Je pense plutôt à un dispositif racleur qui élimine les écorces o
de manière à éviter le colmatage du rotor

"A debarking apparatus including a closed bottom formed into a channel. A plunger is slidable in the channel and pushes bark material along the channel and out an open end of the channel. The plunger has a top surface that closes the channel as it moves through the debarking station. The bark deposited on the surface is wiped off and into the channel upon withdrawal. Preferably a shearing blade provided on the leading upper edge of the plunger shears material that protrudes above the channel opening."
http://www.freepatentsonline.com/4729415.html

"quatre outils racleurs. Les premiers inci-. sent l'écorce, les seconds ...... ge, ainsi que celui des dosses en scierie,. élimine le problème de la ..."
http://www.inrs.fr/inrs-pub/inrs01.nsf/inrs01_pc_view/1CBBEF...$File/nd2193.pdf