US2804132A - Stove - Google Patents

Description

Aug. 27, 1957 c. F. MALLORY STOVE Filed Aug. 17, 1955 INVENTOR.

ra /EM v a//0ry ATTORNEYS 2,804,132 Patented Aug. 27, 1957 Application August 17, 1955, Serial No. 528,990 Claims. (Cl. 158-96) Mallory Ohio, a corporation This application constitutes a continuation-in-part of my co-pending application Serial No. 437,123, filed June 16, 1954, now abandoned.

This invention relates to stoves of the type in which a vaporizable liquid fuel is used, and is particularly directed to a small, easily transportable unit which can be used on camping trips and :the like.

The primary object of the invention is to provide a stove which can be fueled with a small quantity of liquid fuel and which will efficiently vaporize and consume the fuel charge over a long period.

Another object of the invention is to provide a stove of the above character in which the fuel charge is temporarily absorbed in a porous body of the stove itself and is gradually vaporized into a central mixing chamher by the passage of directed air currents across an exposed surface of the porous body, the remaining surfaces of .the porous body being covered or kept from contact With air.

Another object of the invention is to provide a simple and eflicient means for directing primary combustion air across the exposed surface of a fuel-charged body in a mixing chamber whereby fuel is extracted from the body for combustion in a separate combustion chamber, removed from the mixing chamber.

Still another object of the invention is to provide a stove comprising a body of relatively porous heat resistance material in which a fuel charge may be absorbed for subsequent vaporization, said body having a casing or enclosing surface of vapor impermeable material leaving only a pro-selected portion of the body uncoated and exposed for the vaporization of the contained fuel charge.

Other objects and advantages of the invention Will become apparent from the following detailed description of a preferred embodiment thereof, reference being had to the accompanying drawings, in which- Fig. 1 is a side elevational view of a stove embodying the present invention;

Fig. 2 is a section on line 22 of Fig. 1 with. an associated cover shown above the stove body;

Fig. 3 is a bottom plan view of the stove;

Fig. 4 is a section on line 44 of Fig. 2; and

Fig. 5 is a fragmentary section taken on line 5-5 of Fig. 2.

Referring to the drawings and particularly :to Fig. 2 thereof, the stove made in accordance with the present invention comprises a block of fuel absorbing material designated generally 10 which is preferably contained or housed within a can-like outer container 12, the can thus furnishing a vapor impermeable coating to the side Walls and top of the block of fuel absorbing material 10. A central opening 14 is formed in the top surface of the can and registers with .a cylindrical center passage 16 running completely through the block 10 so that it terminates at its upper end at the atmosphere and at its lower end in a mixing chamber 18. The mixing chamber .18 is defined on its upper surface by the exposed, uncoated and vapor permeable walls of the fuel block 10, designated 20in Fig. 2 and atits lower surface by an air di-- rectmg bafile 22. The bafile 22 is riveted or otherwise fixed to a base 24.

The base 24 is preferably formed from sheet metal and is provided with a plurality of small integral. feet 26 which will support the base, and thus the stove, a short distance above any surface on which the unit is mounted. The base 24 is dished upwardly at its center and is formed on its outer periphery with a suitable mating surface for the side Walls of the can enclosure 12. The central dished area of the base is provided with a series of air holes 28 extending into the stove below the baffle 22 so that air passing through the holes 28 cannot have direct access to the vaporizing surface of the fuel block 10 but must pass outwardly, downwardly and thence upwardly along. the surface 20 of the fuel block into the mixing chamber. By thus providing a long surface for the flow of air along the surface of the fuel block a much more intimate mixture of fuel and air is provided over a longer period of time than would be the case if the air were permitted to. pass directly into the mixing chamber and thence upwardly to be burned as hereinafter described.

The fuel absorbing block 10 may be conveniently made of a mixture of asbestos fiber and Portland cement, or of the mineral perli'te and Portland cement, or of fly ash and a suitable binder mixed with an appropriate amount of water and permitted to set in a mold. The block may also be made of a ceramic clay tile material, molded and fired into a porous body of appropriate shape.

Extending upwardly from the mixing chamber 18 is the central passage 16 which forms a combustion chamber terminating at the upper end of the fuel block in the opening 14. The combustion chamber or center opening 16 is separated from the mixing chamber by a screen 30 and burning of the fuel mixture takes place above the screen and cannot flash back into the mixing chamber.

It will be seen that the fuel block 10 is covered on all sides and at the top with the vapor impermeable metal surface of the can. At its surface Where it is formed into the central passage 16 the fuel block is also made vapor impermeable either by coating this surface with .a mixture of neat cement and water into a layer 32 or by fire-hardening the surface of the passage or combustion chamber 16. It has been found that if a sufficiently intense flame is permitted to burn in the passage for a relatively short period of time a vapor impermeable surface will be burned onto the walls of the center chamber although in some instances it is preferred to make this surface vapor impermeable by a coating as mentioned above. Thus the only surface of the fuel block through which the fuel may be extracted is the surface 20 exposed to the mixing chamber.

Preferably the metal container 12 is provided with a rib 31 therearound and relatively close to the upper surface for the reception of a wire grill which may be slipped down over the top of the metal container and into contact with the rib 31. The wire grill may comprise an encircling band 33 with upstanding wire legs welded or otherwise fixed thereto, the legs being of U-form with their free ends attached to the encircling band 33 and crossing each other immediately above the upper end of the central passage 16.

A suitable cover 34 shown only in Fig. 2, is provided for the stove which may conveniently take the place of the wire grill and fit .tightly over the top of the stove and over the sides thereof down against the rib 31 when the stove is to be transported. With the cover in place no air will pass into the mixing chamber and no combustion will take place after the cover is put on.

It is preferred to regulate the quantity of combustion air entering the mixing chamber through the holes 28 by 3 means of a suitable valve mechanism such as a plate 36 pivoted on the central rivet 38 which fastens the baffle 22 to the base 24 of the stove." The plate valve 36 is provided with holes .40 spaced the same as and equal in numher to the holes 28 in the dished base 24. When the holes are completely in registry the maximum air will be permitted to enter beneath the baffle and into the mixing chamber and when the holes are completely out of registry the supply of air to the mixing chamber will be shut off and the stove will thus go out.

An operating handle of appropriate form, designated 42, extends from the plate valve 36 downwardly and outwardly beneath the base 24 between the legs 26 and'is thence extended upwardly to provide a convenient operating handle for movement of the valve without displacing the stove from the surface on which it is resting.

The stove is preferably provided with a filler opening 48 closed by a threaded plug. When the plug 48 is removed, fuel, such as alcohol, may be poured through the filler opening into contact with the block to be absorbed thereby.

i In the operation, liquid fuel such as alcohol is poured into the filler opening 48 and is absorbed by the block 10. The fuel cannot escape through the outer walls of the block or directly into the passage 16 since these surfaces are covered by a vapor impermeable coating and the only surface from which the fuel can exude is the surface forming the upper surface of the mixing chamber. The stove is lighted by inserting a match into or immediately over the central passage 16 and the initial burning takes place in this passage. currents of air flowing through the registering passages 40 and 28 and downwardly beneath the baffle sweep across the lower surface of the porous block 10 and pick up ,7

suflicient fuel to support combustion above the screen 30. When these convection currents have reached their final, stable velocity, the operator can adjust the intensity of the flame by opening or closing the ports 40 with relation to the stationary openings 28 in the base of the stove and thus regulate the intensity of the flame by regulating the fuel-air mixture passing through screen 30 into the center passage 16. The exact location of the flame will depend to a certain extent on the registry of the openings and 28 and thus on the quantity of air entering the stove but cannot ever reach a point below the screen 30 and will in most instances be within the center opening 16 although with very high air supply burning may take place at the opening 14 at the top of the stove.

The operator or user can place the wire grill over the top of the stove down against the rib 31 and a pan or other container can thus be placed on the grill. It has been found in use that one ounce of alcohol fuel will burn with a hot intense flame for a period ranging from minutes to one hour.

When it is desired to put out the flame, as upon completion of a cooking operation, the operator can either move the openings 40 out of registry with the openings 28 or can place the cover 34 over the top of the container and thus cut off the flow of air through the unit. The stove can be then readily transported since the sides thereof do not become heated to any great extent by the combustion in the passage or chamber 18.

While the invention has been disclosed in conjunction with a specific form and disposition of the parts, it should be appreciated that numerous modifications and changes After a short time the convection 4 thereof may be made without departing from the spirit of the appended claims.

What I claim is:

l. A stove or the like comprising a body of porous material capable of absorbing liquid fuel, a central combustion chamber extending vertically through said porous body, a casing of vapor impervious material in contact with and covering the top, outer wall and the wall of the combustion chamber, said casing being spaced from the bottom surface of the porous body leaving a space between the bottom of the porous body and the bottom of the casing, air passages formed in the bottom of said casing and means for regulating the amount of air passing through said passages to said mixing chamber.

2. A stove or the like comprising a body of porous material capable of absorbing liquid fuel, a central passage through said body forming a combustion chamber, a vapor impervious casing for said body surrounding and in contact with the sides and top thereof and extending into said combustion chamber and in contact with the wall thereof, a mixing chamber formed by spacing the bottom wall-of said casingfrom the bottom surface of said body, controllable valve means to admit air into said mixing chamber, baflle means in said chamber to direct air entering through said valve means across substantially the entire exposed surface of said body, whereby fuel absorbed in said body is released as vapor and intimately mixed with air in said mixing chamber to form a combustible mixture in said combustion chamber.

3. A stove in accordance with claim 2 in which said body of porous material comprises a mixture or fibrous material and cement and said vapor impervious coating comprises a metallic sheath.

4. A stove or the like comprising a body of porous material capable of absorbing liquid fuel, a central passage through said body forming a combustion chamber, a vapor impervious casing for said body surrounding and in contact with the sides and top thereof and extending into said combustion chamber and in contact with the wall thereof, a mixing chamber formed by spacing the bottom wall of said casing from the bottom surface of said body, said casing having air openings through the bottom thereof adjacent said mixing chamber, means to control the effective size of said air openings, baflle means to direct air entering said air openings across substantially the entire lower surface of said body, whereby fuel absorbed in said body is released as vapor and intimately mixed with air in said mixing chamber to form a combustible mixture in said combustion chamber.

5. The structure according to claim 4 and having a screen in the bottom of the combustion chamber adjacent the top of the mixing chamber.

References Cited in the file of this patent UNITED STATES PATENTS 286,914 Dimock et al Oct. 16, 1883 698,502 Hosea Apr. 29, 1902 857,064 Holgate June 18, 1907 1,065,834 Pike June 24, 1913 1,650,148 Nathan Nov. 22, 1927 2,422,686 Labiberte June 24, 1947 FOREIGN PATENTS 248,919 Germany July 5, 1912

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