Method for controlling dust on paper machinery and the like

#The present invention relates to controlling dust and other contaminants on paper machinery or similar apparatus.

#A necessary step in presently known paper making, tissue making and similar machinery is the drying of the moist paper web on a drum, known as a “Yankee dryer.” The heated Yankee dryer rotates constantly, with wet paper web being taken up at one spot on the rotation, and being dried before being scraped off the dryer at another spot in the rotation. After being scraped off the dryer, the web usually passes through a sensor, measuring the moisture and thickness of the web, and then is taken up by a reel drum.

#The paper web is scraped off the Yankee dryer by a blade known as a “creping doctor.” Usually following the creping doctor is a “cleaning doctor,” which removes any stray material that was left after the paper web is scraped off the dryer. Finally, the dryer is sprayed with a coating prior to taking up a new section of paper web.

#FIG. 1 shows a view of a preferred embodiment installed on a paper making machine.

#FIG. 2 shows a front view of the embodiment of FIG. 1.

#FIG. 2a shows a view of an alternative embodiment.

#FIG. 1 shows a view of a preferred embodiment installed on a typical paper machine. “Paper machine” and “paper machinery” are used throughout to designate paper machinery and other similar machinery such as tissue making machinery.

#The Yankee dryer of the paper machine is shown at 2. A creping doctor 3, crepes the tissue web or sheet off the dryer. (“Web” and “sheet” are used interchangeably throughout.) Following the creping doctor 3 is a cleaning doctor 4 as well as sprays 5 used for applying cleaning and coating solutions. The sheet, with its attendant boundary layer dust and moisture, shown generally at a, passes by a number of stations, such as upper foils 7a, 7b and 7c, foil 10, sensor 8, and various other stations on the way to a reel drum shown generally at 9. The air carried along with the sheet, as well as any unbalanced exhaust present above or below the sheet, may cause edge curl and other instability. The foils help in minimizing this instability.

#Near foil 10 is a directional air jet 15, a baffle 20, a hood surface cleaning air nozzle 30, a lower sensor hood 35, and a support 40. Turning now to FIG. 2 these components are seen in greater detail. The web passes below upper foil 7c and above foil 10; its direction of travel is shown by the arrows. Foil 10 directs the boundary layer laden with dust away from the sheet. (“Dust” is used throughout as including dust and other contaminants.)