Through-air apparatus to reduce infiltration of ambient air

A method of operating a through-air apparatus for drying or bonding paper, tissue, or nonwoven webs, the method comprising:

• placing a web on a portion of a web-carrying structure;
• moving the web-carrying structure such that the web moves with the web-carrying structure;
• directing process air through the web-carrying structure, wherein the process air exits into a through-air apparatus exhaust duct;
• providing a first component having at least one sealing element adjacent to the web-carrying structure, wherein the at least one sealing element on the first component is configured to reduce the infiltration of ambient air into the through-air apparatus;
• and
• directing heated air to the at least one sealing element to reduce the infiltration of ambient air into the through-air apparatus, wherein the heated air directed to the sealing element is sourced from a location other than the through-air apparatus exhaust duct.

A through-air apparatus for drying or bonding paper, tissue, or nonwoven webs, the apparatus comprising:

• a) a rotating web-carrying structure comprising a carrying surface having a plurality of openings to permit the passage of air, and a web wrap angle defining angular active and inactive zones of the web-carrying structure and creating active and inactive air flow zones of the through-air apparatus;
• b) a stationary structure which the rotating web-carrying structure rotates relative to, wherein the stationary structure is positioned to cover the inactive zone of the through-air apparatus, the stationary structure comprising one or more sealing elements configured to reduce in-leak of ambient air into the active zone of the through-air apparatus relative to an otherwise identical structure lacking the one or more sealing elements;
• and
• c) one or more channels in the stationary structure, for the delivery of recirculated air, or other heated air stream through the stationary structure, to one or more of the sealing elements thereby further reducing the in-leak of ambient air into the active zone of the through-air apparatus, and wherein the one or more channels in the stationary structure cover the inactive zone to direct air through a portion of the web-carrying structure that does not include a web.