IMPROVEMENTS IN GAS STOVES AND IN CHAMBERS HEATED THEREBY
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by James Adams at the Office of the
Commissioners of Patents on the 17th May 1883.
JAMES ADAMS, of Glasgow, in the County of Lanark, Doctor of Medicine,
"IMPROVEMENTS IN GAS STOVES AND IN CHAMBERS HEATED THEREBY,"
This Invention relates to improvements in the construction or combination of
the parts of gas stoves of the kind for which Letters Patent were granted to the
present applicant dated 19 March 1879 (N° 1095) and 11th Feby. 1880 (N° 601)
and are to some extent further developments or modifications of those described
or referred to in the Specifications of these Letters Patent. The Invention also
comprises improvements in chambers heated by "gasfires" for drying, disinfecting
and other purposes.
One improvement consists in an arrangement for controlling by the action of one
stopcook or lever the supply of gas in a "gastire," together with a proportionate
supply of air for its combustion.
A "gas fire" constructed in conformity with the second claim of the said Letters
Patent No 1095 of 1879, and as further described and defined in the first claim of
Letters Patent N° 601 of 1880 consists of a "burner" contained within a
combustion chamber, the walls of which prevent the free and uncontrolled passage
of air among the gas burners or perforated forms which collectively form the
burner or gasfire; but by air inlets of a regulated number and size, permit the
entrance of a quantity of air sufficient and substantially no more than is
necessary to support and complete the combustion and to ventilate the flues. The
floor of the combustion chamber is formed by a flat box containing gas the lid of
which supports the gas jets. The box is fed by a pipe delivering gas the maximum
amount of which is preferably controlled by a gas volume regulator. Under my
present Invention and further improvement, I construct an air chamber underneath
or surrounding the gas box, and I admit the air into this chamber by an opening
placed in the floor or lower level of the chamber.
The size of this opening is equivalent or nearly so, but somewhat less than that
of the combined area of the air holes which give passage to air entering the chamber
and these air holes are pierced through a plate that forms the floor of the combustion
chamber.

page_text: A lid covers the opening for admitting air into the air chamber, and this lid is
hinged or attached to a tube that encircles and moves freely around the gas pipe
supplying the gas box.
This movable tube is connected at its outer extremity with the gas stop cock, so
that when the stop cock is turned the tube turns with it, and the lid that covers
the air entrance into the air chamber is lifted or depressed, and the entrance opened
or closed in accordance with the motion of the stop-cock.
The admission of gas into the gas box, and of air into the air chamber, is
adjusted by this consentaneous movement and the gas with its supply of air is
shut off or turned on at the same moment and are both controlled by one stop-cock
or lever.
This arrangement of duplex valve is also applicable for regulating the supply of
gas, and air to "gasfires" of heating stoves, and for other analogous purposes.
One "burner" or "gasfire," or more than one burner, constructed as described,
may be fitted to a stove for cooking food, or to a heating stove, or to a chamber for
disinfecting clothing, or for various drying processes in arts and manufactures.
The utility of the Invention consists in the arrangement by which an over supply
of air is excluded from the combustion chamber, and in the facility with which a
required temperature can be speedily produced, maintained, or varied, by the
turning on, or the turning off, of one or more "burners or "gasfires," without
at the same time admitting into the flues or heating chambers a large and
unnecessary quantity of cold air which would reduce the heating power of the
apparatus.
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The quick forcing of the heat of the stove through the use of more than one
burner is a desideratum. When fairly heated up a comparatively small supply of
gas then maintains the apparatus at an efficient temperature.
In another modification of my cooking stoves as described in my Specifications
of 1879 and 1880 already referred to, I bring the size of the stove within a more
convenient space, and at same time preserve the essential features of the Invention
whereby numerous processes in cooking may be performed with perfect efficiency
by the use of one burner or gas-fire.
In this modification, the several compartments of the stove are superimposed.
The stove consists of three divisions or stories of compartments. The lower
compartment rests on a wooden frame rising a few inches from the floor.
This frame is enclosed nearly all round, but has an opening to admit air into a
compartment under the centre of the stove, sufficient to supply combustion, but
not in such quantity as to unduly cool the under surface of the stove, as occurs in
stoves that rest on legs or isolated points of support. Within the lower
compartment I place the "burner" or "gas-fire" as described in the Specifications
of the Letters Patent already referred to, or in the improved forin described in the
present Specification. This "burner" consists of two "fires," but may consist of
any larger number, or of one only. Each of these burners or divisions has its
own supply of gas, and its own complement of atmospheric air for combustion.
And although all the gases of combustion from one or any number of the burners
or gas fires may ultimately escape by one flue, (and that is preferably the
arrangement adopted) there does not enter the stove more air than is required for
one fire, if only one fire is in use, or for two fires if two fires are in use, and so on
with any number of gas fires.
The gasfire in the lower compartment plays upon and heats the hot plate
immediately over the fire, and the hot gases are deflected and made to circulate
under the hot plate until they escape into the common flue by an opening below
the level of the hot plate. The gas fire is partly enveloped by an air heating
chamber supplied with air entering by an opening at a low level, and from this
chamber hot air is supplied to the combustion chamber by openings of a number
and size suitable to admit the approximate quantity of air that will complete the
combustion of gas that is being consumed.
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The walls of the combustion chamber, form at same time the inner wall of the

page_text: air heating chamber. The outside of the air-heating chamber is surrounded and
heated by the hot gases escaping from the combustion chamber on their way to
the flue. The relative position of these three constituent parts are therefore
(1) combustion chamber in centre; (2) hot air chamber surrounding the combustion
chamber; (3) hot waste gases partly surrounding the hot air chamber.
The air that supplies combustion is under this arrangement raised to a temperature
much exceeding 800 degrees Fahrenheit, and the gas box being at same time
partly surrounded with this heated air, both gas and air meet and are mingled at
a temperature exceeding 800 degrees Fahrenheit before combustion actually
commences. The principle corresponds with that generally known as "Siemens
Regenerative System," which has been demonstrated to effect a saving of nearly
one half of the fuel. This saving is attributable to the united economy derived
from the use of heated air and of heated fuel, and to the reduced quantity of air
employed in effecting complete combustion.
The hot plate is fitted with the usual openings for inserting pans or other
culinary utensils, as in ordinary close coal fire ranges.
The middle compartment of the stove is fitted with enclosing doors or screens,
by the use of which this division forms a roasting or baking oven if required.
The hot gases ascend from the basement within a flue, very shallow or flat in its
antero-posterior chamber, and placed on a line with the back wall of the
compartment. This flue discharges into a horizontal chamber which forms the
roof of the middle compartment, and at same time the floor of the upper division.
Within the upper division there is fitted an oven, the outer surfaces of which
are traversed by the hot gas of combustion on their way to the common chimney.
These hot gases are so intercepted and distributed by the use of baffle plates
that they are prevented from reaching their ultimate point of escape until they
have effectively warmed the greater part of the outer surface of the oven.
oven itself is ventilated by suitable openings for admission and exit of air.
The
This is a sufficient although general description of the principle of construction,
but there are details which may be referred to, which illustrate the convenience of
the general arrangements. Thus, I supply a Bunsen burner in the middle
compartment which serves for occasional use in boiling a kettle or stew pan when
the gas fires of the basement are not in use.
Also by a special provision I ventilate the middle compartment and prevent
odours and vapours of food while being cooked, or of steam from kettles or pots,
or burned gases which may escape from openings in the hot plate from passing
into the apartment, or from passing into the flues of the stove in a manner that
could lessen the draught of the stove or cool the flues. This is done by fitting in
the roof of the middle division a special ventilating flue into which all objection-
able vapours or gases are delivered into the common chimney. This special
ventilating flue is furnished with a sliding damper, so that the flue does not
remain open unless when required for the ventilation of the middle compartment
of the stove. The sides and back of the stove are formed of double casings as
described in my Specification of 1880 N° 601, and consist of hollow air tight cells
containing only confined air, and the doors of the ovens are in like manner fitted
with a double skin, within which is contained confined air; and this I do to lessen
as much as is practically possible, the radiation and conduction of heat from the
interior to the outside.
In another modification of a cooking stove I construct the apparatus very much
on the lines of an ordinary close coal range, the hot plate of which, together with
the ovens or other compartments are all heated by a single fire. To admit of
numerous operations in cooking being performed simultaneously, the stove hot
plate is of considerable extent in a horizontal direction and furnishes accommo-
dation for numerous culinary utensils, either for standing room, or for their
insertion in the customary openings. In one arrangement there are two ovens,
both heated by a central "gas-fire" placed between the ovens.
The two sides of the combustion chamber form an inner wall to each oven, and

page_text: radiate a powerful heat into the interior of the ovens, while the hot products of
combustion proceeding from the central "gas-fire" pass over the top of one oven,
and surround it on the side and back, pass underneath, and reach the under
surface, the back and sides of the oven on the opposite side, and ascending,
traverse the top of this second oven, and finally discharge into a flue leading to
the chimney.
The hot gases of combustion are met throughout their course by baffle plates,
and at several points are embayed or becalmed so to speak, and are thus prevented
from travelling in a too rapid and direct line, and are on the contrary caused to
deviate from side to side, and to become agitated or broken up, and thoroughly
spread over the entire surfaces to which it is designed they should impart their
heat. The ovens are each provided with ventilators which admit hot air to.
traverse the chambers and permit vapours to escape.
The "gas fires" in this modification are two in number, but may be more or
less, and the gas and air fittings are on the same principle of construction as in the
smaller stove described in this Specification. The fire front of the stove is fitted
with a folding flap which may be turned down when the cover is removed, and
the stove used as an open fire. A door hinged on the under edge is also fitted to
the fire-front, and this door when turned down allows the heat of the "gasfire" to
radiate outwards. The front of the gas-fire is closed by a plate of mica, giving
the cheerful appearance, and permitting the use of an open fire. This hanging.
front door may be used to support a broiling dish, or bread toaster or bachelor's
oven in which food may be cooked in front of the "gasfire"
The vapours generated in the cooking operations conducted on the level of the
hot plate, together with any chance escape of gases of combustion, have an entrance
into the general flue of the stove, which is fitted with a large opening capable of
being closed by folding doors. There is in addition a ventilating flue on the same
principle as in the smaller stove described. And as it is a matter of prime
importance that all cooking operations, especially where the fire occasionally
freely exposed on its upper surface should be carried on under conditions that
ensure that all vapours or gases generated in the processes shall be conveyed away
by a chimney into the open air, I provide a hood of the following construction.
It consists of tin or sheet iron, and preferably is made double, as in the case of
the outer walls of the stove. It rests upon or is attached to the hot plate at the
sides and back, but is open in front. The roof is of a height convenient to permit
the manipulation of cooking utensils, and at the top line is a few inches less in
depth from front to back than the depth from front to back of the hot plate.
The sides of the hood therefore slope downwards to the front edge of the hot
plate.
.
A rod or turned up rim is fitted to the front edge of the hood, and from this
rim there may be suspended one or more screens of light metal. These screens
when banging from the front edge of the hood enclose the hot plate in whole or in
part as may be desirable, and their effect is to prevent the access of cold air to
culinary vessels in use upon the hot-plate, and also to lessen the radiation of heat
from the cooking utensils and from the hot plate. When not required these
screens are simply unhooked and laid aside. A. "Bunsen" burner is connected
that may be used occasionally on the hot plate for boiling a kettle or other simple
process when the gas fires may not be in use, or at their full heat.
Another modification of the air heating gas stove is specially adapted for various
drying processes in the arts and manufactures, as for disinfecting clothing in
public institutions, and generally for purposes where a large volume of heated air
at a sustained temperature is required.
And while the means which I employ for filling the chamber with hot air either
dry or moist are applicable to various forms of hot chambers or stoves, I select for
description the arrangements of a disinfecting closet as furnishing a fair typical
illustration of the principle of construction I employ.
The casings consist of hollow air-tight cells containing only confined air, and

page_text: this I do with the object of rendering unnecessary the packing material that is
usually employed, and which unavoidably absorbs much heat on first lighting the
stove, and thereby prolongs the time necessary for getting up the proper degree of
heat. Atmospheric air when imprisoned within narrow air-tight cells is practically
non-conducting, and more so than the solid materials usually employed, which are
properly and practically accumulators of heat. A disinfecting chamber is
commonly required only for occasional use, and for little more than an hour or two
at a time. It is therefore desirable that the heat should be rapidly generated,
which it cannot be unless under enormous consumpt of fuel, when the walls of the
chamber are formed of solid material.
For
It is further desirable that when the apparatus has fulfilled its intended use,
there should not remain in it a store of heat which costs time in its accumulation
and fuel in its development, and which is afterwards necessarily wasted.
heating the air within this disinfecting chamber, I employ a gas stove as described
in the Specification of Letters Patent N° 601 of 1880.
In this stove the air is made to traverse a considerable length of caliduct, and is
maintained in prolonged contact with powerfully heated surfaces with the result
of delivering air averaging 260 degrees Fahrenheit above the initial temperature.
To ensure and maintain a temperature say of 250 degrees Fahrenheit, the
temperature assumed to be desirable, I provide a special improvement whereby
the desired temperature is automatically maintained. I fit on to the wall of the
chamber a flue for carrying off the heated air which may be in excess, and I
regulate the quantity that passes away by the following contrivance. Within the
waste air flue, which has an area of 16 square inches or thereby, I station a tube
preferably of thin copper, because of its conducting property, and within that tube
a thermometer is rested in such a position that the graduation of the instrument
and the rise of the mercury are plainly visible outside. As this air flue forms
practically a part of the disinfecting chamber, the temperature is under easy
observation.
Immediately beyond the thermometer the air flue is closed by a valve formed of
a thin leaf of metal or other equivalent hung from, or resting upon, a rod that
traverses the flue horizontally, and has its outer extremities supported in the
manner of a balance upon a ledge outside the walls of the flue. The under surfaces
of the outer end of the rod are fashioned in a thin knife edge, so that the balance
may be sensitive. To the extremities of the rod, there is attached a frame through
which a vertical rod having a screw turned upon it is passed. This rod carries a
weight at its extremity, and by rotating the screw the weight is raised or lowered,
the rod shortened or lengthened from its fulcrum, and the potential force of the
lever increased or diminished. The principle of the contrivance is precisely that
of a balance, at one end of which is the elastic force and pressure of air at
250 degrees Fahrenheit, and at the other end the equivalent force or counter-
poising weight of metal. When the air becomes heated above 250 degrees
Fahrenheit, the elastic force and pressure upon the balanced valve is increased,
the valve yields and the heated air escapes. At the same moment, cold air
necessarily enters the chamber by an opening provided at a lower level, and fitted
with a simple valve that permits the entrance but prevents the regurgitation of
the entering air. The cold air that enters, mingling with the heated air of the
chamber, dilutes and maintains a mean maximum temperature within the chamber,
during the period that the stove is in use. The adjustment of the balanced valve
is made when the thermometer registers 250 degrees Fahrenheit, (the temperature
at present assumed for illustration) and the adjustment is made by simply turning
the milled head, which for convenient manipulation is attached to the top of the
screw rod. When the balanced leaf forming the valve remains perfectly vertical,
while the thermometer registers 250 degrees, but yields at 255 degrees Fahrenheit
or thereby, the adjustment is practically perfect and requires no further attention
or adjustment for that temperature. But after the same manner it may be adjusted
for higher or for lower temperatures, and to facilitate such adjustments, lines are

page_text: engraved on the face of the rod, or on a parallel vertical plate, so that by rotating
the milled head, the top of the lever is brought in a line with the temperature
indicated. The same indications are capable of being secured by various subsidiary
modifications. By this contrivance, I dispense with costly and complicated
arrangements easily deranged and in practice not admitting of ready adaptation to
variations in temperature while so far as known to me all other automatic arrange-
ments are very difficult of repair when out of order, and can only be repaired by
· specially skilled workmen.
To meet the requirements of sanitary officials who hold that air charged with
steam vapour is more searching and effective than mere dry air, I make a simple
provision whereby the air of the disinfecting chamber is charged with steam vapour
subject to the same control as in the case of dry air. The gas heating stove, is
provided with a projecting gutter containing water and encircling the top
circumference of the stove, and from this reservoir the heated air absorbs moisture
which becomes steam of the elastic force proper to the temperature of 250 degrees
Fahrenheit. And should the temperature tend to exceed 250 degrees, the escape
valve yields precisely as if the chamber contained dry air only. For in all cases
the sum of the pressures and of the elastic forces of watery vapour and of air, is
equal to the atmospheric pressure which has its counterpoising equivalent in the
weighted balanced valve. A mean temperature of steam charged air is therefore
maintained by the same arrangement that maintains a mean temperature of dry
air, but the arrangement is entirely free from the dangers attendant on the great
elastic force of superheated steam generated in and delivered from a pressure boiler
and controlled by high pressure valves.
To facilitate the emptying of the chamber at the conclusion of an operation, and
to ensure its thorough ventilation with fresh air, I provide an arrangement
whereby the moving of a lever acts upon the valve and holding it open permits
the chamber to be rapidly filled and ventilated or flushed by a flow of pure
cold air.