Patent ID: 6314822
Filing Date: 2001-11-13
Classification: A61B

Abstract:
A device for measuring air-flow comprising:a) an air-flow valve including;at least one rotary blade having a planar surface and carried by a spindle for rotation of the at least one rotary blade about an axis of the spindle to define a path having an outermost part, the planar surface extending radially from the spindle axis to define an outer edge;a stator including an air deflecting surface and at least one air-directing aperture positioned at or adjacent to the outer edge of said blade or the outermost part of a path traced by the blade during rotation about the spindle axis;a valve body for housing the stator and the rotary blade and defining an inlet path for air exhaled in a first direction and an annular chamber about the stator; andan air directing means associated with said at least one air directing aperture to guide air from the chamber through the at least one air directing aperture at or towards the planar surface of the at least one rotary blade causing it to rotate about the spindle axis;whereby air exhaled along the inlet path in the first direction, substantially parallel to the spindle axis, is deflected into the chamber by the air-deflecting surface of the stator, and in the chamber, the air is directed through the at least one air direction aperture and into a second altered direction tangential to the spindle axis and perpendicular to or at least towards the planar surface of said at least one rotary blade;b) optical elements adapted to transmit and receive an infra-red or light beam through said air-flow valve;c) electronics for monitoring interruptions to the beam caused by the rotation of the at least one rotary blade about the spindle axis and for determining a required parameter;d) display means for visually representing the required parameter; ande) a housing for housing the optical elements, electronics and display means;wherein said air-flow valve is releasably connectable to the housing.