| 摘要 |
An inhaler for use with a drug delivery system (25), e.g. an aerosol dispensing container, has a diaphragm 440 and an inverted cup-shaped member 420 defining therebetween a low pressure air chamber 600 for applying a resisting pneumatic force capable of preventing actuation of the aerosol container by a loading spring 460. The resisting low pressure is released by a breath-actuator vane 550 comprising a flexible diaphragm 600 for sealing a valve port 495, the opening of which releases said positive or negative pressure. The flexible diaphragm is carried by the vane 550 such that, on initial movement of the vane, the diaphragm flexes as it is held by said positive or negative pressure against the valve seat until it is finally removed therefrom on further movement of the vane. With the dust cap 510 closed, the spring 460 is held closed and the pressure chamber volume is a minimum. On opening of the cap, the spring urges the inverted cap downwardly which increases the pressure chamber volume until the underpressure developed therein balances the action of the spring. On inhalation, vane 550 is pivoted to open the valve port 495 whereupon spring urges the inverted cup and the aerosol further down to dispense the drug. <IMAGE> |
