| 摘要 |
A SIDESTREAM FLOW SENSOR FOR SPIROMETRY An improved spirometer for measuring the flow rate of breaths includes a mainstream conduit having a fixed or variable restrictor formed therein for producing a pressure differential across the restrictor, and one or more sidestream conduits having a first end in fluid communication with the mainstream conduit, upstream of the restrictor, and a second end in fluid communication with the restrictor. A thermal flow sensor is disposed within each sidestream conduit, and includes a heater element and a pair of temperature sensors located upstream and downstream of the heater element connected in a bridge configuration to generate an analog signal for output to a data processing system to measure the flow rate of breath in the tube.
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