Horizontal Cylinder Still: the Riveted Fire Still (Bell, 1923)

Make it about three times as long as it is wide. Batch stills take overhead about 1.5 gallons per hour per square foot of evaporating surface (two-thirds of diameter x length); continuous ones about 2.5. Give the vapour outlet at least 0.17 sq in per gallon of distillate per hour, placed half to two-thirds of the way from the fire end.

Use fire-box or still-bottom steel 1/2 in thick for the bottom (5/8 in for stills run down to coke; more is not worth it). Up to 10 ft diameter, 3/8 in flange steel does for the sides and top; larger stills, 1/2 in throughout. Up to 30 ft long: bottom of two plates, sides of three, top of narrow barrel plates; longer: three, four and barrel plates 5 to 6 ft wide. Keep the caulking edges of the bottom plates away from the fire. Dish the heads to a radius equal to the diameter, in one piece up to 10 ft, otherwise seamed on the horizontal diameter, as thick as the shell or 1/16 in thicker.

Double-rivet all seams except at flanges and openings, with 3/4 in rivets even in the bottom, so holes can later be reamed to 7/8 or 1 in for repairs. Bevel and caulk the plates inside and out.

Fit (Fig. 15) a 24 in manhole in the front head, 18 in manholes on top, a 12 in vapour outlet, a 2 in steam line, a tar plug and a 4 in bottom outlet; caulk steel details to the shell and give cast-iron ones a caulking pad. Rivet lugs on the sides.

Hang the still on lugs from columns on concrete piers, lugs no more than 7 ft apart, so it is independent of the brickwork (Fig. 21). Set it at least 7 to 8 ft above the grates or burners, or better, put the fire box in a Dutch oven in front, for clean combustion. Batch stills expose about a third of the circumference to the fire; for continuous running raise the lugs 12 in above the centre line with a stiff tie between them and fire the full half circumference.