| 摘要 |
Apparatus for association with a forced air ventilation duct 14 has an inlet means 10 to receive air from the inside of the duct 14 connected outside duct 14 to a dispenser 15 which is itself connected to outlet means 17 terminating within the duct 14 downstream of the inlet means 10 to supply an atmosphere control substance, such as an odorant or deodorant insecticide, water vapour, or inhalation vapour, from dispenser 15 into the air stream. Air flow through the dispenser 15 is accomplished by the differential pressures present at the inlet and outlet means 10 and 17 in the air duct 14. <IMAGE> |
