Contact problem at mill semi finished items with the account of the thermal emission and forces in knife grinding machines

Abstract

Knife grinding machines – the basic process equipment for mill fibrous materials in a pulp and paper industry. In article the forces arising knife gap a backlash at mill chip and fibrous weight of high concentration are investigated. It is centrifugal force, force of friction of a semi finished item about grinding disks, force of pressure steam and axial force. Steam can promote promotion or, on the contrary, braking of movement of a semi finished item in knife gap a backlash. The contact task is considered and solved in view of a thermal emission in a zone mill. Formulas for definition of contact temperatures in a zone mill are received. Settlement values of temperature prove to be true experimental researches. The maximal temperature in a zone of contact is observed in a zone 0.50-0.70 radiuses sets. This zone coincides with a zone of the maximal pressure in which there is a zone of zero speed steam. Current steam is investigated in the field of contact of a rotor and stator. Conditions of movement pair from a zone of zero speed steam to periphery and to the center of grinding disks are revealed. Movement pair to the center of grinding disks is undesirable. Thus productivity of a mill decreases and hydrodynamic impacts grow by elements of a design of a mill. Such mode of movement steam depends on technological and regime factors mill and quite often arises at mill chips in manufactures of a thermomechanical and chemical-thermomechanical wood pulp. The steam is recommended to delete directly from a zone of zero speed.