a air is drawn from the pocket 44 along a slot 49 formed between the l shaped baffle 42 and the leading end 26 of the foil the air is drawn into the first vacuum chamber 40 by a reduced pressure in the first vacuum chamber corresponding to a vacuum of for instance a few inches of water the process of forming tissue paper is a mechanically intense process the wet web is pressed onto the yankee dryer roll thereby bringing the web into intimate contact with the role surface yankee dryer creping aids can be applied to the web in order to control the web 39 s adhesion to the yankee dryer the web adheres tightly to the surface of yankee dryer this adherence is necessary for good creping and heat transfer between the dryer and the web and to holding the web onto the dryer as high velocity air is blown onto the web from an aircap not shown removal of the web from the surface of the yankee dryer involves scraping the web off the surface with a doctor blade the doctor blade not only removes the paper from the surface of the yankee dryer but crepes or compresses the web approximately 3 to 75 percent the creping action breaks some of the fiber bonds in the dried web creating softness and absorbency of the sheet at the same time the creping action results in a certain percentage of the fibers breaking completely free of the web creating a dust problem by drawing air out of the leading edge pocket 44 a large portion of the fibers released by the creping action are.