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Functional and constructive optimization of mixers of continuous action with bar working bodies

Author: Lungu Valeriu
Degree:doctor of engineering
Speciality: 05.05.04 - Construction, road building and mining machines
Scientific adviser: Sergiu Andrievschi
doctor, associate professor (docent), Technical University of Moldova
Institution: Technical University of Moldova


The thesis was presented on the 4 December, 2009
Approved by NCAA on the 11 February, 2010


Adobe PDF document0.64 Mb / in romanian


concrete, intensification, continuous, optimization, planning, stream, bar, mortar, mixer, mixture


The doctoral thesis includes: the introduction part, five chapters (118 text pages, 55 drawings, 12 tables), the general conclusions, the bibliography (146 sources) and 49 annexes. A total of 43 articles were published on the topic of the thesis.

The purpose of the work consists in determining the modality of intensifying the process of preparing building mixes based on theoretical and experimental researches in mixers of continuous action with bar working bodies

The paper brings theoretical proves and experimental confirmations to the hypothesis that the intensification of the process of preparing building mixes in mixers with bar working bodies is possible due to the division of the material into numerous streams, their immediate association and the subsequent repetition of these operations.

The researches were undertaken based on such methods as the mathematical statistics and the theory of probability, the mathematical planning of multifactorial experiment and the tensometric methods of resistance registration.

The findings of the work show the influence of the technological and efficiency factors on the rotary movement through the mixing of the bar working bodies of the mixer, fixed radially on its shaft; the work has also as a result the multifactorial mathematical models, which describe the dependence of resistance, productivity of the mixer, and homogeneity of the mix on the technological and efficiency factors of mixers.

Various designs of bar mixers were developed and proposed. The results of researches on the influence of technological and efficiency factors on the process of mixing of second degree polynoms forms, engineering nomograms which can be used in designing and operation of mixers were proposed. The method of optimizing the mixing process in bars mixers is proposes.

The tests using the bar mixers of continuous action with optimal parameters have shown, that the latter ensure a high homogeneity of the mix, 3 times less mixing time and 2 – 3 times less specific power consumption as compared with blades mixers.