Improvements in Heating Apparatus.
Year: 1898

page_text: Date of Application, 24th May, 1898-Accepted, 6th Aug.,
1898
.COMPLETE SPECIFICATION.
Improvements in Heating Apparatus.
I, IGNAZ TIMAR, of 20, Grosse Hamburgerstrasse, Berlin, in the Empire of
Germany, 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:-
This invention for improvements in heating apparatus relates to that class of
apparatus in which heat is accumulated by melting sodium acetate.
In the employment of this apparatus when a certain quantity of heat has to be
maintained for a long time by the salts containing much water of crystallisation,
which have been previously melted and are to be again crystallised out, several
points have to be observed, in order to ensure satisfactory working.
For instance, it is absolutely necessary that, after the melting of the crystalline
substance, the re-crystallisation, that is to say, the giving off of the heat, can be
set in progress exactly at the time when the material is required for use, and that,
further, for the protection of the sides of the vessel, and for other practical reasons,
the crystallised out material shall not settle down into a solid body but rather
assume the form of a pulp or semi-liquid.
The more or less concentrated
The first of these objects is attained as follows:
solution of salts, chiefly consisting, as is known, of acetate of sodium. is shut off
by means of an air-tight screw-cover, having beneath a pointed stick or rod which
projects into the melted crystalline substance.
The principal condition for the effective action of the rod is that the vessel be
not filled quite to the brim and that there be a free space of about 10 millimeters
in height, above the body of salts. A further advantage of this arrangement is
that, in the re-crystallisation of the salts, the crystalline material being crystallised
out in a condition resembling sand in consistency, has space for expansion, whereby
injury to the vessel is avoided.
If the heating vessel, which may be of varied construction, be now heated for
the purpose of melting the quantity of salts, the very slow and first re-crystallisa-
tion which takes place after the removal from the source of heat, may be employed
for heating any desired substances, eatables or the like.
After the cooling, which proceeds very slowly, a complete re-crystallisation of
the crystalline material does not set in without special action from without. Even
an ordinary shock or vibration is without effect on the salt-solution contained in
the particular vessel.
The re-crystallisation, or giving off of the heat begins, however, if the hitherto
closed screw-cover be opened, and thereby the point of the rod which is in the
liquid be partially withdrawn therefrom. The complete crystallising out of the
salts employed occurs immediately, and the heat thereby set free can be applied
for various purposes.
For the employment of this kind of heat-preserving apparatus with metal or
sheet-metal vessels, it is of importance for the protection of the sides and of still
greater importance in the employment of this heat-preserving apparatus with
pliable sides, that the body of salts be not reduced to a compact form in crystallis-
ing out. but that it should have a soft, pliable texture, more resembling sand.

page_text: For attaining this object a certain quantity of glycerine is added to the solution
of salts, through the mixing of which the body of salts, in crystallising out, is
prevented from settling down in a compact form, but assumes the consistency of
moist sand.
In this way, any objectionable pressure on the sides of the vessel
is prevented. Moreover, if the particular heating vessels consist of india-rubber
or some other similar flexible substance, these sides yield completely to those parts
of the material to which they may be applied.
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;
-
Improvements in heating apparatus as described the distinguishing feature
of which is that the vessel which is not entirely filled with the body of salts to
be used, is, after a suitable quantity of glycerinė has been added, impermeably
closed by means of a screw-cover furnished with a stick or rod projecting into the
body of salts, for the purpose of enabling the first incomplete re-crystallisation to
proceed according to requirements and the second re-crystallisation by the rais-
ing of the screw-cover, so as to utilise the heat given off, and for the purpose of
causing the crystallised out salts to settle not in a compact form, but in a finely-
grained pulp or semi-liquid.
Dated this 24th day of May 1898.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.