Heat exchange for a film heat exchanger and a method for manufacturing the same

A heat exchange element comprising a pair of flexible plastic films positioned opposite to each other and bonded to each other selectively to divide the interior space between the films into ducts defined by the bonds, the films having permanent deformations between the bonds produced by stretching of the films so that the element is expandable by pressurizing the interior ducts, the element having stable vertical and horizontal dimensions and the expansion occurring transversally to said stable dimensions.

A method for manufacturing a heat exchange element for a film heat exchanger, wherein an element intended for a heat exchanger which transfers heat from a pressurized vapor being condensed inside the elements to a liquid being evaporated on the exterior surfaces of the elements is formed from oppositely positioned plastic films, which are bonded at selected points one to another in order to divide the interior of the element into ducts,

• wherein in connection with the manufacture, a permanent deformation is produced in the film constituting the heat exchange surfaces of the element, by stretching it in the intervals between its bonding points, in order to provide leeway for bulging during the pressurization of the interior of the element,
• wherein the heat exchange element is formed, by bonding, from two heat exchange films and at least one support film positioned between them, and
• wherein the heat exchange films are plastic films having a thickness within a range of 10-100 μm, and that the support film, thicker than they, is a plastic film having a thickness within a range of 30 μm-1 mm.

A method for manufacturing a heat exchange element for a film heat exchanger, wherein an element intended for a heat exchanger which transfers heat from a pressurized vapor being condensed inside the elements to a liquid being evaporated on the exterior surfaces of the elements is formed from oppositely positioned plastic films, which are bonded at selected points one to another in order to divide the interior of the element into ducts, wherein, in connection with the manufacture, a permanent deformation is produced in the film constituting the heat exchange surfaces of the element, by stretching it in the intervals between its bonding points, in order to provide leeway for bulging during the pressurization of the interior of the element, the element having stable vertical and horizontal outer dimensions at the pressurization and the bulging expansion occurring transversally to said stable dimensions.

A method for the exchange of heat, comprising the steps of:

• (i) providing a heat exchange element by bonding two oppositely positioned flexible plastic films to divide the interior between the films into ducts, and stretching the films at areas between the bonds to produce permanent deformation of the films, and
• (ii) bringing the element into use for heat exchange comprising pressurizing the interior ducts of the element to bulge them, the previous deformation providing leeway for a bulging expansion, the element having stable vertical and horizontal dimensions at the pressurization and the bulging expansion occurring transversally to said stable dimensions.