Pump, pump for liquid chromatography, and liquid chromatography apparatus

摘要

The invention provides a pump for liquid chromatography excellent in feeding liquid stably at an extremely low flow rate and in discharging bubbles at startup. In a pump for liquid chromatography including a cylinder and a plunger that reciprocates in the cylinder to suck and discharge fluid, the pump further includes a large-flow-rate pump that feeds liquid by the plunger, a small-flow-rate pump that feeds the liquid by the plunger, motion conversion means that converts the rotational motion of a motor to a reciprocating motion, an actuator that directly drives the plunger, and a drive part that drives the actuator, and selectively switches means for driving the plunger.