Letter to the editor.

DEAR MS. BOTTIGLIERI,

My congratulations to you for a lucid exposition. I read with a great deal of pleasure and understanding your article on dryer fabrics ("Pushing performance limits with dryer fabrics," by Jan Bottiglieri, Solutions!, November 2003). I entered the industry as a researcher at the old Albany Felt Company (now Albany International Corp.) in the mid 1960s. At that time, cotton, cotton/synthetic, and cotton/asbestos dryer "felts" (so called then) were fading away because yarns made from nylon and polyester polymers were being developed for use to clothe dryer sections. Your article was interesting for me because of the attention it paid to the air movement associated with dryer fabrics. My associate, F.L.N. Vennos, and I were the first in the industry to measure the air velocities in three dimensions--length-wise, cross-wise, and perpendicular to the fabric--associated with that air flow as the fabric approached the dryer rolls. Our velocity measurements were made at speeds up to about 2,200 fpm (ca. 660 meters per min). The fundamentals still hold. Subsequent to those measurements, Larry Woodside, one of Albany's "marketing icons," suggested the use of grooved dryer rolls in place of plain rolls as a way to reduce the tendency of "air pumping" from one side of the fabric to another and thus reduce the sheet flutter associated with the operation. We measured the difference on the Albany Dryer Pocket Simulator. The differences at that time were not dramatic. I was not surprised to read that the same problems face the papermaker at the higher speeds used today. I could go on, but there is too much history to relate in an e-mail.

My thanks again for an excellent article,