Vertical tube evaporators with downward pressure liquid flow

Claim 1

A CONTINUOUS EVAPORATOR COMPRISING AN EVAPORATOR UNIT COMPRISING AN UPPER LIQUID RECEIVING CHAMBER HAVING A HEADER PLATE FORMING THE BOTTOM THEREOF, A PLURALITY OF SMALL DIAMETER VERTICAL TUBES HAVING THEIR UPPER ENDS SECURED TO THE HEADER PLATE AND OPENING INTO THE CHAMBER, THE FULL DIAMETER OF THE TUBES BEING UNOBSTRUCTED THROUGHOUT THEIR FULL LENGTH, A LOWER HEADER PLATE AT THE BOTTOM ENDS OF THE TUBES, A DUCT OF LARGER CAPACITY THAN THE COMBINED CAPACITY OF ALL OF THE TUBES BELOW THE LOWER HEADER PLATE AND FOR WHICH THE LOWER HEADER PLATE CONSTITUTES THE ENTERING END, AN ENCLOSURE ABOUT THE TUBES BETWEEN THE TWO HEADER PLATES FORMING A STEAM CHEST, A SEPARATOR INTO WHICH THE DUCT OPENS WITH MEANS FOR COLLECTING AND RETAINING LIQUID AT THE BOTTOM THEREOF AND HAVING A VAPOR OFFTAKE SPACE ABOVE THE LIQUID LEVEL, THE DUCT OPENING INTO SAID SPACE AT LEAST PARTLY ABOVE THE LIQUID LEVEL WHEREBY LIQUID AND VAPOR MAY FLOW THROUGH THE DUCT INTO THE SEPARATOR UNOBSTRUCTED BY THE LIQUID IN THE SEPARATOR, A PUMP BELOW THE SEPARATOR FOR WITHDRAWING LIQUID THEREFROM, A CONDUIT FOR CARRYING LIQUID FROM THE PUMP TO THE RECEIVING CHAMBER, THE PUMP AND CONDUIT HAVING A CAPACITY ADEQUATE TO KEEP THE LIQUID IN THE RECEIVING CHAMBER AND THE UPPER PORTIONS OF THE VERTICAL TUBES FULL OF LIQUID UNDER PRESSURE DURING OPERATION OF THE EVAPORATOR, MEANS FOR SUPPLYING LIQUID TO BE EVAPORATED TO THE APPARATUS AT A RATE TO KEEP A SUBSTANTIALLY CONSTANT LEVEL OF LIQUID IN THE BOTTOM OF THE SEPARATOR, MEANS FOR WITHDRAWING LIQUID FROM THE APPARATUS AT A RATE LESS THAN THE RATE OF SUPPLY OF LIQUID TO THE APPARATUS, MEANS FOR WITHDRAWING VAPOR FROM THE SEPARATING SPACE AND MAINTAINING IT AT REDUCED PRESSURE IN THE SEPARATOR AND DUCT WHEREBY THE GRAVITY FLOW OF LIQUID THROUGH THE VERTICAL TUBES IS UNIMPEDED IN THE DUCT AND SEPARATOR, THE VAPOR OFFTAKE SPACE OF THE SEPARATOR BEING DEFINED BY A CYLINDRICAL SHELL, AN INCLINED PARTITION ACROSS THE SHELL BELOW THE TOP OF THE SHELL, SAID MEANS FOR WITHDRAWING VAPOR FROM THE SEPARATOR COMPRISING A CONDUIT LEADING FROM THE SPACE IN THE SEPARATOR BELOW SAID PARTITION, A PRELIMINARY EVAPORATOR POSITIONED TO ONE SIDE OF THE CYLINDRICAL SHELL AND HAVING ITS LONGITUDINAL AXIS INCLINED WITH RESPECT TO THE VERTICAL AXIS OF THE SHELL, THE PRELIMINARY EVAPORATOR COMPRISING A PLURALITY OF TUBES OPENING INTO A COMMON CHAMBER AT EACH END OF THE EVAPORATOR, AN ENCLOSURE AROUND THE TUBES BETWEEN THE END CHAMBERS FORMING A STEAM CHEST, SAID CONDUIT FROM THE SEPARATOR OPENING INTO SAID ENCLOSURE WHEREBY THE VAPOR FROM THE SEPARATOR MAY HEAT LIQUID IN THE PRELIMINARY EVAPORATOR AND THE PRELIMINARY EVAPORATOR CONDENSES SAID VAPORS TO MAINTAIN A REDUCED PRESSURE IN THE SEPARATOR, A DUCT LEADING FROM THE CHAMBER AT THE UPPER END OF THE PRELIMINARY EVAPORATOR TANGENTIALLY INTO THE UPPER PART OF THE CYLINDRICAL SHELL ABOVE THE INCLINED PARTITION, A COVER AT THE TOP OF SAID SHELL HAVING A VAPOR OUTLET DUCT IN THE CENTRAL PORTION THEREOF, A DUCT LEADING FROM THE INTERIOR OF THE SHELL AT THE LEVEL ABOVE THE LOWER EDGE OF THE SAID PARTITION THROUGH WHICH LIQUID IS RETURNED FROM THE SPACE ABOVE THE PARTITION TO THE CHAMBER AT THE LOWER END OF THE PRELIMINARY EVAPORATOR, THE LOWER END OF THE PRELIMINARY EVAPORATOR BEING BELOW THE LOWER EDGE OF THE INCLINED PARTITION AND THE UPPER END THEREOF BEING AT A LEVEL ABOVE THE UPPER EDGE OF THE INCLINED PARTITION, THE SPACE WITHIN THE SHELL ABOVE THE INCLINED PARTITION CONSTITUTING A SECOND CYCLONE SEPARATOR, SAID MEANS FOR SUPPLYING LIQUID TO THE FIRST ABOVE-MENTIONED EVAPORATOR INCLUDING A PIPE CONNECTED WITH THE LOWER PORTION OF THE PRELIMINARY SEPARATOR, AND MEANS FOR SUPPLYING ORIGINAL LIQUID TO THE PRELIMINARY EVAPORATOR.