Process for regulating at least one fluid flow circulating in a simulated moving bed chromatographic separation loop

A process for regulating at least one flow rate of at least one fluid or effluent circulating in a simulated moving bed chromatographic adsorption unit containing an adsorbent and comprising at least three chromatographic zones, each of these zones being constituted by at least one column or column section, at least one point between two zones for injection of a feed to be fractionated, at least one point between two zones for injection of eluent, at least one extract extraction point between each eluent injection point and the feed injection point located downstream in the direction of circulation of the eluent and at least one raffinate extraction point between each point for injecting the mixture and the eluent injection point located downstream in the direction of circulation of the eluent, the ensemble of the columns or sections forming at least one closed loop containing at least one device for introducing an anisotropy of properties, the injection and extraction points of at least one column or section being shifted over time in the same direction, the process wherein each time that an injection point or an extraction point passes from one part to another of said device, a control device which controls a means for regulating the flow rate under consideration, which regulation is about a set value, is caused to stop temporarily, and substantially simultaneously said regulating means is caused to place itself in a position allowing it to approach the desired flow rate and to start to regulate said flow rate at the desired set value.