Involute plate heat exchanger

Claim 1

A HEAT EXCHANGER COMPRISING AN INNER CYLINDRICAL CASING AND AN OUTER ANNULAR CASING, SAID CASINGS HAVING A COMMON AXIS, TWO TOROIDAL MANIFOLDS, ONE OF SAID MANIFOLDS BEING POSITIONED AT EACH END OF SAID OUTER ANNULAR CASING, TOROIDAL HEAT EXCHANGE MEANS COMPRISING AN ANNULAR SERIES OF INVOLUTE PLATES BRIDGING THE SPACE BETWEEN SAID CASINGS AND DEFINING PASSAGES WITH EACH PASSAGE EXTENDING RADIALLY AND OUTWARDLY FROM SAID INNER CASING TO SAID OUTER CASING AND BETWEEN SAID MANIFOLDS, ALTERNATING PASSAGES AS DEFINED BY SAID PLATES CONNECTING SAID MANIFOLDS AND CONDUCTING ONE FLUID, THE REMAINDER OF THE PASSAGES FORMING PATHS PARALLEL TO SAID COMMON AXIS FOR CONDUCTING A SECOND FLUID THERETHROUGH, A CORRUGATED INVOLUTE PLATE IN EACH OF SAID PASSAGES HAVING ITS WIDTH MEASURED IN THE DIRECTION OF THE HEAT EXCHANGER AXIS, EACH CORRUGATED PLATE IN SAID ALTERNATING PASSAGES PROGRESSIVELY INCREASING IN WIDTH FROM SAID INNER CASING TO SAID OUTER CASING AND EACH CORRUGATED PLATE IN THE REMAINING PASSAGES PROGRESSIVELY DECREASING IN WIDTH FROM SAID INNER CASING TO SAID OUTER CASING SO AS TO EFFECT UNIFORMITY OF FLOW RATE OF THE FLUID FLOWING ALONG OPPOSITE SURFACES OF THE CORRUGATED INVOLUTE PLATES.