rotametern.
/ˌrəʊˈtamᵻtə/, U.S. /ˌroʊˈtæmədər/ 1. An apparatus for demonstrating the circular motion of the planets. rare. Now historical.This apparatus was devised by Henry Perigal (1801–98), amateur mathematician, probably in connection with his views on the motion of the moon about the earth as rotation or revolution (see H. Perigal Notes Kinematic Effects Revolution & Rotation (1849), where the term does not occur).
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1878 Nature 19 Dec. 162/2 Mr. H. Perigol [sic], on a kinematic paradox (the rotameter).
1879 Monthly Notices Royal Astron. Soc. 39 548 H. Perigal, Esq. Two Rotameters; an apparatus for showing the effects of double circular motion.
1986 Q. Jrnl. Royal Astron. Soc. 27 214 Items in the RAS apartments, 1985... Perigal's rotameters (2), selenoscope, and lunarium.
2. = rotometer n. 1. Now rare.
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the world > relative properties > measurement > measuring instrument > [noun] > for measuring distances > distance travelled > for measuring on a map or diagram
rotameter1897
rotometer1908
1897 Proc. Philadelphia County Med. Soc. 18 263/2 To express areas of [percussive] dulness the rotameter is very accurate... One can express the weight of the heart in grams by multiplying the length of the periphery of superficial cardiac dulness..by the constant 5.6.
1899 Science 1 Dec. 794/1 The instrument is also provided with a rotameter, which rests on the surface of the cylinder and indicates the linear..distance between records.
1901 F. W. Taylor Art of Cutting Metals (ed. 3) 91 The small wheel..which projects beyond the rim of the rotameter is firmly pressed directly against the surface of the rotating forging.
1946 Ecol. Monogr. 16 416/2 The length of the curved line is then measured with a rotameter reading in mm.
1971 W. N. Alerich Electr. Constr. Wiring xvii. 456/2 The measuring can be done with the aid of a rotameter or an architect's scale.
3. Also with capital initial. A device with a transparent wall that can be fitted into a pipe or tube to indicate the rate of flow of fluid passing along it. Cf. rotometer n. 2.A proprietary name in the United Kingdom.
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the world > matter > liquid > liquid flow > action or process of flowing > [noun] > rate of flow > instrument to regulate or measure rate
module1852
rotameter1911
flow-meter1920
1911 Chem. Abstr. 5 1695 (heading) The rotameter.
1925 Industr. Chem. 1 474/2 In oxy-acetylene welding, if rotameters are inserted in the oxygen and acetylene tubes, it is possible to obtain perfect uniformity.
1949 E. Chain in H. W. Florey et al. Antibiotics II. xvii. 701 From the air-filter the air passed through a rotameter..and a check-valve..into the fermenter through the sparger.
1979 A. L. Lydersen Fluid Flow & Heat Transfer iii. 61 Standard rotameters are delivered for connection to pipes with diameters from 3 to 150 mm.
2009 Chem. Engin. Jrnl. 150 65/1 The flow rate of the liquid was measured by a rotameter.
This entry has been updated (OED Third Edition, November 2010; most recently modified version published online March 2022).
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n.1878