Heat-exchanger and method for its utilization

Claim 1

In a plate-type heat exchanger comprising a plurality of metal plates (11a, 11b and 12) having a substantially similar contour and being parallel to and spaced apart from each other along a first axis, said exchanger comprising a first closure means (13) coupling said plates to each other along the edge of each plate, said first closure means and said plates delimiting a plurality of passages (14, 15 and 25); at least three consecutive plates defining respectively a first passage (14) for the reception of one portion taken from one of a first fluid in liquid form (4) and a second fluid in gaseous form (5), comprised between a first plate (11a) and a second plate (12), and at least one second passage (15) for receiving another portion taken from the other (4) of said first fluid and said second fluid and for circulating said one portion and said another portion combined together in directions parallel to a second axis extending parallel to said metal plates, comprised between said second plate (12) and a third plate (11b); a transfer zone (60) formed in said second plate (12) for transferring at least part of said one portion from said first passage (14) towards said second passage (15), said zone extending in a direction parallel to a third axis perpendicular to said first and second axes; said first closure means (13) defining respectively a first inlet (16) toward said first passage (14) for introducing said one portion, and at least one second inlet (33) towards said second passage (15), adjacent to one extremity of said second passage, for introducing said another portion, said transfer zone (60) being provided between said first and said second inlets; first distribution means (18, 19) disposed in said first passage (14) for distributing said one portion from said first inlet (16) towards the interior of said first passage (14), over a distance in a direction parallel to said third axis; second distribution means (35, 36) disposed in said second passage (15) for distributing said another portion from the second inlet toward the interior of said second passage, over a distance in a direction parallel to said third axis; said first closure means (13) defining at least one first outlet (34) from said second passage (15) adjacent to the other extremity of said second passage, for evacuating the combined said one portion and said another portion; and means acting in heat exchange relation with at least said second passage (15) for defining a third passage (25) for a third fluid; the improvement comprising a third inlet (17) toward said first passage, defined by said first closure means (13), adjacent to said second inlet (33) and to one extremity of said first passage, for introducing into said first passage (14) a further portion of the fluid (4) from which said another portion is taken, so as to establish a level of said first fluid in liquid form within said first passage; and third distribution means (20, 21) arranged in said first passage for distributing said further portion, from the third inlet (17) toward the interior of said first passage, over a distance in a direction parallel to said third axis, said transfer zone extending also in a direction parallel to said second axis.