Fig. 353 shows this breadthener or expander as im proved by Messrs. Duncan Stewart and Co. It consists of a brass roller made up of segments A B, D E, half tho surfaces of which are plain, as at B and E, and half obliquely corrugated, as at D and A. These segments exe fastened by screws, joints, &c,, to the two rings C C, which are set on the shaft F obliquely, so that they diverge in the direction of the moving cloth. The whole revolves by the friction of the passing piece, and, at the same time, each corrugated segment moves and stretches the cloth from centre to selvage.
Fig. 354 represents the drying machine in general use. It consists of a series of nineteen to twenty-three hollow cylinders, about 2 ft. in diameter, made of tin or copper sheeting, generally driven by bevelled gearing, and properly strengthened by ring-stays in the interior. The axes are hollow, the steam entering by the one, the condensed water escaping by the other. The arrange ment for effecting this latter should be of the most perfect kind, especially in the few front cylinders where the condensation of water is greatest. Fig. 355 represents a most effective yet simple arrangement as devised by H. Adam, of Bonhill. As the cylinder revolves, the condensed water is scooped up by the funnel A ; it at once enters the triangular tube at B, and moves along to the other end C; here it enters the tube D, and is thus conducted into the conical reservoir E, whence its makes it exit by the hollow axis F. The whule of this interior arrangement is made of tin plate soldered together. The cylinders themselves are best made of copper, since experience proves that they dry oonsiderably quicker than t,in ones, owing to the difference in the heat conducting power of the two metals.
In starting the drying machine, it is very necessary to allow the cylinders to revolve for some time before turtling on the steam ; it is well also, when the day's work is ended, to allow them to revolve for some short time after the steam is turned off, in order to discharge tbe condensed water lying in the cylinders, otherwise the latter are very apt to collapse through the formation of a vacuum, caused by the steam being suddenly condensed by the cold water present. Both ends of each cylinder are provided with spring air-valves, opening inwardly, to avoid this as much as possible ; but they must never be entirely relied upon. even when iu perfect order. Another im
portant matter, which it is well to note in connection with the drying cylinders, is that they should ou no account be fed with exhaust steam from the engine, because the fatty matter used in lubricating the engine cylinder finds its way with the steam into the drying cylinders, and, being decomposed by the action of the heat and steam, produces fatty acids which act energetically and corrosively on the internal arrangements : if the cylinders are of tin plate, they will be themselves rapidly destroyed.
As the pieces leave the drying cylinders, they are plaited down by tbe folders. It will be sem from the above description, that from the final washing to the opened-out dried state, the pieces are never touched by hand.
Turkey-red Bleach.—When goods are to be dyed Turkey red, it is not necessary to give them a full madder bleach, because the die is plain, and no white requires to be preserved. The following is a summary of the operations :— 40 cwt. Cloth. Low-press Kier. 8 lb. pressure.
1. Wash (no singeing previously).
2. Boil in water 2 hours, and wash.
3. Ley boils : 1st. 20 gallons caustic soda at 70° Tw., 10 hours boil, and wash.
2nd. 15 4. Sour : sulphuric acid at 2° Tw., steep 2 hours.
5. Wash well, and dry.
The machinery is the same as that already described ; for the souring, large stone cisterns are used ; into these, when filled with pieces, the acid liquor is pumped till the latter are submerged.
Market Bleaching.—"Market bleaching refers to goods wIdeh are bleached, and sold as finished white goods in the market. For these, it is only necessary that the white should please the eye. For heavy cloths, eambrics, shirtings, &c., the processes and machinery may be exactly the same as for the madder-bleach, though the use of resin soap is not necessary, and only soda ash or caustic soda may be employed for the ley boils. Subjoined is a sketch of two processes in use at the present time, each for 12,000 lb. oloth, and employing low-press kiers.
English Process.
1. Lime into kier.
2. Lime boil : 720 lb. lime, boil 12 hours, and wash.
3. Lime sour : hydrochloric acid 2° Tw., steep 2 to 4 hours, wash.