Apparatus for removing impurities from vapors released in evaporation process

Claim 1

APPARATUS FOR RECOVERING VAPORIZABLE FLUORINE COMPOUNDS FROM RAW RELATIVELY WEAK PHOSPHORIC ACID LIQUOR COMPRISING AN EVAPORATOR HAVING AN INLET FOR SAID LIQUOR AND HAVING IN ITS UPPER PORTION AN OUTLET CONDUIT FOR FLUORINE COMPOUND VAPORS AND WATER VAPOR VAPORIZED FROM SAID LIQUOR AND HAVING IN ITS LOWER PORTION AND OUTLET FOR DELIVERING RELATIVELY STRONG PHOSPHORIC ACID LIQUOR RELATIVELY FREE OF FLUORINE COMPOUNDS, A DIRECT CONTACT CONDENSER HAVING A VAPOR INLET IN ITS LOWER PORTION COMMUNICATING WITH THE VAPOR OUTLET CONDUIT OF THE EVAPORATOR FOR RECEIVING SAID VAPORS THEREFROM, A FLASH TANK, CONDUIT MEANS FORMING A CLOSED CIRCUIT INCLUDING SAID DIRECT CONTACT CONDENSER AND FLASH TANK, A PUMP FOR CONTINUOUSLY RECIRCULATING A STREAM OF WATER THROUGH SAID CLOSED CIRCUIT, FLUID REMOVAL MEANS FOR MAINTINING A SUB-ATMOSPHERIC PRESSURE IN SAID FLASH TANK WHILE THE DIRECT CONTACT CONDENSER ESTABLISHED HEAT TRANSFER RELATION BETWEEN THE WATER AND THE VAPORS ENTERING THROUGH SAID VAPOR INLET AND WHILE FLUORINE COMPOUND VAPORS CONDENSE IN THE WATER FLOWING IN THE CLOSED CIRCUIT, AN OUTLET IN THE UPPER PORTION OF THE FLASH TANK FOR DISCHARGING VAPORS NOT CONDENSED THEREIN, MEANS FOR CONTINUOUSLY REMOVING FROM THE CLOSED CIRCUIT INCLUDING THE DIRECT CONTACT CONDENSER AND FLASH TANK A PORTION OF THE WATER CONTAINING SAID FLUORINE COMPOUNDS IN SOLUTION, AND LIQUID INLET MEANS FOR REPLENISHING THE WATER IN SAID CLOSED CIRCUIT.