Method and apparatus for damping a pulsating flow of liquid

Claim 1

IN AN IMPROVEMENT IN A CHROMATOGRAPHIC COLUMN APPARATUS WHICH INCLUDES A LIQUID SUPPLY, CHROMATOGRAPHIC COLUMN, AND A PUMP TO PROVIDE A FLOW OF SAID LIQUID TO SAID COLUMN, SAID COLUMN BEING CHARACTERIZED AS BEING RESISTANT TO LIQUID FLOW THEREIN, SAID PUMP BEING CHARACTERIZED AS PRODUCING SURGES OF PRESSURE IN SAID FLUID FLOW WHEN SAID PUMP ACTS AGAINST THE RESISTANCE TO FLOW OF SAID COLUMN AND A CHAMBER FILLED WITH SAID LIQUID, SAID CHAMBER CONNECTED IN SERIES WITH AND INTERMEDIATE SAID PUMP AND SAID CHROMATOGAPHIC COLUMN, THE IMPROVEMENT WHICH COMPRISES: A SEALED BELLOWS ARRANGEMENT IMMERSED IN SAID LIQUID-FILLED CHAMBER, SAID BELLOWS BEING FILLED WITH A VOLUME OF A SUBSTANTIALLY INCOMPRESSIBLE LIQUID BEING EQUAL TO THE TOTAL VOLUME OF THE BELLOWS AT ITS MECHANICAL COMPRESSION LIMIT, AND A VOLUME OF GAS SUBSTANTIALLY INSOLUBLE IN SAID LIQUID BEING EQUAL TO THE DIFFERENCE BETWEEN THE VOLUMES OF THE BELLOWS AT ITS MECHANICAL COMPRESSION AND EXTENSION LIMITS, SAID GAS BEING AT ABOUT ATMOSPHERIC PRESSURE AT THE EXTENDED LIMIT OF THE BELLOWS.