Multivalving sample injection system

Abstract

A sample inject valve system is described, which enables a modified sample injection valve to perform many functions that are required to inject a sample into a chromatographic column, to minimize the amount of laboratory table space previously occupied by equipment and to organize and minimize the number of tubular fluid connections. The modified valve includes a stator (70) with twelve passages (1-12) lying on a circle (74) centered on a rotor axis (76) and a rotor (72) with four channels (A, B, C, D) for connecting selected passages. The stator passages are spaced 30.degree. apart to lie at the twelve positions of a clock face. Each rotor channel has channel ends spaced by 30.degree. and with the ends of different but adjacent channels spaced apart by 60.degree.. Not only are the usual column (17), pump (44), sample loop ends, and metering syringe (42) connected to stator passages, but a rinse syringe (52), rinse reservoir (60), waste syringe (62), and rinse nozzle (56) are connected to other stator passages. The rotor has a radially-extending channel part (90) with its outer end lying halfway between first and second channels (A, B) and with its inner end lying at the rotor axis and connected to a stator passage part (100) that extends along the axis, to couple the pump to a third passage at all rotor positions.