| abstract |
Process for continuously transferring heat to a moving band of solid material, for example, a textile, a film, particles, or any shaped or unshaped article, the band preferably comprising a disperse dyeable synthetic polymer, for example, a polyester or polyamide, said process comprising passing the band through a substantially enclosed purging-drying region containing the superheated condensable vapor of a liquid having an atmospheric pressure boiling point of less than 120 DEG C., thence immediately thereafter through a substantially enclosed, heat-transfer region containing the superheated condensable vapor of a fluorocarbon having a fluorine to carbon atom ratio of at least 1.5, a solubility parameter of not more than 6.5 and a molecular weight of at least about 300, the pressure in the heat transfer region being no greater than that in the purging-drying region, thence immediately thereafter through a substantially enclosed purging region containing dry steam, the pressure in the purging region being no less than that in the heat-transfer region, and thereafter recovering the band of material, said process characterized by efficient heat transfer resulting from rapid convective movement of superheated fluorocarbon in the heat-transfer region and by minimum loss of such vapor to the atmosphere. |