IMPROVEMENTS IN FURNACES FOR DECOMPOSING CHLORIDES OF SODIUM AND POTASSIUM, MANUFACTURING ALKALIES, AND FOR OTHER SUCH LIKE PURPOSES
Year: 1876

page_text: LETTERS PATENT to George Dryden Mease, of the Lake Chemical Works,
South Shields, for the Invention of "IMPROVEMENTS IN FURNACES FOR
DECOMPOSING CHLORIDES OF SODIUM AND POTASSIUM, MANUFACTURING
ALKALIES, AND FOR OTHER SUCH LIKE PURPOSES."
Sealed the 13th April 1877, and dated the 31st October 1876.
PROVISIONAL SPECIFICATION left by the said George Dryden Mease at the
Office of the Commissioners of Patents on the 31st October 1876.
GEORGE DRYDEN MEASE, of the Lake Chemical Works, South Shields. "IMPROVE-
MENTS IN FURNACES FOR DECOMPOSING CHLORIDES OF SODIUM AND POTASSIUM,
MANUFACTURING ALKALIES, AND FOR OTHER SUCH LIKE PURPOSES."
This Invention has for its object improvements in furnaces for decomposing:
chlorides of sodium and potassium, manufacturing alkalies, and for other such like
purposes.
In decomposing chlorides of sodium and potassium in furnaces worked by steam
power it is usual to conduct the operation in a flat metal segmental pan with a
perpendicular rim. The middle of the pan being more exposed to heat than the
circumference expands more than the sides, and the pan is thus strained and often
broken. To obviate this I make the pan annular with a curved bottom. I prefer
to make the section of annulus of two elliptic curves, so that there are no straight
lines, by which the greatest play is given to the elasticity of the metal. By this
means it is possible to cast the pan in one piece, and in some cases I do so.
When decomposing or calcining chlorides of sodium or potassium or calcining
alkalies in furnaces in which the pan or furnace bottom revolves it is usual to
make a perpendicular rim.
I find that it is very difficult to get the materials over the edge of such a or
pan; the materials being in a semi-fused state when drawn they are very cohesive.
I form the pan with a rim sloping upwards at an angle of about 30 degrees from
the horizontal line. To discharge the contents I fasten one end of a discharging
blade to a hinge just outside the circumference of the pan. This blade is long
enough to reach to the bottom of the slope of the rim when lying at an angle of 45

page_text: degrees or thereabout to the radius of pan. I work the loose end of this blade to
and fro across the slope by hand or steam power; I give it an intermittent reci-
procating action. The periods of rest are when the blade is pointing down the
slope; during these pauses the material accumulates against the blade, and it is
afterwards at the next movement thrown over the slope; or the material may be
worked over the slope by gradually letting down a blade into it at an angle of 45
degrees or thereabout to the radius of pan.
I stir the material in revolving furnaces as follows:-Across the radius of the
pan I place a row of blades, the next of which are fixed laterally by passing
through circular sockets or eyes which may be set in the arch of the furnace, but
they are free to revolve. The blades are made to oscillate about 22 degrees on
each side of the concentric lines of the furnace. The motion may be given to the
blades by horizontal arms fastened to their heads, which are worked by a rod which
is fastened to a crank.
When I wish to discharge the material I alter the rod by attaching a different
part of it to the crank so as to cause the blades to oscillate between the concentric
lines of the pan and 45 degrees off them, or the blades may be left stationary at the
last named angle. This arrangement works the material to the bottom of the slope,
where it is taken up by the discharging blade mentioned above. Or I obtain the
same effect without continuous motion by using a series of two bladed ploughs,
each blade of which is set at an angle of about 22 degrees to the concentric lines,
and they are on opposite sides of it.
When it is wished to discharge the ploughs are moved round 22 degrees, so
that one blade is then on the concentric line and the other blade 45 degrees off it.
In revolving furnaces as heretofore constructed a great loss of heat takes place
by ingress of air to the furnace round the circumference.
Various methods of luting by sand or by the material under operation are
adopted which act. imperfectly and cause friction. I remedy this as follows:-I
support the whole weight of pan on an axis resting upon one footstep; above this
I put the driving wheel, and above this again the guiding brasses; I enclose these
parts in a casing, through the crown of which the shaft passes by an opening of just
sufficient size to allow it to work freely, and the casing is just wide enough to take
the driving wheel. By this means no air can get access to the furnace except through
the small annulus around the shaft.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said George Dryden Mease in the Great Seal Patent Office on the 30th April
1877.
GEORGE DRYDEN MEASE, of the Lake Chemical Works, South Shields. "IMPROVE-
MENTS IN FURNACES FOR DECOMPOSING CHLORIDES OF SODIUM AND POTASSIUM,
MANUFACTURING ALKALIES, AND FOR OTHER SUCH LIKE PURPOSES."
This Invention has for its object improvements in furnaces for decomposing
chlorides of sodium and potassium, manufacturing alkalies, and for other such like
purposes.
In decomposing chlorides of sodium and potassium in furnaces worked by steam
power it is usual to conduct the operation in a flat metal segmental pan with a
perpendicular rim; the middle of the pan being more exposed to the heat than the
circumference expands more than the sides, and the pan is thus strained and often
broken. To obviate this I make the pan with a double curve in the bottom, by
which great play is given to the elasticity of the metal.
When decomposing or calcining chlorides of sodium or potassium or calcining
alkalies in furnaces in which the pan or furnace bottom revolves, it is usual to make
a perpendicular rim.
I find that it is very difficult to get the materials over the edge of such a pan,
the materials when requiring to be drawn being in a semi-fused state and very

page_text: cohesive. I form the pan with a rim sloping upwards at an angle of from 30 to 45
degrees from the horizontal line. To discharge the contents I fasten one end of a
discharging blade to a hinge just outside of the circumference of pan. This blade is
long enough to reach to the bottom of the slope of the rim when lying at an angle
of 45 degrees or thereabouts to the radius of the pan. I work the loose end of
this blade to and fro across the slope by hand or steam power; I give it an
intermittent reciprocating action. When the blade is pointing down the slope the
material accumulates against the blade, and it is afterwards at the next movement
thrown over the slope.
In order to stir the material in the pan and to aid in discharging it I suspend
over the pan a girder or beam carrying two series of ploughs set at opposite angles.
The lower ploughs are so inclined that they tend when the pan revolves to press
the material outwards from the centre, whilst the upper ploughs tend to convey it
back towards the centre, and thus a circulation is maintained.
When the pan has been partially emptied the upper ploughs become inoperative,
and then the tendency of the stirring apparatus is altogether to convey the material
outwards from the centre and to bring it within range of the emptying blade.
In revolving furnaces as heretofore constructed a great loss of heat takes place by
ingress of air to the furnace round the circumference.
Various methods of luting by sand or by the material under operation are
adopted, which act imperfectly and cause friction. I remedy this as follows:-I
support the whole weight of the pan or furnace bottom on an axis upon one foot-
step; above this I put the driving wheel, and above this again the guiding brasses.
I mount these parts in a casing, through the crown of which the shaft passes by an
opening of just sufficient size to allow it to work freely, and the casing is just wide
enough to take the driving wheel. By this means no air can get access to the
furnace except through the small annulus around the shaft.
In order that my said Invention may be most fully understood and readily carried
into effect, I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a longitudinal section of a furnace constructed according to my
Invention for decomposing salt; Figure 2 is a cross section; Figure 3 is a sectional
plan; Figure 4 is an elevation; and Figure 5 is a sectional plan of the support for
the revolving pan with parts in connection therewith.
A is the footstep; B is the driving wheel, a worm gears with it; C are the
guiding brasses; D is the top of the axis forming a table inside the furnace to
support the pan; E is the metal pan, it has a double curved bottom, and the rise in
the centre may be carried to the extent of making the pan annular, but I now
prefer to make it of the form shown; F is a girder to which the plough blades or
stirrers are attached. There are two sets of blades for stirring the material, all of
which are set about 45 degrees off the radial lines of the pan. The top row of
blades works the material to the centre of pan, and the bottom row of blades works
the material to the circumference. G shows the top row of plough blades. H shows
the bottom row of plough blades. I shows the rods by which the girder is
suspended at cach end, and it is partially balanced by the weight J applied to a
lever having its fulcrum at K, and so the pressure of the stirrers is regulated.
A chain sheave and counterpoise may be used to suspend the girder instead of
the apparatus shown. L shows tie rods passing from the sides of the furnace to the
girder to prevent side motion; these are fastened outside of the furnace, and they
will permit a small amount of vertical play. M shows the discharging blade
working upon hinges at the outside end, and which is moved to and fro by hand or
engine.
The joint pin on which the discharging blade M is mounted is at right angles to
the inclined side of the pan, and the blade receives its motion conveniently by
means of a rod hooked into an eye in the side of the blade and passing by a small

page_text: passage formed for it in the wall of the furnace to a crank on the outside. The
arrangement is such that when the discharging blade is not required it can be
removed, and when next required for use replaced without difficulty. N shows the
columns upon which the girder O is supported, which passes across the furnace
outside, and upon which the centres K rest. P shows the plates forming the top of
casing which is covered by brickwork; an arch may be substituted. Q shows four
standards, which are bolted to the bed plate T and also to the upper casing plate P.
The two standards near together also support a screw R and shafting S, which is
driven at such a speed as to cause the pan to make from one to two revolutions in
a minute. The guiding brasses C are supported by a bracket bolted to the
plates P.
When constructing a furnace for working soda ash or alkali I make it in the same
way as shown in the Drawings as respects the footstep A, driving wheel B, guiding
brasses C, top of axis D, metal fan E, discharger M, plates or arch P, and I line the
metal pan with brickwork to protect it from the heat, and form a level surface for
the material.
Having thus described the nature of my said Invention, and the manner of per-
forming the same, I would have it understood that I claim,-.
First. The combination of parts constituting a furnace for decomposing chlorides
of sodium and potassium, substantially as d scribed.
Second. The revolving metal pan with double curved bottom, substantially as
described.
Third. The mechanism for supporting and driving the pan in such manner as to
avoid ingress of air, substantially as described.
Fourth. The mechanism for stirring the material in the revolving pan, substan-
tially as described.
Fifth. The mechanism for discharging the material from the revolving pan,
substantially as described.
In witness whereof, I, the said George Dryden Mease, have hereunto set my
hand and seal, this Twenty-fifth day of April, in the year of our Lord
One thousand eight hundred and seventy-seven.
ANINAN
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AUDANT