FIELD: instrumentation engineering; measurement of flow rates of liquids, gases or vapors; power engineering; transport; oil, petrochemical, chemical, food-processing and medical industries. SUBSTANCE: flow sensor has body, jet-directing apparatus, sensitive element made in form of magnet or electromagnet located concentrically relative to body and axially magnetized; said magnet (or electromagnet) is engageable with ring-shaped body of revolution which is also magnetized axially and is located in body for rolling over surface of magnet which is brought in contact with it by unlike poles; signal pick- off unit has magnet or electromagnet which is located inside ring-shaped body of revolution and is engageable with its inner surface; outer surface of ring-shaped body of revolution forms gap with inner surface of body. EFFECT: enhanced reliability of measurements and extended field of application. 5 cl, 4 dwg
