Research On Fault Analysis And Monitoring Technology Of Cooling Tower Fan Gearbox

Cooling tower fan is the key technical equipment used in circulation of industrial cooling water in petrochemical industry. A petrochemical company’s cooling tower fan gear reducer appeared premature failure problems continuously which lead to unnormal operation and serious influence on production. Therefore,it is necessary to conduct research on fault reason and fault monitoring technology of cooling tower gear.This article conducted deep research of the causes premature failure from three aspects, including gear failure mechanism, macro and micro fracture of gear and gear strength check. The main causes of cooling tower fan gear failure were found out from gear design, machining process, heat treatment, lubrication etc.. Aming to these reasons, the corresponding improvement measures were put forward.In gear design, the gearmodification coefficient was reselected according to the special running environment and failure types of cooling tower fan gear, in order to improve the comprehensive performance of gear. In gear processing, a variety of gear surface strengthening technology were studied and a new fan gear strengthening technology was made which including carburizing and quenching, low temperature tempering, and ultrasonic shot peening.In the view of cooling tower fan gear elastic fluid lubrication analysis, lubrication state of gear pair in meshing process and the minimum oil film thickness under different working speed were analysed. Thus the best speed range of gear operation process was obtained, the use of reasonable lubricating oil viscosity was recommend, the effective gear lubrication and lubrication management strategy were put forward.Comprehensive research and analysis were carried on traditional gear fault monitoring methods which including torsional vibration analysis, noise analysis, torsional vibration analysis and oil sample analysis. Traditional monitoring methods are generally used in the condition which fault had occurred,which can not monitor gear fault real-time effectively. Therefore,this article put forward the early gear fault monitoring system which based on acoustic emission and gear oil on-line monitoring technology. Acoustic emission monitoring system can detect early gear crack, gear wear and causes of gear premature failure effectively and remind operators of equipment maintenance in order to avoid serious fault. Gear box oil online monitoring system monitor the quality of gear lubrication oil, pollution, etc., which can avoid gear failure timely.The conclusion of this paper is not only suitable for cooling tower fan gear transmission,but also has a certain reference value to other class of gear transmission.