Production of deuterium oxide

Claim 1

A METHOD OF CONCENTRATING A DESIRED ISOTOPIC SPECIES OF AN ELEMENT IN A LIQUID BY CATALYTIC EXCHANGE OF ISOTOPIC SPECIES BETWEEN VAPOR OF SAID LIQUID AND A GAS WHEREIN BOTH SAID LIQUID AND SAID GAS CONTAIN SAID ELEMENT AND BOTH ARE CAPABLE OF CONTAINING SAID DESIRED ISOTOPIC SPECIES AND AT LEAST ONE OTHER ISOTOPIC SPECIES OF SAID ELEMENT, COMPRSING THE STEPS OF PASSING SAID GAS COUNTERCURRENTLY THROUGH SUCCESSIVE BODIES OF SAID LIQUID, CAUSING SAID GAS TO MIX INTIMATELY WITH SAID LIQUID WHEREBY THE GAS LEAVING EACH OF SAID LIQUID BODIES IS ASSOCIATED WITH THE VAPOR OF SAID LIQUID CONTAINING APPROXIMATELY THE SAME CONCENTRATION OF SAID DESIRED ISOTOPE AS IS CONTAINED IN SAID LIQUID BODY, INTERMITTENTLY PASSING SAID GAS AND SAID ASSOCIATED VAPOR OVER CATALYST MASSES TO CAUSE AN EXCHANGE OF ISOTOPIC SPECIES TO TAKE PLACE BETWEEN SAID GAS AND VAPOR, WHEREBY THE CONCENTRATION OF ONE OF SAID ISOTOPIC SPECIES IN SAID GAS IS SUCCESSIVELY INCREASED, AND HEATING THE GAS-VAPOR MIXTURE PASSING TO EACH OF SAID CATALYST MASSES TO AN EXTENT SUFFICIENT TO PREVENT CONDENSATION OF SAID VAPOR ON THE SURFACE OF SAID CATALYST.