Protective jacket for assembly about cold fluid-conveying ducts

Claim 1

A TUBULAR JACKET ADAPTED TO BE OPENED INTO A CONTINUOUS LONG GENERALLY FLAT STRIP FOR PACKAGING AND SHIPPING AND TO BE READILY ASSEMBLED ABOUT A DUCT ADAPTED TO CONVEY COLD FLUIDS AND EFFECTIVE IN PREVENTING MOISTURE CONTAINED IN HIGH HUMIDITY AIR FROM CONTACTING SAID DUCT, SAID JACKET COMPRISING A CONTINUOUS SINGLE ONEPIECE THIN-WALLED TUBE OF SUPPLE FLEXIBLE SHEET PLASTIC MATERIAL HAVING POOR HEAT CONDUCTIVITY, SAID JACKET BEING APPRECIABLY LARGER IN DIAMETER THAN THE DUCT FOR WHICH IT IS DESIGNED AND HAVING FLUID-TIGHT RECLOSABLE SEAM-FORMING MEANS OF PLASTIC NONHEAT CONDUCTING MATERIAL EXTENDING FROM END-TO-END THEREOF TO FACILITATE ASSEMBLY OF THE JACKET ABOUT INSTALLED DUCT SYSTEMS, SPACEDAPART PORTIONS OF SAID JACKET PROJECTING RADIALLY INWARDLY AND BEING COOPERABLE WITH THE EXTERIOR OF THE DUCT TO SUPPORT SAID JACKETING CONCENTRICALLY AND SPACED OUTWARDLY AWAY FROM SAID DUCT TO PROVIDE AN ANNULAR DEAD AIR SPACE THEREABOUT FREE OF INSULATING MATERIAL AND EFFECTIVE IN AUGMENTING THE POOR HEAT CONDUCTIVE PROPERTIES OF SAID JACKET FOR THE PURPOSE OF PREVENTING THE COOLING OF THE JACKET BELOW THE DEWPOINT OF AMBIENT AIR SURROUNDING SAID JACKET.