1457290-A is referenced by 2 patents.
1457290 Spirometers ALLEN & HANBURYS Ltd 14 Dec 1973 [4 Jan 1973] 57982/ 7,3 Heading A5K [Also in Division Fl] A spirometer comprises a body 1, an impaller 7 rotatably mounted on a shaft 8 in the body, an inlet through which. air can be blown tangentially on to the impeller, a reduction gear . assembly arranged to be driven by the shaft 8 and an indicator driven by the reduction gear assembly to indicate the number of revolutions of the impeller. The cylindrical body I having axially separated chambers 2, 3 is closed at both ends by covens 5, 6 which, are provided along their peripheries with a series of spaced apertures 29, the cover 6 also having a graduated scale (28) on its outer face. An indicator disc 26 embossed with a radial line (27) on its outer base is splined to a shaft 25 of the final gear 19.; A tubular portion (10) extending tangentially from the chamber 2 housing the impeller may be provided with a non-return inlet valve (12).