4. Different types of operation

The purpose of all these operations is to separate mixtures into their constituent parts. Several methodological divisions can be applied to them, according to :

• on the one hand, the presence or absence of a segmentation of the device into individual cells or stages: in the first case, the device is compartmentalized; in the second case, the device operates with permanent contact (if, of course, two phases circulate in the device);

• secondly, the organization of flows within the device.

It's this last point of view that we're developing now.