Air Shield v. Air Reduction177 U.S.P.Q. (BNA) 247 7th Cir.1973Check Treatment474 F.2d 1351 177 U.S.P.Q. 247 Air Shieldv.Air Reduction 71-1453, 71-1454 UNITED STATES COURT OF APPEALS Seventh Circuit 3/2/73 N.D.Ill., 331 F.Supp. 673 AFFIRMED