Counter-current liquid-solid mass transfer method and apparatus

Claim 1

IN A METHOD WHEREIN A FLUID STARTING MIXTURE TO BE TREATED IS FED FROM AN OUTSIDE SOURCE AS A STREAM TO A COLUMN IN A TREATING SYSTEM, WHICH COLUMN CONTAINS A COMPACT BED OF SOLID PARTICULATE MATERIAL HAVING A PROPERTY OF ABSORBING AT LEAST ONE INGREDIENT OF THE FLUID STARTING MIXTURE IN PREFERENCE TO ANOTHER INGREDIENT OF SAID MIXTURE AND WHICH COLUMN CONSTITUTES A PORTION OF A LOOP THROUGH WHICH THE SOLID PARTICULATE MATERIAL IS CIRCULATED, WHEREIN THE STREAM IS PASSED THROUGH ONE SEGMENT OF THE LOOP IN THE COLUMN CONTAINING AT LEAST A PORTION OF THE BED AND SUBSTANTIALLY WITHDRAWN FROM THE LOOP AT A POINT IN SAID ONE SEGMENT, AND A STRIPPING FLUID IS FED FROM AN OUTSIDE SOURCE TO AND THROUGH A SECOND SEGMENT OF THE LOOP CONTAINING A PORTION OF THE SOLID PARTICULATE MATERIAL FOR STRIPPING SUCH MATERIAL AND IS SUBSTANTIALLY WITHDRAWN FROM THE LOOP AT A POINT IN THE SECOND SEGMENT THEREOF, PASSING SAID FLUIDS TO AND THROUGH SAID RESPECTIVE SEGMENTS OF THE LOOP WHILE THE BED OF SOLID PARTICULATE MATERIAL IN SAID COLUMN IS SUBSTANTIALLY STATIONARY, CHARACTERIZED BY THE IMPROVEMETNS OF PERIODICALLY CONCURRENTLY INTERRUPTING THE FEEDS TO AND