| 释义 |
> as lemmasdouble (or triple) expansion The improvement introduced by Watt's patent of 1782 consisted in the economizing of steam by allowing the piston to be propelled, during the latter portion of its excursion, by the ‘expansion’ of the steam first introduced. An engine in which this is done is said to work ‘by expansion’. A double (or triple) expansion engine is one in which the steam passes from one cylinder into another, so that the expansive force is used twice (or thrice).< |