Patent GB-733722-A (GB)
Title: Improvements in or relating to methods of drying cellulose derivatives, alginates orthe like
IPC: C08B11/20
Filed: 1953-03-30
Abstract: <PICT:0733722/IV (a)/1> Cellulose derivatives and other film-forming materials are dried and at the same time brought into a readily soluble form by passing the material along the heated inner surface of a container by means of a rotor with a number of arms or carriers, and during this movement subjecting it to a pressure which urges it against the heated surface so that, by the friction against the surface, the material is rolled together into the form of relatively hard rolls, cylinders or the like.  The process may be applied to water-soluble cellulose derivatives such as carboxymethyl cellulose, methyl cellulose, ethyl hydroxyethyl cellulose or cellulose sulphate. The raw material may be treated with a liquid which dissolves out impurities such as alkali, salts and other products of the etherification reaction, e.g. hot water may be used for methyl or ethyl cellulose and methyl, ethyl or other alcohol may be used for carboxymethyl cellulose or cellulose sulphate.  The moist purified product, which may be in lumps or in fibrous form, may then be subjected to the drying treatment.  The solvent evaporated by contact of the material with the heated surface may be removed by connecting the drying vessel to a vacuum pump.  The process may be carried out in a drying machine consisting of a container with outer wall 1 and inner wall 2, the space 3 between the walls being connected to a steam conduit 4. In the container, a rotor 5 is arranged and provided with carriers 6 so formed that the material to be dried is passed along the wall 2.  A charging opening 7 with cover 8 is provided. The material is charged into the container to such a quantity that upon the movement of the rotor the weight of the material produces a frictional resistance sufficiently great to effect the desired rolling effect.  The evaporated solvent is sucked off by means of a vacuum pump 9 which is connected to a condenser 10, and the condensed solvent is collected in container 11.ALSO:<PICT:0733722/IV (b)/1> Alginates or other film-forming materials are dried and at the same time brought into a readily soluble form by passing the material along the heated inner surface of a container by means of a rotor with a number of arms or carriers, and during this movement subjecting it to a pressure which urges it against the heated surface so that, by the friction against the surface, the material is rolled together into the form of relatively hard rolls, cylinders or the like.  The raw material may be treated with a liquid which dissolves out impurities.  The moist purified product, which may be in lumps or fibrous form, may then be subjected to the drying treatment.  The solvent evaporated by contact of the material with the heated surface may be removed by connecting the container to a vacuum pump.  The process may be carried out in a container with outer wall 1 and inner wall 2, the space 3 between the walls being connected to a steam conduit 4. In the container, a rotor 5 is arranged and is provided with carriers 6 so formed that the material is passed along the wall 2. A charging opening 7 with a cover 8 is provided.  The material to be dried is charged into the container to such a quantity that, upon movement of the rotor, the weight of the material produces a frictional resistance sufficiently great to have the desired rolling effect.  The evaporated solvent is sucked off by means of a vacuum pump 9 which is connected to a condenser 10, and the condensed solvent is collected in container 11.