Improvements in and relating to the Manufacture of Porous Earthenware Building Material.
Year: 1890

page_text: Date of Application, 28th June, 1890
Complete Specification Left, 26th Mar., 1891-Accepted, 2nd May, 1891
PROVISIONAL SPECIFICATION.
Improvements in and relating to the Manufacture of Porous
Earthenware Building Material.
I, JOHN PITT BAYLY, of 18 Fulham Place Paddington, in the County of
London, Patent Agent, (a communication to me from abroad by William Lenderoth,
of Deseronto, Ontario, Canada, Civil Engineer,) do hereby declare the nature of
this invention to be as follows:-
This invention relates, firstly, to the improved porous earthenware, building
material, and secondly to the process of manufacturing it.
The porous earthenware and building material consists of bricks having internal
incrusted cells, the coating of said cells being harder than the rest of the material.
The process of forming porous earthenware consists in subjecting a mixture of
clay, sand, sawdust, and lime, first to such a degree of heat as will reduce the
sawdust to ashes and will combine said ashes with the heated lime into a flux, and
in afterwards increasing the temperature to cause said flux of lime and ashes to
incrust and vitrify around the cells without at the same time vitrifying the mixture
of clay and sand.
Do 1...
Jun 1000
J. P. BAYLY,
Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to the Manufacture of Porous
Earthenware Building Material.
I, JOHN PITT BAYLY, of 18 Fulham Place, Paddington, in the County of
London, Patent Agent, do hereby declare the nature of this invention (a com-
munication to me from abroad by William Lenderoth, of Deseronto, Ontario, Canada,
Civil Engineer,) to be as follows:-
The object of my invention is to provide an improved process for manufacturing
porous earthenware building material, which material shall be able to withstand the
action of high temperatures, and be strong to resist without cracking or crushing
the pressure of high walls, arches, etc.
In carrying out my invention I make a mixture of dampened clay of any of the
varieties, and sand or sandy fire clay, in such proportions that the mixture will not
vitrify when exposed to a temperature hot enough to reduce to ashes saw-dust or
the like. For instance, I take eighty-five parts of pure clay and fifteen parts of
sand for the mixture. I then take saw-dust, coal-dust, chopped straw, or other
suitable combustible material, and add to it lime, cryolite, baryta, or other suitable
material. The saw-dust or its equivalents should be thoroughly saturated with
water so that each grain or particle will absorb all the water it can, thus expanding
to its largest dimensions. I then add this mixture of combustible material, lime or
its equivalent, and water to the clay-and-sand mixture before mentioned, and
thoroughly intermix them in any suitable manner.
The proportions of clay mixture, saw-dust. or its equivalents, and lime or its
equivalent, may vary, and are dependent upon the amount of porosity required in
the product and the heat or hardness desired. In practice I find that three parts

page_text: of the clay mixture and from two to six parts of saturated saw-dust and from two
to fifteen per cent. of lime or its equivalent produces good results.
The object of having the saw-dust or its equivalents saturated with water is to
prevent the particles absorbing water from the clay and from expanding after being
mixed, with the clay and thereby producing strains or cracks.
66
After thoroughly mixing the above ingredients I preferably pass the mixture
through a machine having rollers revolving toward each other, the one of which has
a higher surface velocity than the other. By the action of these rollers a more
thorough and perfect mixture of the clay and other ingredients is obtained.
Sufficient water is used to make the mass plastic, and it is put into a pug-mill."
I prefer an auger or screw press; but any of the presses commonly used for this
class of work will answer. The plastic mixture is by this machine expressed through
suitable dies in the form of a column of whatever section it is desired the die should
produce. It is thus cut into such lengths as may be desired, and the blocks thus
formed are removed to a drying room or shed. In this shed the mixture is partially
dried by exposure to warm air. I then remove the blocks to a kiln or other suitable
receptacle and subject them to a heat of about 1800° Fahrenheit, which reduces the
saw-dust or the like, and the mixture to ashes, thereby leaving cells in the mixture.
The heat at this time is not permitted to become greater than is necessary to reduce
to ashes the saw-dust or other combustible ingredient. The ashes thus produced
together with the lime or its equivalents previously added to the mixture form a
flux in the mixture. By keeping the heat low enough-namely, at about 1800°
Fahrenheit to merely reduce the saw-dust, etc., to ashes, and form a flux, I prevent.
the clay and sand from vitrifying. After the flux is created the temperature upon
the mixture is increased till it is sufficiently high to cause the said flux to produce
vitrifaction or partial vitrifaction around the cells within the blocks, thereby
producing a mass of glazed or incrusted cells, which, when the blocks are cold is
harder and stronger than the other parts of the material, but which leaves the block
porous between the incrusted cells. These blocks, when removed from the kiln and
ready for use are free from cracks, and when struck a sharp blow ring like a piece
of sound crockery.
By adding sand to the clay or by mixing various kinds of clay having different
compositions, mixtures may be produced which will vitrify on the cells at higher or lower
temperatures, some being subjected to vitrifaction at comparatively low temperatures,
while others will remain unchanged at a temperature that would melt cast iron. As
'compared with the porous blocks hitherto made those produced by my process are
stronger and will safely resist a greater pressure. They are not so easily injured
by fire or by efforts to extinguish fire. They also resist the action of acids
more successfully and hold nails more firmly than any other porous material
known to me.
I am aware that clay and saw-dust, and clay and coal-dust have long been used
to produce porous terra-cotta, porous bricks, porous hollow-ware, and such like
material, and I am acquainted with the various processes of their manufacture.
I am acquainted with a process of mixing saw-dust, clay free from grit, and
straw or vegetable fibre, which produces a building material to be worked with edge
tools. I am also acquainted with a process of making porous earthenware by mixing
clay and saw-dust and straw cat in short pieces, but my process and the material
produced by it, differs from any of these in particular, in the following points:
First, in making and using a clay mixture that will not vitrify at a temperature
.sufficient to consume the saw-dust or material used instead of saw-dust; second, in
adding lime or its equivalents to the saw-dust to form a flux only with the ashes of
the saw-dust, or other material; third, in keeping the temperature of the kiln
comparatively low until the combustible portion of the mixture is reduced to ashes,
and then raising the temperature sufficiently high to cause the flux to act, and so
produce the incrustations around the cells; fourth, the resulting product differs from
all other porous building material known to me, in being stronger, and in having
the glazing or incrusting surface around the cells, as described.

page_text: Having now particularly described and ascertained the nature of this my said
invention, and in what manner the same is to be performed, I declare that what I
claim is :
1. The process herein described of forming porous earthen-ware, which consists
in subjecting a mixture of clay, sand, saw-dust, and lime, first to such a degree of
heat as described, to ashes, and will combine said ashes with the heated lime into
the flux, and in afterwards increasing the temperature to cause said flux of lime and
ashes to increase and vitrify around the cells, at the same time vitrifying the mixture
of clay and sand, substantially as specified.
2. As a new article of manufacture, a brick having a series of internal incrusted
cells, the incrusted coating around the cells being harder than the rest of the
material, substantially as described.
J. P. BAYLY,
Applicant.