Heat-Seal System and Method

Abstract

A heat-seal device generally includes a heat source, a thermal conductor, which encapsulates at least a portion of the heat source and is capable of transferring heat from the heat source, and a thermal insulator, which substantially surrounds the thermal conductor but leaves a portion thereof exposed, the exposed portion of the thermal conductor providing a heat-seal contact surface, which is adapted to be brought into sliding contact with a material to be sealed.

What is claimed is: 
     
         1 . A method for sealing together two juxtaposed film plies via a continuous longitudinal seal, comprising:
 a. providing a heat-seal device, comprising
 1) a heat source capable of producing heat, 
 2) a thermal conductor, which encapsulates at least a portion of said heat source and is capable of assuming a temperature that corresponds, at least in part, to the heat produced by said heat source, and 
 3) a thermal insulator, which substantially surrounds said thermal conductor but leaves a portion thereof exposed, said exposed portion of said thermal conductor providing a heat-seal contact surface, which is adapted to be brought into sliding contact with the juxtaposed film plies; 
   b. conveying the juxtaposed film plies in a longitudinal direction against said heat-seal contact surface of said heat-seal device such that said heat-seal contact surface is in sliding contact with said juxtaposed film plies to seal said film plies together in the form of a continuous longitudinal seal;   c. measuring the temperature within said thermal conductor with a temperature-measuring device; and   d. controlling the temperature of said thermal conductor with a controller, which is in operative communication with said heat source and with said temperature-measuring device, said controller
 1) receiving input from said temperature-measuring device, which is indicative of the measured temperature of said thermal conductor, and 
 2) sending output to said heat source, which causes said heat source to produce more heat, less heat, or an unchanged amount of heat, 
   whereby, said thermal conductor is maintained at a temperature that falls within a range of a selected temperature.   
     
     
         2 . The method of  claim 1 , further comprising the step of changing the temperature of said thermal conductor based on a speed change in said conveyance of said film plies. 
     
     
         3 . The method of  claim 1 , further comprising the step of conveying the film plies at varying speeds. 
     
     
         4 . The method of  claim 1 , further comprising the steps of:
 conveying the film plies at varying speeds; and   changing the temperature of said thermal conductor based on changes in said speeds at which the film plies are conveyed.   
     
     
         5 . The method of  claim 1 , wherein said heat-seal contact surface is adapted to provide a desired coefficient of friction between said heat-seal contact surface and said juxtaposed film plies during said formation of said continuous longitudinal seal via said sliding contact. 
     
     
         6 . The method of  claim 1 , wherein said heat-seal contact surface has a surface finish thereon, which reduces abrasion between said heat-seal contact surface and said juxtaposed film plies during said formation of said continuous longitudinal seal via said sliding contact. 
     
     
         7 . The method of  claim 1 , wherein at least a portion of said temperature-measuring device is encapsulated with said heat source in said thermal conductor. 
     
     
         8 . The method of  claim 7 , wherein the encapsulated portion of said temperature-measuring device is positioned between said heat source and said heat-seal contact surface. 
     
     
         9 . The method of  claim 1 , wherein said thermal conductor is selected from the group consisting of high-temperature epoxies, ceramic cements, zircon-based cements, and aluminum-nitride-filled ceramic potting compounds.