Tubulous vapour generators

Claim 1

IN A FLUID HEAT EXCHANGE INSTALLATION, A VERTICALLY EXTENDING PRESSURE VESSEL, A HEATING FLUID INLET AND A HEATING FLUID OUTLET IN THE WALL OF THE PRESSURE VESSEL, MEANS WITHIN THE PRESSURE VESSEL DEFINING A PASSAGE FOR THE VERTICAL FLOW THEREIN OF HEATING FLUID PASSING FROM THE SAID INLET TO THE SAID OUTLET, A PLURALITY OF SIMILAR VAPOUR GENERATING UNITS DISPOSED SIDE BY SIDE WITHIN THE SAID PASSAGE FOR THE FLOW OF HEATING FLUID IN PARALLEL FLOW THEREOVER, EACH VAPOUR GENERATING UNIT COMPRISING A VERTICAL VAPOUR GENERATING TUBE EXTENDING ON THE AXIS OF THE UNIT, AN ANNULAR ROW OF SIX VAPOUR GENERATING TUBES EQUALLY SPACED FROM SAID AXIS AND DISTRIBUTED EQUIANGULARLY THEREAROUND, AN UPPER OUTLET HEADER AND A LOWER INLET HEADER EACH FORMED BY A HEMISPHERICAL PART AND A DISHED PART COMPRISING A PLATE CONVEX AS SEEN FROM THE EXTERIOR OF THE HEADER AND WELDED AT ITS EDGE TO THE EDGE OF THE HEMISPHERICAL PART AND FORMED WITH A CENTRAL APERTURE FOR THE AXIALLY EXTENDING TUBE OF THE UNIT AND AN ANNULAR ROW OF SIX APERTURES FOR THE OTHER SIX VAPOUR GENERATING TUBES OF THE UNIT, THE VAPOUR GENERATING TUBES OF THE UNIT CONNECTING AT THEIR ENDS NORMALLY WITH THE DISHED PARTS AT THE RESPECTIVE TUBE APERTURES THEREIN AND THE SIX TUBES OF THE ANNULAR ROW EXTENDING VERTICALLY OVER THEIR LENGTHS APART FROM THE END LENGTHS THEREOF, A STRAIGHT LIQUID SUPPLY TUBE EXTENDING THROUGH THE OUTLET HEADER AND EXTENDING WITH ANNULAR CLEARANCE THEREAROUND THROUGH THE LENGTH OF THE AXIALLY EXTENDING TUBE OF THE UNIT AND HAVING A FREE LOWER END AND DEBOUCHING WITHIN THE INLET HEADER, MEANS FOR SUPPORTING THE PLURALITY OF VAPOUR GENERATING UNITS THROUGH THE RESPECTIVE OUTLET HEADERS THEREOF, LIQUID INLET CONNECTIONS LEADING THROUGH THE WALL OF THE PRESSURE VESSEL TO THE LIQUID SUPPLY TUBES OF THE RESPECTIVE VAPOUR GENERATING UNITS, AND VAPOUR AND LIQUID OUTLET CONNECTIONS LEADING THROUGH THE WALL OF THE PRESSURE VESSEL FROM THE UPPER OUTLET HEADERS OF THE RESPECTIVE VAPOUR GENERATING UNITS.