Justification of the impeller speed choice for optimization of the continuous mixing mode in a facility for preparation of liquid feed mixtures

Abstract

BACKGROUND: In the coming years, most of the main livestock production will be produced on farms under their collective lease, as well as on individual farms, which will ensure intensive development of the industry.
 AIMS: The paper is devoted to the study of the liquid feed mixtures preparation under different impeller speeds, under different temperatures of the liquid and with further parameters optimization.
 MATERIALS AND METHODS: The experimental facility for the liquid feed mixtures preparation is a multifunctional technical equipment, capable of performing following 3 functions: dosing of material (the whole milk replacer), liquid supply (the pumping function) and mixture preparation (the mixer function).
 RESULTS: The study of facilities, based on blade pumps, revealed that the rotational speed n in the range of 1750 to 3000 min-1 is not always effective. Then, the indicators of performance or mixture supply are bigger for these values. Thus, the experiment is carried out based on the synchronism of the rotational speeds of the electric motor and the impeller: n = 750, 1000, 1250, 1500 and 1750 min-1. The application of an asynchronous electric motor implies taking account of slip s being 23%.
 CONCLUSIONS: The study of the mixing facility at the continuous mixing mode shows that it is not necessary to take the mixing time into account with given design parameters, as the mixture processing occurs instantly, for a very short time intervals Tc = 0.020.006 s. Experimental studies show that the impeller speed under different temperatures of the liquid affects the degree of the mixture homogeneity, while the number of fixed blades is also considered. Thus, in the continuous mixing mode, the degree of homogeneity Ѳ is 85.2% for a speed n = 9501490 min-1, while the water temperature t is 2024 C.