Institut Francais Du Pe'trole

Institute Francais Du Petrole

Francois Couillard

Francedillaois Couillard

Dominique A Garnier

Andre Renot

The present invention is a pumping system which mixes liquids with a well-controlled proportioning and flow rate. The pumping system according to the invention comprises a liquid mixing device (MX) placed upstream from a pump (P). The liquids are taken from vessels (RA, RB), cyclically introduced, in a determined proportion, in a mixing chamber (9) through alternate opening of on-off solenoid valves (EVA, EVB). The system is controlled at the input by using a damping means such as bellows (11A, 11B) in antechambers (8A, 8B) in order to avoid the effects of velocity discontinuities at the time of the opening and of the closing of the valves. The delivery of pump (P) is controlled at the input as well as at the discharge end. The system may be used for liquid chromatography plants.

Pumping process and system for mixing liquids

A pumping system in accordance with the invention comprises n (n.gtoreq.1) piston or diaphragm primary pumping modules (P1 to Pn) including each at least one pumping unit, connected by means of unidirectional valves (V11-V1n) respectively to n tanks (R1-Rn) containing fluids, a collecting head (CH) receiving the fluids delivered by the various primary modules, and a secondary piston pumping unit (S) for discharging the mixture of fluids collected in this head with a substantially constant flow rate. The pistons are shifted alternately for example by the translation motion of endless screws (9) driven by motors (12). A control set (17-20) associated with position detectors (AC1-ACn) and pressure detectors (C1 to Cn, Cs) proportion the fluids injected and adjust the phases, the piston strokes and their velocities in order to obtain a substantially constant discharge rate. Each primary module can also comprise a second pumping module also allowing a constant rate to be obtained during the suction phase. The invention has application to liquid chromatography.

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Noyalo, France

Francedillaois Couillard