GB939271A - Digester - Google Patents

Abstract

939,271. Continuous treatment digesters. BAUER BROS CO. Nov. 29, 1960 [Nov. 30, 1959], No. 41056/60. Class 64 (1). A continuous treatment digester of the moving conveyer type has means for circulating conditioning fluids relative to the fibrous material through zones in the tube shell, these zones lying beneath the surface 19 of the liquor. The digester includes a tube shell 10, a partition 16 extending longitudinally in the shell, an inlet 13 and an outlet 15 for a fibrous material for treatment, a continuous conveyer consisting of an endless chain 21 with flights 22 arranged longitudinally in the shell taking a path over the ends of the partition 16. The conveyer conducts the fibrous material from the inlet 13 to the outlet 15 in a continuous moving fashion. The central partition 16 presents upper and lower surfaces 34 and 35 respectively which, in width, correspond approximately to the internal diameter of the tube shell 10, facing upper and lower flow or flight paths 17 and 18 respectively. The walls defining such surfaces are held apart by spacers 36. In surface 34 there are formed recesses 37, 38 and 39, and similarly in surface 35, recesses 41 and 42. These recesses serve selectively as inlet and outlet chambers for circulating the liquor or different liquors, and each have individual connections 44 to the exterior of the shell 10. Also, each recess has a rectangular hollow screen 45 which prevents clogging of the connection 44. Consider outlet chamber 38 and inlet chamber 37. Conditioning fluid is drawn from outlet 38 by pump 47 via line 46 and returned to the inlet 37. Unit 49 can be used to change the temperature or chemical concentration or both of the circulating fluids. Similarly, chamber 39 is an inlet and chamber 41 an outlet, and chamber 42 is an outlet with inlet 43 situated in the wall of the tube shell 10. Under certain conditions conditioning fluid may be sprayed into the digester above the surface 19 of the liquor.