US3171398A - Wick type kerosene stove - Google Patents

Description

March 2, 1965 F. w. LAWSON WICK TYPE KEROSENE STOVE 2 Sheets-Sheet 1 Filed June 14, 1962 Frcmk W. Lawson Inventor Pbfent Attorney March 2, 1965 Filed June 14, 1962 F. W- LAWSON WICK TYPE KEROSENE STOVE 2 Sheets-Sheet. 2

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Frank W. Lawson Inventor Patent Attorney United States Patent 3,171,??98 WIQK TYPE KERGSENE STOVE Frank W. Lawson, Princeton, N..l., assignor to Esso Research and Engineering Company, a corporation of Delaware Filed June 14, 1962, Ser. No. 292,532 4 Claims. (Cl. 126-4) The present invention relates to an improved wick type kerosene stove. It relates particularly to a compact stove suitable for cooking or small scale space heating, designed to give efficient heating while at the same time being of simple and economical construction and requiring a minimum shipping and storage space.

In many areas of the world, and particularly in rural areas and in undeveloped countries, there is a very large demand for small, economical, oil burning stoves for cooking and for small-scale heating. In the past, large numbers of such stoves have been distributed throughout the world operating primarily on liquid hydrocarbon fuels, especially kerosene and analogous distillate petroleum fuels. In general, these stoves have been of the wick type, primarily because Wick-fed stoves are relatively simple and inexpensive. They are easy to operate and maintain, and they have a reasonably constant and generally controllable burning rate.

A particularly favored type of stove in the past has been one consisting mainly of a fuel tank which also serves as a base, a wick and burner unit and a chimney which supports the cooking vessel. These units each may, and frequently do, comprise a number of separate parts. One example is the so-called Hong Kong stove. This device consists of a base cylindrical fuel tank into which wick elements are suspended. The base tank is surmounted by a wick burner assembly comprising separate perforate inner and outer wall elements, and a suitable chimney structure, usually of cylindrical form. Spacer or support elements atop the chimney hold the cooking vessel and provide for escape of combustion products thereunder. A stove typical of this general class is described, for example, in U.S. Patent No. 2,800,174. Stoves of this general type have been distributed by the hundreds of thousands. On the whole they have given reasonably satisfactory performance. They have occasionally given trouble due to wick char, and because of light and rather flimsy construction they have not been as durable as might be desired. Moreover, considering the weight and capacity of the unit, they have consumed an inordinate amount of shipping and storage space. A typical stove of common size has required about /2 cubic foot of shipping or storage space, even though the actual material of which the stove is constructed occupies only a very few cubic inches. Since transportation charges, particularly in marine vessels, are based largely on cubic space occupied, a very substantial reduction in shipping space requirements is urgently needed to reduce costs. Moreover, the stoves of the prior art have generally been made of a relatively large number of component parts so that their manufacture and assembly is unduly costly. Small, separate or loose parts are often mislaid and lost or damaged. Hence, one primary object of the present invention is to design a stove of the general type described above which is superior in all or most of the the respects just mentioned.

The invention will be more fully understood by a detailed description which will now be given in connection with the accompanying drawings.

in the drawings, FIG. 1 represents a sectional elevation of a stove made according to the present invention. This section is taken substantially on line 1-1 of FIG. 2;

FIG. 2 is a top plan view of the apparatus of FIG. 1;

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FIG. 3 is a fragmentary detail with certain parts broken away showing an improved arrangement for controlling burning rate and therefore heat by variable wick exposure means;

FIG. 4 is a view of a single assembled stove packed for shipping, the general layout being approximately the same construction as that of FIG. 1; and

FIG. 5 is a vertical sectional view showing a group of stoves separated into groups of components and packaged in bulk to further reduce shipping space requirements.

Referring first to FIG. 1, there is shown a fuel tank 11 in the form of an open vessel of moderately deep-dish construction. As shown, the vessel has sloping walls, i.e., it is of inverted frusto-conical shape, to permit compact nesting of similar shaped parts. This vessel may be drawn, molded, or otherwise formed from suitable sheet or plastic material, preferably a noncorrosive metal such as aluminum, brass or stainless steel (although for some purposes ordinary steel or other material, e.g., moldable or extrudable plastic composition, etc., may be used). It has suitable capacity for cooking one or more meals for an average family, or for giving off its maximum heat for an extended period of time. A typical fuel tank should contain from at least one pint to two quarts or more of liquid fuel.

The vessel or reservoir 11 is formed with a closure seat 13 and a surmounting rim or bead 15 for reinforcement. A lid or closure plate 17 is designed to fit with a frietionally tight seal suitable to prevent liquid spillage within the seat 13. As shown in FIG. 1, the lid also has wick ports l in the form of arcuate depressions, flanged openings, or ferrules in or through which wicks 21 may be positioned to project upwardly. Such wicks are preferably held in their proper positions in the lid by friction. The wicks 21 shown in FIG. 1 are of the common and well known woven web fabric type, but these may be replaced, according to one preferred embodiment, by a porous ceramic structure of suitable capillarity which will draw fuel at an appropriate rate from the tank to the burning surface at the upper end of the wick. The feed rate should be adequate to support the hottest flame for which the stove is designed.

In FIG. 3 a modification is shown fragmentarily wherein a wick 21A, in the form of a fabric rope or heavy cord, extends upward through an opening 25A, along the arcuate seat 19A and back downward through the lid through opening 25B. For purposes of this portion of the description, these various wicks may all be considered generally equivalent.

The lid or cover 17 is provided with a central filler opening 27 which is normally closed when the stove is in use by a separate closure member 29. The latter is formed integrally with the support structure and chimney which will next be described. The outer edge of the lid or cover 17 is formed with a downturned flange 31 which fits snugly about beads 15 to assist in retaining the lid tightly but removably in frictional attachment to the fuel container.

The chimney 35 which also supports the cooking vessel or equivalent above the flame, when the stove is in use, it formed so as to carry out several functions. It sits directly on the fuel tank cover, making a compact unit. This device provides an air supply through its outer wall to the inside as well as the outside of the burner mechanism to be described below. Because of its construction, it can be set directly on lid 17. It serves through closure element 29, formed integrally therewith, to plug the tank filler opening and thereby to prevent spillage of the fuel in the tank ll. This arrangement is such that the burner must be removed and flame extinguished before the fuel tank can be refilled, an important safety feature. It also supports and holds in proper position the burner mechanism per se, the latter being at all times held and disposed in proper relation to the wicks when the stove is in use. In addition, a horizontal component or land area 45 of the member 35 through the spaced arcuate slots 39, FIG. 3, is designed to control the rate of burning by selectively exposing more or less'of the exposed upper end area of the wicks, the area exposed being the onlyburning area, and adjusts the flame or heat output as desired depending on the heat requirements at the moment.

The structure 35 may bespun,.drawn, molded, or otherwise formed from sheet material, preferably metal or ceramic, with an outer wall member 41 which fits snugly within the flanger outer rim,31 of the lid or cover 17. These parts preferably are held in assembled position by a frictional fit. At its top, the member 35 is folded inwardly to provide an integral second or inner wall 43 which then turns radially inward into a horizontal seat element 45 designed to provide a groove 4'] which is adapted to receive and hold by friction the burner unit to be described below. inwardly of the seat 45, the member 35 has an annulararea upraised at 49, which may be called a land or a slightly raised horizontal element portion. This serves to support and retain in place by friction the burner unit to be described. It also comprises the arcuate burner control openings 39 through which the wicks are partially or wholly exposed, as desired, for controlling burning rate, depending on cooking or other heating requirements.

Inwardly of the annular or land portion 49 which. occupies the same general area as the wick elements, the member 35 has a displaced horizontal seat area 51 which receives and seats an inner wall structure of the burner. Seat area 51 may preferably be somewhat lower or a little higher, but where simplicity is important it can be on the same general level as area 49. The central part of the unit 35 is pressed downwardly with somewhat sloping or nestable Walls at 53, to fit snugly in filler opening 27 and thus provide the closure member 29 previously mentioned.

The outer wall 41 of the chimney-support unit 35 is provided with a series of openings 55 t-hrough which air can flow inwardly and through or under inner wall 43 to support the flame. A series of openings 57 is formed through the inner wall 43 to provide air for the outer portion of the burner, and another series of holes 59 inside the area 49 affords an air supply for the inner part of the burner. It will thus be understood, FIG. 1, that air can flow in through openings 55 and on through inner wall openings 57 and under and through inner openings 59 to supply burner air requirements.

The burner unit 70 itself is of annular configuration comprising inner and outer walls 72 and 71, respectively. These are spaced apart at the bottom a sufficient distance to span the land or horizontal area 4, and the wicks 21 which project through openings in the land area. The

structure is unitized, that is, the outer and inner walls converge at the top and are joined by a rounded told 73 which is interrupted by openings or combustion, gas outlets 74. Combustion takes place between the two walls 71 and 72, air being supplied thereto by a multiplicity of openings 75 in the outer wall and 76in the inner wall. Air fed through openings 57 flows in through openings 75 to support the flame at the wicks, being supplemented by air which flows upwardly through outlets 59 and laterally through the multiple openings 76 of inner wall 72. The combustion products including the heated air, etc., pass upwardly through the outlet openings 74. By proper selection of the number and size of the air openings, a hot,

essentially blue flame can be produced. A cooking :vessel not shown, suchas a pan, kettle, etc., may be supported on the upper end 80 of the chimney assembly 41. The latter preferably is indented or depressed as at 81, to P mi .thfl .cornbustinn products to escapefrom under the cooking receptacle. Alternatively, raised support elements, not shown, may be used as will be obvious.

Referring in more detail to FIG. 3, the lid member 17 is shown (but only fragmentarily) with the wick recesses or openings 19A (and special openings 25A, 25B for the rope-like wick 21A when the latter is employed). The central filler opening 27 here is shown open except for a small fragmentary part of stopper portion 29 of the chimney unit 35. As previously noted, the closure element 29 fits into the filler opening 27 sufficiently tightly to prevent substantial loss of fuel on accidental tilting of the stove, though it may have a very small opening or a dent in its periphery to permit the small but needed air inflow to replace'fuel consumption. The air inlet openings 59 are shown, as are also the control slots 39, which regulate the heat capacity of the stove by exposing a predetermined portion of the wicks 21' or 21A. By rotating the chimney member 35 with respect to the lid 17, more or less of the wicks may be exposed to give off more or less as needed. Thus the element 35 provides a simple but accurate and effectivecontrol over the burning rate. V

Referring now to FIG. 4, it Will be seen how the construction heretofore described makes possible the convenient and compact assembly of the components for shipping or storage. Here the fuel vessel .11 serves as the principal container; A plurality of wicks or Wick elements 21B, which may represent generically any of the the type of Wicks mentioned above or shown in any of the other figures, or variations thereof, may be placed within the vessel 11 and inside chimney member 35 which is inverted therein. Prior to inversion of the chimney member, the burner element 70 may be either frictionally or loosely fitted in position over the annular raised land surface 49 previously mentioned. 'With member 35 (and the burner unit 70 inside thereof) placed'in the vessel 11 in inverted position, the'lid or cover member 17 is finally placed on top, if desired,'with its central opening 27 being closed when desired, by the projecting closure element 29 of the chimney unit 35. In order to hold the parts in assembled position, two or more light spring clips 91 may be snappedinto place under the bead 15 of the fuel vessel and over the outer flange 31of the lid or cover. In FIG. 5, another arrangement is shown forpackaging a plurality of the stoves'in a compact package. Here the major components are separated and packed by nesting similar parts such as the chimney components 35' in one group, the burner units 70' in another group, the vessels 11 inanother, and the lidsor covers 17 in still another group. Wick elements 19 may be placed, if desired, in the annular space of the uppermost chimney unit 35'. With this arrangement asubstantial number of complete stoves may be packed very compactly. As one example, it

was found thatabout 33 stoves of a certain size could be packaged within one cubic foot of shipping space, as compared with about two fully-assembled stoves .of the conventional Hong Kong type of the same general capacity.

It will be understood that various modifications may be made and that various-types of components including chimneys, burners, wicks, etc. can be used and theparts fitted together more or less tightly by specialdesign of the interfitting or frictionally assembled elements as will be obvious to those skilled in the art. Because of their particular shapes, the various parts are designed to contribute to safety and efiiciency. The sloping side walls inside the chimney, for example, may reflect heat more efiiciently from burner to cooking vessel above than a vertical walled chimney. ,The cover member 17 is so designed that it serves as a broad funnel, so that fuel such as kerosene can be poured into the filler opening 27. Fuel spilled on the cover 17 around the opening I 27 also will draininto the fuel compartment.

'By designing the chimney and burner-base unit 35 properly, to fit closely over the wicks, complete and clean flame extinction can be accomplished by mere rotation of unit 35. This not only prevents lingering and objectionable after-fumes, but also wipes the wicks clean for the next use of the stove. By using porous ceramic wicks instead of conventional fabric, there is no problem of char and wick trimming. However, for many uses, fabric or fibrous Webs of conventional type are acceptable. The burner base within the upraised chimney walls of unit 35 is preferably a black or near-black body, to maximize radiation and efiicient heat transfer. Obviously, the cooking vessel above may be of any type, but it preferably has a black or near-black lower surface. For more efiicient packing and shipping, the cooking vessel or vessels may be designed with tapering walls and of appropriate diameter, etc., so that they may be nested within the stove itself, or with appropriate components thereof.

Most parts may be made of inexpensive sheet metal, aluminum being preferred to resist corrosion and rust. However, the burner unit 70 per se, being exposed to flame at high tempearture, is preferably made of a heatresistant metal or alloy such as stainless steel. For greater structural strength, especially where thin gauge metals are used, the vessel 11, and units 17, 35 and/ or 70 may be formed of corrugated construction.

Other variations will suggest themselves as ancillary to this invention. It is intended to cover the modifications named above, and all other modifications which may occur to those skilled in the art, as broadly as the following claims will properly permit in view of the state of the prior art.

What is claimed is:

1. A wick type stove for burning liquid fuel comprising a fuel tank adapted to contain a quantity of liquid fuel having upwardly outwardly flaring walls, a cover lid seated on said tank and defining at least one wick opening, a wick element held by said lid suspended in said fuel and protruding upwardly from said wick opening, a chimney unit mounted on said cover lid for rotation relative thereto, said chimney unit having oppositely sloping joined inner and outer wall elements and a generally horizontal burner element support portion, said burner element support portion defining an opening which may be positioned into registry with said wick and wick opening by rotation of said chimney unit relative to said lil to selectively expose more or less of said wick element through said burner opening for combustion control, and a burner element having oppositely sloping inner and outer wall elements spaced apart to straddle the burner element support portion of said chimney unit to rest thereupon, said burner element and chimney unit defining a plurality of openings providing access of air to said burner element support portion.

2. A wick type stove according to claim 1 in which the sloping outer wall element of the chimney unit is angularly oriented and proportioned to nest, when inverted, within the walls of said fuel tank thereby defining within the inner wall of said chimney unit and the bottom of the fuel tank a chamber for the storage of said burner and wick elements, the cover lid and chimney unit being fitted normally together, and means for securing said cover lid to the fuel tank for holding the lid and chimney unit in a stored position with respect to said fuel tank.

3. A plurality of wick type stoves according to claiml in packaged relationship wherein the cover lids are generally flat and are stacked one upon the other, a plurality of fuel tanks are nested in telescoping relation one within the other, the uppermost of said fuel tanks being open in said telescoping relation to receive a plurality of burner elements each one stacked within the other, and a plurality of chimney units nesting in telescoping relation with said plurality being inverted and the lowermost chimney unit thereof placed over the stack of burner elements.

4. A wick type stove according to claim 1 in which said cover lid is generally flat and defines a central open ing communicating with the interior of said fuel tank for refilling said tank with fuel, the chimney unit defines a central plug adapted to fit Within a central opening in the cover lid to seal said opening, the outer wall of the chimney unit rests upon peripheral portions of said cover lid and together with the plug supports the chimney unit upon the cover lid to permit relative rotation of the chimney unit with respect to the cover lid, the horizontal burner element support portion of the chimney unit being spaced for a predetermined distance above the cover lid to permit protrusion of the wick element toward and under the burner element support portion of the chimney unit, the wick element protruding thereunder substantially adjacent to the undersurface of said chimney unit whereby rotation of the chimney unit wipes the upper end of the wick element when the chimney unit is rotated to move the opening therein in the burner element support portion out of registry with said wick element.

References Cited in the file of this patent UNITED STATES PATENTS 163,202 Houston May 11, 1875 648,413 Julhe May 1, 1900 945,529 Haswell Jan. 4, 1910 1,125,014 Dunn Jan. 12, 1915 1,170,606 Chadwick Feb. 8, 1916 1,993,955 Benner et al Mar. 12, 1935 2,800,174 Konstandt July 23, 1957 3,046,969 Davis July 31, 1962 FOREIGN PATENTS 532,239 Great Britain Jan. 21, 1941

Claims (1)

1. A WICK TYPE STOVE FOR BURNING LIQUID FUEL COMPRISING A FUEL TANK ADAPTED TO CONTAIN A QUANTITY OF LIQUID FUEL HAVING UPWARDLY OUTWARDLY FLARING WALLS, A COVER LID SEATED ON SAID TANK AND DEFINING AT LEAST ONE WICK OPENING, A WICK ELEMENT HELD BY SAID LID SUSPENDED IN SAID FUEL AND PROTRUDING UPWARDLY FROM SAID WICK OPENING, A CHIMNEY UNIT MOUNTED ON SAID COVER LID FOR ROTATION RELATIVE THERETO, SAID CHIMNEY UNIT HAVING OPPOSITELY SLOPING JOINED INNER AND OUTER WALL ELEMENTS AND A GENERALLY HORIZONTAL BURNER ELEMENT SUPPORT PORTION, SAID BURNER ELEMENT SUPPORT PORTION DEFINING AN OPENING WHICH MAY BE POSITIONED INTO REGISTRY WITH SAID WICK AND WICK OPENING BY ROTATION OF SAID CHIMNEY UNIT RELATIVE TO SAID LID TO SELECTIVELY EXPOSE MORE OR LESS OF SAID WICK ELEMENT THROUGH SAID BURNER OPENING FOR COMBUSTION CONTROL, AND A BURNER ELEMENT HAVING OPPOSITELY SLOPING INNER AND OUTER WALL ELEMENTS SPACED APART TO STRADDLE THE BURNER ELEMENT SUPPORT PORTION OF SAID CHIMNEY UNIT TO REST THEREUPON, SAID BURNER ELEMENT AND CHIMNEY UNIT DEFINING A PLURALITY OF OPENINGS PROVIDING ACCESS OF AIR TO SAID BURNER ELEMENT SUPPORT PORTION.

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