Method of purifying water

Claim 1

THE METHOD OF TREATING WATER CONTAINING CATIONS IN SOLUTION TO REPLACE CATIONS THEREIN WITH OTHER CATIONS, COMPRISING THE CYCLICAL OPERATION OF ALTERNATELY PASSING THE WATER THROUGH A BED OF SOLID WATER-INSOLUBLE CATION EXCHANGE MATERIAL IN ONE DIRECTION, THEREBY SUBSTITUTING A CATION FROM SAID EXCHANGE MATERIAL FOR CATIONS IN THE WATER, AND PASSING A REGENERANT SOLUTION, CONTAINING REGENERANT CATIONS IN A CONCENTRATION OF NO MORE THAN ONE EQUIVALENT PER LITER, IN THE OPPOSITE DIRECTION THROUGH SAID BED IN AN AMOUNT SUFFICIENT TO REGENERATE SAID BED TO LESS THAN ABOUT TWOTHIRDS OF ITS TOTAL ION EXCHANGE CAPACITY, THEREBY TO ESTABLISH A GRADIENT ION EXCHANGE CAPACITY THROUGH SAID BED, THE FLOW THROUGH SAID BED BEING CONTROLLED THROUGHOUT TO MAINTAIN SUBSTANTIALLY THE EXISTING GRADIENT OF ION EXCHANGE CAPACITY.

Claim 2

THE METHOD OF TREATING WATER CONTAINING CATIONS IN SOLUTION TO REPLACE CATIONS THEREIN WITH OTHER CATIONS, COMPRISING THE CYCLICAL OPERATION OF ALTERNATELY PASSING THE WATER THROUGH A BED OF SOLID WATER-INSOLUBLE CATION EXCHANGE MATERIAL IN ONE DIRECTION, THEREBY SUBSTITUTING A CATION FROM SAID EXCHANGE MATERIAL FOR CATIONS IN THE WATER, AND PASSING A REGENERANT SOLUTION, CONTAINING REGENERANT CATIONS IN A CONCENTRATION OF NO MORE THAN ONE EQUIVALENT PER LITER, IN THE OPPOSITE DIRECTION THROUGH SAID BED IN AN AMOUNT SUFFICIENT TO REGENERATE SAID BED TO LESS THAN ABOUT TWOTHIRDS OF ITS TOTAL ION EXCHANGE CAPACITY, THEREBY TO ESTABLISH A GRADIENT ION EXCHANGE CAPACITY THROUGH SAID BED, THE FLOW THROUGH SAID BED BEING CONTROLLED THROUGHOUT TO MAINTAIN SUBSTANTIALLY THE EXISTING GRADIENT OF ION EXCHANGE CAPACITY.