The prior art discloses various air fresheners including U.S. Pat. No. 4,544,592 to Spector which discloses an aroma generating capsule adhesively attached to the surface of an incandescent bulb. The capsule includes a plastic skin and a vent hole through which an aroma is forced into the atmosphere.
Of particular interest is U.S. Pat. No. 4,849,606 to Martens which is the same general area of art as the present invention. The Martens patent discloses a tamper-resistant container suitable for use with an electrically heated vapor dispensing apparatus. The container includes a packaged gel which is inserted into a dispensing apparatus having an inner wall with an integrally molded electrical plug and an outer wall having a plurality of openings through which the scented aroma is dispensed.
U.S. Pat. No. 4,571,485 discloses an electrically heated aromatic generator utilizing a replaceable aroma cube which is inserted into a well in the generator. U.S. Pat. No. 4,731,520 discloses an aroma diffuser assembly for dispensing a scent from a replaceable and expendable cartridge. A heater assembly is also provided to vaporize the cartridge liquid which exits through an aperture into the atmosphere.
The prior art also includes U.S. Pat. No. 4,837,421 which shows a fragrance dispensing apparatus which releases a fragrance from a solid polyamide resin. A heating resistor is provided to maintain an elevated temperature. Also of interest are U.S. Pat. No. 3,895,298 to Moran, U.S. Pat. No. 4,425,302 to Pons Pons and U.S. Pat. No. 4,804,821 to Glucksman.
The prior art does not disclose an adjustable air freshener of the type set forth herein which is inexpensive and easy to manufacture and use. In the present invention the aroma dispensing can be regulated to conform to the size of a room and waste can be minimized. The disadvantage of an overpowering scent present in the prior art is thus avoided. Further, the useful life of the gel is extended since all of the product is not continuously exposed to the heater at the same time in contrast to the Martens patent.
Certain factors influence the amount of fragrance released by an air freshener utilizing a heated gel including:
1. Temperature of the heating element or surface; PA1 2. Surface area of contact between the gel and heated surface; PA1 3. Time of contact; PA1 4 Surface area of permeation (surface area of the film covering the gel); PA1 5. Permeability of the film encapsulating the gel; and PA1 6. The amount of the gel or oil fragrance, and PA1 7. The flow of hot air.
In the present invention, factors 1, 4, 5, and 6 are fixed and factor 3 (time) starts from the moment of plug-in and continues until the gel is exhausted. The only factor over which control may be exerted without employing expensive regulating mechanisms is factor 2 (area of contact) and factor 7. The time factor can be regulated by an on-off switch, which is subject to human error, or by an automatic device set at a predetermined interval--both costly and affecting the size of the device. This invention proposes to regulate the scent from an air freshener or dispenser by controlling the area of contact between the heater and gel with a rotatable cover which cooperates with a unique base. The dial is rotated to place the scented gel in contact with the heated surface to produce the desired scent. A dividing wall across the center of the cover restricts the hot air affecting only the portion of gel which is moved up to the heated compartment. The portion of gel which remains in the cold compartment is protected from the contact of the hot air by the dividing wall.