Abstract: The invention is, on the one hand, a heat exchanger comprising at least one tube (1) and at least one ribbing made of a heat conducting material folded to a concertina-like shape, where the ribbing has ribs (2), each of them being substantially perpendicular to the axis (10) of the tube (1) and comprising wings (4A, 4B) and a rib base (3) between them, and where the ribs (2) are attached to the tube (1) at their rib base (3). At least one of said wings (4A, 4B) of each ribs (2) comprises patterns interrupting the continuity of the wing material, and/or bent surfaces making an acute angle (.alpha.) to a plane perpendicular to the axis (10) of the tube (1). The patterns may be cutouts (7A, 7B), holes (8), outpressed parts (9) or embossings (17A, 17B).

Abstract: Apparatus for carrying out thermodynamic processes in which a work medium undergoes mutually opposite phase transitions. The apparatus comprises casings consisting of confining plates and spacers therebetween, the casings being arranged in stacked relationship. Each casing encloses a plurality of phase transition compartments in superposed relationship. There are orifices in the confining plates through which pairs of phase transition compartments open directly into one another so as to form a number of work chambers. These are also passages delimited by the spacers in the casings for connecting the work chambers in series and passages delimited by the spacers in the casings for introducing and drawing work medium into and from the phase transition compartments. Finally, there are passages delimited by the spacers in the casings for supplying and abducting heat to and from the work medium.

Abstract: Installation and process for multi-flash evaporation, in particular for the desalinization of sea water, in which the liquid to be evaporated is led through at least one passage channel which is constituted by a series of alternately snail-shell-shaped or volute spaces in which evaporation takes place and buffer spaces acting as a liquid slot or syphon for transporting liquid from a snail-shell-shaped space to the next snail-shell-shaped space.

Abstract: An apparatus for use in transferring heat and mass, having a receptacle for a liquid with a pile lock and a liquid distributor surface onto which the pile lock supplies a film of the liquid. The distributor surface faces downwards and liquid withdrawing means act to withdraw the film of liquid from the surface and carry it to an outlet means. The heat and mass transfer takes place on the liquid withdrawing means.