Improvements in Gas Stoves for Heating, Cooking, and other Purposes.
Year: 1896

page_text: Date of Application, 25th Jan., 1896-Accepted, 21st Mar., 1896
COMPLETE SPECIFICATION.
Improvements in Gas Stoves for Heating, Cooking, and other
Purposes.
A communication by ROBERT GILMOUR FINLAY, of 339, West Fifteenth Street,
New York, in the County and State of New York, United States of America,
Manufacturer.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of The Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street,
Manchester, both in the County of Lancaster, 118 New Street, Birmingham, in
the County of Warwick, and 31, High Holborn, in the County of Middlesex,
Civil Engineer, 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 :-
The object my correspondent has in view is the production of a gas stove for
heating, cooking, and other purposes in which the parts are so constructed, arranged,
and proportioned, as to insure complete flameless combustion.
In the drawings accompanying this Specification:-
Figure 1, is a vertical central section of a stove embodying this invention in its
preferred form for heating purposes;
Figure 2, is a plan of the air admission register.;
Figure 3, is a detail sectional view on enlarged scale of the joint between the
several parts at the top of the expansion chamber.
The shape of the stove may be varied considerably so long as enough air can be
admitted for the supply of gas for which the stove is intended, and so long as there is
adequate room between the air and gas admission and the point of combustion to
insure that intimate mixture of this adequate supply of air with the gas which is
essential to complete combustion.
The body of the stove consists of an upright tubular portion A (which is a mixing
chamber) surmounted by an expansion chamber A' (which is really part of the
mixing chamber) and at its base terminating in a conical or flaring portion A 2,
designed to afford the increased area needed for the accommodation of an air register
through which the needed supply of air is admitted into the stove.
The expansion chamber may be surrounded by an ornamental drum B, and the
flaring lower portion may be surrounded by an ornamental base C. Gas may be
admitted into the lower part of the mixing chamber through any suitable or desired
number of tips. In this instance one tip D is employed. The gas supply pipe to
which the tip is connected passes up centrally through the air register, and is supplied
with the usual cock m. The air register consists of a stationary perforated plate E
and a rotatable perforated plate El provided with a handle n, by which the plate
may be turned to bring its holes into and out of register with those in the fixed
plate E.
The body A, A, A 2 may be of any suitable material, preferably cast metal.
The top of the expansion chamber is closed by a concave-convex perforated
diaphragm or burner plate a; placed convex side uppermost; and immediately
below it is flat perforated screen or disk b, which prevents back-firing. These
plates or disks are held in place by an annular plate holder c, which overhangs and
bears upon the burner plate. Its lower edge is received and seated in an annular
socket d, formed for it in the top of the expansion chamber. Packing of plumbago,

page_text: fire-clay or other refractory material is provided at the points x, y, to prevent
possibility of gas escaping, and one or more set screws 3, are used to prevent the
holder c, from lifting. The plate holder also furnishes a seat for an ornamental open-
work removable cap d' which serves to secure the combustion of any gases that may
escape combustion at the burner plate.
The perforated fire guard or screen b, is usually made of sheet metal, preferably
sheet brass. The burner plate may be made of fire-clay, metal, or other suitable
material. In practice it has been found that sheet brass gives excellent results.
The cap d which also may be of any suitable material, is, in practice, made of metal
cast in some openwork ornamental pattern.
The foregoing are the parts required for the purpose of effecting complete flameless
combustion. The stove is surmounted by a removable perforated basket tope having
an ornamental deflector cap f.
The stove is lighted at the burner plate a, the basket top and the cap d
first having been removed; and these parts are then replaced in their original
position.
While my correspondent does not desire to be understood as limiting himself to
precise dimensions, yet to a full understanding of the invention, it will be profitable
to state the dimensions of the parts shown in the drawings making up as they do,
the structure in which he has been enabled to obtain continuously complete and
apparently flameless combustion of the gas.
The tube A, has an internal diameter of three inches and is about fourteen
inches in length. The area of the register holes when fully open is say, nine
square inches. The expansion chamber in its greatest width is between six and
seven inches, and is seven inches in height to the back fire screen. The diameter of
the burner plate is about five inches; it is of fine mesh, and at its highest point is
about three-sixteenths of an inch above the back-fire screen, which latter in practice
is of the same mesh as the burner plate.
It has been found very desirable to bring the back-fire screen and the burner
plate thus close together for several reasons. In the first place, there is very much
less liability to back-firing and it has been found that the further the screen is
removed from the plate, the more apt is back-firing to occur. But aside from this,
the bringing of these two parts thus close together has a material bearing upon the
combustion for they enclose between them what becomes in effect a combustion
chamber, in which contracted space the mixture of gas and air that filters through
the screen is held almost in film form, becoming at once intensely heated, and
producing what apparently is flameless combustion, manifested only by the bright
red of the burner plate.
If the back fire screen be removed entirely, or if it be separated from the burner
plate by a considerable distance, the effect is at once apparent. The burner plate
becomes dark, losing appreciably its incandescence and there appears flame upon
and above the surface of the plate. Thus the plate b, which for want of a better
term, is denominated the back-ire screen, because it does act to prevent back-firing
or flashing, is a material factor in the problem of combustion, and it is in the latter
connection that its more important function is found, constituting, as it does, the
lower wall of a combustion chamber. The top plate of the stove or burner is in
fact a compound top plate made up of the burner plate and back-fire screen brought
closely together and enclosing between them a shallow space which constitutes a
combustion chamber. The secondary chamber or space enclosed between the
burner plate and the cap d' above may be, and in practice is, of greater dimensions.
In this secondary chamber all traces of gases are consumed. The above dimensions
are designed with particular reference to a six-foot gas burner, or a tip or tips
having singly in the one case, or conjointly in the other, a discharge capacity
of six feet per hour. One six-foot tip or six one-foot tips may be used
indifferently.
Of course with burners or tips of greater capacity the air register must have
correspondingly greater capacity and the mixing chamber must have proportionately

page_text: increased dimensions, with an increase also in the size of the burner plate and its
related parts.
To use the stove for cooking purposes the basket top e and deflector fare
replaced by a suitable superstructure designed to support or contain the dishes or the
like holding to food to be cooked. The cap d¹ can also be dispensed with, leaving
the burner to consist only of the two plates a b.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated
to me by my foreign correspondent I declare that what I claim is :
1. The combination with the mixing chamber, the inlets for supplying air and
gas thereto and means for regulating the same, of the shallow contracted combustion
chamber, included between and formed by the back-fire screen and the finely
perforated burner plate placed immediately above and in close proximity to the
screen, substantially as and for the purposes herein before set forth.
2. In a gas stove, a mixing chamber, inlets for supplying air and gas thereto
and means for regulating the same in combination with a perforated diaphragm
or burner plate closing the outlet of said chamber and interposed between a
back-fire screen on the one side, and a reticulated or open work cap on the other
side, the spaces included between said parts constituting primary and secondary
combustion chambers, substantially as and for the purposes set forth.
Dated this 24th day of January 1896.
WM. P. THOMPSON & Co.,
Agents.