Process for the Production of Materials for Preventing the Radiation or Transmission of Heat.
Year: 1899

page_text: Date of Application, 20th Sept., 1899
Complete Specification Left, 15th June, 1900-Accepted, 11th Aug., 1900
Process for the Production of Materials for Preventing the Radiation
or Transmission of Heat.
I, GEORGE ALBERT HERDMAN, of 73, Basinghall Street, in the City of London,
Slag Wool Manufacturer, do hereby declare the nature of this invention to be
as follows:-
My invention has for its object the production of a non-conducting medium
which is adapted to prevent the radiation or transmission of heat, and is especially
suited for the construction of the walls of refrigerators, cold storage chambers,
and the like, and the invention consists in a process whereby comparatively inex-
pensive materials may be utilized for the production of a substance possessing all
the qualities necessary for the above mentioned purpose.
The invention consists in manufacturing a product resembling pumice-stone in
structure and character, from sandstone (or silica) and lime or from blast furnace
slag (which but for my invention would not be available for the purpose owing
to the sulphur which it contains) by melting (or re-melting) the material or
materials in a cupola furnace, as in foundry practice, in conjunction with a sub-
stance capable of fixing the sulphur contained in the fuel so as to avoid the
objections incidental to a product containing sulphur in its free or uncombined
state.
The substance I employ for fixing the sulphur may be manganese either pure
or in the form of spiegel-slag, or ferro-manganese slag.
The proportions of the materials are about as follows:-
50% sandstone or silica;
30% lime;
20% manganese or spiegel-slag or ferro-manganese slag; coke being the fuel
employed.
In lieu of manganese, whether pure or in the form of spiegel-slag or ferro-
manganese slag, I may however employ soda as the fixing agent, about 5% of
soda (more or less) being sufficient for the purpose.
Datod this 20th day of September 1809

page_text: what manner the same is to be performed to be particularly described and ascer-
tained in and. by the following statement:-
:
My invention consists in a process whereby comparatively inexpensive materials
may be utilised for the production of a substance which is adapted to prevent
the radiation or transmission of heat and which by reason of its non-conductive
and other properties is especially suited for packing the walls of refrigerators
cold storage chambers and the like.
The invention consists in manufacturing a product resembling pumice-stone in
structure and character from sand-stone (or other form of silica) and lime or from
blast furnace slag by melting the said materials or material along with coke in
a cupola furnace with the aid of an air blast (as in reducing pig iron for casting
in foundry practice) in conjunction with a substance capable of fixing the sulphur
contained in the materials and fuel so as to avoid the objections incidental to a
product containing sulphur in a volatile form.
The substance I employ for fixing the sulphur may be manganese either pure
or in the form of spiegel-slag or ferro-manganese slag. The proportions of the
materials are about as follows, but it is to be understood that these are given
merely as examples and that I do not in any way limit myself thereto as they
would require to be varied according to the quality of the materials and other
circumstances.
Sandstone (or other form of silica)
Lime -
Spiegel slag or ferro-manganese slag
or Broken blast furnace slag
Spiegel-slag, or ferro-manganese slag
50% ;
30% ;
20% ;
80%;
20%.
If pure manganese be employed the quantity required would be only about
2% for 97% of blast furnace slag, or 61% of sandstone and 36% lime.
In either case in lieu of manganese, whether pure or in the form of spiegel-slag
or ferro-manganese slag, I may employ soda (carbonate of soda) as the fixing
agent, about 5% of soda (more or less) being sufficient for the purpose.
The pumice-like structure is imparted by cooling the molten mass as it comes
from the cupola by throwing cold water upon it, the steam suddenly generated
causing the mass to swell up and set or harden in the form of a highly porous or
sponge-like mass possessing non-conducting qualities which render it eminently
suitable for packing the hollow walls of refrigerators and other structures to or
from which the transmission or radiation of heat is to be prevented.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is:-
The herein described process of producing a pumice-like material possessing
non-conducting qualities and free from sulphur in a volatile form, which process
consists essentially in melting sandstone (or other form of silica) and lime, or
blast furnace slag along with fuel and a substance capable of fixing the sulphur
such as manganese, spiegel-slag, ferro-manganese slag, or soda, the molten mass
being rendered porous by water in the usual way.
Dated this 15th day of June 1900.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.