Abstract A fluid-powered flowmeter for measuring the flow rate of human breath or other relatively low levels of flow. The meter includes an open-ended flow tube for receiving the subject stream, the tube being provided with an inlet port for injecting therein a fluid from a regulated power source to produce a radial air pattern in the tube. Mounted on the outer circumference of the tube is a collector port adapted to capture the diverging jet stream, the collector being coupled to a flow transducer for converting the jet flow rate into corresponding electrical values. When the subject stream is blown into the tube, the radial air pattern is deflected away from the collector to an extent depending on the flow rate of the subject stream, thereby producing a proportional change in the electrical output which may be indicated or recorded, or fed into a computer for comparison with established norms.
A meter for measuring the flow rate of human breath or other relatively low levels of fluid flow, said meter comprising: a. a flow tube through which the subject stream to be measured is axially directed, said tube having input means to inject an air stream into said tube to create a radial air pattern therein which is transversely directed relative to the subject stream, and a collector port positioned to normally capture said radial air stream, b. means to apply regulated air power to said input means to produce said radial air pattern which is normally captured bY said collector port, said radial air pattern being deflected by said subject stream away from said collector port to a degree depending on the flow rate of the subject stream, c. a flow transducer coupled to said collector port for converting the flow derived from the collector port into corresponding signals indicative of the flow rate of the subject stream, and d. an indicator coupled to said transducer to indicate said signals.
Claim 2
Dependent Claim
171 words
A meter for measuring the flow rate of human breath or other relatively low levels of fluid flow, said meter comprising: a. a flow tube through which the subject stream to be measured is axially directed, said tube having input means to inject an air stream into said tube to create a radial air pattern therein which is transversely directed relative to the subject stream, and a collector port positioned to normally capture said radial air stream, b. means to apply regulated air power to said input means to produce said radial air pattern which is normally captured bY said collector port, said radial air pattern being deflected by said subject stream away from said collector port to a degree depending on the flow rate of the subject stream, c. a flow transducer coupled to said collector port for converting the flow derived from the collector port into corresponding signals indicative of the flow rate of the subject stream, and d. an indicator coupled to said transducer to indicate said signals.
Claim 3
Dependent Claim
25 words
A meter as set forth in claim 1, wherein said tube is provided with a disposable mouthpiece for testing the lungs of a human patient.
Claim 4
Dependent Claim
25 words
A meter as set forth in claim 1, wherein said air power is produced by a blower whose output is governed by a pressure-regulating valve.
Claim 5
Dependent Claim
31 words
A meter as set forth in claim 1, wherein said input means is constituted by two jet ports coupled to opposing nozzles to produce said radial jet pattern across said tube.