Patent ID: 6095141
Filing Date: 2000-08-01
Classification: A61M

Abstract:
An aerosol flow control apparatus providing automatic discharge of medication responsive to an inspiratory effort of a user, the apparatus comprising:a pressurized canister of medication including a canister body and a hollow discharge stem which is movable with respect to the canister body between an inoperative position in which discharge of medication is prevented and an operative position in which medication is discharged through the discharge stem;a housing adapted to support the canister and permit movement thereof between a first position in which the discharge stem is in the inoperative position to a second position in which the discharge stem is in the operative position, the housing further defining a primary air passage including an outlet through which a user can inhale and also defining a secondary air passage extending between the primary air passage and ambient air outside the primary air passage, the secondary air passage including a venturi having a throat;a variable-volume device supported within the housing and including a wall which is movable with respect to the housing, the variable-volume device defining a variable-volume chamber therein in fluid communication with the venturi throat;a canister restraint affixed to the movable wall of the variable-volume device, the canister restraint being movable with the movable wall from a rest position in which the canister is in the first position and relative movement between the canister body and discharge stem is prevented, to a discharge position in which the canister is free to move into the second position;a resilient member which urges the canister into the second position upon movement of the canister restraint into its discharge position; andthe variable-volume chamber being in fluid communication with the primary air passage, whereby inhalation of a user through the outlet causes air to be drawn through the venturi throat thereby creating a low pressure in the throat which is communicated to the variable-volume chamber, the low pressure causing air to be evacuated from the chamber and thereby cause the movable wall to move the canister restraint into the discharge position.