improvements in ectrical eaters of Resistances.
Year: 1899

page_text: improvements in ectrical eaters of Resistances.
I, ARNE BARMAN, of 32, Holdenby Road, Crofton Park, Brockley, London,
Electrician, do hereby declare the nature of this invention to be as follows:-
These improvements have for object to construct electrical heaters which with
a small weight and size combine the advantages of great surface quick heating,
heat retaining power and small consumption of current.
For this purpose
employ improved forms of conductor, insulating material and receptacles wherein
the said conductors and insulating material are enclosed. I employ flat ribbon of
manganin, nickel steel, reotan or other suitable alloy for the conductor which
is to form the means for producing heat when the electric current is passed through
it. This ribbon is laid Hat in a shallow box-shaped receptacle, and carried back-
wards and forwards, the entry and exit being at the same end and the ribbon
being bent over twice at the ends. Or I may arrange the ribbon in a spiral
being bent over at frequent intervals. The ribbon is enclosed in suitable insulating
material for which I prefer a mixture of lime 2%, magneisum 23, clay 22, oxide
of iron 23 and silicic acid 30. The ribbon is bedded thereon, and covered there-
with, and the lid of the box pressed down upon it. The box and its lid are
ribbed so as to present a large heat radiating surface. A switch is provided
for admitting the current as required.
The box may be of cast iron, or where great lightness is required aluminium
is used, provided with ribs on the outside. For the same purpose I may use
mica as the insulating material instead of the aforesaid compound. The switch
end of the aluminium box is provided with a flange for connecting the switch
thereto.
The apparatus may advantageously be applied for drying purposes, and also in
connection with electric lamps.

page_text: 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:-
These improvements have for object to construct electrical heaters which with
a small weight and size combine the advantages of great radiating surface, quick
heating, great heat retaining power and small consumption of current. For this
purpose 1 employ flat ribbon of manganin, nickel steel or other suitable not easily
oxidizable material for the conductor or resistance which is to form the means
or vehicle for producing heat when the electric current is passed through it.
This ribbon is laid flat in a shallow box shaped receptacle and carried backwards
and forwards, the entry and exit being by preference at the same end, and the
ribbon being bent over twice at the ends." I prefer to wrap the ribbon round a
thin glass plate. The ribbon is enclosed in suitable insulating material for
which I prefer a mixture of lime 2 parts, magnesia 22, clay 22, oxide of iron, 22,
and silicic acid 28; the moisture contained would amount to another 10 or 12
parts. A very similar composition is the so called natural compound talc which
I find very suitable for ny purpose. In any case the insulating material should
be made perfectly dry before use. The ribbon is bedded therein and covered
therewith, and the lid of the box pressed down upon it. A switch on or in con-
nection with the heater is provided for admitting the current as required. The
box and its lid may be of cast iron provided with ribs on the outsides thus
affording a large radiating surface together with lightness and strength.
In the accompanying drawing Fig. 1 is a plan view of such a heater the lid of
its box being partly removed and Fig. 2 a cross section of same. Fig. 3 is a
plan view of a modified form, the lid being removed, and Fig. 4 a cross section.
In the form shewn in Figs. 1 and 2 the flat metal ribbon a, of nickel steel
manganin, or other suitable not easily oxidizable conducting material is laid
flat in the talc, or other suitable insulating material or compound material b,
which latter is in a powdered or comminuted condition in the cast iron box c;
the ribbon is carried backwards and forwards from the inlet terminal d to the
outlet terminal e and is for this purpose folded over at the ends as shewn at i.
The talc must be perfectly dry before it is used and is for this purpose first made
red hot in order to drive out the moisture; while still hot it is pressed down
evenly in the box to form a bed for the ribbon a and the tale placed on it
is also well and evenly compressed, the securing of the lid f to the box by the
bolts g with nuts being also a means to this end. The lid and the box are ribbed
as shewn in order to increase the radiating surface, and I thus also obtain light-
ness combined with strength. The lid has a feather k on its underside for
entering the compressed insulating material b and making joint.
In Figs. 3 and 4 the ribbon a from the terminal d is shewn wrapped round a
glass plate h helically from one end to the other end where it is folded over as
shewn at and then carried back helically to the terminal e. By the use of
the glass plate 1 facilitate the wrapping of the ribbon and am enabled to use
more of it within the same space or size of box without fear of short circuiting.
Or the plate may be of other suitable insulating material, not affected by the
heat.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. In an electric heater the combination of a metallic box with lid, tale or
other suitable insulating material in a comminuted condition pressed down into
the box, and an electric conductor of metallic ribbon of nickel steel, manganin
or other suitable not easily oxidizable material embedded in and covered by the
tale, substantially as set forth.
2. In an electric heater the combination of a metallic box with lid, talc or
other suitable insulating material in a comminuted condition pressed down into

page_text: the box, a glass plate embedded in and covered by the insulating material, and
an electric conductor of metallic ribbon of nickel steel, manganin or other suitable
not easily oxidizable material wrapped helically around said plate, substantially
as set forth.
3. The construction of electric heater described with reference to Figs. 1 and 2.
4. The construction of electric heater described with reference to Figs. 3 and 4.
Dated this Ninth day of October 1899.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.