Patent ID: 6886576

Claim:
A flow system with controlled flow of a particle-containing liquid, the flow system comprising: (a) a channel for leading a flow of the particle-containing liquid ( 1 ) to be controlled; (b) a carrier-liquid enveloping means for enveloping the flow of particle-containing liquid in a carrier liquid ( 2 ) in the channel so that the particles are hydrodynamically focussed in the flow of particle-containing liquid to flow in an individual manner; (c) an observation area ( 4 ) in the channel; (d) a measuring equipment for providing a measurement signal of the flow of particle-containing liquid in the observation area; and (e) a branching point ( 7 ) for dividing the flow of particle-containing liquid into two or more outlets ( 8 , 9 ) in response to the measurement signal; the system further comprising: (f) a merging point ( 30 ), or merging area ( 31 ) for introducing a control liquid into the channel from at least one control channel ( 5 , 6 ), and (g) at least one electro-kinetic pump ( 11 , 12 , 13 ) for controlling the amount of said control liquid from said at least one control channel; said control of the amount of control liquid being controlled by controlling the pump effect of said at least one electro-kinetic pump in response to the measurement signal.