IMPROVEMENTS IN OR CONNECTED WITH GLASS FURNACES
Year: 1882

page_text: LETTERS PATENT to John Henry Johnson of 47 Lincolns Inn Fields in the
County of Middlesex Gentleman for an Invention of "IMPROVEMENTS IN
OR CONNECTED WITH GLASS FURNACES Communicated to him from
Alexandre Duchet a person resident at Paris in the Republic of France Master
SOL
"
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 29th November 1882.
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN OR CONNECTED WITH GLASS FURNACES a com-
munication to me from abroad by Alexandre Duchet a person resident at Paris in
the Republic of France Master of Glass Works
"
This invention relates to furnaces for melting and refining glass in which the
process is carried on in a continuous manner in a hearth or melting chamber and it
has for its object to provide efficient means for preventing the impurities or
imperfectly fusced materials on the surface of the molten glass from passing
over to that side of the furnace where the pure or refined glass is taken out.
Various devices have heretofore been employed to accomplish this object but
they are attended with numerous disadvantages. The imperfectly fused vitrifiable
matter has hitherto usually been prevented from mixing with the melted and
refined glass that is ready for the blower by means of walls or barriers made of fire
bricks dividing the furnace into several compartments but this arrangement is not
perfectly effectual and the walls are found to wear out rapidly thereby occasioning
frequent interruptions in the working of the furnaces.
Fire clay floats of various forms and dimensions have also been employed with
the object of separating the unvitrified matter from the glass that has been
refined and is ready for blowing but these floats are costly and tedious to make
and fail to give satisfaction for various reasons too numerous to mention.
According to this Invention the desired result is obtained in an efficient and
practical manner by means of a submerged barrier acting in combination with
floats both the barrier and the floats being constructed and arranged as hereinafter
described.

page_text: Passages for air are formed in the barrier which take in air at both extremities
thereof and first conduct it along the upper side of the barrier as far as the centre
and then downwards and backwards so as to discharge the air into suitable flues or
chimneys which create a powerful draught
The air passages for ventilating or cooling the barrier may however be arranged
in any other convenient manner if preferred.
The upper side of the barrier being generally some eight inches below the surface
of the glass offers in itself no impediment to the passage of the molten glass or of
the imperfectly fused vitrifiable matter floating on its surface. In order to prevent
this imperfectly fused vitrifiable matter from passing over the barrier a number of
floats of annular or other convenient form are introduced into the furnace on the
charging side These floats project about two or three inches above the surface of
the glass and their lower extremities are immersed to such a depth as to render
them incapable of passing over the submerged barrier-One or more rows of such
floats arranged against the side of the barrier do not impede the passage of the
pure melted glass but effectually prevent any objectionable matter from being
carried over to that side of the furnace where the said glass is removed and the
said floats are maintained in position automatically by the pressure of the glass
and vitrified matter behind them.
The floats being made of suitable fire proof materials will last for two or three
weeks and when worn out may be replaced by new ones without any interruption
of the working of the furnace-The barrier being entirely submerged below the
surface of the glass is not liable to be consumed by contact with the vitrifiable
matter and will last as long as the other parts of the furnace as it may be cooled
to the desired extent by the circulation of air in its interior without being liable to
cause any solidification of glass to take place in consequence

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Seal Patent Office on the
26th May 1883.
"
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN OR CONNECTED WITH GLASS FURNACES a com-
munication to me from Alexander [sic] Duchet a person resident at Paris in the
Republic of France Master of Glass Works
This Invention relates to furnaces for melting and refining glass in which the
process is carried on in a continuous manner in a melting chamber and it has for
its object to provide efficient means for preventing the impurities or imperfectly
fused materials on the surface of the molten glass from passing over to that side
of the furnace where the pure or refined glass is taken out. Various devices have
heretofore been employed to accomplish this object but they are attended with
numerous disadvantages. The imperfectly fused vitrifiable matter has hitherto
usually been prevented from mixing with the melted and refined glass that is
ready for the blower by means of barriers made of fire bricks dividing the
furnace into several compartments but this arrangement is not perfectly effectual
and the barriers are found to wear out rapidly thereby occasioning frequent
interruptions in the working of the furnaces. Fire clay floats of various forms and
dimensions have also been employed with the object of separating the unvitrified
matter from the glass that has been refined and is ready for blowing but these
floats are costly and tedious to make and fail to give satisfaction for various reasons
too numerous to mention.
According to this invention the desired result is obtained in an efficient and
practical manner by means of a submerged dam or barrier acting in combination
with floats or rings both the barrier and the floats being constructed and arranged
as hereinafter described.
And in order that the said Invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures on the annexed sheet of drawings the same letters of reference indicating
corresponding parts in all the figures.
Figure 1 of the accompanying drawings is a vertical section of the melting
chamber of a glass furnace provided with a dam or barrier and floats or rings
according to this invention and Figure 2 is a horizontal section of the same taken
along the line 1-2 figure 1 but showing also the floats or rings in position.
Figure 3 is a transverse section of the said barrier the section being taken along
the line 3-4 figure 1.
According to the said Invention a dam or barrier Y of fire bricks extends across
the melting chamber G below the surface of the glass which is shown at x. This
barrier in the example illustrated is about twenty two inches high and about
thirty inches wide, its upper surface being about eight inches below the surface of
the glass. The dam or barrier Y is hollow and is divided internally by a vertical
transverse partition R at about the centre of its length. Passages B for air are
formed in the barrier which take in air at both extremities thereof at A A' and
first conduct it along the upper side X of the barrier as far as the central partition R
and then downwards at o and backwards as shown by the arrows so as to discharge
the air into suitable flues or chimneys B¹ which create a powerful draft. The air
passages for ventilating or cooling the barrier may however be arranged in any
other convenient manner if preferred.
The upper side of the barrier being generally some eight inches below the surface
of the glass offers in itself no impediment to the passage of the molten glass or of

page_text: the imperfectly fused vitrifiable matter Bloating on its surface. In order to prevent
this imperfectly fused vitrifiable matter from passing over the barrier a number of
floats H of annular or other convenient form are introduced into the furnace on
the charging side. These floats project about two or three inches above the surface
of the glass and their lower extremities are immersed to such a depth as to cause
them to come in contact with the upper edge of the submerged barrier as shown
at P figure 3 and prevent them from passing over it. One or more rows of such
floats arranged against the side of the barrier do not impede the passage of tho
pure melted glass but effectually prevent any objectionable matter from being
carried over to the working out side of the furnace or side where the said glass is
removed and the said floats are maintained in position automatically by the
pressure of the glass and unvitrified matter behind them. Two or more rows of
such floats may be arranged behind the barrier as shown in the drawing.
These floats being made of suitable fire proof materials will last for two or three
weeks and when worn out may be replaced by new ones without any interruption
of the working of the furnace. The barrier being entirely submerged below the
surface of the glass as shown at V figure 3 is not liable to be consumed by contact
with the vitrifiable matter and will last as long as the other parts of the furnace
as it may be cooled to the desired extent by the circulation of air in its interior
without being liable to cause any solidification of glass to take place.
Having now described and particularly ascertained the nature of the said
invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the herein before in part
recited Letters Patent is :-
First-In glass furnaces the employment of a dam or barrier submerged below
the surface of the bath in combination with floats or rings resting against it
substantially as and for the purpose herein before described with reference to the
accompanying drawings.
Second In glass furnaces the employment of a dam or barrier submerged
below the surface of the glass and provided with internal passages for cooling
the same in combination with floats or rings resting against it substantially as
and for the purposes hereinbefore described with reference to the accompanying
drawings.
In witness whereof I the said John Henry Johnson have to this my
Specification set my hand and seal this twenty fourth day of May One
thousand eight hundred and eighty three.