Industrial technique

A heat exchanger comprising an upright pressure vessel, a plurality of tubes extending through the vessel, shroud means surrounding the tubes to form a vapor generating and superheating passage and cooperating with the vessel to form inlet and outlet passages communicating with the vapor generating and superheating passage, means for directing a heating fluid through the tubes, means for introducing and serially directing a feedfluid in through the inlet passage, through the vapor generating and superheating passage in indirect heat exchange relation with the heating fluid, and out through the outlet passage, means for withdrawing a portion of the vaporized feedfluid from the vapor generating and superheating passage for mixing with the feedfluid entering the inlet passage, and wherein the means for introducing feedfluid into the inlet passage includes a plurality of spaced coplanar nozzles discharging into the inlet passage, each of the nozzles comprising horizontally disposed inner and outer tubular members having closed adjacent end faces and cooperating with one another to form an enclosed chamber therebetween, the inner tubular member having outlet means extending along the top thereof for discharging feedfluid into the chamber, and the outer tubular member having outlet means extending along the bottom thereof for discharging feedfluid from the chamber to said inlet passage.