DESIGN AND TEST OF HORIZONTAL RICE MIXER WITH RIBBON STIRRING BLADE

Abstract

This research article aims to design a horizontal rice mixer with ribbon stirring blade, and to test the suitable speed and time for mixing of rice in Thongdee Agricultural Processing Community Enterprise in Ban Mor Subdistrict, Pichai District, Uttaradit Province. The design of the mixer was divided into three main parts including the first part was a mixer tank. The second part was a ribbon stirring blade which was a double helix. The final part was a motor which functioned to transfer energy to rotary shaft of ribbon stirring blade. The main motor operated through a control unit that could set the speed and rotation direction of the mixer. In the mixing test to determine the mixing speed and time for mixing, 200 kg. with red seed coat of White Hom Mali rice and Tum Tim Chum Phae was used at the ratio of 3:1. Then, a test was performed at three inverter frequencies of 15, 20 and 25 Hz (accounted for 21.75, 29 and 36.25 rpm, respectively) by using 5,000 orange beads of 5 mm. diameter as representation of the mixed rice. The results were converted into the coefficient of variation (CV) as a criterion for mixing which took durations of mixing including 300, 180 and 30 seconds, respectively with the coefficient of variation of less than 30%. The data obtained from the experiment was used to create an equation to assess the value that caused the mixing to have the distribution coefficient in the acceptable range (CV≤30%), and it revealed the time of mixing at 277, 165 and 7 seconds, respectively. The results of the rice mixer design and testing to determine the appropriate mixing speed and time could help increase the production capacity of the same labor and it could reduce the use of electricity accordingly.