Determining the Maintainability of Burning Ovens from Cement Factory

Abstract

For any industrial entity put into operation, it is of interest to its ability to fulfil its mission under certain conditions, at a given time or during a given period of time, assuming that the means of maintenance are provided. This represents availability and is a complex form of system / product quality, as it includes both reliability and maintainability. Availability can be increased by: maximum reliability, maintenance, respectively by maximum maintainability, correct use of equipment / machines, renewal, optimization of reliability and maintainability characteristics, but provided that such balancing does not lead to contradictory solutions. The availability of a product will be higher the more reliable it is and requires less maintenance. It should be borne in mind that in order to ensure a certain level of reliability, maintenance costs must not exceed 10...20% of the purchase price of the product each year [1]. Restoration of reliability to a normal level is achieved through corrective or preventive maintenance. In practice, a compromise is sought between the purchase price, the service imposed and the accepted risk, as in order to achieve availability through reliability, very reliable parts must be used, which cost 5-10 times more than usual [2]. Maintenance-based availability results from the consideration that reliability is a probability of trouble-free operation over a period of time. Reliability is technically and financially limited. Defects in the initial period of operation of the product, as well as those in the final period derive from inevitable physical phenomena, and defects in the maturity period have a normal accidental character. In addition, the reliability can deteriorate over time even during storage, thus causing additional damage. Reliability is restored to its normal level through corrective or preventive maintenance, as failures are foreseeable or unpredictable. Product availability is the result of a combination of reliability and maintainability and they support each other. Increasing the maintainability of products leads to increased availability. In this case, the real maintainability of a burning oven of a cement factory was studied, with the aim of finding practical solutions to increase the service life. Achieving the proposed objective required monitoring the operation / failure of such equipment for nine months and statistical processing of the information obtained.