GB412311A - Improvements in or relating to methods and apparatus for drying materials - Google Patents

Abstract

412,311. Drying systems. SOC. FRANCCOMTOISE DES BOIS SECS, 40, Rue GÚr¶me, Vesoul, Haute-Saone, France. Jan. 18, 1933, Nos. 1729, 1730, and 1731. Convention dates, Jan. 18, 1932, May 23, 1932, and July 23, 1932. [Class 34 (ii).] In the drying of wood or other material the charge is suspended in a weighing apparatus or balance, which is subjected to the action of means maintaining it in equilibrium if the drying proceeds in accordance with a predetermined law. If the drying proceeds too rapidly or too slowly, the apparatus is set in momentary disequilibrium, and operates, e.g., through suitable relays, elements adapted to vary the conditions of drying, e.g., the temperature or hygrometric state of the oven, or the velocity of the gas current, or the speed of the moving support if such be used. In one form, Fig. 23, the charge A in the dryer B is attached through levers to the graduated beam S of a Roman balance. Initial adjustment may be obtained by varying the weight of the counterpoise m, which is suspended from a runner r. This runner moves in accordance with the movements of a fingerpiece r' engaging in a groove formed in a continuously rotated cylinder r<5>, the groove corresponding in form to the predetermined law of desiccation. Movement of the beam from the position of equilibrium is transmitted through a rod u<1> to a pressure relay u which operates the air admission ports c of the dryer. It is preferred to operate the dryer at constant temperature. To prevent too rapid oscillation of the air admission ports, the pressure relay is also controlled by means acting in accordance with a predetermined law expressing the hygrometric state of the atmosphere in the kiln as a function of time. These means may comprise a gasfilled wet thermometer x<2> connected to a dynamometer x<3> acting on a lever x<1> to which a valve u<20> in the pressure relay is attached. The lever pivots on a member x<4> moved by a cam x<5> of profile determined by the hygrometric law. To give rapid restoration of the main balance beam s when it is excessively deflected, a lever attached thereto is caused to uncouple a clutch in the drive of the cylinder r<5>, the coupling being restored with the equilibrium of the beam. In another form, Fig. 1, the weight of the charge is applied to a lever l<1>, and the moving weight r is operated by a cam s<1>. Levers l<1>, s act through levers t<1>, t<2> on a single oscillating element t<3> controlling the pressure relay u. Dynamometers p<1>, p<2> are graduated to indicate theoretical and actual proportions of water in the charge.