IMPROVEMENTS IN FURNACES TO BE USED IN THE MANUFACTURE OF ALKALINE CARBONATES AND IN OBTAINING COPPER
Year: 1876

page_text: LETTERS PATENT to James Mactear, of Glasgow, in the County of Lanark,
North Britain, Chemist, for the Invention of "IMPROVEMENTS IN FURNACES TO
BE USED IN THE MANUFACTURE OF ALKALINE CARBONATES AND IN OBTAINING
COPPER."
Scaled the 9th September 1876, and dated the 17th May 1876.
PROVISIONAL SPECIFICATION left by the said James Mactear at the Office of
the Commissioners of Patents on the 17th May 1876.
JAMES MACTEAR, of Glasgow, in the County of Lanark, North Britain, Chemist.
"IMPROVEMENTS IN FURNACES TO BE USED IN THE MANUFACTURE OF ALKALINE
CARBONATES AND IN OBTAINING COPPER."
This Invention relates to furnaces which, when made with the improvements
comprised in it, are advantageously applicable in the manufacture of alkalino
carbonates, for the process known as "balling," for roasting or calcining soda ash,
or "alkali," or carbonate of potash, and for other similar operations, and also in the
obtainment of copper by what is known as the "wet" process, for calcining the
burnt copper ore with salt.
The improvements are applied to a furnace having a horizontal circular revolving
bottom, made of iron lined with fire-brick or other suitable refractory material, and
formed with a raised rim round the outer edge.
The Invention consists principally in providing for the withdrawal of the finished
charges of materials down through the centre of the furnace bottom.
The forms of the discharge opening and of the closing detail or valve may be
varied, but in a preferable modification a cylindrical aperture is formed quite
through the bottom and lining and is cased with iron, and a similar opening, but
larger in size is formed through or partly through the roof or arch of the furnace.
The closing detail is an iron cylinder jacketed with fire-clay, or other refractory
material, and when in the closing position rests on the surface of the bottom lining
round the central discharge aperture. Air is allowed to pass up through the
discharge aperture and through the valve or closing detail, so as to prevent the
metal parts from being overheated. The discharge aperture is opened to the interior
of the furnace by raising the valve into the opening or recess in the centre of the

page_text: roof or furnace arch, and the contents of the furnace may then be discharged into
a wagon under the furnace, or into any suitable receptacle. The fire-gases are led
into the furnace space between the revolving bottom and roof, by preference through
openings at one side, and pass towards the opposite side, finding egress by two flues
separated a short distance from each other, whilst stirring apparatus is arranged by 5
preference in the part of the furnace space between the two exit flues.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said James Mactear in the Great Seal Patent Office on the 16th September
1876.
JAMES MACTEAR, of Glasgow, in the County of Lanark, North Britain, Chemist.
"IMPROVEMENTS IN FURNACES TO BE USED IN THE MANUFACTURE OF ALKALINE
CARBONATES AND IN OBTAINING COPPER."
My said Invention relates to furnaces which, when made with the improvements
comprised in it, are advantageously applicable in the manufacture of alkaline
carbonates, for the process known as "balling," for roasting or calcining soda ash,
or "alkali," or carbonate of potash, and for other similar operations, and also in the
obtainment of copper by what is known as the "wet" process, for calcining the
burnt copper ore with salt.
My improvements are applied to a furnace having a horizontal circular revolving
bottom, made of iron lined with fire-brick, or other suitable refractory material, and
formed with a raised rim round the outer edge.
My Invention consists principally in providing for the withdrawal of the finished
charges of materials down through the centre of the furnace bottom.
In a modification of the improved furnace, which I prefer, the fire-gases are led
into the furnace space between the revolving bottom and roof, through openings at
one side, and pass towards the opposite side, finding egress by two flues separated a
short distance from each other, whilst stirring apparatus is arranged in the part of
the furnace space between the two exit flues.
'
And in order that my said Invention, and the manner of performing the same,
may be properly understood, I hereunto append a Shect of explanatory Drawings,
to be hercin-after referred to, and representing a calcining furnace, as constructed
with one modification of my improvements. In these Drawings the same reference
numerals are used to mark the same or like parts wherever they are repeated.
Figure 1 of the Drawings is a horizontal section of the furnace, and Figure 2 is
a corresponding vertical section. The circular furnace bottom 1 consists of plate
iron lined with fire-brick, and is fixed on frame pieces 2 which are fitted with
wheels 3 arranged to run on a circular flanged tram plate, 4, fixed beneath the
furnace. The furnace bottom 1 is made with a raised rim 5, and is covered by a
roof or arch 6 of fire-brick carried by arc-shaped girders 7, which are supported on
pillars 8, indicated by dotted lines in Figure 1. Two fire-places 9 communicate by
a passage 10 with the reverberatory chamber or space enclosed between the roof or
arch 6 and the circular bottom; and after the fire-gases have acted in that chamber
they pass off by two exit flues 11 nearly opposite to the inlet passage 10.
For charging the furnace one or more openings (not shown in the Drawings),
which are closed when the furnace is in operation, are provided at any convenient
part of the roof or arch 6. The discharge aperture is a cylindrical or nearly
cylindrical opening 12 made quite through the bottom 1 and its lining at the
centre, and this opening 12 is fitted with an iron casing 13 which projects below
the bottom. A somewhat larger opening 14 is formed through the roof or arch 6,
and is fitted with an iron lining. The closing detail is an iron cylinder 15, which
is jacketed with fire-brick or other refractory material, and when in the closing,
position, as shown in Figure 2, rests on the top edge of the iron lining of the

page_text: discharge opening 12 in the furnace bottom, whilst its upper part closes the
opening 14 in the roof G. The cylindrical closing detail or valve 15 is made with
two sets of arms 16, 17, to the upper set of which there is attached an oye bolt for
the connection of a chain 18 for raising the valve, whilst to the lower set 17 there
is attached a spindle 19 which passes through a guide 20 fixed by arms in the
opening 12 below. Air is allowed to pass up through the discharge opening 12 and
through the valve 15, so as to prevent the metal parts from becoming overheated.
The discharge aperture 12 is opened to the interior of the furnace chamber by
raising the cylindrical valve 15 into the opening or recess 14 in the roof or arch 6,
and the contents of the furnace may then be discharged into a wagon placed
beneath the furnace, or into any suitable receptacle. The stirring apparatus is
arranged to act between the central valve 15 and the outer rim 5 of the furnace
bottom, at the part between the two exit flues 11, and it comprises a set of forks 21
fixed on the lower ends of vertical shafts 22, which are held in a frame 23 and
geared together by spur wheels 24 at their upper ends, so as to rotate in alternate
directions; the forks 21, which are disposed diametrically, being arranged so as not
to interfere with each other, although they are large enough to work over over-
lapping areas. The stirring apparatus can be raised out of action or lowered more
or less as may be required, the frame 23 being fitted to slide in vertical guides 25 on
a fixed framing, and being formed with vertical rucks 26, with which there gear
pinions on a horizontal shaft 27 arranged to bo turned by means of a crank handle.
The driving power is applied to the outermost of the vertical stirrer shafts 22,
which is elongated to pass up through a bevil wheel 28, to which it is geared by a
groove and feather admitting of its vertical movement with the frame 23. Tho
bevil wheel 27 gears with a bevil wheel on a short horizontal shaft 29 driven as
herein-before described.
The finished charges of materials may be pushed towards the central discharge
outlet 12 by means of scrapers or other implements worked by hand through the
openings herein-before referred to as for charging in the materials. I however
prefer to use mechanical discharging apparatus of the kind shown in the Drawings,
and which comprises a series of pushers or scrapers 30 attached to an endless
chain 31 carried and moved by pulleys 32 on the lower ends of vertical shafts 33, 34.
These shafts 33, 34, are carried by a frame 35 which is fitted to work in vertical
guides 36, and has racks 37 on it in gear with pinions 38 on a horizontal shaft 39,
so that it can be raised or lowered, as required, by means of a crank handle. The
discharging apparatus is worked by means of one 33 of the vertical shafts, which
is elongated to pass up through a bevil wheel 40 connected to it by a groove and
feather, to admit of the vertical movement of the frame 35. The bevil wheel 40
is in gear with a bevil wheel 41 on a horizontal shaft 42, which has also on it a
spur wheel 43 gearing with a spur wheel 44 on the horizontal shaft 29 of the
stirring apparatus. The shaft 42 has on it clutches, in connection with the
wheels 41 and 43, so that either can be put into or out from gear as required; and
this shaft 42 is itself driven by bevil wheels 45 from a vertical shaft 46 geared by
bevil wheels 47 to the shaft 48, which imparts rotation to the furnace bottom 1, and
is driven by means of a pulley and belt, or otherwise, from any suitable prime
mover. The furnace bottom 1 is turned by means of a pinion 49 on the shaft 48,
and gearing with a circular rack 50 fixed to the framing of the furnace bottom.
gutter 51 is formed round the outside of the rim 5 of the furnace bottom, to contain
loose materials from the inside of the furnace, or sand, into which the vertical
flange of the girders 7 dips, so as to form a closed connection between the rotating
bottom 1 and fixed roof or arch 6 of the furnace, as usual in furnaces with rotating
bottoms.
A
Having thus particularly described my said Invention and the manner of per-
forming the same, I have to state that I do not restrict myself to the precise details
herein-before described and shown in the accompanying Drawings, as the forms of
the discharge opening and closing details and the arrangements of the stirring and
discharging apparatus may be greatly varied, but that what I believe to be novel

page_text: and original, and claim as the Invention secured to me by the herein-before in part
recited Letters Patent is, the forming of the revolving bottom of the furnace with a
central discharge opening, substantially as herein-before described.
In witness whereof, I, the said James Mactear, have hereunto set my hand
and scal, this Thirteenth day of November, in the year of our Lord One
thousand eight hundred and seventy-six.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
JAMES MACTEAR. (LS.)