Measurement of Static Pressure

Abstract The paper describes a new instrument for measuring static pressures in air-flow determinations. Made in the form of concentric brass tubes, the outer of which is 1/4 in. diameter, the instrument is easily introduced into air ducts through small openings, such as a bolt hole. Pressure is communicated to manometers through two holes, one to the inner tube and the other to the concentric space between the tubes, about 78.5 deg. apart. The instrument is held perpendicular to the flow in such a manner that the direction of flow bisects the angle between the axes of the holes. In this position, which can be determined by balancing the pressures on one manometer, the reading on a second manometer gives the static pressure. The instrument has less error in turbulent flow than other types.