Lubricating oil treating process

Claim 1

IN A CONTINUOUS COUNTERFLOW PROCESS FOR CONTACTING LUBRICATING OILS WITH SILICA GEL IN A VERTICAL TREATING ZONE INTO WHICH THE SILICA GEL IS INTRODUCED AT THE TOP OF THE ZONE, IS PASSED DOWNWARDLY THROUGH THE ZONE AND IS WITHDRAWN FROM THE BOTTOM OF THE ZONE, THE OIL TOGETHER WITH OTHER LIQUID CONSTITUENTS TO BE CONTACTED BEING INTRODUCED SUBSTANTIALLY AT THE MIDDLE OF THE TREATING ZONE AND BEING REMOVED FROM THE TOP OF THE TREATING ZONE, THE IMPROVEMENT WHICH COMPRISES INTRODUCING A LOW MOLECULAR WEIGHT PARAFFIN HYDROCARBON AT THE BOTTOM OF THE ZONE, AND AT LEAST PARTIALLY WITHDRAWING SAID LOW MOLECULAR WEIGHT PARAFFINIC HYDROCARBON AT A POINT PARTWAY OF THE ZONE BELOW THE POINT OF INTRODUCTION OF THE OIL TOGETHER WITH THE OTHER LIQUID CONSTITUENTS PRESENT IN THE TREATING ZONE, SAID WITHDRAWN PARAFFINIC HYDROCARBON AND LIQUID CONSTITUENTS BEING PASSED TO A DISTILLATION ZONE, RETURNING TO THE BOTTOM OF THE SAID TREATING ZONE THE OVERHEAD OF THE DISTILLATION ZONE AND RETURNING THE BOTTOMS PRODUCT OF THE DISTILLATION ZONE TO THE TREATING ZONE AT A POINT ABOVE THE INTRODUCTION OF THE OIL TO BE TREATED.