A dish plate heat exchanger comprising: a mounting plate; a plurality of nested dish plates mounted on the mounting plate, the dish plates having inclined, peripheral, overlapping walls, the mounting plate being positioned underneath the plurality of nested dish plates and extending beyond the outer periphery of the walls of the nested dish plates; and a reinforcing element comprising: a generally planar base portion positioned between the mounting plate and the plurality of nested dish plates; a peripheral flange attached to the periphery of at least a portion of the base portion, the flange being in generally parallel, overlapping contact with at least a portion of the inclined peripheral wall of at least one dish plate in the plurality of nested dish plates; and a tongue portion extending outwardly from the base portion, the tongue portion being configured to overlap a high-stress area of the mounting plate extending beyond the outer periphery of the walls of the nested dish plates; wherein the peripheral flange continues from the base portion along the periphery of at least a portion of the tongue portion; wherein the peripheral flange terminates at a pair of end edges along one of the inclined, peripheral walls of the nested dish plates; and wherein after said end edges, said base portion continues without a peripheral flange. a mounting plate; a plurality of nested dish plates mounted on the mounting plate, the dish plates having inclined, peripheral, overlapping walls, the mounting plate being positioned underneath the plurality of nested dish plates and extending beyond the outer periphery of the walls of the nested dish plates; and a reinforcing element comprising: a generally planar base portion positioned between the mounting plate and the plurality of nested dish plates; a peripheral flange attached to the periphery of at least a portion of the base portion, the flange being in generally parallel, overlapping contact with at least a portion of the inclined peripheral wall of at least one dish plate in the plurality of nested dish plates; and a tongue portion extending outwardly from the base portion, the tongue portion being configured to overlap a high-stress area of the mounting plate extending beyond the outer periphery of the walls of the nested dish plates; a generally planar base portion positioned between the mounting plate and the plurality of nested dish plates; a peripheral flange attached to the periphery of at least a portion of the base portion, the flange being in generally parallel, overlapping contact with at least a portion of the inclined peripheral wall of at least one dish plate in the plurality of nested dish plates; and a tongue portion extending outwardly from the base portion, the tongue portion being configured to overlap a high-stress area of the mounting plate extending beyond the outer periphery of the walls of the nested dish plates; wherein the peripheral flange continues from the base portion along the periphery of at least a portion of the tongue portion; wherein the peripheral flange terminates at a pair of end edges along one of the inclined, peripheral walls of the nested dish plates; and wherein after said end edges, said base portion continues without a peripheral flange.