IMPROVEMENTS IN THE PRODUCTION OF POTTERY, OR ARTICLES OR SUBSTITUTES THEREFOR
Year: 1881

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for an Invention of "IMPROVEMENTS IN
THE PRODUCTION OF POTTERY, OR ARTICLES OR SUBSTITUTES THEREFOR."
A communication from abroad by Paul Dodé, of Paris, in the Republic of
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 2nd May 1881.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman. "IMPROVEMENTS IN THE PRODUCTION OF POTTERY OR
ARTICLES, OR SUBSTITUTES THEREFOR." A communication from abroad by Paul
Dodé, of Paris, in the Republic of France.
This Invention relates to the production of pottery or ceramic articles of every
description, or substitutes therefor, by means of an improved process hereinafter
described. The processes heretofore employed involve, as is well known, many
tedious, delicate, and expensive operations for preparing the materials or clay mass
moulding and rough turning, arranging, or setting in the oven and baking.
According to this improved process, in lieu of first moulding the cold clay and
afterwards baking the same the baking is proceeded with in the first instance, and
this is rendered possible by dispensing with clay in general, and thereby enabling
the moulding to be performed with materials in a heated condition.
In carrying out the said Invention I proceed in the following manner, the
proportions being merely given as examples, which have been found to produce
good results in practice. About one hundred parts by weight of finely ground or
powdered glass, for example, are mixed as thoroughly as possible with, say, about
five hundred parts of white or other sand, according to the color which it is desired
to produce, and to this mixture are added inetallic oxides, such, for example, as
oxides of cobalt, copper, silver, chronium, iron, uranium, gold, purple, and the like,
according to the color required, the quantities being also varied according to the
shade.
A small quantity of water is added to the mixture in order to bind it together
and form a pastly mass, or balls, or slabs, according to the nature of the article to

page_text: be produced. These balls or slabs are placed upon plates of fire clay, and conveyed
to a furnace provided with small trucks or travellers generally resembling the
furnaces employed in glass works for annealing articles just finished, but the mode
of proceeding is reversed, the balls or slabs being placed at the exit door and
moved on gradually to the entrance. The fire is urged to a somewhat elevated
temperature in order to soften, the glass; in this condition the balls, slabs, or
squares are removed from the fire proof plate and thrown into a mould made of
steel iron, cast iron, copper, or other suitable material, according to the strength
required; this mould is placed under a rammer, which descends each time
that a moulded article is withdrawn, and a fresh quantity of the material is placed
in the mould. This operation occupies from about 5 to 6 seconds.
The articles taken out of the niould are carried to a stove, one upon the other,
and allowed to cool when the stove is full.
Silica, kaolin, and the like may be treated in the same manner, but the nature of
each earth must be considered, as the quantity of glass which serves as a bond
varies with the fusibility of the materials employed.
The degree of fusibility of the vitreous material or flux should correspond with
the requirements of the description of earthy or silicious matter employed. It is
desirable to avoid the use of lead as far as possible, but alkaline compositions may
be employed with advantage.
In order to obtain the purest quantity of white, broken porcelain is employed,
the same being ground or reduced to an impalpable powder and treated in the same
manner as the sand. By these means articles are produced resembling ordinary
porcelain in every respect.
The vitreous materials or flux employed to bind the ingredients together may be
prepared and mixed directly, but it is always preferable to make the mixture with
Hluxes that have already been fused, as this saves time and yields a superior
result.
The improved materials are adapted for use for all purposes for which pottery
or ceramic products are or may be employed, as, for example, for the production of
drain tiles, or pipes, chimney pieces, hearth stones, statuettes, decorations for
buildings, combining lightness, strength, and impermeabilility; also paving blocks,
roofing tiles, and bricks exposed to the action of water or placed in moist situations,
fancy articles, plates, dishes, and other like articles.

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
18th October 1881.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman. "IMPROVEMENTS IN THE PRODUCTION OF POTTERY, OR
CERAMIC ARTICLES OR SUBSTITUTES THEREFOR." A communication from abroad
by Paul Dodé, of Paris, in the Republic of France.
The said Invention relates to the production of pottery or ceramic articles of
every description, or substitutes therefor, by means of an improved process herein-
after described.
The processes heretofore employed involve, as is well known, many tedious,
delicate, and expensive operations for preparing the materials or clay mass, moulding
and rough turning, arranging or setting in the oven, and baking.
According to this improved process, in lieu of first moulding clay in a cold
condition and subsequently exposing it to the action of heat, the heating is pro-
ceeded with in the first instance, the ingredients selected being of such a nature as
to admit of the moulding operation being performed when the materials are in a
heated and plastic condition. A very important saving of time and labour is thus
effected in comparison with the methods heretofore employed.
In carrying out the said Invention a good result is obtained by the admixture of
finely ground or powdered glass in the proportion of, say, about one hundred parts
by weight with, say, about five hundred parts by weight of white or other sand,
according to the colour which it is desired to produce, the ingredients being
incorporated together as completely as possible. The proportions mentioned may
however be varied, but those given yield beneficial results in practice. To this
mixture are added metallic oxides, such for example, as oxides of cobalt, copper,
silver, chromium, iron, uranium, goid, purple, and the like, according to the colour
required, the quantities of such coloring inatter being also varied according to the
shade.
A small quantity of water is added to the mixture in order to bind it together
and form a pasty inass, which is then formed into balls, slabs, or squares, according
to the nature of the article to be ultimately produced. These balls, slabs, or squares
are placed upon plates of fire clay, and conveyed to a furnace provided with small
trucks or travellers, and resembling in its general construction the furnaces
employed in glass works for annealing finished articles, but the ordinary mode of
proceeding is reversed, the balls, slabs, or squares being placed near the exit door in
the first place, and moved on gradually to the entrance. The fire is urged to a
somewhat elevated temperature in order to soften the glass, and in this plastic
condition the balls, slabs, or squares are removed from the tire proof plates, and
placed in a mould made of steel, iron, cast iron, copper, or other suitable material,
according to the strength required. This mould is placed under a rammer, which
descends each time that a moulded article is withdrawn and a fresh quantity of the
material is placed in the mould. The articles when taken out of the mould are
carried to a stove, where they are placed one above the other and allowed to cool
when the stove is full.
The operation is conducted in a similar manner with the employment of silica or
vitrifiable earth, kaolin, and the like in lieu of the sand, but the proportions are
modified according to the nature of each earth, as the quantity of glass employed
as a bond must vary with the degree of fusibility possessed by the other
materials.
The degree of fusibility of the glass, vitreous material, or flux should correspond
with the requirements of the description of earthy or silicious matter employed.

page_text: It is desirable to avoid the use of lead, as far as possible, but alkaline compositions
may be employed with advantage. In order to obtain the purest quality of white
broken porcelain is employed, the same being ground or reduced to an impalpable
powder, and treated in the same manner as the sand hereinbefore described. By
these means articles are produced resembling ordinary porcelain in every respect.
The glass, vitreous material, or flux employed to bind the other ingredients
together may be compounded and mixed directly with the other materials, but it is
always preferable to make the mixture with fluxes that have already been fused, as
this saves time and yields a superior result.
Articles manufactured in the manner hereinbefore described are applicable to all
purposes for which pottery or ceramic materials are usually employed; for example,
drain-tiles or pipes, chimney pieces, hearth stones, statuettes, decorations for buildings
combining lightness, strength, and impermeability, also paving blocks, roofing tiles,
and bricks exposed to the action of water or placed in moist situations, fancy
articles, plates, dishes, and other like articles may be manufactured with great
facility and economy by means of the improved process herein before described.
Having now described and particularly ascertained the nature of the said Inven-
tion, 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,-
The system or mode of producing pottery or ceramic articles, or substitutes
therefor, by moulding compositions when in a heated condition, substantially as
hereinbefore described.
In witness whereof, I, the said John Henry Johnson, liave to this my
Specification set my hand and seal, this Twelfth day of October, One
thousand eight hundred and eighty one.
J. HENRY JOHNSON. (L.S.)