Fabrication of heat exchangers

Claim 1

THE METHOD OF MAKING A HOLLOW ARTICLE OF THE CHARACTER DESCRIBED, COMPRISING, (A) FORMING A FIRST OUTER SHEET BY (1) SUPERPOSING A FIRST COMPONENT SHEET UPON A SECOND COMPONENT SHEET, AND (2) INTERPOSING A WELD-INHIBITING MATERIAL BETWEEN SAID FIRST AND SECOND COMPONENT SHEETS IN A PATTERN CORRESPONDING TO A DESIRED SYSTEM OF FLUID PASSAGES, (B) FORMING AT LEAST ONE INNER SHEET WITH A PLUARALITY OF SPACED-APART SECTIONS BY SLITTING SAID INNER SHEET ALONG A PLURALITY OF LINES, (1) SAID LINES BEING SPACED FROM EACH OTHER ACROSS THE WIDTH OF SAID INNER SHEET, (2) SAID LINES EXTENDING ALONG THE LENGTH OF SAID INNER SHEET FOR SUBSTANTIALLY THE FULL EXTENT THEREOF, (3) SAID LINES TERMINATING SUFFICIENTLY SHORT OF AN EDGE OF SAID INNER SHEET TO PROVIDE AN UNSLIT MARGINAL PORTION ALONG THE WIDTH OF SAID INNER SHEET JOINING ONE END OF EACH OF SAID SECTIONS, (C) PARTIALLY COATING SAID SECTIONS WITH WELD-INHIBITING MATERIAL, WITH SAID COATING APPLIED TO EACH OF SAID SECTIONS IN A PATTERN PROVIDING ON EACH SIDE OF SAID SECTION A BAND OF SAID MATERIAL ALONG THE LENGTH OF SAID SECTION AND A BAND FREE OF SAID MATERIAL ALONG THE LENGTH OF SAID SECTION, SAID BANDS OF MATERIAL AT SUCCESSIVELY ALTERNATE LATERAL EDGES DEFINIGN SAID SECTIONS ON ONE SIDE OF SAID SECTION WITH LIKE BANDS ON THE OPPOSITE SIDE THEREOF IN STAGGERED AND OVERLAPPING RELATIONSHIP, (D) SUPERPOSING SAID FIRST OUTER SHEET AND SAID INNER SHEET UPON A SECOND OUTER SHEET, (E) PRESSURE WELDING SAID SUPERPOSED FIRST OUTER SHEET, INNER SHEET, AND SECOND OUTER SHEET TO UNIFY THE PORTIONS THEREOF NOT COATED BY WELD-INHIBITING MATERIAL, (F) SPACING APART SAID FIRST AND SECOND OUTER SHEETS INTO THE DESIRED SPACED RELATIONSHIP, AND (G) EXPANDING SAID FIRST OUTER SHEET TO FORM THE DESIRED SYSTEM OF FLUID PASSAGES, WHEREBY SAID SECTIONS OF SAID INNER SHEET WILL FORM INTEGRAL CROSS-MEMBERS EXTENDING TRANSVERSLY BETWEEN SAID FIRST AND SECOND OUTER SHEETS.

Claim 2

THE METHOD OF MAKING A HOLLOW ARTICLE OF THE CHARACTER DESCRIBED, COMPRISING, (A) FORMING A FIRST OUTER SHEET BY (1) SUPERPOSING A FIRST COMPONENT SHEET UPON A SECOND COMPONENT SHEET, AND (2) INTERPOSING A WELD-INHIBITING MATERIAL BETWEEN SAID FIRST AND SECOND COMPONENT SHEETS IN A PATTERN CORRESPONDING TO A DESIRED SYSTEM OF FLUID PASSAGES, (B) FORMING AT LEAST ONE INNER SHEET WITH A PLUARALITY OF SPACED-APART SECTIONS BY SLITTING SAID INNER SHEET ALONG A PLURALITY OF LINES, (1) SAID LINES BEING SPACED FROM EACH OTHER ACROSS THE WIDTH OF SAID INNER SHEET, (2) SAID LINES EXTENDING ALONG THE LENGTH OF SAID INNER SHEET FOR SUBSTANTIALLY THE FULL EXTENT THEREOF, (3) SAID LINES TERMINATING SUFFICIENTLY SHORT OF AN EDGE OF SAID INNER SHEET TO PROVIDE AN UNSLIT MARGINAL PORTION ALONG THE WIDTH OF SAID INNER SHEET JOINING ONE END OF EACH OF SAID SECTIONS, (C) PARTIALLY COATING SAID SECTIONS WITH WELD-INHIBITING MATERIAL, WITH SAID COATING APPLIED TO EACH OF SAID SECTIONS IN A PATTERN PROVIDING ON EACH SIDE OF SAID SECTION A BAND OF SAID MATERIAL ALONG THE LENGTH OF SAID SECTION AND A BAND FREE OF SAID MATERIAL ALONG THE LENGTH OF SAID SECTION, SAID BANDS OF MATERIAL AT SUCCESSIVELY ALTERNATE LATERAL EDGES DEFINIGN SAID SECTIONS ON ONE SIDE OF SAID SECTION WITH LIKE BANDS ON THE OPPOSITE SIDE THEREOF IN STAGGERED AND OVERLAPPING RELATIONSHIP, (D) SUPERPOSING SAID FIRST OUTER SHEET AND SAID INNER SHEET UPON A SECOND OUTER SHEET, (E) PRESSURE WELDING SAID SUPERPOSED FIRST OUTER SHEET, INNER SHEET, AND SECOND OUTER SHEET TO UNIFY THE PORTIONS THEREOF NOT COATED BY WELD-INHIBITING MATERIAL, (F) SPACING APART SAID FIRST AND SECOND OUTER SHEETS INTO THE DESIRED SPACED RELATIONSHIP, AND (G) EXPANDING SAID FIRST OUTER SHEET TO FORM THE DESIRED SYSTEM OF FLUID PASSAGES, WHEREBY SAID SECTIONS OF SAID INNER SHEET WILL FORM INTEGRAL CROSS-MEMBERS EXTENDING TRANSVERSLY BETWEEN SAID FIRST AND SECOND OUTER SHEETS.