Column types Stedman

Fig. 257). They have also been studied extensively by Westhaver [26], Donnell and Kennedy [27] and recently by Jantzen and Wieckhorst [28], who compared them with columns containing Stedman packing and wire spirals. As shown by Fig. 255, tlie concentric-tube column is superior to the last-named types at loads below KX) ml/h. The loss in pressure in a concentric-tube column can be calculated [21] by...

The Stedman-type column is shown in Fig. 11, 56, 25. The characteristic features are (i) the use of a fine stainless steel wire cloth formed into conical discs, and (ii) an accurately fitting Pyrex glass jacket, produced by shrinking Pyrex glass on mandrels to the required inside dimensions. Modifications incorporating a silvered vacuum jacket and an electrically-heated jacket are marketed. This column is said to possess high efficiency but is expensive. It is generally employed in conjunction with a total-condensation variable take-off still head. 

Stedman Packing Available in metal only, usually used in batch and continuous distillation in small diameter columns not exceeding 24-inches dia. High fractionation ability per unit height, best suited for laboratory work. Conical and triangular types available. Not much industrial data available. 

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