Improvements in Kilns or Furnaces applicable for the Drying and Incineration of Spent Soda Solutions.
Year: 1892

page_text: Date of Application, 1st Apr., 1892
Complete Specification Left, 24th Dec., 1892-Accepted, 28th Jan., 1893
PROVISIONAL SPECIFICATION.
Improvements in Kilns or Furnaces applicable for the Drying and
Incineration of Spent Soda Solutions.
I, THOMAS THORNLEY, of Woolfold, near Bury, in the County of Lancaster,
Manager, do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in the kilns or furnaces in which the
incineration and recovery of soda ash is effected after the same has been employed
in the production of pulp from straw, esparto wood or similar materials for use in
the manufacture of paper and other industries.
The soda solution after it has been used for boiling the straw or other material
and reducing it to pulp is concentrated in the usual way such as by multiple effect
evaporation or other known process and then requires to be dried and incinerated
to remove combustible materials and render it fit for use again in a fresh solution.
My invention is designed to provide a kiln or furnace in which this incineration
and recovery can be carried out with the least possible expenditure of fuel by
utilizing the combustible matters mixed with the concentrated soda ash to supply
the heat necessary to carry out the process.
It consists essentially of a kiln or furnace constructed with one or more fire places
or furnaces of sufficient size or capacity to start the operation and of a series of
hearths and wells or pans placed alternately so that the heat from each hearth will
pass over and in contact with the contents of the adjoining well or pan and with a
series of pits or vaults below the hearths to receive the incinerated material in
which it can burn out and cool.
In carrying out the invention I construct a kiln with a fire place or furnace for
fuel at one end and next to this I place a hearth built of fire tiles fire-bricks or
similar material. Beside this hearth 1 build or form a well or pan preferably
built of the same fire-tiles or bricks at a level of say 6 or 8 inches below the hearth
so that the top of the well will be about on the same level as the hearth. Next
this well I form a second hearth and then another well and so on alternately with
another fire place or furnace for fuel placed at intervals of say every two or three
sets of hearths and wells. By this arrangement I get a continuous succession of
hearths each followed by a well or pan.
Under the hearths are placed a number of pits, ovens, or receptacles with
shoots leading thereto from the hearths through which the contents of the hearths
can be raked. Each hearth is preferably connected with two of these pits by
separate shoots, so that one can be closed for emptying it or the like whilst the
other is being filled. These pits are preferably made with a door or opening at.
the back and a manhole in front over which a raised platform from which the
hearths and fires can be worked and attended to.
The liquor preferably in a highly concentrated state is run into the well or pans
which are preferably rectangular in shape and built of fire tiles and the several
fires are lighted the heat from which passes over the wells in close proximity to the
surface of the contents and evaporates the same to dryness. The dry contents of
the pan owing to the admixture of a large amount of combustible material itself
takes fire and continues to burn. The crust or burning mass is then lifted from
each of the wells to the adjoining hearth where the incineration continues. The
wells are then again filled with the concentrated liquor and the heat from the
material burning upon the hearth passes over the surface of the well and is sufficient
without additional fuel to dry and set on fire a similar quantity of the material in
the well or pan which is in turn lifted out onto the hearth and the well refilled

page_text: with liquor and so on a continuous evaporation and incineration may be carried on
without the addition of fresh fuel and the fuel fires may be allowed to go out.
When the second or succeeding charge of material is lifted out onto the hearth
the first or preceding one is raked down the shoot into the pit or oven below and
there allowed to burn off and cool and the heat therefrom finds its way back again
through the shoot onto the hearth.
The hearths and wells are enclosed in a brick arched chamber which forms a
continuous passage over the several hearths to the flue and keeps the heat in
contact with the surface of the contents of the wells.
I am quite aware that attempts have been made to utilize the combustible
material contained in the concentrated soda solution for the purpose of incinerating
it and to utilize the heat thereof to assist in the evaporation of the material to
dryness.
Dated this 30th day of March 1892.
WM. P. THOMPSON & Co.,
6, Bank Street, Manchester, Patent Agents.
COMPLETE SPECIFICATION.
Improvements in Kilns or Furnaces applicable for the Drying and
Incineration of Spent. Soda Solutions.
I, THOMAS THORNLEY, of Woolfold near Bury in the County of Lancaster,
Manager, 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 :---
This invention relates to kilns and furnaces in which concentrated spent and
waste soda solutions may be finally evaporated and the residues burnt for the
recovery of the soda ash, and it is especially applicable for the recovery of the
soda from the waste soda solutions of paper works, where the recovered ash may be
again utilised on the spot.
In the process of recovery by means of the apparatus constructed according to
these improvements, the concentrated soda solution is conveyed into a shallow pan
which is heated above by hot gases and below by radiation from the hot recovered
soda. As the soda in the pan crystallises out, it is raked upon an adjacent hearth
together with any carbonaceous and other residues, where it is subjected further to
the heating effect of the hot gases above and the radiation from below. From the
hearth, the soda is pushed or raked through suitable holes or shoots into a chamber
below, whence it may be periodically withdrawn.
In the waste soda from paper works, there is generally a considerable amount of
carbonaceous matter, and I utilise this in the following manner-At the commence-
ment of the operation, hot gases from a suitable furnace are caused to pass over
the hearth and pan, and as the drying of the soda and combustible matter proceeds,
the latter becomes ignited and the hot gases from this ignition are utilised in
drying fresh quantities of the concentrated solutions.
The ignition commences upon the crust formed on the pan, continues in the
material upon the hearth, and finally terminates either upon the hearth or in the
chamber below. When the quantity of carbonaceous matter is sufficient, the fire
in the furnace may, after the ignition has commenced, be lowered or extinguished,
since the requisite heat may be derived from the combustion of the carbonaceous
matters. In other cases, the furnace may be used as an auxiliary source of heat.
The accompanying drawings illustrate an apparatus constructed according to
this invention and for the purpose of carrying out the herein before described
process.
Figure 1 is a front elevation ;
Figure 2 a horizontal section taken along the line a-b, Figure 4 ;
Figure 3 a similar section taken alone the line
Fionn

page_text: Figure 4 a vertical longitudinal section taken along the line e-f Figure 2;
Figure an end view; and
Figure 6 a transverse vertical section.
At the upper part of the apparatus there is arranged a tank A into which the
concentrated solution is run and from which it may be conveyed as required to the
shallow pan B. The drawings represent a duplex apparatus in each of which there
is a furnace, a hearth, a pan, and a lower chamber, but I may employ a single set
or as many sets as may be convenient. Also, I may vary the arrangement in some
cases by using a single furnace arranged at the commencement of the first set.
Above the pans B and hearth H there is an enclosed passage or flue C, extending.
from the first furnace to the outlet D leading to a chimney.
The furnace or furnaces E are externally fired through the doors F, the doors G G
are arranged in the front wall through which the materials in the pans and on the.
hearths may be manipulated. These doors may conveniently be arranged to slide.
within vertical guides and be suspended by chains passing over pulleys and weighted
at their opposite ends.
The pans, the hearths, and the flue C, may be constructed of fire bricks, and
fire tiles, and the level of the hearths may be about six or eight inches above the
level of the bottoms of the pans.
Below the pans and hearths, vaulted chambers I I are constructed and communi-
cate with the hearths through the openings J J. These vaulted chambers are
constructed or lined with fire bricks and there may be one or preferably two (as
shewn) to each set of the apparatus. In the front wall of each chamber there is an
opening K for inspection, and at the back a larger opening L through which the
cool material may be withdrawn. These openings may be ordinarily closed by
temporary brick-work or otherwise.
The outer walls of the apparatus may be bolted and braced together by means.
of the bolts M M, the ends of which pass through the plates N.
It is preferred to connect each hearth with two of the vaulted chambers by
separate shoots J J in order that one of the chambers may be available for the
reception of the hot soda whilst the other is being emptied.
In front of the apparatus there may be erected a platform or stage P, for the
convenience of the men manipulating the material in the pans and on the hearths.
The process conducted as herein before described in the apparatus is continuous,.
a charge of material being run into the pan as soon as the former charge has been
withdrawn on the hearth, the charge previously on the hearth having been raked
into the vaulted chamber to make room for it.
I am aware that it has already been proposed to utilise the carbonaceous matter
contained in concentration soda solutions from paper works, by its combustion for
the purpose
of reducing the waste soda to soda ash and to assist in the evaporation
of the material to dryness, and I therefore wish it to be understood that I make no.
specific claim to such use of the combustible matter.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. Apparatus for the drying and incineration of concentrated soda solutions, .
constructed and arranged substantially as hereinbefore described and as illustrated
by the accompanying drawings.
2. In apparatus for drying and incinerating soda solutions the combination and
arrangement of a furnace E, a hearth H, a drying pan B, a flue C, and a receiving
chamber or chambers I, substantially as herein before described and as illustrated.
by the accompanying drawings.
Dated this 23rd day of December A.D. 1892
WILLIAM E. HEYS,
Agent for the Applicant.