3.RESULTS
3.1. optimum. belt. Width in terms of engineering-economics
Figure. 2 shows the relationship between the total cost of the conveyor and the belt width. The vertical axis shows the conveyor total cost (baht), while the horizontal axis shows the belt width (mm). The conveyor capacity shown in the Fig.2. is 50-500 ton h^-1. Figure 2a-2b show the calculation for the conveyor with the inclination angle of 0*, whose length is 10 and 100 m respectively, while Fig. 2c-2d show the calculation for the conveyor whith the inclination of 20*
It was found from Fig. 2a-2b that for every belt width and every conveyor inclination angle, with the conveyor capacity of 50 ton h^-1, the belt width contributing to the lowest total cost of the conveyor was 400 mm. It was also found that when the belt width increased,the total cost of the conveyor increased. When the conveyor capacity was higher than 50 ton h^-1 the belt width contributing to the lowest total cost was 500mm. The total cost of conveyor tented to decrease when the belt width was increase from 400 to 500 mm,while the total cost tented to increase when the belt width was larger than 500 mm. This cost characteristics could be found for every conveyor length and inclination angle of 50 ton h^-1 conveyor