Flexible plate heat exchangers with variable spacing

Claim 1

IN HEAT EXCHANGER CONSTRUCTION, A PAIR OF SPACED FLEXIBLE HEAT EXCHANGER PLATES FORMING A CHANNEL FOR THE PASSAGE OF HEAT EXCHANGE MEDIUM THEREBETWEEN, AND SPACER MEANS SEPARATE FROM THE PLATES MOUNTED IN SAID CHANNEL FOR LIMITING THE FLEXING OF SAID PLATES TOWARD EACH OTHER, SAID SPACER MEANS HAVING AN INTERMEDIATE PORTION LYING WITHIN A PORTION OF SAID CHANNEL INTERMEDIATE A PAIR OF THE BORDERS THEREOF FORMED TO LIMIT FLEXING OF SAID PLATES TOWARD EACH OTHER TO A UNIFORM EXTENT AND SAID SPACER MEANS INCLUDING BORDERING PORTIONS LYING WITHIN PORTIONS OF THE CHANNEL AT THE BORDERS THEREOF FOR LIMITING THE FLEXING OF BORDERING PORTIONS OF SAID PLATE BETWEEN SAID INTERMEDIATE PORTION OF SAID CHANNEL AND SAID PAIR OF BORDERS THEREOF IN VARYING DEGREE, BOTH THE INTERMEDIATE AND BORDERING PORTIONS OF SAID SPACER MEANS BEING FORMED OF THIN METALLIC SHEET MATERIAL AND HAVING A PLURALITY OF OPPOSITELY EXTENDING PROJECTIONS THEREON, THE PROJECTIONS ON THE BORDERING PORTIONS OF THE SPACER MEANS BEING OF VARYING HEIGHT AS MEASURED BETWEEN THE HEAT EXCHANGER PLATES.