impingern.

1922 Rep. Investigations U.S. Bureau of Mines No. 2392. 3 The analytical procedure necessary when using this new impinger-bubbler apparatus is almost identical with that employed with the Palmer apparatus.

1932 Jrnl. Industr. Hygiene & Toxicol. 14 301/1 The Greenburg-Smith impinger was introduced in 1922.

1936 P. Drinker & T. Hatch Industr. Dust vii. 116 The impinger flasks, stoppers, etc., should be washed..in..the sampling fluid.

1945 K. R. May in Jrnl. Sci. Instrum. 22 188 The method which has been adopted for depositing the sample is direct impaction of the particles on to glass slides which may be coated with a suitable medium... The terms ‘impactor’ and ‘impaction’ were suggested by Prof. J. H. Gaddum to avoid confusion with ‘impinger’ instruments... In ‘impingers’ a fine jet of air is directed at very high speed on to a flat surface to obtain the maximum efficiency of deposition of small particles. In the case of ‘impactors’ jet speeds are lower and larger particles are dealt with.

1972 Blakeslee & Reckner in R. D. Ross Air Pollution & Industry v. 270 Dry impingers are capable of depositing particles in distinct size ranges on surfaces such as microscope slides. Several units are connected in series, each containing an orifice which is aimed at the surface.