IMPROVEMENTS IN THE MANUFACTURE of CONCRETE SUITABLE FOR RECEIVING AN ENAMELLED SURFACE."
Year: 1881

page_text: LETTERS PATENT to John Berger Spence, of Lombard Street, in the City of
London, and Edward Ormerod, of Belvedere, in the County of Kent, Manager
of Works, for an Invention of "IMPROVEMENTS IN THE MANUFACTURE of
CONCRETE SUITABLE FOR RECEIVING AN ENAMELLED SURFACE."
PROVISIONAL SPECIFICATION left by the said John Berger Spence and
Edward Ormerod at the Office of the Commissioners of Patents on the
4th November 1881.
JOHN BERGER SPENCE, of Lombard Street, in the City of London, and EDWARD
ORMEROD, of Belvedere, in the County of Kent, Manager of Works. IMPROVE-
MENTS IN THE MANUFACTURE OF CONCRETE SUITABLE FOR RECEIVING AN
ENAMELLED SURFACE."
In making enamelled slabs for various purposes it has hitherto been found that
slate answers best as the base or backing for the enamel, it being unaffected by
the heat to which the enamel must be submitted to cause it to set.
Attempts have been made to use concrete for the backing, the cost of the
concrete being much less than that of the slate; but it has been found that
concrete as ordinarily made decrepitates so rapidly under the influence of heat that
it is quite useless for the purpose.
Now the object of the present Invention is to produce a concrete from which
slabs and other articles can be made, and which will stand the heat necessary in the
process of enamelling such slabs or articles.
In carrying out our Invention we take, say, one part of Portland cement or
other suitable binding material, one part of calcined flint or slag from iron or
copper works or other suitable material (ground to powder) which has been
subjected to the action of fire and about 10 per cent. of red hæmatite also in
Dowder.

page_text: These materials we intimately mix in a dry state. We then mix therewith in
the ordinary way with water, crushed bricks, burnt ballast, breeze, pottery refuse,
or other suitable material which has previously been subjected to great heat in
the proportions of from half-and-half to 3 of ballast to 1 of cement, according to
the nature of the article to be formed.
We prefer that the lumps of ballast or other material used shall not exceed the
size of a nut, though the size may be increased for some purposes and diminished
for others.
The concrete when mixed is placed in moulds to be formed into slabs or other
articles in the ordinary way, and when sufficiently set is placed under cover to
harden and dry.
At the end of about ten days the concrete will be sufficiently hard to handle,
and we then prefer to dry the formed article by artificial means at a temperature
of about 120 degrees for three or more days, according to the thickness of the
article.
When quite dry the article is ready to be enamelled in the ordinary way.
By making concrete as above described we obtain a compound which will stand
the heat necessary for enamelling without decrepitating, and we are enabled to
enamel articles of any form which has hitherto been almost impossible.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Berger Spence and Edward Ormerod in the Great Seal
Patent Office on the 4th May 1882.
JOHN BERGER SPENCE, of Lombard Street, in the City of London, and EDWARD
ORMEROD, of Belvedere, in the County of Kent, Manager of Works. "IMPROVE-
MENTS IN THE MANUFACTURE OF CONCRETE SUITABLE FOR RECEIVING AN
ENAMELLED SURFACE."
In making enamelled slabs for various purposes it has hitherto been found that
slato answers best as the base or backing for the enamel, it being unaffected by the
heat to which the enamel must be submitted to cause it to flow.
Attempts have been made to use concrete for the backing, the cost of the
concrete being much less than that of the slate; but it has been found that
concrete as ordinarily made decrepitates so rapidly under the influence of heat that
it is quite useless for the purpose.
Now the object of the present Invention is to produce a concrete from which
slabs and other articles can be made, and which will stand the heat used in the
process of enamelling such slabs or articles.
In carrying out our Invention we take one part by weight of Portland cement,
and add thereto one part by weight of slag from iron or copper works ground to
a fine powder. To these materials we add about ten per cent. by weight of
hæmatite, also in powder, and intimately mix the whole together in a dry state.
We then add to this mixture crushed bricks, burnt ballast, breeze, pottery refuse,
or other suitable material which has previously been subjected to great heat in the
proportions of from one of ballast or its equivalent to one of cement, to three of
ballast or its equivalent to one of cement (Portland cement, slag, and bæmatito
combined) according to the nature of the article to be formed. The whole is then
mixed together with water in the usual manner of making concrete.
We prefer that the lumps of ballast or its equivalent shall not exceed, say, half
an inch in diameter, though the size may be increased for some purposes and
diminished for others.
The concrete when mixed is placed in moulds to be formed into slabs or other
articles in the ordinary way, and when sufficiently set is placed under cover to
harden and dry. At the end of about ten days the concrete will be sufficiently
hard to handle, and we then in order to hasten the drying of the formed article
subject it to the action of heat placing it in a chamber or closed vessel heated to
a temperature of about 120 degrees for three or more days, according to the
thickness of the article. When quite dry the article is ready to be enamelled in
the ordinary way.
By making concrete as above described we obtain a compound which will stand
the heat used in enamelling without decrepitating as heretofore.
We would remark that we do not intend to confine ourselves to the proportions
given, as they may be varied according to circumstances, but we have found the
above mentioned proportions answer the purpose well.
Neither do we intend to confine ourselves to the exact materials mentioned, as
these are open to variation; thus in place of the Portland cement we may employ
other cements or binding material of suitable character. For the slag we may use
pulverized calcined flint or other material containing a large per centage of silica,
and which has been subjected to the action of fire, and for the hæmatite we may
employ other oxides of iron.
In carrying out our Invention we propose to mould articles of various forms for
architectural and other purposes, to color them in imitation of marbles and coat

page_text: them with a transparent enamel. By these means we are enabled to produce at a
comparatively cheap rate architectural ornaments for both the external and internal
decoration of buildings.
Having now described the nature of our Invention for "Improvements in the
Manufacture of Concrete, Suitable for Receiving an Enamelled Surface," and
having explained the manner of carrying the same into effect we claim,-
Manufacturing concrete suitable for the moulding of slabs and other articles
intended to be enamelled, substantially as and for the purpose herein described.
In witness whereof, I, the said John Berger Spence, have hereunto set my
hand and seal, this Fourth day of May, in the year of our Lord One
thousand eight hundred and eighty two.
J. BERGER SPENCE. (L.S.)