Improvement of dust collectors for implementation in the food industry

Abstract

This paper presents a study of the processes occurring in apparatus with counter–swirling flows and proposes a mathematical model for calculating the fractional and overall efficiency of the devices. An experimental stand was used to investigate a typical design and an advanced apparatus with counter–swirling flows. For determination of the overall efficiency, the samples were examined on a disperse composition using a scanning electron microscope with a low vacuum camera SEM–106 I and a ribbon with sprayed silver in the vacuum universal post VUP–5M. The disadvantage of the typical design of the improved apparatus with counter–swirling flows (ACSF) is the reduced rotational motion of the primary flow, which slows down the separation process and leads to a decrease in the fractional efficiency of cleaning of medium and small fractions of the dusty product from the air. The inhibitory effect is due to the small input momentum of motion in the primary flow compared to the momentum of motion in the secondary flow. One way to increase the rotational motion of the primary stream may be to double Minput1 , according to the law of conservation of momentum, due to geometric changes in the lower cylindrical part of the apparatus. That is, it is necessary to increase the diameter of the lower part of the ACSF, in order to increase the momentum in the primary flow of the axial swirler. In this case, the ratio of flow rates of air and impulses will be offset and the braking effect will be eliminated. Thanks to the developed mathematical model, it is seen that with increasing the momentum of motion in the primary flow of the axial swirler increases the efficiency of trapping fine particles of sawtooth product in the external and internal layers of the separation chamber of the improved ACSF. This has the effect of improving overall performance overall. After preparing the samples for analysis and examining them on a raster microscope, we obtained images of the dispersed composition of the product, which calculated the number of particles of a certain diameter, and then calculated them in percentage to the total number of particles in one sample, so that we obtained efficiency for each fraction of particles. Namely, the smallest fraction of particles captured was 1.99 microns of advanced ACSF, the typical design of the ACSF is 2.55 microns. Due to the developed mathematical model of the momentum of motion for the primary swirler, an improved design of the ACSF was created.