and entirely consumed, thus
requiring no auxiliary firc. Also mixers, distributors, or agitators for
breaking up the crust which forms on the lye applied from back of
furnace, worked back and forward by means of racks and pinions,
keeping the thickening liquid in motion and exposing it fully to the
flame. At the same time the said mixers are constructed to serve as
rakes to draw the charge without being taken out or changed.
The furnace is built of fire-brick sides, ends, arches, or beds, and
consists of a fire-place or places at one end or position as may be thought
best to give the greatest heating power; their sizes, breadth, and length
will be determined by the evaporating capacity required; the beds are
formed by arches thrown from side to side of furnace. At one end of
top bed and above fire-place is placed a rainer or liquid distributor in the
shape of a pipe, or it may be a cistern the whole length of top bed
having a perforated false bottom. On the top of said pipe is placed a
supply cistern having a false bottom, the full diameter of pipe perforated
with small holes, and in the bottom of cistern a valve is set so that the
supply to the roaster can be shut off when required. When the valve is
lifted the liquid immediately flows through the tray and rains into top
bed of furnace, overflows the same, and fills up the bottom roasting bed
to the required depth.
During the time the bottom bed is being roasted off the top bed is
also kept full, and on account of the great heat both from top and bottom
causes the lye in said bed to thicken; immediately the bottom bed is
emptied a massive sluice valve is lowered at the one end of the top bed.

page_text: and the lye which has lain and thickened is allowed to flow into the
bottom bed in a half prepared or evaporated state. The valve is screwed
up and refilling is commenced, and the same operation goes on con-
tinuously, the top bed being gradually filled by the small rain-like
drops.
In the roasting beds I employ agitators to stir up the lye as it becomes
crusted; they are made to work back and forward on the beds by means
.of racks or pinions, or any eccentric action; they are also constructed
so as to be employed as rakes to draw the charges into the soda ash
chamber without the trouble of taking them out or changing them.
The charge when quite burned off is then drawn into the chamber called
the recovered ash chamber, where the ash may be allowed to burn off
until the pungent fumes have disappeared. The fumes are drawn from
this said chamber by means of a flue passing underneath the bed of
furnace and led into the air chamber immediately behind the bridge, so
that the former are drawn into the flames coming off the fire and are
thus consumed.
Having thus far particularly described the nature of my said Inven-
tion, and to some extent described in what manner the same is to be
performed, I will now in further compliance with the condition in the
said Letters Patent contained proceed to more fully and particularly
describe describe and ascertain in what manner the same is to be per-
formed or carried out in practice by referring to the Drawings
accompanying these Presents.

page_text: lye or liquid in under roasting bed A, and thence passes above the
valve C over the lye or liquid in the upper bed B, the products of com-
bustion passing off through the flue. When the charge in the under
bed A is burned off it is drawn out by the agitator I into the ash
chamber H, as before explained. The fumes pass down and out through
the fume flue (as shown in the Drawing by the arrows).
Having now particularly described and ascertained the nature and
object of my said Invention, and in what manner the same is to be per-
formed or carried out in practice, I hereby declare that I claim the herein-
before described Invention of "Improved Evaporating or Recovering
Furnace or Apparatus to be used for Evaporating the Water in Soda
Lye or Liquids containing any Valuable Sediment or Body so that the
same may be Rendered Fit for being again Used for Manufacturing
Purposes," as herein-before set forth and described, and illustrated by
the Drawings, it being understood that I do not limit or confine myself
to the precise details of construction provided the peculiar and important
features of my Invention are adopted.
In witness whereof, I, the said Charles Stevenson, have hereunto
set my hand and seal, this Twenty-third day of October in the
year of our Lord One thousand eight hundred and seventy-four.
Witness,
JAMES PAURIE CARMICHAEL,
Westfield,
Dalkeith.
CHARLES STEVENSON. (L.S.)