Improvements in Electric Heaters,
Year: 1898

page_text: Date of Application, 30th July, 1898
Complete Specification Left 28th Anr 1800-Accented 24th June 1899
PROVISIONAL SPECIFICATION.
Improvements in Electric Heaters,
I, HENRY LYON, of 38, Whitevale Street, in the County of Glasgow, North
Britain, Electrical Engineer, do hereby declare the nature of this invention
to be as follows, that is to say:-
My said invention comprises improvements designed to render electric heaters
efficient, reliable, economical, and not requiring frequent repairs,
In constructing an improved heater I employ a slab or block made of a mixture
of fireclay and lampblack and having formed on it a number of small grooves.
A high resistance wire may be wound upon the slab in the grooves its ends being
connected to terminals arranged to receive the wires of an electric circuit.
however prefer, instead of a fine resistance wire, to employ a composition having
a suitable resistance and which is connected to the terminals. This composition
consists of fine carbon combined with vegetable fibres which have been treated
with sulphuric acid and a suitable cement. The slab after being moulded and
dried is fired in a kiln or furnace; and thereafter when the resistance com-
position has been applied to the slab heat is again applied to bake the composition.
The slab is enclosed in a metal case but with a non-conducting layer interposed
all round it, this layer being formed by filling the space with a strong solution
of rock salt and evaporating the water therefrom, until the space is completely
filled with the dry salt. Instead of the rock salt a mixture of silicate of soda,
carbonate of soda and lampblack may be used; or tale or mica may be inter-
posed between the slab and its metal casing.
1
1000
EDMUND HUNT,
Applicant's Agent.
COMPLETE SPECIFICATION.
Improvements in Electric Heaters.
I, HENRY LYON, of 38, Whitevale Street, in the County of Glasgow, North
Britain, Electrical Engineer, 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, that is to say;-
My said invention comprises improvements designed to render electric heaters,
efficient, reliable, economical, and not requiring frequent repairs.
And in order that my said invention and the manner of performing the same
may be properly understood I hereunto append a sheet of explanatory drawings
to be hereinafter referred to in describing my improvements.
Figure, 1, of the drawings is a longitudinal vertical section, and Figure, 2,
is a transverse vertical section of an electric heater provided with my improve-
Q77

page_text: ments. Figures, 3, and 4, are views similar to Figures, 1, and 2, of another
modification of my improvements. In these drawings the same reference letters
are used to mark the same or like parts wherever they are repeated.
My improved heater as constructed according to the first modification of my
invention, shown in Figures, 1, and 2, comprises a slab, or block, A, of rect-
angular shape but which may be of any convenient form made of a mixture of
fireclay and lampblack and enclosed in a steel or iron casing, B. The slab, A,
has formed in its circumference small helical grooves, C, there being wound in
the grooves around the slab, a conductor, D, consisting of a metal wire of high
resistance its ends being connected to separate external terminals, E, F, to
which the wires of the electric circuit are to be fixed, the terminals being fixed
to a plate, G, fixed to the flanged end, H, of the casing, B. Instead of employ-
ing a fine resistance wire, D, as hereinbefore described, I may prefer to employ
a composition having a suitable resistance and which is connected to the ter-
minals, E, F. This composition or filament may vary, but in a preferable
example it consists of 2 parts by weight of fine carbon combined with 8 parts
vegetable fibres which have been treated with sulphuric acid, and a suitable
cement consisting of, for example equal parts lamp black, black lead, sugar and
crushed coke or carbon. The slab, A, after being moulded and dried, is fired
in a kiln or furnace; and thereafter, when the resistance composition has been
applied to the slab, heat is again applied to bake the composition. The space
between the slab, A, and its metal case, B, is filled with a non-conducting
substance, J, composed of a strong solution of rock salt, the solution being filled
into the space and the water thereafter evaporated from it, until the space is
completely filled with the dry salt. Instead of the rock salt, a mixture of about
3 parts by weight of silicate of soda, 6 parts carbonate of soda, and 2 parts lamp-
black may be used; or tale or mica may be interposed between the slab, A, and
its metal casing, B, either alone or combined with silicate and carbonate of soda
in the proportion of 4 parts each carbonate of soda and mica or tale with one
part silicate of soda.
In the modification shown in Figures, 3, and 4, the block, A, and casing, B,
are made of cylindrical form, and instead of the return wire or filament proceed-
ing to the terminal, F, along the outside of the block, A, it passes through the
block, transverse and longitudinal perforations or passages, K, L, being formed
in the block for that purpose. The other end of the wire or filament connected to
the terminal, E, passes through the block, A, in a similar way, the longitudinal
passage, L, in this instance however only requiring to extend a short distance
into the block.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed I declare that what I
claim is
Improved electric heater comprising a slab or block made of fireclay and lamp-
black enclosed in a case, the block being formed with helical grooves to receive
a conductor composed of a fine or high resistance wire, or a filament made of
carbon and vegetable fibres and a suitable cement the ends of the conductor
being connected to external terminals and the space between the block and its
case being filled with a suitable non-conducting substance substantially as herein-
before described with reference to the accompanying drawings.
Dated this Twenty-seventh day of April 1899.
EDMUND HUNT,
Applicant's Agent.