Improved Thermophor with Electric Heating Arrangement.
Year: 1899

page_text: Date of Application, 26th Sept., 1899-Accepted, 30th Dec., 1899
COMPLETE SPECIFICATION.
Improved Thermophor with Electric Heating Arrangement.
I, IGNAZ TIMAR, of 14, Kommandantenstrasse, Berlin, in the Empire of Germany,
Company Director, 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:-
Thermophors, as is known, are composed principally of a hollow vessel, within
the double walls of which substances are contained, which, when heated, melt into
water of crystallisation and therefore, when crystallised back, give off the latent
heat again, as for instance, crystallised acetate of soda or crystallised hyposulphite
of soda or caustic baryta, etc.
By means of the quantity of heat so obtained, it is possible for substances, such,
for instance as provisions, etc., contained in the vessels to be kept warm or in this
way the heating of the surrounding free space may be effected."
The melting substance contained in the thermophors can be heated in two
ways. In the one case, the vessel is heated on an open fire, or by contact with
heated surfaces or bodies, such as hearth flutes, water baths or vapour baths etc.,
and in the second, the melting is effected by means of the electric current.
In heating by the electric current, it has been usual hitherto to effect the melting
by introducing the current through the wires, arranged directly in the melting
mass.
In the process now referred to, the electric wires however, do not lie freely
in the melting mass, but are embedded in some sort of protecting casing made
of solid bodies or formed of air. Such an insulation of the conducting wires
from the melting mass not only affords the assurance of reliable working of the
heating arrangement, but is necessary for practically carrying out the whole
operation for the following reasons:-
Upon the current passing through the wire, the latter is heated and the heat
transmitted to the melting mass by direct contact of the mass with the conducting
wires. The portions of the melting mass which are in direct contact with the
wire are very quickly and considerably heated and therefore lose their water of
crystallisation. This water becomes volatilised, and is condensed on the outer
portions of the melting mass. The portions of the melting mass lying next to
the wires thus become free of water and therefore difficult to melt: they do not
melt and form around the wires an insulation which conducts heat badly.
The melting mass freed from water of crystallisation is now further heated by
the heated conducting wires, and in this way there is a danger of the melting mass
being completely decomposed by electrolysis. In particular, the disadvantage of
the volatilising of the water and of the dissociation will be sensibly felt, if
working with a strong current, but, even with the employment at the beginning
of a weak current, which is only later on raised to a strong current, it is not

page_text: possible to obviate the evil. It will be seen that with such unfavourable methods
of working, especially when the heating is frequently repeated, the working
capacity of the apparatus is considerably effected, and finally reduced to nil.
In the following specification, an apparatus is described, which entirely and
easily obviates the disadvantage mentioned above.
Within hollow bodies made of any preferred material in cylindrical or other
form, electric conducting wires are so placed that no contact can take place
between the wires and the sides of the hollow bodies. The electric current is con-
ducted, as source of heat, through the wires. Around these hollow bodies, again,
are one or more other hollow spaces, which being closed like vessels, serve to
receive the substances, melting into water of crystallisation, with or without an
addition of glycerine. If, now, the electric current be conducted through the
wires, the current first heats the stratum of air in the electric conducting spaces;
the heated stratum of air, in turn, transmits its heat through the metal sides
to the hollow spaces in which is the acetate of soda etc. For the reasons given
above the melting of the substances, which melt into water of crystallisation is
rendered possible without any direct action of the current thereon and therefore
no electrolytic decomposition of the substances takes place. As, in this manner,
the heating of the acetate of soda is effected by means of a much larger surface
and as moreover a direct contact of the salt with the heated wires is out of the
question, it is absolutely certain that even upon heating and further heating with
a strong current being effected, there can be no loss of water.
The arrangement of the hollow spaces and of the insulated stratum of air, in
which the electric current circulates, can be carried out in various ways; the
principal of these are described in the following statement:-
Fig. 1. Around a hollow space b with metal surroundings, in which are the
electric wires a, is a vessel c with insulation d containing the acetate of soda etc.
Fig. 2, is distinguished from Fig. 1, in this, that the mass of acetate of soda etc.
instead of being traversed by one large hollow space with metal surroundings,
is traversed by a series of small ones, each with one or more conducting wires a.
In Fig. 3, is shewn an arrangement wherein four electric wires a, each in an
independent vessel e, are arranged within one common insulation d.
Fig. 4, is similar to Fig. 2, as the mass of acetate of soda etc. which is melted
by the electric conducting tubes, surrounds the hollow space in cylindrical
fashion, so that the insulation is applied at the outer edge of the receptacle for
the acetate of soda etc.
Fig. 5, illustrates the closing arrangement by means of which, in all the
forms, the hollow spaces are closed when these forms of the apparatus are employed
for heating spaces, in order that the air space in the interior should be heated
as quickly as possible and be opened, as desired, as soon as the latent heat has
been given off.
In consequence of its being possible with this arrangement to use a strong
current, the acetate of soda is very quickly melted and rendered suitable for
giving off heat.
By the employment of a screw, the point of which dips into the melted mass
of salt, it is possible by removing the same from the melting mass, and subsequent
immersion thereof in the mass, whereby the latter is "inoculated" to bring about
a rapid and certain re-crystallisation (Fig. 8).
Thermophors of this kind with electric heating arrangements are capable of
being very extensively employed.
Fig. 7, shows a vessel, which serves for the reception of provisions etc., and the
arrangement of the several parts of the same is at once apparent from the drawing.
The hollow space in the interior of the vessel serves to receive the substances to lie
kept warm.
Fig. 6, shows the arrangement when thermophors of the kind are employed
for heating in connection with carriages driven by electricity. The thermophor
in the form of a heating pipe is placed, for example, under the seats, and at

page_text: both ends of the pipe, or in the sides thereof also, valves are arranged, which can
be opened when the carriage is to be heated. It will be seen that particularly
in the case of electric tramways with mixed or simple accumulator working, an
electric heating of the carriage is of great practical value, as the thermophor mass
can be melted independently of the current necessary for driving the carriage,
thus for instance, by night, by means of an inexpensive direct current; and
is then fully suitable for giving off heat by day.
In this example, the screw serving for the introduction of the re-crystallisation
is given.
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: -
The improved thermophor with electric heating arrangement for heating sub-
stances or hollow bodies and keeping them warm, the distinguishing feature being
that chemical substances, for example, acetate of soda or hyposulphite of soda
or caustic baryta etc., which deliquesce under the action of heat can be melted in
the interior of vessels made of any preferred material, with or without an addition
of glycerine, by electrically heated wires, which are placed inside one or more
completely closed air-spaces, so that the chemical substance which surround these
closed spaces or chambers, cannot come into direct contact with the wires, any
loss of water or other electrolytic decomposition being thus prevented and in
consequence of this, it is also possible to effect the heating by a strong current,
and finally, distinguished by the employment of a screw, which reliably introduces
the re-crystallisation of the melted mass as may be desired, substantially as
shewn and described.
Th 001
C
1800
HUGHES & YOUNG,
55 and 56, Chancery Lane, London, W.C., Agents for Applicant.