Apparatus for automatically periodically measuring and displaying the total air expired by a subject during each of a succession of given time intervals

Claim 1

Apparatus for automatically periodically measuring and displaying the total air expired by a subject during each of a succession of given time intervals, said apparatus including: volume measuring apparatus including metering means for receiving the expired air from the subject, said metering means including a member driven by the expired air at a rate proportional to the volume of the expired air for each of the succession of time intervals, and further including transducer means coupled to said member for generating electrical output pulses having a repetition frequency representative of the volume of air expired by the subject during successive time intervals and under standard temperature comditions; a volume computer coupled to said volume measuring apparatus and including multiplier circuit means for multiplying each pulse of the electrical output pulses therefrom by a predetermined number and further including divider circuit means for subsequently dividing the pulses from the multiplier circuit by a predetermined number for computing the volume of air expired during each of said time intervals corrected to body temperature conditions, and output circuit means coupled to said divider circuit means for producing electrical output pulse signals representative of said corrected volume; and electrical display means coupled to said output circuit means of said volume computer and responsive to said electrical output pulse signals for providing a reading of the volume of air expired during each of the successive time intervals at body temperature, ambient pressure, and saturated with water vapor.