Method for determining the distance for installing the danger detector of emergency stop system of a belt-type conveyor
According to the analysis of accidents occurred in the operation and maintenance of belt-type conveyors, it is established that the main danger is maintenance personnel near hazardous areas of rotating working bodies such as conveyor drive, tension and end drums or loading and unloading nodes, etc. The damage of the rotating working bodies of the belt-type conveyor can be the following danger: risk of cutting or crushing; risk of being seized; shock hazard; falling from height, etc. To eliminate accidents in the operation and maintenance of belt-type conveyors, to minimize access of maintenance personnel to hazardous areas the system of emergency stop is proposed, providing automatic stop and braking of the working bodies of the belt-type conveyor when a person appears in the hazardous area. Emergency stop system includes the following elements: a danger detector sending a signal about switching the actuator off and switching the brake pipeline on; electrical equipment, which switches off the conveyor drive and switches on a brake by a danger detector signal; the conveyor brake (usually it is a shoe-type brake or some other friction brake). A general feature of an emergency stop system of a belt-type conveyor when the danger detector is triggered is the time comprising two components: maximum time required for stopping the belt-type conveyor and the response time of danger detector. Methodical recommendations for determining the distance for installing the danger detector of emergency stop system of a belt-type conveyor at the design stage are given. They allow installing the danger detector without performing experiments in each case, determining the distance of the danger detector from the hazardous area based on an average response time of its individual elements (danger detector, electrical brake control and brakes of various types) as well as choosing elements of the emergency stop system according to the degree of their influence on the magnitude of the hazardous area.