CLASSIFICATION OF PROTECTION DEVICES OF JAW CRUSHERS

Abstract

A method of classification of jaw crushers protection devices was developed, based on the following classification criteria: crushing machine subsystem, recoverability of the protection device after operation and necessary setting parameters. Separation of protection devices by subsystems forms an additional level in hierarchical structure of technological process automated control system. At this level, subsystems monitoring operability of crusher with significant deviance of calculated parameters from their nominal value, i.e. in emergency situation are located. Classification of protective devices based on restorability, that is, by ability to restore their properties after restoring of design parameter value, and on parameters of protective devices of various subsystems is necessary to determine the method of protective devices design. Their specific features are also to be taken into account during their implementation. The following parameters were considered: force acting from the crusher jaw side; pressure that occurs in hydraulic system of protective device exposed to the action of a crusher jaw; the moment developed by a crusher drive; current value in the drive of the crusher - for electrical subsystem protective devices; temperature of the crusher motor; frequency range of current consumed by electric motor. The proposed classification improves accuracy of crusher’s condition diagnosis: in terms of direct evaluation, which is the most rapid, based on changes in electrical subsystem parameters; in terms of indirect evaluation, which is more accurate, based on change in crusher output parameters as a whole, with constant parameters of electrical subsystem. Joint use of direct and indirect evaluation of the crusher state increases accuracy and efficiency of crusher control, increasing accordingly reliability of crusher unit as a whole.