Instrumentation for the measurement of low velocities with a pilot tube.

Abstract

Abstract The advantages of the pitot tube for stack and duct sampling include: ruggedness, reliability, ability to be used in dusty, corrosive, or hot atmospheres, and no need of calibration. The main disadvantage is its lack of preciseness in velocities below 700 to 1000 fpm. A simple electrical sensing manometer which retains the trouble-free characteristic of a U-tube manometer has been developed. This manometer will give repeatable readings within 0.0003 inch with different observers. Preliminary wind tunnel tests have indicated that velocities as low as 250 to 300 fpm can be measured.