Improvements in the Manufacture of Bricks, Tiles, and similar Articles.
Year: 1895

page_text: Date of Application, 4th July, 1895-Accepted, 10th Aug.,
1895
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Improvements in the Manufacture of Bricks, Tiles, and similar
Articles.
I HENRY WOOD of Granville Road, St. Albans, in the County of Herts,
Merchant and Contractor, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :—
My present invention relates more particularly to the manufacture of bricks for
building purposes, but it has reference also to paving. blocks, roofing tiles, and
other articles of a like nature.
In carrying out my invention, I take burnt clay, commonly called "burnt
ballast," stone chips, old fire-bricks, brick rubbish, or other inexpensive materials
of a hard and gritty nature, incapable of becoming softened by the addition of
water, that substance being preferred which is most readily obtainable. These
materials, or any of them, which are to form the body of the brick or tile, I grind
to powder in a mill like a mortar mill, and I mix therewith, preferably in the mill,
a percentage of cement. From the mill, the ground materials pass to a mixing
trough, where the mixture is slightly damped, by allowing water from a tap to run.
upon it while the mixture is being stirred by blades revolving in the trough.
In damping the ground materials, great care must be taken not to reduce the
mixture to a plastic condition.
The powdered or granulated state of the mixture should not be destroyed, and
the addition of water to the materials should be such as to produce only a slight
dampness, hardly perceptible to the touch.
The mixer is arranged, by preference, above the hopper of a brick-moulding
machine or press, so that the materials, on leaving the mixer, fall into the hopper,.
and pass thence, by gravity, into moulds, where the bricks or tiles are formed by
pressure in the manner well understood in the "semi-dry" process of brick-
making.
The bricks and tiles produced by my method, when taken from the press, are
stacked out on a floor to dry or set, and are fit for use in a few days without firing
or any further treatment. The amount of pressure necessary to sufficiently
compress a brick of the ordinary size is about 100 tons, but the pressure may be
considerably varied according to circumstances. The absence of a superfluity of
moisture in the mass enables the compression of the brick to be thoroughly
effected, such moisture as is contained being only sufficient, when the pressure is
applied, to permeate the mass and set the cement, which binds the whole into a
solid block.
It will be understood that this is an essentially different process from the
manufacture of concrete, and artificial stone and marble, for in these the materials
are reduced to a plastic condition, thereby precluding the manufacture of a cement
building brick at remunerative prices. The reason for this is to be found in the
difficulty of compressing plastic substances to a condition of solidity, and in the
expense of manipulating the materials in a state in which they will not, by gravity,
move themselves, or lend themselves to be easily moved, but have to be lifted
entirely by mechanism or by hand labour.
The proportion of cement found to give good results is 10%, but I do not wish
to confine myself to that proportion, as it may be increased or diminished according

page_text: to the quality of brick or tile desired to be produced. The best Portland cement
is what I propose generally to employ.
I may here remark that the mortar mill above referred to may have a perforated
pan, through the holes in which the materials, when ground, fall into a pit beneath,
whence they are raised by an endless chain of buckets, or an equivalent elevator,
to the mixing trough placed over the press.
Having now particularly described and ascertained the nature of my said 'inven-
tion and in what manner the same is to be performed, I declare that what I
.claim is
The manufacture of bricks, tiles, and similar articles, in the manner explained,
that is to say, by mixing ground burnt ballast, brick rubbish, clinker, or other
material of a hard and gritty nature, as above indicated, with cement, and
compressing the mixture, when in a powdered, or granulated, slightly damp state,
into the articles to be produced, in such a way that the moisture permeates the
whole mass and sets the cement, as described.
d dow of July 1895
NEWTON & SON,
Agents for the Applicant.