Improvements in Heat and Electrical Insulating and Fireproofing Structures and Compositions.
Year: 1890

page_text: Date of Application, 9th Aug., 1890-Accepted, 6th Sept., 1890
COMPLETE SPECIFICATION.
Improvements in Heat and Electrical Insulating and Fireproofing
Structures and Compositions.
I, JOSIAH CLIFTON FIRTH of Auckland, New Zealand, Miller 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 :-
My invention refers to insulators or non-conductors of heat and cold, and the inven-
tion is mainly designed to be applied to structures of various kinds ashore and afloat
for the purpose of excluding or retaining heat or cold being devoid of fungoid germs
and therefore preventing fungoid growth, also for fireproofing purposes, for preventing
the cooling of the surfaces of steam boilers, steam cylinders or steam pipes and
generally for heat and cold insulating purposes.
The material used as the basis of my new or improved heat or cold insulating and
fireproofing composition is a volcanic substance known as pumice stone treated in the
manner as hereafter described.
According to my invention I take pumice stone and I first reduce it to lumps of
regulated size preferably aboutthe size of a pigeon's egg so as to easily pack into
spaces of varying contour although the size may vary above and below these dimensions,
and in order to fill up and utilize the intervening space between such lumps some of the
pumice material is further reduced to a granular state and carefully packed therein so
as to form a compact non-conducting mass of material. The pumice prepared in
lumps for the purposes of my invention as before described may with advantage be
washed in a solution of Portland or other cement and water and a suitable proportion
of such solution is say to one gallon of Portland cement ten gallons of water but I do
not limit myself to any such proportions. The lumps thus washed are packed in the
space to be protected and the spaces or interstices between the lumps are filled up with
granulated pumice as before described. When the lumps are not built directly round
the spaces to be insulated I prepare lumps for the purposes of my invention made up
and consolidated into a brick or block form and for this purpose I insert the lumps of
pumice in a mould filling up the interspaces with granulated pumice and pour therein
a solution of Portland or other cement and water which may also contain in suspension
some fine granulated pumice, and I thus form a consolidated block which may be
conveniently used for building round or into the spaces to be protected and such
blocks prepared as before described form vendible articles and can be built or put
together as bricks now are. When the structure is complete the surfaces may be
coated with cement when necessary.
Pumice stone treated and packed in the manner before described forms a very
superior insulating material for cool rooms or chambers or refrigerators of ships,
steamers, railway or other carriages also for cool rooms or chambers in establishments
on land for the preservation of meat, fruit, cheese, butter, and other perishable articles,
as well as an insulator for rendering safes, strong rooms and safe deposit buildings
absolutely impregnable against fire. The advantages of pumice stone as a heat or
cold insulating and fireproofing composition when treated and applied in the manner
before described are due to the fact that (owing to the action of the cement on the
cellular structure of the pumice stone lumps) there is imprisoned within its substance
large bodies of air in minute cells thereby forming a non-conductor to heat and cold ;
the material itself is practically infusible and while being a non-conducting material
does not oxydise or decompose under the influence of heat or moisture is not subject
to spontaneous combustion and fungous growth as is charcoal and other organic sub-
stances and moreover is very light in weight and consequently of great value as applied
for example to the construction of cool clambers in ships.
It will be obvious that some proportion of other non-conducting substances may be

page_text: introduced together with the granulated pumice, but care must be taken that the
proportion is not sufficient to produce any injurious consequences under the influence
of heat or moisture.
When my composition is applied as an insulator to the surfaces of steam boilers,
steam cylinders or steam pipes and for insulating electric wires the pumice stone in a
fine granulated state should be mixed with coal tar, Portland or other cement or other
equivalent material. I have found Portland cement to answer the purpose well and
when such is used the proportions should be about 1 part of cement to 3 of the
granulated pumice. The coal tar, granulated punice and cement may be rolled into
sheets of any requisite thickness and utilized as may be required.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is:-
==
First Forming a non-conducting or heat insulating covering for diminishing the
transmission of heat through the walls of structures of various kinds wherein the
covering is composed of pumice stone prepared and packed between the inner and
outer walls of such structures substantially as herein described.
:
Second The heat and cold insulating and fireproofing compositions or materials for
the lining of cool chambers in vessels and for the retention or exclusion of heat or
cold, composed of pumice stone reduced to lumps or coherent masses and treated with
Portland or other cement packed together and held in fixed relation to one another
with a filling of granulated pumice combined with cement whereby the cellular
structure has imprisoned in it large bodies of air all substantially as and for the
purposes set forthi.
Third: The heat and cold insulating and fireproofing material made up into lumps
or blocks in brick like form as set forth.
Fourth The insulating composition composed of Portland cement, coal tar or other
equivalent binding and sealing material in combination with granulated pumice stone
substantially as and for the purposes set forth.
Dated this 9th day of August 1890.
Dated this 9th day of August 1890.
J. C. FIRTH.
By Brewer & Son,
33, Chancery Lane, London, Patent Agents.