Abstract: In a pump in which dual plunger is reciprocated with cams attached to the rotating shaft of a motor, the delivery pressure of liquid is measured during a certain period in each cycle of the pump. By setting the pressure during the certain period as a standard pressure value, the motor is controlled so that the delivery pressure during the remaining period in each cycle approaches to the standard pressure value. In this pump, rotating-speed-priority control and pressure-priority control are alternatingly performed to decrease pulsation during delivering liquid.

Abstract: A casing structure for chromatograph having a plurality of casings respectively installing at least a separating column, a sample inducing portion and/or a detector portion of the chromatograph and the casings are vertically stacked one on another or horizontally juxtaposed one to another. The casing structure further comprises a passage for installing reagent feed pipes therein, and the passage is respectively provided in respective side portions of the casing for communicating with that of another casing when in the stacked state or in the juxtaposed state, and has an inner hole at an inner side thereof for connecting the reagent feed pipes to a pipe connecting portion arranged in the casings, and the passage has a cover at an outer side thereof for being opened outside of the casing.

Abstract: A liquid chromatography system and a method of utilizing the same, comprising a plurality of separated-component vessels for collecting components eluted in a separation column, a flowing system conduit for component extraction through which the components separated in the separation column are individually delivered to the separated-component vessels. The system further comprises a flowing system conduit for sample introduction through which any of the separated components collected in the plurality of separated-component vessels is selectively drawn from its vessel and introduced to the upstream side of the separation column. The present invention allows a plurality of components in a sample of a mixture to be individual collected, and also allows any of the collected components to be re-separated selectively and automatically.