Miller Magazine Issue: 121 January 2020

65 ARTICLE MILLER / JANUARY 2020 duced in industrial sizes [4] and became widespread. Today, around 750 million tons of wheat is produced annually worldwide [1]. Annual wheat production in our country is around 20 million tons and Konya province has a 10% produc- tion share. 2. Sifter machines During the processing of wheat, there are many processing machines of differ- ent capacity and type to conduct clean- ing, destoning, conditioning, husking, grinding, screening and handling. Plansifter is a machine used in flour and semolina factories for the purpose of sorting the wheat, which is grinded in the roller mills, into sizes by sifting. In general, classical sifters consist of two sifting parts and one drive part located in-between these. Thanks to the cen- trifugal force produced by an eccentric mass in the drive part, the machine is enabled to make circular moves on a horizontal plane. Screening section is divided into parts called passage and the grinded product is sorted out from The sieving section is divided into parts called passage, and the product grinded through sieves lined up one over the other in every passage, is sorted by being screened from top to bottom. Examples of modern sieves used today are shown in Figure 2. There are N type and B type types according to sieve frame types, sifters are named according to number of passages and number of frames in a passage. For exam- ple, in a system called 8x24 screen, there are 8 passag- es and sieve structure with maximum 24 frames in each passage. The required number of passage is determined by considering the sieving area calculated according to the type of product to be screened and the capacity of the plant. Sieving area value is taken into account rather than capacity in sieves. As far as the drive modes are concerned, it is seen that the commonly used drive mode is the circular movement of the sieve machine in the horizontal plane by the centrif- ugal force of the mass mounted on a shaft placed vertical- ly in the drive section. However, in today's inventory, there are different alternatives such as the use of timing belts instead of v-belts, placing the electric motor on the top or bottom of the machine. As a general rule, it is known that the machine performs the most efficient screening in the range of 240 - 250 rpm and 60 - 65 mm oscillation circle. Apart from this; rather than the general structure of the machine and the way it works, the factors such as the quality and tightness of the sieve cases in it, optimum cleaning of the sieve pores and the sieve tension are the factors affecting the quality of the sieved flour. 3. Determining dynamic behaviors The dynamic behavior of a sieve is effective in deter- mining both the quality and quantity of the product to be obtained and the tension and energy consumption of the mechanical system. In this respect, in addition to obtaining the desired quality product, minimum tension and energy consumption formation is essential. It must be ensured that the system enters the regula- tion until the start of the sieving process and the product flow begins, and also the tensions that occur during op- eration comply with the limits predicted in the design. In Figure 1. Production of wheat [2] and flour [3] in ancient world