| 摘要 |
<p>Pump units with reciprocably movable pistons driven by linear electric motors move substantially equal volumes of fluid on each stroke. Two pistons (10,11) can be moved alternately towards and away from each other, or a piston assembly comprising a piston (60;85) is reciprocated in a cylinder (61;82) together with a discharge tube (56;99) extending from the piston into a discharge duct (75;102).</p> |
