- (of a steam pump) having the steam pistons connected directly to the pump pistons without a crankshaft or flywheel.
Origin of direct-acting
First recorded in 1855–60
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for direct-acting
Direct-acting compressors are liable to center when doing work at slow speed.
Ricketts later engines had spur wheels; but his last engines were direct-acting.
Fishers carriages were driven by direct-acting engines, one cylinder on each side of the smoke-box.
Each was fitted with a Blake, horizontal, direct-acting, vacuum pump.
It was worked by a pair of direct-acting engines, coupled to the crank shaft.