Patent GB-677496-A (GB)
Title: Portable cooking stove
IPC: F24C5/20
Filed: 1950-10-17
Abstract: 677,496. Vapour burners ; portable stoves. ALADDIN INDUSTRIES, Inc. Oct. 17, 1950 [Oct. 21, 1949; Sept. 5, 1950], No. 25306/50. Classes 75(i) and 126 [Also in Group XXIX] A portable stove comprises tubes 8, 9, packed with capillary material 37 and secured to the top of a liquid fuel tank 1 and depending thereinto with the upper ends of the tube secured in and supporting a valve housing 34 but with the capillary material ending shortly below such housing thereby to form a vaporizing space, the valve housing having thereon a tube 69, Fig. 3, with opposite lateral orifices 56, 57 therein for the discharge of the vaporized fuel into an annular trough 41 forming the combustion space and surrounding and being supported on the valve housing whereby heat is conveyed to the vaporizing space, such trough being in part formed by a cap member secured on the orifice tube or valve housing. The fuel valve, Fig. 3, comprises a sleeve 63 inserted into a bore in the housing 34 and having at one end a bevelled flange 70 which is drawn into engagement with the housing by a tube 65 screwed on to the other end of the sleeve. The sleeve communicates through inlet passages 54, 55 with the vaporizing chambers and its outlet 68 leading to the discharge orifices 56, 56 is controlled by a valve member on the end of a stem 66 screwed into the sleeve and extending through the tube 65. Leakage of vapour along the valve stem is prevented by a packing gland screwed into the tube 65 and additionally by a second valve member 73 which engages with a seat on the inner end of the tube 65 when the first valve member is in open position. The burner, Fig. 3b, comprises an inverted metal cup 42a secured inside a larger upright metal cup 43a the bottom of which is cut along two arcuates lines and bent to form air inlets 43c, d and also walls 43c, f which grip the vertical sides of the lower part of the valve housing. The portion 43g between the fold lines rests on the upper surface of the lower portion of the valve housing and has a hole for the passage of the upper part of the housing. The vertical side wall of the inner cup has diametrically opposed openings 58, 59, Fig. 1, for the passage of the fuel mixture into the flame trough between the cups and its bottom wall which is secured by a nut to a stud 36 on the upper part of the valve housing, may have integral vanes in line with the openings 58, 59 for the mixture and extending upwardly and outwardly to the rim of the outer cup. A disc large enough to extend over the flame trough may be superposed on the bottom wall of the inner cup. Two grooves 60, 61 Fig. 3, are formed in the bottom wall of the outer cup to extend from the openings 58, 59 across the bottom of the flame trough, the grooves having the same width as the openings at their inner ends but becoming shallower and narrower in an outward direction. The generator tubes 8, 9 are made of a metal of low heat conductivity such as nickel silver or stainless steel and are welded to the screw-threaded cap of the fuel tank which cap comprises an annular part 5 which engages with a circular rib on the rim of the tank inlet and two annular alternative seatings 11, 13 at different levels for an expansible stand 23 supporting a vessel above the burner. The stand comprises a cylindrical resilient frame with two free vertical edges 26, 27, Fig. 8, which are fastened together by engaging hooks 28, 29 on one edge with either of two pairs of peripherally spaced slots 30, 31 in the portion adjacent the' other edge, the engagement chosen determining the diameter of the frame and consequently which seating 11, 13 on the cap the cylinder will engage with. When the stand is seated on the lower seating 11 its upper end is below the level of the burner and the complete apparatus can be covered by a casing 19, (usable as a cooking vessel) which screws on to a thread around the lower part of the fuel tank. A preheating torch projects upwardly from the cap 3 beside the generator tubes and comprises a tube 44, Fig. 2a, containing loosely packed stranded glass wool fibres and slidably mounted within a fixed sleeve 10. The lower end of the tube is closed by a plug 49 which co-operates with an aperture 52 in the sleeve to form a first valve and a ring 50 of packing material in a recess in the plug co-operates with a circular rib 48 on the lower side of an inwardly directed flange 47 on the sleeve 10 to form a second valve, both valves being opened by depressing the tube against the action of a spring 45 to allow fuel to enter an inlet 51 in the tube. A catch pan 33 is secured to the generator tubes. The wick material in the generator tubes consists of tightly packed glass wool fibres. In a modified construction, Figs. 11, 12, 15, the fuel valve comprises a valve member 103 which has a first valve surface cc-cperating with a seating at the end of a fuel vapour inlet passage 106 to the cylindrical valve chamber 102 and a second valve surface which co-operates with a seating on a plug 109 closing the end of the valve chamber. The second valve prevents leakage along the valve stem when the first valve is open and any fuel that leaks along the spindle between the opening of the first valve and the closing of the second valve is allowed to burn, the hand of the operator being protected from the flame therefrom by a conical flange 114 on a cylindrical member 112 which is secured to the valve stem and is a sliding fit in a counterbore 111 in the plug 109. The fuel discharge orifices 96 are formed in a vertical tube 86 which has a flat-sided (e.g. hexagonal) collar 116 which is held by a threaded sleeve in a seat 117 of similar shape in an upwardly projecting extension of the valve chamber 102, the arrangement facilitating the alignment of the discharge orifices 96 with the inlet apertures 58, 59 in the flame trough. The extension contains an asbestosfibre filter 119. An arcuate brass bar 120 is silver soldered to the lower surface of the bottom wall of the inner burner cup and extends through the inlet apertures 58, 59 to the flame trough to terminate near the outer wall thereof. The nut 85 securing the inner burner cup to the orifice tube 86 is reduced where it passes through the bar 120 and is spun outwardly so that the nut is held captive. In the torch preheater, Fig. 15, the outer fixed sleeve comprises two parts 87, 88 screwed together, the upper part 87 being secured to the top of the tank cap 80 and being flared at 131 to receive condensed fuel from the wick tube 89. A valve sleeve 121 slidable on the wick tube has a ring 122 of resilient valve material co-operating with a valve member 123 held rigidly between the freed sleeve parts 87; 88. The plug 126 on the lower end of the wick tube has a ring 125 of resilient material co-operating with a valve member 124 on the lower end of the valve sleeve 121. When the wick tube is depressed against the action of its spring 45 by a handle 91 the sleeve 121 initially moves downwardly with the wick tube to open the valve 123 whereby excess vapour pressure within the tank is dissipated through a port 129 in the outer fixed sleeve 88, the valve 123 and the spacing between the wick tube and its bearing surfaces. A shoulder 127 on the valve sleeve 121 then engages a shoulder on the fixed outer sleeve 88 so that further movement of the wick tube opens the lower valve 124 to allow fuel to enter the wick tube through a hole 130 therein. The catch pan 81 secured to the generator tubes 8, 9 has an opening 90 through which the wick tube 89 projects and has a semi-cylindrical wind guard 92 to protect the flame of the torch. A cylindrical wind shield 94 surrounding the burner flame trough is secured by studs 95 to support member 93 seemed to the catch pan, the annular space between the shield and its support forming an air entrance to the burner. Three utensil-supporting arms 100 are pivoted to brackets 98 on the rim, of the wind shield 94 by means of pivot rods 99 which are inclined to the radii of the shield and also to the supporting arms so that the arms in open position lie radially and when folded they clear each other. The catch pan 81 and wind shield 94 with its support 93 may be an integral stamping, an opening being provided to clear the valve housing and to allow air to enter; and additional air inlets may be formed by bending inwardly vanes cut in the stamping.