Middling stream

Nayak, A.K., Raha, R., Das, A., Das, A.K., 1995. Organochlorine pesticide residues in middle stream of the Ganga river, India. Bull. Environ. Contam. Toxicol. 54, 68-75. 

The separation cell acts like two settlers, one on top of the other. In the lower settler the sand settles down, whereas in the upper settler the bitumen floats. The bulk of the sand in the feed is removed from the bottom of the separation cell as tailings. A large portion of the feed bitumen floats to the surface of the separation cell and is removed as froth. A middlings stream consists mostly of water with some suspended fine minerals and bitumen particles. 

A final application of EO F is the ability to direct and control the stream profile. Besselink et al. have developed a system that is designed to accurately position the middle of three streams in a laminar flow chamber [287]. They proposed that the system can be used for sending the middle fluid to selected parts of a chip, which contains a multi-sample array. The system is designed such that three parallel microchannels feed into the flow chamber (a wider channel). The two outer streams sandwich the middle stream to be analyzed. The guiding action of the two outer streams causes the center stream to flow across the chamber. By increasing the flow of one outer stream and decreasing the flow of the other, the middle stream is pushed to the side, as shown schematically in Fig. 7.25 and pictorially in Fig. 7.26. Control of the middle stream s width is adjusted by the flow rate ratio of the guiding streams and the sample stream [287]. 

Fig. 7.25 Flow guiding illustration. The position of the middle stream is controlled by adjusting the outer two flow streams [287. ...

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