GRADIENTENSYSTEM.

摘要

Gradient systems for liquid chromatographs are provided with (a) a high-pressure pump and a low-pressure pump; (b) a controller for the flow rate of fluid from the high pressure pump; and (c) a reservoir into which liquids are pumped from any of several sources for pumping by the high-pressure pump such that (d) the demand circuit for supplying fluid to the high-pressure pump from the low-pressure pump has a valve system for applying each liquid to the low-pressure pump sequentially from the sources of the liquids for a programmed time and a control circuit for coordinating the valve system, low-pressure pump and high-pressure pump to control the programmed time so as to supply a controlled amount of each liquid to the low pressure pump.