Monitoring devices for inhaler valves

摘要

The operation of a valve in a medicament dispenser can be monitored by an optical system such that when the valve is moved to its open position a light passage from a valve component 16 to a light sensor 12 is defined. Each operation of the valve which allows light to pass along the passage the sensor sends a signal to a counter which keeps a record of use of the valve. The light passage is from a reflective surface on the valve component 16 to the light sensor 12. A light source 10 is at a fixed location relative to the sensor 12. The light sensor 12 may be an array which may comprise of a matrix of photo silicon. A power source for the device may be one of a piezoelectric crystal and a voltaic polymer. The operation of the valve can be monitored using a pressure chamber 32 contractible upon movement of the valve from the closed position to the valve open position to pressurise the contents of the chamber 32. The chamber 32 is coupled to a counting device 34 which generates a signal each time a threshold pressure is sensed in the chamber. The threshold pressure is established as the pressure reached upon the first movement of the valve from the closed position to the valve open position. The pressure chamber 32 can be a bellows arrangement. The valve monitoring device could utilise a variable resistor which comprises a component 36 mounted on the valve stem 4 and an element 38 mounted to a framework proximate thereto. The resistance varies as the component 36 moves between the valve closed position and the valve open position and a sensor is coupled to the variable resistor to sense the resistance in the valve open position and a counting device generates a signal each time that resistance is sensed.