| 摘要 |
<p>892,348. Breath-testing appliances. VYZKUMNY A ZKUSEBNI LETECKY USTAV. Nov. 4, 1959 [Nov. 6, 1958], No. 37415/59. Class 81 (2). [Also in Group XXXVIII] A device for measuring the carbon dioxide content in exhaled air consists of a measuring tube 1 with mouthpiece 24, within the measuring tube an anemometric tube 2 having front and rear ports 26, 27 connected through hoses 3, 4 to chambers 6, 7 of a differential pressure indicator 22 for measuring the pressure difference between the inhaled and exhaled air, and measuring and thermal compensating chambers 19, 20 in which are located hot wires 17, 32 connected in the arms of a resistance bridge and which communicate through moisture removing chambers 21, 29 (16, 31 are bags of silicagel) distributing chambers 18, 28 and hoses 13, 14 with the chambers 6, 7 of the differential pressure indicator. Sliding valves in the distributing chambers 18, 28 are moved upwards after samples of air have been admitted to the measuring and compensating chambers 19, 20. The cooling of the hot wires 17, 32 by the air samples in chambers 19 and 20 provides a bridge deviation proportional to the carbon dioxide content of the exhaled air. The differential pressure indicator 22 includes a pressure equalizing cavity 8 which is connected through a hose 5 to a central port 25 of the anemometric tube 2 picking up static pressure, and through hoses 9, 12 to the distributing chambers 18, 28 and hoses 10, 11 to the measuring and compensating chambers 19, 20. The arrangement is such that the air samples in chambers 19 and 20 are static while the measurements are carried out.</p> |
