A measuring conduit adapted for flow rate and concentration of a fluid for use in a measuring apparatus which measures both the flow rate of the fluid such as a respiratory gas containing a particular gas component, for example, carbon dioxide, using an ultrasonic wave and the concentration of the particular...http://www.google.co.uk/patents/US4581942?utm_source=gb-gplus-sharePatent US4581942 - Measuring conduit for flow rate and concentration of fluid
