DOCTOR FOR A PAPER OR BOARD MACHINE

摘要

The invention relates to a doctor for a paper or board machine, which doctor is disposed in connection with a roll or a cylinder/drum (10) of the paper o r board machine to keep the surface of the roll or the cylinder/drum (10) clea n, which doctor (20) comprises a doctor blade (21) of the doctor to prevent a w eb (W) from wrapping around the roll or the cylinder/drum (10) during a web bre ak and to help the threading of the web (W). A blow-down device (25) is arrange d in connection with the doctor (20) to produce a blow (PA) in order to preven t the web (W) form hitting the doctor (20) and to guide the web (W) past the doctor (20) in a controlled manner.