Improvements in Spirit Stoves.
Year: 1891

page_text: Date of Application, 10th Dec., 1891
Complete Specification. Left, 16th Feb., 1892-Accepted, 21st May, 1892
PROVISIONAL SPECIFICATION.
Improvements in Spirit Stoves.
I, GEORGE FREDERICK REDFERN, of the firm of G. F. Redfern & Co., The
General Patent Office, No. 4, South Street, Finsbury, in the County of Middlesex,
Patent Agents, do hereby declare the nature of this invention (a communication
to me by Julius Heller, of Teplitz, in the Empire of Austria, Manufacturer)
to be as follows
My invention relates to spirit stoves and is distinguished by the fact, that the
spirit employed is vapourized before the combustion, and that previously heated
fresh air for combustion is supplied to it, whilst the apparatus is accessible in all
its parts so that at any time a thorough cleaning can be effected.
The reservoir which holds the combustible material, possesses in its centre a
hollow cone rising inwards, over which is fitted a hollow cone, the upper end of
which is furnished with openings, for the purpose of creating a hollow space in the
reservoir for the combustible material in which this material is vapourized and
mixed with fresh air before being burnt.
The bottom of the reservoir for the combustible material is covered by a vessel
placed at such a distance that a layer of air always exists between the reservoir for
the combustible material and the supporting surface of the apparatus, which at once
cools the spirit reservoir and warms the air before combustion at the same time
furnishing protection for the surface which supports the apparatus.
In some cases a helmet shaped cover is employed, constructed with an opening
for the exit of the heating flame and with air openings, this cover being connected
either permanently or movably with another cover fitting over the said opening
for the flame and provided likewise with an opening for the heating flaine, for the
purpose of securing complete combustion of the heating gases, the production of a
small flame for warming purposes after the cooking is finished and preventing the
formation of vapour of spirit after the flame is extinguished by allowing the
residue of spirit remaining after cooking is over to burn itself out.
Dated the 10th day of December 1891.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Spirit Stoves.
I, GEORGE FREDERICK REDFERN, of the firm of G. F. Redfern & Co., The
General Patent Office, No. 4, South Street, Finsbury, in the County of London,
Patent Agents, do hereby declare the nature of this invention (a communication
to me by Julius Heller, of Teplitz, in the Empire of Austria, Manufacturer,) and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
My invention relates to spirit stoves and is distinguished by the fact, that the
spirit employed is vapourized before the combustion, and that previously heated
fresh air for combustion is supplied to it, whilst the apparatus is accessible in all its
parts so that at any time a thorough cleaning can be effected.
A further, and very important improvement in the spirit stove consists in the
employment of a peculiarly constructed cover, by the assistance of which it is

page_text: possible so to regulate the size of the flame that the spirit stove can be used
either as a rapid heater or for keeping food or drink warm.
In the accompanying drawings,-
Figure 1 is a vertical section; aud,
Figure 2 is a plan of a spirit stove constructed according to this invention; and,
Figures 3 to 6 are detached views of parts of the same:
Figures 7 and 8 are vertical sections illustrating the use of the novel cover with
the improved spirit stove shewn in Figure 1:
Figure 9 is a perspective view illustrating the use of the said cover with a spirit
stove of known construction; and, .
Figures 10 and 11 are detached elevations shewing the cover in two different
positions.
The spirit reservoir A, Figure 1, is constructed from a single piece of sheet
metal with an interior hollow truncated cone a having curved sides extending
upwards from its bottom, as clearly shewn in Figures 3 and 4 which are re-
spectively a plan and a vertical section of the reservoir A. At the base of this
cone is an annular bead or projection which serves to retain in a central position
a hollow cone B (having a dome-shaped top provided with holes, and stamped
out of sheet metal), when the cone B is placed over the cone a the result of
which is that the axes of the two cones B and a coincide. A detached view
of the cone B is shewn in plan and vertical section respectively at Figures 5
and 6. If spirit or other suitable combustible fluid be poured into the reservoir A,
it will flow through apertures e provided at the base of the hollow cone B into
the annular space between the two cones, and will fill this space to the level of
the fluid in the reservoir A. The spirit being then set alight the flame will heat
the cone B and vapourize the spirit, and the vapour will escape through the holes
in the dome of the cone B and feed the flame.
Meanwhile a rarefaction of the air above the cone a of course takes place from
the action of the flame and, as the cone a becomes simultaneously heated, air
will rush through the cone a from below into the cone B, mingle with the
evolved spirit vapour in the dome thereof and burn with an intensely hot
flame.
When the vapourization of the combustible material has commenced, which is
indicated by the upward rushing of a hot blue flame, and a characteristic hissing
sound, a cover C is placed upon the reservoir. A, the cover having in its centre
an opening through which the perforated dome of the cone B projects, as shewn in
Figure 1.
The spirit surrounding the cone B can no longer burn but only vapourizes
gradually, whilst the evaporation proceeds at a more rapid rate in the annular space
between the two cones B and a. The distance between the edge of the aperture
in the cover and the cone B is small, so that the spirit vapour passing out between
these two parts becomes thoroughly mixed with the mixture of spirit vapour and
air which escapes from the cone B.
'
In order to increase the heat of combustion, and at the same time to reduce the
evaporation of the spirit in the space round the cone B as much as possible, and
also to prevent conduction of the heat of the apparatus to the surface which
supports it, the reservoir A is surrounded at its lower part by a vessel D, from the
centre of the bottom of which projects a cone d, a portion of which enters the
hollow cone a. The vessel D has on its edge projections f, which are rivetted to
the feet F of the tripod which supports the cooking vessel and gives them such
rigidity that the tripod can be constructed of comparatively thin metal and yet
possess sufficient strength to support the cooking vessel. The cooking vessel itself
rests on lugs G rivetted to the tripod. At its upper part the tripod is provided
with a flange turned inwards and provided with holes, and this serves for the
reception and support of the spirit reservoir A. which rests upon the flange of the
tripod with its own flange which is turned outwards, as shewn in Figure 1.
When the apparatus is in use as above described the air that is passing toward

page_text: the hollow cone a streams through from above into the vessel D passes over the
sides and bottom of the spirit reservoir, abstracts the heat from the latter and
finally arrives in the hollow cone a, where the cone d which projects into the
latter causes it to pass as nearly as possible in contact with the heated wall of the
cone a.
The fresh air for combustion thus rushing in, is supplied at a high temperature
to the spirit vapour in the cone B and thus raises the heat of combustion of the
latter very considerably. The air thus cools the spirit which surrounds the cone B
so that the chief vapourization takes place in the annular space between the two
cones B and a, and since the air, during the time when it is still but slightly heated,
forms an insulating layer between the hot spirit reservoir and the surface upon
which the apparatus stands, it prevents the heat from exercising an injurious
influence upon the supporting surface, and the apparatus can without danger be
placed upon any convenient surface.
When the flame is required to be extinguished the small cover c, which is con-
nected to the cover C by a hinge, is placed over the opening of the latter, so that
the flame must of necessity be extinguished but when the stove is in use the cover
lies back upon the rest c¹ which also serves as a handle.
When the stove is to be employed as a rapid heater and for keeping warm what
has been cooked, the cover shewn in Figures 10 and 11 is employed in place of
the small cover c and the arrangement is then as shewn in Figures 7 and 8.
A second cover h is attached to the chief cover H by means of a hinge i, the
cover H being furnished with a handle.
Both covers H, are constructed of a convex form, and each has a central
opening K, respectively bounded by the walls of the covers which taper
upwards.
In the rapid heater shewn in Figures 7 and 8, after the heater has been filled
with spirit and lighted, the cover H is placed upon it, as shewn in Figure 7. The
cover H extends not only over the spirit reservoir A but also over the air-holes in
the flange g of the tripod. The air which enters through these holes becomes heated
from contact with the inner wall of the cover H as it passes over it, and flows,
highly heated, to the flame. By this means a blue flame of intense heating
power is generated, and a perfect combustion is caused of the spirit or spirit
vapour.
If the size of the flame is to be decreased for warming purposes the cover h
is turned over onto the opening K of the cover H, as shewn in Figure 8. The
flame now passes through the considerably narrower opening k onto the bottom of
the vessel. Complete combustion of the spirit is also effected in the present case,
because as in the former case, only air at a high temperature is supplied for the
combustion. If more air is required to be admitted to the flame, the cover H can
be provided with air-inlets near its lower edge, but these openings are only
necessary when the spirit stove itself does not possess any, or the inlet for the
current of air is not sufficient.
In Figure 9 the improved cover is shewn in dotted lines applied to an existing
rapid heating spirit stove.
In this case also the air-inlets ; in the flange g are covered by the cover H which
acts in precisely the same way as in the combination with the rapid heater shewn
in Figures 7 and 8.
The new cover H, is intentionally left unprovided with a cover to close the
openings K or k, sinoe it is better under all circumstances to allow the small
amount of spirit left after the cooking is completed to burn itself out, than to
extinguish the flame by putting down the lid which closes the cover, as the heat
absorbed during the cooking is certain to evaporate the spirit which is left, so that
the remainder cannot be made use of. The vapour of spirit thus generated
constitutes moreover a source of danger, since it is liable to ignite, and not being
able to escape upwards would stream down in a lighted condition and endanger the
table or other object on which it was placed.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. A spirit stove in which the reservoir which holds the combustible material,
possesses in its centre a hollow truncated cone rising inwards, over which is fitted
a hollow cone, perforated at its upper end and forming in the reservoir a chamber
or space in which the combustible material is vapourized and mixed with fresh air
before being burnt, substantially as hereinbefore described and illustrated in Figure 1
of the accompanying drawings.
2. The combination with a spirit stove of a vessel covering the bottom of the
reservoir for the combustible material at such a distance that the air for supporting
combustion passes in a continuous current between the reservoir for the combustible
material and the stand or support of the apparatus thereby cooling the spirit
reservoir and stand, the heat of which at the same time warns the air before com-
bustion, substantially as hereinbefore described and illustrated in Figure 1 of the
accompanying drawings.
3. The use in combination with spirit stoves of a cover such as H constructed
with an opening for the exit of the heating flame and adapted to cover air-holes in
the stand of the spirit. stove, and a second cover fitting over the said opening for
the flame and provided likewise with an opening for the heating flame, for the
purpose of securing complete combustion of the heating gases, and the production
of a small flame for warming purposes after the cooking is finished, and
preventing the formation of vapour of spirit after the flame is extinguished.
by allowing the residue of spirit remaining after cooking is over to burn itself out,
substantially as hereinbefore described and illustrated in Figures 7 to 11 of the
accompanying drawings.
4. The improved spirit stove herein before described and illustrated in Figures 1,
7 and 8 of the accompanying drawings.
Dated the 16th day of February 1809
16th day of February 1802
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.