Heat exchanger plate

Claim 1

A RECTANGULAR PLATE FOR USE AS A PRIMARY HEAT EXCHANGE ELEMENT IN THE CONSTRUCTION OF A HEAT EXCHANGER OF THE STATED TYPE, WITH TWO PARALLEL NARROW FLAT MARGINS AND A ZONE BETWEEN SAID MARGINS COMPRISING CONTINUOUS CORRUGATIONS INTEGRALLY FORMED IN THE PLATE AND HAVING ALTERNATE HALF WAVES PROJECTING ON OPPOSITE SIDES OF THE MEDIAN PLANE OF SAID PLATE, THE CORRUGATIONS EXTENDING PARALLEL TO SAID MARGINS AND TERMINATING SHORT OF EACH END OF THE PLATE OF TWO PARALLEL, OBLIQUE LINES, ONE OF SAID OBLIQUE LINES EXTENDING FROM ADJACENT THE END OF ONE OF SAID FLAT MARGINS TO AN INTERMEDIATE POINT IN THE LENGTH OF THE OTHER SAID MARGINS, AND THE OTHER OF SAID LINES EXTENDING OBLIQUELY FROM ADJACENT THE END OF SAID OTHER MARGIN TO AN INTERMEDIATE POINT IN THE LENGTH OF SAID ONE MARGIN, EACH OF SAID OBLIQUE LINES AND A NARROW, FLAT MARGIN OF THE ADJACENT END OF THE PLATE DEFINING ONE OF TWO INTERGRAL FLAT TRIANGULAR END ZONES OF THE PLATE IN THE PLATE OF SAID NARROW MARGINS, AND TRIANGULAR PORTIONS OF WHOLLY CORRUGATED SHEEL METAL WELDED ON ONE SIDE OF THE PLATE OF THE SURFACE OF EACH END ZONE, THE TOTAL DEPTH OF THE CORRUGATIONS OF SAID TRIANGULAR PORTIONS BEING EQUAL TO THE PROJECTIONS OF THE CORRUGATIONS FROM THE SURFACES OF BOTH SIDES OF THE PLATES.