Interaction of vibroimpact lattice and screen sieve in anti-phase oscillation mode

Introduction. One of basic technological operations in construction technology is a process of classification of fine grained mineral materials, for example, natural sand. The related actual problem is connected with increasing performance and effectiveness of screening of sand medium, in particular reducing the contamination of screening surface of vibrating screens from seal particles and sticking in sieve holes wedge-shaped grains. The solution of this problem concludes in performing by the use of vibroimpact screens of various operating principle. One of innovative vibroimpact screen constructions is a screen with vibroimpact lattice, mounted under sieve with a gap on spring elements, which provides an impulse impact on all sieve surface area. Such construction provides increasing the effectiveness of sieve cleaning due to the transfer to sieve impact impulse in each screen oscillation period and reducing its excessive damage and abrasion by increasing the area of vibroimpact lattice and sieve interaction. The purpose of the work is to determinate functional relationships of dynamical interaction between elements of three-mass vibroimpact ‘screen body – vibroimpact lattice – sieve’ system for providing the necessary value of impact impulse transferred to sieve in relation to screen body oscillation frequency and amount of gap between lattice and sieve.
Materials and methods. The research is based on a method of mathematical modelling. On the first stage the research is being conducted with using two-mass ‘screen body – vibroimpact lattice’ model without consideration the impact between lattice and sieve for determination the oscillation frequency range of in-phase oscillation regime and gap values providing an impact between lattice and sieve. For the calculation of displacement of screen elements and for research the relationships of its parameters in selected range the three-mass model of vibroimpact model of screen with one impact pair is used on a second stage of research.
Results. As a result of calculation obtained the functional relationships of correlation of the gap between vibroimpact lattice and screen sieve and oscillation frequency on the impact impulse transferred to sieve and sieve double amplitude were obtained. The developed recommendations for practical using of obtained relationships for adjustment operating regimes of vibroimpact screen which allow to establish the screen operating oscillation frequency and value of gap between lattice and sieve for providing high effectiveness of sieve holes cleaning from contaminating particles.
Discussion and Conclusions. Performed mathematical modelling allowed to obtain dependencies of influence of gap between sieve and vibroimpact lattice and screen elements oscillation frequency on impulse transferred on screen sieve and sieve double amplitude. Developed practical recommendations of obtained dependencies allow to perform an effective adjustment of vibroimpact screen operating regimes and reduce the labor intensity of works being performed during its starting-up and maintenance.

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