Tubes, connecting serpentine

An integral part of the system is a Vacu Jet Dryer—a serpentine tube-type evaporator, which is typically 8 to 80 m long with a diameter of 8 to 50 millimeters. The inlet of the evaporator is connected to the feeding system, which supplies the liquid material diluted with a solvent if necessary. In the... 

The curves in Figure 8 clearly demonstrate the relative performance of tubes of different geometry. Although the coiled tube has a high variance, the peak is almost symmetrical, but obviously, the curve from the serpentine form is both better in shape and contributes less variance. Nevertheless, the dispersion is still very large when compared with the dispersion from the small bore column previously discussed. Ipso facto connecting tubes should be made as short as possible whatever their geometric form. 

It is seen that the dispersion varies significantly with flow rate but in a rather complicated way. The dispersion of the serpentine connecting tube is fairly high at low flow rates but is reduced to a relatively small value at high flow rates. This would be expected from the curves shown in Figure 7. The cell on the other hand has relatively small dispersion at low flow rates but increases very significantly at high flow rates which would... 

Another important detector specification is the total detector system dispersion. It is made up of the dispersion in the connecting tube and that in the sensing cell. The dispersion inherent in the detector controls the minimum column radius that can be used and consequently, the solvent consumption. Detector dispersion also indirectly controls the mass sensitivity. Connecting tubes can take various forms straight, coiled or serpentine. Serpentine connecting tubes are recommended, as they provide the... 

Figure 9. Improved mixing performance using a low dispersion serpentine connecting tube. A = 1 pg of Cu without serpentine tube B = 0.5 pg of Cu with a 5-cm length of serpentine tube.

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