Improvements relating to the Manufacture of Terra Cotta Pottery and the like.
Year: 1899

page_text: Date of Application, 14th Feb., 1899-Accepted, 26th Aug,,
1899
[Communicated from abroad by Professor VINCENZO MICHELI, of 10, Piazza Pitti,
Florence, in the Kingdom of Italy, Civil Engineer, Director of the Academy
of Fine Arts.]
Improvements relating to the Manufacture of Terra Cotta Pottery
and the like.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, 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 to the manufacture of terra-cotta, pottery, bricks
and other building materials as well as liquid proof vessels, and consists in first
drying the earths of which the articles are to be made in clods, in their natural
condition, either by the action of the air or of the sun, or artificially in suitable
drying houses, and then reducing the same to powder, such powdered mass being
then burnt or baked and afterwards used for manufacturing the desired articles.
The powdered earths may be burnt or baked in any suitable oven or kiln, such
for instance as the continuous kilns in which the powdered earth runs down
inclined planes or walls of sheet iron or fire bricks so as to be brought into direct
contact with the products of combustion whereby it is heated to a very high
temperature.
During this operation the earth is caused to contract, and is also dehydrated
and chemically altered in accordance with the nature of the earths originally
used.
Before the powder is fed into the kiln and if it does not contain a sufficient
quantity of lime, magnesia or the like. I may add to it a suitable quantity of
natural earths or other suitable substances, previously powdered, and the mass
so mixed is then ready for baking or burning. In this way I can obtain a
mixture having the desired properties for the particular work which I desire
to manufacture and which is more suitable for the purpose than the original
natural earth.
The difference therefore between this invention and existing methods is that
I first bake or burn the materials in the form of powder and then shape the
articles therefrom instead of the reverse as heretofore, and thus I obtain two
distinct advantages of the highest importance viz. the deformation of a large
percentage of articles are prevented, and further all kinds of earths, including
non-plastic earths which could not be used for clay goods can now be rendered
suitable owing to their conditions, both phisically and chemically being altered
by the preliminary burning.
Thus by baking or burning the earth in a powdered condition I am enabled
to utilize for the manufacture of the above mentioned materials turfy, sandy,
and alkaline earths and clays of inferior quality, bolary and fossiliferrous earths,
as well as all those earths which, on account of containing an excessive quantity
of lime, or of their not being sufficinetly plastic, or of owing to other drawbacks,

page_text: are not suitable for moulding and baking in the usual manner for making
terra cotta and pottery articles.
The following comparative statements serve to explain the nature of the
invention.
Earths containing carbonate of lime in form of grit, especially earthy marl
which contains above 20% of finely divided carbonate of lime, are considered
non-plastic and unsuitable for use in ceramic, as the caustic lime formed in the
article by baking would cause it to crumble away on exposure to the air owing
to its hygroscopic properties.
This however is different when the material is treated according to this inven-
tion by first drying the earths and earthy marls or the like in their natural
condition, then pulverizing the same in a suitable disintegrator and finally burn-
ing the pulverized materials. The caustic lime contained in the burnt material
forms the same into a fatty lime paste when water is added and thus constitutes
a natural binding medium for the other substances. Thus if the burnt materials
contained about 30 to 40% of lime no further binding substance will be required
in order to render the material plastic and suitable for ceramic purposes.
Therefore the presence of caustic lime which formerly was a disadvantage
is now turned into an advantage.
Again peat-soil hitherto could not be used for pottery and like purposes as
the vegetable constituent parts thereof burn away, leaving the article with holes
more or less. According to my invention these kinds of earths are rendered
suitable for the purpose stated by burning away the vegetable constituents from
the pulverized earths and then adding thereto, if necessary, any binding substance
for forming them into articles.
In some cases according to the nature of the soil it may be required to add
thereto binding substances before the burning operation while others require
such an addition to be made after burning.
By my invention I am enabled not only to use any kind of earth but also to
manufacture on the spot where the terra cotta and similar articles are required
for use which saves the cost of freight and transport which in certain cases would
be very expensive, with the present methods of manufacturing pottery and
building materials.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
The method of manufacturing terra cotta, pottery and building materials
consisting in first drying and pulverizing the earths and then burning the same
prior to their being used for the manufacture of articles, substantially as herein-
before described.
T
1 11.
03
1
C T
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.