The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 16, 2007
Filed:
Mar. 17, 2003
Kiyotoshi Mori, Hitachinaka, JP;
Kenichiro Takahashi, Naka-gun, JP;
Masanori Takaki, Hitachinaka, JP;
Masato Fukuda, Mito, JP;
Masahito Ito, Hitachinaka, JP;
Hironori Kaji, Hitachinaka, JP;
Kiyotoshi Mori, Hitachinaka, JP;
Kenichiro Takahashi, Naka-gun, JP;
Masanori Takaki, Hitachinaka, JP;
Masato Fukuda, Mito, JP;
Masahito Ito, Hitachinaka, JP;
Hironori Kaji, Hitachinaka, JP;
Hitachi High-Technologies Corporation, Tokyo, JP;
Hitachi Science Systems, Ltd., Hitachinaka, unknown;
Abstract
A gradient liquid feed pump system capable of liquid feed in a correct mixing ratio even in the case of liquid feed in which the mixing ratio varies. Specifically, it comprises a first plunger pump for sucking and delivering an eluate, a second the first and second plunger pumps through a cam, a first pressure sensor for measuring the pressure in the flow path of the second plunger pump, a second pressure sensor for measuring the pressure in the fist plunger pump, a cam position detecting sensor for detecting the cam position, wherein when the cam position is in a delivery interval, the rotary speed of the motor is increased, and the period for decreasing the rotary speed is determined on the basis of the difference between the pressure values obtained from the first and second pressure sensors, respectively. Thereby, liquid feed can be smoothly effected with correct mixing ratio while avoiding pressure interference between pumps.