IMPROVEMENTS IN THE CONSTRUCTION OF COOKING STOVES AND BAKER'S OVENS HEATED BY GAS OR OTHER FUEL
Year: 1885

page_text: I CAMPBELL MORFIT of 23 Southampton Buildings in the County of Middlesex,
Consulting Chemist do hereby declare the nature of the said Invention for
IMPROVEMENTS IN THE CONSTRUCTION OF COOKING STOVES AND BAKER'S OVENS
HEATED BY GAS OR OTHER FUEL, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
My improved stove and oven consists of two parts, namely, the upper or hot air
chamber and the lower or heater; Figure 1 is a cross section on the line 1, 1, of
Figure 2 and
Figure 2 is a longitudinal section, both views showing the entire apparatus.
Figure 3 is a plan, partly in section of the heater separately; and Figures 4
and 5 show the gas burners detached from the apparatus and in their extended
and retracted positions respectively.
The same letters refer to the same parts in each figure. The upper part A is a
square or oblong box with an outer casing and intervening space of about an inch
around all of the sides thereof except the bottom.
This intervening space b is filled with slag wool or other non conducting
material.
The sides, the top of the casing and the lining are made of stiff iron plate; but
the bottom is of cast iron, these and all other pieces or parts of the apparatus being
preferably rendered rust proof by the Barff-Bower process.
The bottom is about an inch thick to within a few inches of its side edges where
it takes an extra thickness of half an inch as shown at c.
Through this bottom longitudinally at these dips c on each side runs a bore of
about one inch calibre to within a short distance of the back, the openings at the
front being closed with very closely fitting iron plugs.
Proceeding laterally and inwardly from these tubes with a slight upward incline
are numerous smaller tubes d of about of an inch calibre, bored or cast so that
they communicate at one end with the larger conduits c, and open at the other into
the interior of the stove or oven. These tubes or ways convey and discharge hot air
into the baking chamber for heating and ventilating it, and without introducing
any products of the combustion of the fuel.

page_text: As will be seen some of these tubes or ways are longer than others and the
positions of the whole so arranged as to promote diffusion of the heated air
throughout the interior of the stove or oven, and prevent scorching or unequal
baking in any part.
The lateral tubes or ways d are fed with hot air by the side conduits c and these
in turn by eight or more lengths of iron gas pipe f of about 4 inch bore placed
under the cast iron bottom of the stove or oven.
These lengths of gas pipe are tightly joined to cross pieces g g' of rather larger
bore, that one of which at the back communicates at h with the outer air, while
the one in front connects at either end with the conduits c in the sides of the cast
iron bottom of the stove or oven.
The upper part A, rests and fits closely in a cast iron box B, which is the heater
or chamber for the gas burners. These latter start from a swivel or knuckle joint
tube at j near the bottom and front of the stove and extend backwards nearly the
whole length of the stove or oven. They are in folds each ten or twelve inches
long so that the whole may be drawn out and put back easily under the bottom as
may be required by means of a long hook or other suitable instrument; for, to
prevent possible explosions in a confined space the burners should be lit at the
front or opening of the heater.
The upper part or oven A is divided vertically into five drawers or compartments,
(more or less) of about ten inches in height, each nicely adjusted to separate it from
the other compartments.
The lowest of these compartments is intended as a buffer chamber or equalizing
chamber to prevent the heat radiated from the iron bottom itself striking directly
and suddenly upon the bread or other articles placed in the cooking chambers
above.
The division of each compartment, except the buffer chamber, is formed by the
bottom of the moveable drawer a and of perforated stiff iron plate fitted with
wheels or runners of about an inch diameter, which wheels are nicely adjusted to
This arrange-
run on rail supports affixed to the side walls of the stove or oven.
ment allows the up-rising heated air to pass to every part of the stove's or oven's
interior and facilitates the drawing out and pushing in of the shelf trays whenever
it may be required to charge or unload them with articles to be cooked or baked,
and at the same time keeps the whole close and tight during the baking.
In the rear end of each of the cooking compartments is an opening of about
half an inch for ventilation; and in the sides pyrometers m are placed opposite to
each other to serve as indicators of the temperature within the stove or oven.
The gas burners in the lower chamber B, being lighted, the cold air entering
the cross tube g from without at h becomes heated as it passes forward above the
gas flame through the tubes f to the side conduits c and enters the interior of the
stove or oven through the numerous tubular openings, passages or ways d d¹.
The heat thus conveyed is supplemented by that radiated from the cast iron
bottom heated directly by the gas flames beneath, which are at the same time
heating the air passing through its passages.
By this arrangement, the heat is under control by means of taps and a gas
regulator for any degree of temperature up to about 500° or 600° Fahrenheit that
may be required; and all possibility of the products of the combustion of the fuel
and gas fumes entering the cooking chambers to contaminate the foods is prevented,
as they are made to pass off from B, through the opening o provided at the
rear end.
For this purpose also the joints are made practically air-tight throughout the
apparatus.
The currents of hot air entering the interior of the oven at the same time that
they effect the baking, carry off through the rear end holes k the exhalations from
the cooking food and thus promote continuous ventilation without disturbing the
cooking operation by lowering the temperature within, even momentarily.

page_text: The bread or other food under treatment is thus not only kept free from its own
vapours but is insured a perfect cooking without any liability to become scorched
or in any way injured.
Although I have shown the application of, and described gas as the heating
medium it is evident that other descriptions of fuel may be employed in lieu
thereof, in which case the form of the beater would require to be suitably
modified.
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
1. In a cooking stove or baker's oven the employment of a series of tubes ways
or pipes heated by gas or other fuel through which pure air is drawn from without
and passed hot into the interior of the oven.
2. In a cooking stove or bakers oven the general combination and arrangement
of parts consisting of an upper chamber A formed with a double casing b and
provided with drawers a openings and k and a lower chamber B, furnished with
cross tubes g, g¹, tubes or pipes f and tubes or ways d d¹ heated by gas or other
fuel and all acting in manner substantially as herein shown and described and for
the purpose stated.
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