An Electronic Recording Flowmeter

Abstract

An instrument for measuring and automatically recording small steady liquid flows or the mean value of small pulsating liquid flows is described. The detecting unit employs a rotameter, or variable area meter, which consists of a vertical tube having a tapered bore in which a metal ``float'' is supported by the stream. Damping of motion of the ``float'' is obtained by means of an attached plunger whose cross‐sectional area is slightly less than that of a chamber which communicates with the measuring tube. The position of the ``float,'' which varies almost linearly with flow, is determined electromagnetically with the aid of an electronic circuit and is optically recorded on moving sensitized paper. Interchangeable detecting units allow a wide range of flows to be measured. A detecting unit covering the range of 1 ml/min. to 200 ml/min. is described in detail.