scavenging, vbl. n.
(ˈskævəndʒɪŋ)
[f. scavenge v. + -ing1.]
1. Street-cleaning; removal of filth; also, the cleaning of a river, etc.
| 1851 Mayhew Lond. Labour II. 208/1 The private scavenging of the metropolitan mews. 1883 Summary 26 July 6/4 He considers..that nothing short of a daily scavenging [of the Regent's Canal] will be satisfactory. |
| transf. 1862 Sat. Rev. XIII. 618/2 He was accustomed to cut a number of sermons out of the volumes in order to carry on his scavenging in his own garret. |
2. a. Removal of combustion products from the cylinders of internal-combustion engines. Also as
ppl. a.| 1894 Work 17 Feb. 73/3 Questions such as late ignitions, scavenging, varying explosive charges [etc.]. 1896 B. Donkin Text-bk. Gas, Oil, & Air Engines (ed. 2) i. xix. 269 The increase in economy obtained with the new (1894) ‘scavenging’ Crossley-Atkinson engine. 1915 Illustr. London News 13 Mar. 340 Scavenging-pump for expelling used gases at the end of each stroke. 1924 Times Trade & Engin. Suppl. 29 Nov. 250/3 As is usual with large Sulzer engines the scavenging air is supplied from electrically driven turbo blowers installed in the engine-room. 1954 E. J. Kates Diesel & High-Compression Gas Engines ii. 24 Instead of rotary blowers, many two-cycle diesels employ what is called crankcase-scavenging. Ibid. 25 The outside atmospheric pressure then pushed open the scavenging valve and permitted a fresh supply of air to enter the crankcase. 1962 J. M. Doherty Diesel Locomotive Practice ii. 25 To obtain efficient scavenging in two-stroke engines, the air is always admitted to the cylinder under pressure. 1975 M. J. Nunney Automotive Engine x. 248 The mean effective pressures developed by a two-stroke engine..depend upon its scavenging efficiency. |
b. Chem. The action of
scavenge v. 4 b.
| 1955 Jrnl. Amer. Chem. Soc. LXXVII. 3245/2 There must be two reactions which produce the dinitrile, one which is subject to scavenging by the mercaptan and one which is not. 1978 Nature 1 June 374/1 Lal et al. have shown that from 12 to 15% of dissolved silicate can be removed from seawater by scavenging during precipitation of finely dispersed ferric hydroxide. |