US Patent 7622073 Apparatus for and method of dispensing active materials

An apparatus for dispensing active materials comprises a housing and control circuitry disposed within the housing. The control circuitry implements programming for a mode of operation in which during a first period of time a first active material is emitted, during a second period of time the first active material and a second active material are emitted, and during a third period of time the second active material is emitted, wherein during the second period of time, the first and second fragrances are alternated.