Respiratory exchange ratio sensor
First Claim
Patent Images
1. A device for directly measuring a person'"'"'s respiratory exchange ratio comprising, in combination:
- (a) a housing having a lumen extending therethrough through which inspired and expired air is adapted to flow;
(b) an oxygen fuel cell battery positioned in said lumen with an air inlet port of said battery facing a source of the expired air;
(c) a constant current load circuit coupled to the oxygen fuel cell battery; and
(d) a flowmeter circuit having a sensor element disposed at a location between the source of expired air and the air inlet port of said battery, said flowmeter circuit operative to produce an output signal proportional to a relative ratio of carbon dioxide to oxygen present in air expired by the person.
5 Assignments
0 Petitions
Accused Products
Abstract
A device for directly measuring a person'"'"'s respiratory exchange ratio (RER) utilizes a Zn-air battery cell and a constant current load circuit as an O2 pump capable of drawing oxygen from expired air. A thermistor located in the flow path forms a leg of a bridge circuit whose output is proportional to oxygen concentration in the expired air and, therefore, to oxygen uptake. The thermistor flowmeter circuit utilizes the thermal conductivity differences between O2 and CO2 to provide a measure at the relative ratio of the two gases present.
29 Citations
23 Claims
-
1. A device for directly measuring a person'"'"'s respiratory exchange ratio comprising, in combination:
-
(a) a housing having a lumen extending therethrough through which inspired and expired air is adapted to flow; (b) an oxygen fuel cell battery positioned in said lumen with an air inlet port of said battery facing a source of the expired air; (c) a constant current load circuit coupled to the oxygen fuel cell battery; and (d) a flowmeter circuit having a sensor element disposed at a location between the source of expired air and the air inlet port of said battery, said flowmeter circuit operative to produce an output signal proportional to a relative ratio of carbon dioxide to oxygen present in air expired by the person. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 17, 18, 19, 20, 21, 22, 23)
-
-
14. A device for directly measuring a person'"'"'s respiratory exchange ratio comprising in combination:
-
(a) a tubular mouthpiece member; (b) a sampling tube centrally disposed in a lumen of the tubular mouthpiece member, the sampling tube having an expiratory air inlet port and an inspiratory air inlet port, an expiratory air outlet port and an inspiratory air outlet port; (c) an ionomer tube exhibiting a selective permeability to water vapor coupled between the expiratory air inlet port and a sample chamber for drying expired air passing through the ionomer tube to the sampling chamber; (d) a passageway for carrying inspired air over an exterior of the ionomer tube in traveling from the inspired air inlet port to the inspired air outlet port; and (e) a sensor module secured to the mouthpiece and arranged to draw oxygen from the air in said sample chamber where the flow of oxygen is proportional to the oxygen concentration of the air in the sample chamber. - View Dependent Claims (15, 16)
-
Specification