Hitachi-high-technologies Corporation

Hiroyuki Wada

Hironori Kaji

Masato Fukuda

Masahito Ito

Kimihiko Ishii

Naoya Yasuhara

Kosaku Toyosaki

The present invention provides a liquid delivery device for liquid chromatographs which, by performing liquid delivery at an accurate flow rate with limited pulsation, gives accurate results of analysis. The present invention, with a view to preventing erroneous operation due to errors in measurements at the time of judgment of completion of compression of liquid, establishes the judgment point before the pressure measured by a cylinder pressure detector agrees with the pressure measured by a discharge pressure detector and also calculates the point of completion of compression. Control in this manner prevents pressure fluctuation. It also calculates for control the point of completion of compression from the history of compression performed previously.

Liquid delivery device, liquid chromatograph, and method for operation of liquid delivery device

An object of the present invention is to improve the accuracy in analysis repeatability of a liquid chromatography apparatus that feeds different eluent by use of a plurality of pumps and achieves the mixture of eluent. Each of the pumps includes means for notifying an automatic sampler and a higher-level control unit that the specified timing of a liquid feeding cycle is reached. A pump whose liquid feeding cycle is the slowest transmits own information so that analysis is synchronized with a liquid feeding cycle. Moreover, a cycle position of a liquid feeding cycle at the end of analysis is expected, and the analysis time is automatically adjusted so that the wait time until the start of the next analysis becomes the shortest.

Liquid chromatography apparatus and liquid chromatography analysis method

Disclosed herein is a stable solvent delivery device capable of delivering solvent both at high pressure and at constant flow rate. A solvent delivery device comprises a plurality of plungers which reciprocate in the respective pump chambers including an eluent charge side pump chamber and an eluent discharge side pump chamber, a motor to reciprocate these plungers, a control unit to control the operation of the motor, valves which are respectively set at the eluent inlet and outlet of the eluent charge side pump chamber, a first sensor to measure the quantity of load received by the plunger in the eluent charge side pump chamber, and a second sensor to measure the pressure of the eluent discharged from the eluent discharge side pump chamber.

Solvent delivery device and analytical system

The present invention provides a liquid delivery device for liquid chromatographs which, by performing liquid delivery at an accurate flow rate with limited pulsation, gives accurate results of analyses. The present invention, with a view to preventing erroneous operation due to errors in measurements at the time of judgment of completion of compression of liquid, establishes the judgment point before the pressure measured by a cylinder pressure detector agrees with the pressure measured by a discharge pressure detector and also calculates the point of completion of compression. Control in this manner prevents pressure fluctuation. It also calculates for control the point of completion of compression from the history of compression performed previously.

Growing community of inventors

Hitachinaka, Japan

Hiroyuki Wada