Technical and Economic Substantiation of the Effectiveness of the Use Of Screw Mixers

Screw transport and technological mechanisms have gained the greatest use as conveyors and mixers of materials. This combination of processes allows for the use of one mechanism instead of two. However, the intensity of mixing in such tools is not always high. Therefore, often, in order to obtain the required quality, a significant number of shoveling of the mixture is required, which requires either an increase in the length of the technical means, or ensuring the cyclical operation of it. Therefore, the purpose of the work is to carry out a technical and economic substantiation of the feasibility of using screw conveyors-mixers with rotating casings. An important task of their research was to find ways to ensure the quality of mixing of loose components due to the development and modernization of original designs of screw conveyors-mixers. In order to ensure significant productivity of the transport and technological process of transportation and the quality of mixing of loose materials, the design of a screw conveyor-mixer with a rotating casing was developed, patented and researched. In the existing designs of screw mixers, high quality mixing can be obtained either due to a significant length of mixing, or due to the cyclic mode of operation, which does not ensure the movement of materials. The developed design of the screw conveyor-mixer with a rotating casing allows for a short length of movement of the mixture, due to the necessary friction of the auger with the material and casing, to perform the required number of shoveling and ensure high quality of mixing. In the article, calculations were made and the following conclusions were drawn: 1. Screw mixers with a rotating casing are the most cost-effective means with screw elements for mixing and can provide the lowest mixture heterogeneity at the lowest costs compared to other typical representatives. The cost of mixing 1 ton of mixture when it is used is 1.09 times lower than when it is mixed with a screw conveyor-mixer and 3.41 times lower than when it is mixed with a screw mixer with overflow. It was established that the aggregated costs of mixing 1 ton of the mixture when using a screw mixer with a rotating casing are UAH 21.91, a screw rigid conveyor-mixer is UAH 23.8, and a screw mixer with overflow is UAH 74.66. 2. Achieving the quality of the mixture with a screw rigid conveyor-mixer similar to the quality obtained as a result of its mixing with a screw conveyor-mixer with a rotating casing, the process of shoveling it should be at least three times longer, which is accordingly reflected in its overall dimensions (the working length of the mixing zone and movement of the mixture). When using screw mixers with overflow, there are increased costs of electricity, given the significant number of cycles for shoveling the mixture, and it is often impossible to move the mixture in the desired direction and the need for an additional conveyor.