Heated volatile dispensing device with dye-based use-up indicator

• Main Authors: BRIAN T. DAVIS, JOEL E. ADAIR, PADMA PRABODH VARANASI, GOPAL P. ANANTH
• Format: Patent
• Language: English
• Published: 09.08.2007
• Subjects: AGRICULTURE; ANIMAL HUSBANDRY; APPARATUS FOR THE DESTRUCTION OF NOXIOUS ANIMALS OR NOXIOUSPLANTS; ARRANGEMENTS OR ADAPTATIONS OF HEATING, COOLING, VENTILATING,OR OTHER AIR-TREATING DEVICES SPECIALLY FOR PASSENGER OR GOODSSPACES OF VEHICLES; CATCHING, TRAPPING OR SCARING OF ANIMALS; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS, ORSURGICAL ARTICLES; DISINFECTION, STERILISATION, OR DEODORISATION OF AIR; FISHING; FORESTRY; HOROLOGY; HUMAN NECESSITIES; HUNTING; HYGIENE; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS, OR SURGICALARTICLES; MEASURING; MEDICAL OR VETERINARY SCIENCE; METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS INGENERAL; PERFORMING OPERATIONS; PHYSICS; TESTING; TIME-INTERVAL MEASURING; TRANSPORTING; TRAPPING; VEHICLES IN GENERAL

Heated volatile dispensers are disclosed that are provided with automated dye-based use-up indicators. Multiple migrateable dyes of different colors are positioned adjacent a porous substrate. Heating of the substrate, such as a slab impregnated with an insect repellent, both causes the impregnated chemical to dispense from the slab and the indicator dyes to migrate to one or more visible positions. One dye migrates to a visible position faster than a dye of a different color. Further heating may cause one or both dyes to change color at a visible position. The dye movement imparts information about the degree of use-up of the impregnating chemical.