초록 ▼

In a spirometer, a breath transmission passage has first and second ends open to the atmosphere and a restriction between the first and second ends. An elongated conduit has a first port at one end, a second port at the other end, and a third port intermediate to the first and second ports to form a

In a spirometer, a breath transmission passage has first and second ends open to the atmosphere and a restriction between the first and second ends. An elongated conduit has a first port at one end, a second port at the other end, and a third port intermediate to the first and second ports to form a first flow measurement passage in the conduit between the first and third ports and a second flow measurement passage in the conduit between the second and third ports. The first end of the breath transmission passage at a point near the restriction is interconnected to the first port, and the second end of the breath transmission passage at a point near the restriction is interconnected to the second port. A source of bias gas is connected to the third port. The difference between the rate of gas flow through the first and second flow measurement passages responsive to inhalation from the exhalation to the breath transmission passage is sensed to provide a bipolar indication thereof. First and second hot wires are bent in half to extend side by side along the length of a cavity. At one end, the first and second hot wires are electrically connected to each other to form in effect a single hot wire equal in length to the first and second hot wires.

대표청구항 ▼

Fluid measuring apparatus comprising: a housing having an elongated cavity enclosed on its sides; a first thin elongated hot wire bent in half to extend along the length of the cavity away from a junction; a second thin elongated hot wire bent in half to extend along the length of the cavity away fr

Fluid measuring apparatus comprising: a housing having an elongated cavity enclosed on its sides; a first thin elongated hot wire bent in half to extend along the length of the cavity away from a junction; a second thin elongated hot wire bent in half to extend along the length of the cavity away from the junction in the same direction as the first hot wire so the first and second hot wires are side by side in the cavity; first means at the junction for supporting the ends of each hot wire in spaced electrically isolated relationship from each other and connecting one end of the first and second hot wires to each other to form in effect a first single hot wiRe equal in length to the first and second hot wires; second means spaced along the length of the cavity from the junction for supporting the middle of the first hot wire to exert tension thereon as the length of the first hot wire changes; third means spaced along the length of the cavity from the junction aside of the second supporting means for supporting the middle of the second hot wire to exert tension thereon as the length of the second hot wire changes; means for forming in the housing a fluid entrance to the cavity; means for forming in the housing a fluid exit from the cavity longitudinally spaced from the entrance so the hot wires lie between the entrance and the exit; and means for measuring the change in resistance of the hot wires.