797 15 th International Research/Expert Conference ”Trends in the Development of Machinery and Associated Technology” TMT 2011, Prague, Czech Republic, 12-18 September 2011 ANALYSIS OF OPERATION OF PROCESS FANS BY TREATMENT OF SOUND SIGNALS Dr. Sc. Safet Brdarević, Dr. Sc. Mustafa Imamović, Dr. Sc. Sabahudin Jašarević, University of Zenica, Fakultetska 1,72000 Zenica BiH M.Sc. Alić Senad, B.Sc. Mech. Eng. „ARCELOR MITTAL“ Zenica, Zenica ABSTRACT This paper describes technical diagnosing by monitoring of sound signals of el motor operation, impellor and sliding bearings on process fans which have high power and high rotating speed. By this type of monitoring of sound signals, using suitable sensors in the vicinity of el motor, impellor and slide bearings, gives an opportunity to monitor without any contact i.e. consideration of validity of change of sound signals on machine. This type of monitoring enables, in inexpensive and contactless way, consideration of time period when machines operation is correct. It also enables having a computer diagrams related to operation of these machines what provides consideration of possibilities for improvement of maintenance of these facilities. Also, in this way it is possible to provide continuous monitoring of sound signals and their tracking by computer. This approach and analysis of sound signals and conversion into diagrams can provide timely detection of anomalies in operation of such facilities; results can be compared with other types of diagnostics, feasibility of planned shutdowns as well as inspections, detection and maintenance. This type of diagnostics can identify critical events in some parts or complete facility. This is significant from the aspect of safety of employees who operate these facilities and from the aspect of importance of these facilities for production process. Key words: sound signals, el motor, impellor, slide bearings, computer processing of sound signal 1. INTRODUCTION In modern conditions of life, production and use of steel as a strategic metal in all spheres of the economy has, among other materials, the most important role. The steel making process is done by using iron ore, coke, limestone, natural gas and heated air in the metallurgical facilities such as sintering plant, blast furnaces and steel mills. In order to produce sinter in sinter machines, which serves as the main input in the blast furnace, they must have exhausters (fans) of power of 2.5 [MW], n = 1500 [rpm]. They are used for suction, enabling of burning process (sintering) of sinter in sinter machines and for dedusting through electrostatic precipitators. 2. MECHANICAL ANALYSIS OF EXHAUSTERS 4, 5 AND 6 OPERATION Exhauster type 6500 - II - 4 is a centrifugal fan that is designed and manufactured in the Novska factory for producing of machines, VI Lenin, and is designed to suck air through the mixture in sinter machine which is burning, and removal of gases generated in sinter machine in case of dry gas cleaning. Basic exhauster parameters are: - volume of wet gas in relation to the basic conditions 6500 [m³ / min] - capacity of dry gas compared to 0 º C and 1 bar of mercury column 3680 [Nm ³ / min] - increase of pressure/ difference between absolute static final