The paper discusses a decision support system for a butter oil unit of a dairy plant at the National Dairy Research Institute (NDRI). The total plant is divided into many sections like milk marketing section, condensing and drying section, cheese and butter section, quality control section and packaging section. The plant comprises various mechanical systems working in series and parallel configuration. Failure and repair rates are assumed to be constant. The mathematical model of the butter oil unit has been developed using the Markov Birth-Death process. The differential equations have been developed on the basis of probabilistic approach using a transition diagram. These equations are further solved using normalizing conditions in order to develop the steady state availability, which is the measure of performance of a system concerned. The system performance has been further analyzed with the help of decision matrices. These matrices provide various availability levels for different combinations of failures and repair rates for various subsystems. Furthermore, the decision support system has also been developed based on decision matrices of butter oil system of a NDRI plant.

A state-of-the-art commercial dairy plant was established in the year 1996 at the National Dairy Research Institute (NDRI), Karnal. The plant has been designed to handle 60,000 L of milk per day and is presently running in full capacity. The raw milk is received from the institute dairy farm and the model dairy plant. The milk as received from these sections is weighed and evaluated for the fat and Solid Not Fat (SNF) contents. Immediately thereafter, most of the milk quantity received is pasteurized, cooled at refrigeration temperature (4-5 °C) and sent to the storage tank. From this chilled milk, cream is separated using a cream separator and the milk is standardized for various purposes. Butter is obtained by churning the cream continuously in the butter making machine. Two types of butter, i.e., table butter and cooking butter are made in this section. Ghee is made by (Rajiv et al., 2008) cooking butter in the kettle machine which is then clarified in the filtrate machine at a temperature of 105-110 °C. The products made in the plant are tested in the quality control section by different methods. These products are then packed in hygienic conditions in the packaging section by using computerized machines.

The mechanical systems have attracted the attention of several researchers in the area of reliability theory. Dhillon and Natesan (1983) discussed the power system in a fluctuating environment. Dayal and Singh (1992) studied reliability analysis of a system in a fluctuating environment. Gupta et al. (2005) studied the behavior of cement manufacturing plant. Kumar et al. (1988a and 1988b) discussed feeding systems in the sugar industry and paper industry. Kumar and Singh (1989) analyzed the availability of a washing system in the paper industry. Singh et al. (1990) and Kumar et al. (1992) reported reliability analysis of mechanical systems in the fertilizer and sugar industry. Kiureghian and Ditlevson (2007) analyzed the availability, reliability and downtime of system with repairable components. Rajiv et al. (2008) reported the availability analysis of the bleaching system of a paper plant. Kumar et al. (2009) discussed the performance evaluation and availability analysis of ammonia synthesis unit of a fertilizer plant using the probabilistic approach. Tewari et al. (2009) analyzed the performance evaluation and optimization for urea crystallization system in a fertilizer plant using Genetic Algorithm. Khanduja et al. (2009) developed the decision support system and performance model of a digesting system of a paper plant using a probabilistic approach. Deepika et al. (2009) developed the mathematical model of a cattle feed plant using a birth-death Markov process. The differential equations have been solved for the steady state. The system performance has also been studied.

Science and Technology Journal, Decision Support System, Butter Oil System, Differential Equations, Markov Process, Bleaching System, Mechanical Systems, Pumping Systems, Churn Machine, Plant Management, Decision Model, Mathematical Modeling, Agitator Machine Subsystem.