Productivity of a double spiral mixer for concentrated feeds

In the diets of farm animals, the main component and the most expensive is concentrated feed. To reduce their cost, feed should be prepared from our own feed base directly on the farms. When preparing a dry concentrated mixture, it is advisable to use spiral mixers that provide high mixing quality, low energy consumption and high productivity. The article presents a spiral mixer, in the body of which there are two concentrically arranged screw spirals along its length. In this case, the inner spiral has the ability, in addition to the rotational movement due to the cam protrusion, to perform axial reciprocating movement. With the simultaneous rotational and reciprocating movement of the spiral with a small diameter inside the spiral of a larger diameter, an additional shift of the layers of feed is provided, which improves mixing of the components into a homogeneous feed mixture, which is discharged from the mixer through the outlet. The results of theoretical studies on the determination of the throughput are presented. The influence of the internal helical spiral on the overall performance of the mixer under development has been theoretically determined. It was found that with an increase in the constructive coefficient, which means the ratio of the diameters of the helical spirals, the mixer performance increases. The range of variation of the constructive coefficient should be in the range of 1,5-2,0. In this case, the diameter of the outer spiral, due to a significant speed gradient, should not be taken more than 0,1 meters. The effect of the movement of the inner spiral on productivity is insignificant. It is re-commended that the height of the protrusion of the beveled base of the cam, which provides the axial displacement of the inner helical spiral, is taken equal to a quarter of the pitch of the inner spiral. At this value, the mixer performance is maximized. The results of theoretical studies can be used to substantiate the parameters of a mixer with two coaxially placed helical spirals along the body.