Research On Safety Assessment Method And Monitoring System Of Hoist Braking Quality

Mine hoist undertakes the important task of hoisting coal and gangue, coupled withdrawing material, staffs and equipments, so it occupies an extremely important role in theentire process of coal mine production. Braking system is the final protective measure toprevent major accidents after other protection device is failure. So its work station willdirectly affect the safety running of the hoist, and also it relates to the safety of staff. In orderto reduce and avoid the hoisting and transportation accidents, it is necessary to do hazardidentification and safety assessment on braking system in advance, and then the importantparameters should be monitored.Based on analyzing the main factors affecting the hoist’s failure in detail, this paperestablished the braking failure fault tree of the hoist. During the qualitative analysis of faulttree, the method of Boolean algebra was applied to calculate the Minimum cuts, and then thestructure importance was analyzed on each basic reason event. During the quantitativeanalysis of fault tree, firstly, the method of Delphi was used to obtain the fuzzy occurrenceprobability of basic reason event, and the quantization was completed. And then, aiming at thecharacteristics of these indicators, the fuzzy set theory was adopted, in addition, the triangularfuzzy number was applied to characterize the occurrence probability of the hoist brakingsystem. The fuzzy probability importance analysis of fault tree analysis was adopted toanalyze each basic event, by which the key factors affecting the braking failure of hoist andthe vital parameters need to be monitored can be obtained.According to the monitored important parameters which are got after safety assessmenton analysis of braking failure of the hoist, monitoring system was designed in this paper.The hardware of monitoring system consists of sensor, signal conditioning circuit, dataacquisition card and industrial control. The monitoring analysis software used LabVIEW8.5 to design and develop. The monitoring system realized real-time monitoring on mainparameters such as brake shoe clearance, oil pressure of hydraulic station, temperature of thebrake shoe, the deflection of brake disc, idle motion time and so on. Finally, the experimentalverification was done on software and hardware of the monitoring system, the results showedthat, this system can realize the prospective functions.