| 摘要 |
Disposable mouthpieces for use with spirometers are disclosed. Known mouthpieces have a cylindrical cardboard tube 15, with a plastics valve unit consisting of a generally cylindrical short tubular moulding 1 which is a press fit in the interior of the cardboard tube 15, and having internally a hub 6 connected via spokes 5 to the interior wall of the tubular moulding, and a flap valve diaphragm 9 supported on the hub and against the spokes and a circular seating. The moulding 1 has an integral flange 2 to prevent the valve unit being pushed all the way into the cardboard tube. In accordance with the invention, the exterior of the flange 2 is oval, sized so it cannot be inserted into the circular aperture of the spirometer flow tube, so the mouthpiece cannot be inserted the wrong way round. The plastics body may also be oval, to distort the cardboard tube and improve the friction fit therebetween. The flange may project from the body not more than the wall thickness of the cardboard tube, so that it is not pulled off by a user after use. |
