Portable vaporizing apparatus
US 2023402 A
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Dec. m 1935. E. BROWN PORTABLE VAPORIZING APPARATUS Filed Jan. 12, 1935 INVENTOR fan/0v Bean N BY ATTORNE Patented Dec. 1Q, 1935 UNITED STATES PATENT OFFICE 5 Claims.
This invention relates generally to apparatus for the slow but prolonged vaporization of liquids, but is more specifically designed to produce a small, portable, simple device in which a solution containing a relatively volatile medicament may be uniformly and slowly vaporized at small expense during a relatively long period of time, say throughout the usual hours of sleeping at night.
A further object of the invention is the perfecting of such an apparatus which shall not waste, by radiation, more than a small part of the heat being developed therein and which can be picked up while in operation without burning the fingers grasping it, and in which a candle can be used economically and without smoking or the production of the unpleasant odors resulting from a partly consumed wick falling down in the partly melted material of which 30 the candle body is formed.
One of the main problems solved by my invention after long experimentation is the correct proportioning of the cubic contents of the combustion chamber with reference to the eifective area of the openings for admitting air thereto, and for the discharge of gases of combustion therefrom, and the proper location of said openings with reference to the locus of combustion.
Preferably I use a special form of short, squat candle having a small tubular wick enclosing a core of fusible material which will be slowly melted at the center of greatest heat in the candle flame but will maintain the rigidity of its lower portions sufficiently to hold all unconsumed portions of said wick erect, and place such candle in the bottom of a cylindrical cup provided with vertical slots of carefully regulated length and area around its upper edge or mouth, in which is placed a shallow pan for holding the liquid to be vaporized.
I am aware that it has been heretofore proposed to place a candle under a vaporizing pan in a combustion chamber having large, substantlally square openings in its side walls extending down to the level of the candle flame, but such prior described apparatus will not produce the slow, uniform rate of combustion and efficient conservation of heat necessary for the successful operation of devices of this character, and which results are most satisfactorily obtained by my present invention.
The best form of apparatus at present known to me embodying my said invention is illustrated in the accompanying sheet of drawings in which Fig. l is a vertical section of the apparatus in operation and Fig. 2 is a horizontal section on. line 2-2 of Fig. 1.
Throughout the drawing like reference char- 5 acters indicate like parts. I is a cup-shaped candle holder with substantially cylindrical vertically arranged walls having eight vertically extending slots 2 in their upper portions. 3 represents generally a shallow pan for holding the liquid 10 to be vaporized which has a circumferential flange 3 resting on the upper edge or mouth of the cup, and a raised central portion 5. In the bottom of the cup is a short, squat candle indicated generally at S, composed of a cylindrical 15 body of wax or other similar combustible material, and provided with a small tubular wick 8 woven about a central core 8 of fusible alloy which will melt slowly in the hottest portion of the zone of combustion formed when the candle -20 is burning. This core is firmly set in a metal base IE3 at the bottom of the candle so that it will always be held erect, even what is left of it after the combustible material :1 of the candle has been entirely consumed. The flame I l of the candle is always well below the plane of the lower ends of slots 2, 2.
The preferred dimensions of the above described structure are as follows: The cup is about 3% inches deepv and has a slight outward flare :30 at its mouth beginning at a level somewhat below the level of the bottom of the pan. At its mouth the cup has internal diameter of about 2 inches, but at the level of the lower ends of the slots its internal diameter is only about 2%. The pan is located in the so created flare of the cup mouth, and there is an annular clearance space of about inch left between the two, The .pan is inch deep and has an external diameter approximately the same as the above 49 noted internal diameter of the cup at the level of the lower ends of the slots (1. e. 2 inches). The eight slots are each about 1 inches long and 7/64 inch wide.
The total area of the portions of the eight 45 slots below the pan is therefore, a little over half a square inch and the area of the annular clearance around the pan is about 1 square inches, so that the total outlet area for vapor under and around the pan is a little over two 50 square inches, or about two-thirds of the cross section of the cup at that point. When these proportions are retained and the cup or candle container I is made of a material such as one of the well known phenol condensation products 55 which have relatively low rates of heat conduction, and correspondingly high heat insulating properties, a candle of the type shown of approximately the height indicated in the drawing will burn slowly and evenly for a long time, generating just suificient heat to slowly vaporize the liquid in the pan 3, without smoking or producing any unpleasant odor from overheated or partially burned wax. At the same time the exterior of the cup I will not be raised above a temperature at which it can be grasped by the hand to move it about. The confining of the heat to the interior of the cup by the low conductivity thereof also permits a slow rate of consumption of the wax while maintaining the desired temperature of liquid in the pan 3, and the proper circulation of air inward through the lower portions of slots 2, 2, and of heated air and gases of combustion outward around the pan through the upper portions of said slots.
The location of the candle flame below the level of the bottom ends of slots 2, 2, enables the solid lower and middle portions of the cup walls to protect the candle flame from side drafts, so that slow combustion at a uniform rate is secured. Also, as plate l0 and core 9 hold the wick erect at all times, every drop of melted wax or other combustible liquid produced by the slow fusion of the candle body 7, is consumed before the flame H is finally extinguished by lack of fuel.
I prefer to employ about eight narrow slots 2, as shown, rather than a smaller number of broader ones. With the dimensions above given the width of each slot is about one-nineteenth of the internal diameter of the candle holder at the level of said slots lower ends, and the total area of their portions below the pan about one-sixth of the cross-sectional area of the holder within the locus of said slots.
Having described my invention, I claim:
1. In a vaporizing apparatus the combination of a substantially cylindrical, vertically arranged, cup-shaped candle holder, a shallow pan for holding liquid to be vaporized set in the upper, open end of said holder, and a short candle having a wick provided with a fusible alloy core set in a metal base resting on the bottom of said holder, the upper end of said holder having a plurality of short vertical slots out therein, of a depth such that the length of each slot exposed below the pan will be about one-third of the internal diameter of said holder, and of such width that the total area of all said exposed slot portions shall be about one-sixth of the cross sectional area of the holder within the locus of said slots.
4. In a vaporizing apparatus the combination of a cup-shaped candle holder made of incombustible material having a substantially low coeflicient of heat conduction provided with a plurality of vertically disposed slots evenly spaced about the circumference of the upper half of its otherwise imperforate walls, a shallow liquid holding pan set in the top of said cup, and a short candle set in the bottom of said cup and provided with means for holding its wick in a vertical position while it is being burned and after the body of the candle has been melted down; said slots being proportioned to admit just enough air to support slow combustion of the candle within the cup at the high temperature maintained therein by reason of the slow dissipation of heat by the heat insulating material of the cup walls.
5. A combination such as defined in claim 4 in which an annular clearance space is left between the exterior of said pan and the surrounding walls of said cup, the total outlet area afforded by said annular space around said pan and the slot openings beneath it being about twothirds that of said cup cross section at the level of said pan bottom.