IMPROVEMENTS IN COMBINED COOKING STOVES AND HOT AIR FURNACES
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by Thomas Jefferson Whitehead at
the Office of the Commissioners of Patents, with his Petition, on
the 15th December 1874.
I, THOMAS JEFFERSON WHITEHEAD, of South Paris, in the County of.
› Oxford, State of Maine, one of the United States of America (Mechanic),
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
COMBINED COOKING STOVES AND HOT AIR FURNACES," to be as follows:-
My Invention relates more especially to that class of stoves which are
designed for both cooking and heating purposes, and consists in a novel
construction and arrangement of the parts by which a cheaper, simpler,
and more effective device of this character is produced than is now in
cominon use.
It is well known that with the ordinary portable cooking stove a
comparatively small proportion only of the heat is utilized, the larger
portion being either. radiated or passing off with the smoke and other
products of combustion. This radiation causes not only great loss of
fuel, but frequently so raises the temperature of the apartment in which

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sometimes unbearable, where the cooking room is of limited capacity,
and is also very detrimental to health.
My Invention is designed to obviate these difficulties and objections, and
to that end I construct a cooking stove with a non-radiating casing, and
by a system of pipes, ovens, chambers, dampers, and doors properly
arranged and operating in respect to each other, produce a very simple and
economical apparatus for the purposes for which it is designed. The said
stove has a casing or heat insulator standing on legs and provided with
doors and a lid. The doors are jointed or constructed with wings, and are
also provided with smaller doors opening outwardly and through which fuel
is introduced to the fire-pot or furnace of the stove. The walls of the
casing are double, having a dead air space between their outer and inner
surfaces, and are constructed of galvanized iron or other non-radiating
material. I use an ordinary cooking stove provided with the usual fire-
pot or grate, a smoke pipe or funnel, an ash pan having the proper
dampers and grates, and also with the usual apertures for cooking
utensils. This stove is arranged within and supported by the heat
. insulating case, the, construction and arrangement of the same in
reference to the stove being such as to form two ovens or hot-air
chambers when its doors are closed. These ovens I designate as the
front and rear ovens, and for the purpose of heating the latter more"
effectually and rapidly than could otherwise be done a chamber is
arranged to divide the same into two smaller ovens or compartments.
This chamber is a part of the stove and is connected directly with the
funnel but does not extend to the top of the rear oven there being a
small air space between the top of the chamber and the interior wall of
the casing. A hot-air or gas pipe connects the rear ovens with the
funnel and is provided with a damper. Leading into the said gas pipe is
a steam pipe connecting the front oven, which is formed by closing the
doors and lid through the said pipe, with the smoke pipe or funnel.
Between the front and rear ovens there is a hot-air pipe provided with a
plug or damper. A hot-air pipe also connects the rear oven with any
room or compartment which it is desired to heat.

page_text: From the above description it will be readily understood by all
conversant with such matters that when a fire is placed in the grate or
pot and the doors and lid of the insulating case are closed a very large
proportion of the heat which would otherwise be radiated or lost will be
retained within the apparatus and utilized for cooking purposes, or may
be conveyed through the last-named hot air pipe and used for heating,
thus greatly economizing fuel and rendering the room or apartment in
which the stove is located much more comfortable than is possible in the
use of any other description of stove with which I am familiar. This
feature of my Invention is of great value in hot climates, and also where
stoves are used in very small rooms or on ship-board.
It will also be obvious that all the fumes or gases arising from cooking-
food can be readily conveyed from both the front and rear ovens to the
smoke funnel, thus obviating one of the most objectionable features of
the ordinary cooking stove.
To convert the said apparatus from a cooking stove into a hot air
furnace all that is necessary is to close the damper and open the two
last-named hot air pipes, first removing all food being cooked or which
may remain in either of the ovens.
Whenever it is desirable to retain a part of the heat in the apartment
where the stove is located, and at the same time heat another room at a
distance, without conveying to it in combination with the hot air any of
the disagreeable odors or fumes arising from cooking, the doors and lid
can be thrown open, at the same time closing the aforesaid damper and
opening the last-named hot air pipe (which is also provided with a
proper damper). The food can then be cooked at the front of the stove,
while the rear oven being disconnected from the other can at the same
time be used for furnishing pure hot air to the said hot air pipe.
I sometimes construct the steam pipe with a branch pipe leading into
the said hot air pipe, the two being provided with the necessary dampers
therefor, so that when food is cooking in the rear oven the damper or
plug can be closed and hot air conveyed from the front part of the stove
to the hot air pipe without passing through the rear oven.
For use in restaurants, ships, and hotels, I usually construct one of the
doors with apertures, through which the faucet of a tea or coffee urn or
pot can project, so that tea or coffee may be drawn from a vessel within
or over the fire without opening the door.

page_text: In an alternate form of construction the dividing chamber extends
vertically and transversely through the stove behind the fire pot,
provision being made at the ends of the chamber for the passage of the
heat and products of combustion to the cooking utensils farthest from
the pot, and I employ doors, lids, and pipes, substantially the same as
above described in the construction of the casing. It should be under-
stood that the said chamber is extended upwardly to connect with the
smoke pipe, and that its upper section may be composed of galvanized
iron, zinc, tin, or ordinary sheet iron, as preferred. Glazed windows of
mica or ordinary glass may be inserted in the lids or sides of the stove,
for the purpose of admitting light or permitting the progress of the
cooking to be seen without opening the casing.
To render the insulation perfect, the walls of the casing are con-
structed to form two air. spaces entirely around the stove if desired.
The said casing may also be ornamented by enameling or japanning, or
both.