Rheodyne, LLC

Beckman Instruments, Inc.

Kristine Olsen

Nelson H Cooke

John Harris

Brian Hauck

A single selection valve allows the selection of three or more alternate flow routes without any unswept volume along any of the routes. The selection valve has a rotor (22) that can pivot about an axis (30) on a stator (12), the stator having ports (1-8) generally lying on a port circle (54) that is centered on the axis and the rotor having channels (60, 62) on its front face that faces the rear of the stator. Each rotor channel has a radial groove (70) with a port end (72) lying on the port circle, and each channel has an arc groove (74) that connects to the radial groove and that extends substantially circumferentially along an arc circle (76) that is centered on the axis, but that has a smaller radius than the radius of the port circle. The stator rear face has stator channels (90, 92), with each stator channel having a radial stator groove (94) with a port end (102) connected to one of the ports, and with a stator arc groove (96) that connects to the stator radial groove and that extends substantially circumferentially along the arc circle. Each stator arc groove and each rotor arc groove has a free end (80, 100), and the arc grooves extend sufficiently so their free ends overlap at every rotor position where fluid passes through the channels, to avoid any unswept volume.

Multi-route full sweep selection valve

A sample injector is provided, which enables changing of the volume of the sample chamber between a very small volume and larger volumes. The injector includes a housing, a stator (16, FIG. 3) mounted in the housing, and a rotor(26) pivotally mounted in the housing, with the stator and rotor having facewise adjacent faces extending perpendicular to the pivot axis. First and second stators are alternately mountable in the housing, with the first stator having a disc element (44, FIG. 3) that includes a storage channel (62) in one of its faces to form an internal storage chamber of small volume. The other, alternate stator has at least one disc element (44X, FIG. 5) that includes a pair of through passages (52X, 56X) therein that are constructed to connect to sample ports (52, 56) of a disc element that hold the opposite ends of an external sample loop (90) to enable the injector to be used with a larger storage volume.

Internal-external sample injector

A liquid chromatographic analytical column includes an end cap that is abutted with an end edge of a holder body when the analytical column is fully inserted into a bore in the holder body. An end cap mounted to a precolumn is compressed between the end cap of the analytical column and an end nut connected to a holder union. The holder union has a central passage that admits the precolumn therethrough and a stop that engages a ferrule placed around the precolumn to compress the ferrule against the analytical column end cap to form a seal.

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Richmond, CA, United States of America

Kristine Olsen