Fig. 8.
Donkin's "Devil."—For removing the dust and dirt from coarse and very dirty rags, oakum, rope, etc., the presence of which would seriously injure the quality of the paper, a still more powerful machine has been introduced, called the "devil," which is constructed on the same principle as the willow, but revolves at a lower speed. The revolving axle of this machine is conical, and is provided with teeth, arranged in a spiral form. The case in which it rotates is fed continuously, instead of intermittently; and although it facilitates the subsequent treatment of the fibre, it is said to be wasteful, while also consuming a considerable amount of power. A machine, or "devil," for cleaning rags or half stuff is manufactured by Messrs. Donkin and Co., a representation of which is shown in Fig. 8.
[CHAPTER IV.]
TREATMENT OF RAGS (continued).
Boiling Rags.—Bertrams' Rag Boiler.—Donkin's Rag Boiler.—Washing and Breaking.—Bertrams' Rag Engine.—Bentley and Jackson's Rag Engine.—Draining.—Torrance's Drainer.
Boiling Rags.—To remove greasy matters, and also to dissolve out the cementing substances from the stems of flax and shell of the cotton, the rags are next boiled in a solution of caustic soda, caustic lime, or a mixture of carbonate of soda and lime. The boiling has also the effect of loosening the dirt contained in the rags, whereby the colour of the material is greatly improved, while at the same time it is rendered more susceptible to the action of the bleaching agent. Strong linen rags will sometimes lose from one-third to one-fifth of their weight by the process of boiling. The vessels for boiling rags are of various construction, and have been the subject of numerous ingenious patents. These boilers are either cylindrical or spherical, and are also stationary or rotary—the latter form being devised for the purpose of keeping the caustic alkali solution freely diffused throughout the mass of fibre during the boiling.
