Patent GB-190508960-A (GB)
Title: Improvements in the Manufacture of Cellulose from Vegetable Fibres.
Inventor: MATHER WILLIAM
Filed: 1905-04-28
Granted: 1906-07-28
Abstract: 8960. Mather, W. April 28. Nitrocellulose.-Relates to a method and apparatus whereby vegetable fibres, such as flax, straw, or cotton hulls, can be treated in a practically continuous manner for the production of cellulose for gun-cotton &c., without handling or disturbing the material during or between the various stages of the process. This method may be used in connexion with the process for making cellulose described in Specification No 24,542, A.D. 1902, [Abridgment Class Spinning], or with modifications thereof. Suitably broken up and prepared fibre is introduced at the apartment 1, Fig. 1, within a number of chambers a, which are formed of stone or slate and have one or more cells, and is treated successively when in positions c, d, e,f to the action of the various liquids and gases to be used in the production of cellulose. Thus the material may be treated at c with very weak alkali at a suitable temperature, then washed by circulation of water, and drained, and passed on to position d, where it may be treated with chlorine gas, the direction of flow being reversed one or mare times, and, after further washing, it may be treated at position e with alkali solution such as soda-ash and further washing. The product may be treated with bleaching-liquor if desired and the bleached cellulose removed from the chamber in an apartment 10. A final washing may be performed in the chamber, or the material may be so treated in an open fixed tank such as a " potcher." The chambers are mounted on rails b, and turntables j are provided for transferring them from one line of rails to the other. The reagent vessels may be mounted on rails and the chambers fixed. At the top and bottom, the chambers have perforated diaphragms or sieves q, Fig. 4, formed of small pieces of glass, flint, stone, or the like held between perforated states. These retain the material treated but admit of the passage of liquids or gases. Attached to a movable cover k, jointed to the sides y at x, are pipes o<1>, p<1>, and attached to the bottom are pipes o, p. For each operation, the liquid or gas with which the material is treated is forced into the chamber by a pump u, connected to the chamber by a swivel pipe v and by a telescopic joint p<2>, a four-way valve w being provided for the reversal of circulation. The material may be removed from the chambers after treatment through outlets r. To facilitate draining after each washing operation, the pressure in the chamber may be reduced or a current of air may be forced through, separate control being provided for each cell. The treatment with gaseous chlorine is performed under a hood or funnel 4, Fig. 1, lined with cement, brickwork, or other suitable material, and having gas-tight doors 5 which may be raised and lowered by the aid of chains 7 and balance weights 9. In order to avoid excess of gas, a measured quantity is admitted, suitably diluted with air and cooled to prevent too violent action. Rapid circulation is effected by the pump. Excess of chlorine may be circulated until the fibres are sufficiently acted upon. All the free gas should be afterwards pumped out and water passed upwards through the material until the whole is immersed. The chlorine found in the hood, or that left after the action is finished, either as gas or in solution in water, may be absorbed by milk of lime and subsequently used. Chlorination may be effected in two or more compartments arranged in series. Low-strength chlorine is led through the series in turn, and after passing through the last compartment, containing untreated material, will be practically free from chlorine. Stronger chlorine is then passed through with the same result. When the first compartment has been sufficiently chlorinated, water is admitted to drive out the chlorine ; then it is moved out of the series, the second one takes its place, and a compartment containing fresh untreated fibre is attached to the end of the series, and chlorination repeated, the lowstrength chlorine being first used and the strength gradually increased.