US 2743350 A
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April 24, 1956 R. p, UERFEL E AL 2,743,350
ELECTRIC VAPORIZER Filed Nov. 25, 1953 INVENTORS. Rosem- P WUERF'L BY MILTON A. H0 4 aha-162m United States Patent 2,743,350 ELECTRIC VAPORIZER Robert-P. Wuerfel, Baxter, and Nlilton A. Hogan, Ann Arbor, Mich., assignors to Lindavap, Inc., Ann Arbor, Micln, a corporation of Michigan Application November 25, 1953, Serial No. $514,399 1 Claim. (Cl. 219-44) The present invention; relates toavaporizer for use with solid particles or solutionsof a deodorantfumigant insecticide, medicinal material, or the like. More particularly, the present invention relates to a device wherein a solid fumigant insecticide or solution thereof is heated in an electrically heated. ceramic, cup and the vapors produced thereby are diifused into an air stream and circulated withinthe space to be treated by the convection air-currents which are ,intensifiedand controlled by the'novelqstructure of a vaporizer embodying the present invention;
Prior to the present invention various devices have been used to heat a solid substance and distribute the vapors therefrom throughout a space to be treated thereby. Such devices have utilized various means of heating the solid material, such as supporting the material a short distance above an electrical resistance coil, and providing for a flow of air up and around the coil and material thereby driving off vapors from the material and carrying them throughout the space to be treated.
Such prior devices have not been entirely satisfactory, however, because they have not assured uniform distribution of the vapors throughout the space to be treated and also they have not been economical of the solid material since after a certain amount thereof has been vaporized the particles are no longer large enough to stay in the structure provided to suspend them above the heating coil.
Other prior devices have utilized a steam generator with an outlet therefrom to conduct the escaping steam around a receptacle in which the material to be vaporized is placed. Such devices require a comparatively large heating element to produce the amount of steam required to heat the material to be vaporized. Also, when the material is vaporized, the vapors are immediately diluted with steam and carried throughout the area to be treated in such diluted form. There is a tendency for the steam carrying the vapors to condense on cool surfaces and deposit crystals of the vaporant material which oftentimes is a dangerous poison and which also may stain any surface with which it comes in contact.
Such devices are also comparatively expensive because of the inherent necessity of providing a large water reservoir within the steam generator if the device is to operate for extended periods and such devices must also provide some automatic shut-off means to avoid damage to the device should the water supply be exhausted and also to prevent the device from becoming so greatly overheated in such a case that it would cause a fire.
It is accordingly one object of the present invention to provide a vaporizer having an integral ceramic cup and heating coil supported within a hollow base wherein the base serves to direct the flow of air up around said cup which results in the air flow distributing the vapors and insulating the cup from the base so that the base remains relatively cool and can be handled.
Another object of the present invention is to provide a vaporizer equally. adapted foruse with solid materials and solutions.
A further object of the present invention is to provide a vaporizer having, an integral ceramic cup and heating element which will not be harmed by continuedoperation after the vaporant material is exhausted andtwhich will not overheat 'sufiicientlyto cause a fire.
Other objects of this invention will appear inthefollowing description and appended c1aim, referencebeing had to the accompanyingdrawings forming a part of this specification wherein like reference characters designatecorresponding parts in the several views.
In the drawings:
Fig. 1 is a top view of a vaporizer embodying the present invention,
Fig. 2 is a vertical 2-2 of Fig. 1, and
Fig. 3 is a bottom view of vaporizer of Figs. l and 2.
Before explaining the present invention indetail, it is to be understood that the invention is not limited in its application to the details of'construction and arrangement of parts illustrated in the accompanying drawings, since the inventionis capable of otherv embodiments and of being practiced or carried out in variousways. Also, it is to be understood that the phraseologly or terminology employed herein is for the purpose of description and not of limitation.
Referring to the drawings and particularly to Fig. 2, the vaporizer 10 of the present invention includes the ceramic cup 12 having the electrical resistance heating coil 14 imbedded therein and integral therewith. The cup 12 is mounted in base 16 and the bafiie plate 18 is provided across the bottom of the base.
As is shown in the drawing the base 16 is a hollow truncated cone. At the upper end thereof a number of inwardly depending fingers 20 are provided to receive the ceramic cup 12 therebetween. The ceramic cup 12 is provided with the flange portion 22 which rests on the top of the fingers 20. The reduced portion 24 of cup 12 is a press fit between the fingers 20 and in cooperation with the upper end of the base 16 defines the slots 26 around the periphery of the cup 12.
A plurality of legs 28 are provided on the bottom of the base 16 and the bathe plate 18 is a press fit in the bottom of the base. The slots 30 are provided in the bafile plate 18.
The design of the base 16 provides a large area at the bottom thereof which diminishes toward the top. The slots 26 defined between the cup 12 and the top of the base give a restricted outlet for the air flowing upwardly through the base. Heating the cup 12 produces a low pressure area immediately above the cup thereby developing a pressure differential between that point and the bottom of base 16.
sectional view taken along the line the embodiment of the out the slots 26. This natural convection flow is increased and intensified by the converging sides of the base and the restricted area of the slots 26 which give a venturi effect to the flow of air upwardly through the base and around the periphery of cup 12.
In operation, a particle of vaporant material is placed in the cup 12, the heating coil 14 is connected to an electrical power source so that cup 12 is heated and the vaporant material begins to vaporize. Air enters underneath the bottom edge of base 16, passes upward through the slots 30 in battle plate 18, up on the inside of base 16, around cup 12 and up and out through the slots 26. As the air passes upwardly past the edge of cup 12 it picks up the vapors and carries them through the space to be treated. This flow of air also serves to continually wash periphery of the cup. The air flow also serves to insulate the cup 12 from the base 16 thereby preventing the base from becoming too hot to handle or from overheating and causing a fire.
We have found it advantageous to mold the base 16 of athermosetting plastic. This simplifies the construction of our vaporizer thereby reducing its cost and also the plastic material has a relatively low heat conductivity which aids in keeping the base cool.
' From the foregoing it can be seen that we have provided a novel vaporizer which includes a ceramic cup having an electrical heating coil formed integrally therewith mounted on a base which is designed to intensify the natural convection currents of air up around said cup and which utilizes this flow of air also to help insulate the cup from the base. Our vaporizer is also capable of continuous operation without damage thereto from overheating because of the insulating air flow and because of the novel ceramic cup having the heating element formed integrally therewith. Our vaporizer will also not be damaged by exhaustion of the vaporizing material and will not overheat and cause a fire. It can also be seen that the simple design of our vaporizer adapts it to mass production manufacturing methods thereby reducing the cost thereof.
Having thus described our invention, we claim:
A vaporizer for producing vapors from a vaporant material, said vaporizer comprising a cup to receive said vaporant material and having heating means integral therewith and a base member comprising a hollow truncated cone having a plurality of legs on the bottom thereof and a plurality of inwardly depending fingers at the top thereof, said cup having a flange and a reduced portion and being positioned in the top of said'base member with said reduced portion between the inner ends of said fingers and said flange resting on the top of said fingers, said reduced portion of said cup cooperating with the upper edge of said base member to define a plurality of air passages around said cup which in conjunction with said base portion form a venturi to intensify the natural convection flow of air induced by heating said cup up around the periphery of said flange portion, and a transverse baffie plate having a plurality of air passages therein disposed across said hollow base member adjacent the bottom thereof, said air passages in said baffle plate being greater in total area than the aforesaid air passages around said cup.
References Cited in the file of thispatent UNITED STATES PATENTS Laibow Oct. 28, 1952