A review on the advanced design techniques and methods of vibrating screen for coal preparation

Impact of screening coals on screen surface and multi-index optimization for coal cleaning production

In the present work, an innovative design strategy for the optimization of the dynamic performances and the structural loads of heavy loaded vibrating screens is presented. A dynamic model of a vibrating screen for the selection of inert materials in an asphalt plant is proposed, and a numerical optimization procedure is applied to selected design parameters and geometrical features. The algorithm provides a tool to improve the dynamic behavior of vibrating screens of different geometric and inertial properties. The results are analyzed, in order to find the parameters apt to minimize the pitching angle of the examined screen during stationary working conditions, thus providing a better material selection by reducing gravel throwback. A numerical FEM model analysis and an experimental strain-gage campaign have been conducted on a realization of the vibrating screen, testing two optimized and un-optimized configurations, to verify the FEM model results. The complete work gives the machine designer a powerful tool, validated by means of full scale experimental tests, to optimize the dynamic behavior of the screen and to verify its fatigue resistance.

A dynamic optimization theoretical method for heavy loaded vibrating screens

Innovative structural solution for heavy loaded vibrating screens

A new concept of banana vibrating screen which has the same effect as traditional banana vibrating screen in a new way was put forward. The dynamic model of vibrating screen was established and its working principle was analyzed when the action line of the exciting force did not act through the centroid of screen box. Moreover, the dynamic differential equations of centroid and screen surface were obtained. The motions of centroid and screen surface were simulated with actual parameters of the design example in Matlab/Simulink. The results show that not only the amplitude has a significant decrease from 9.38 to 4.10 mm, but also the throwing index and vibrating direction angle have a significant decrease from 10.49 to 4.59, and from 58.10° to 33.29°, respectively, along the screen surface, which indicates that motion characteristics of vibrating screen are consistent with those of traditional banana vibrating screen only by means of a single angle of screen surface. What’s more, such banana vibrating screen of variable linear trajectory with greater processing capacity could be obtained by adjusting the relative position of force center and the centroid of screen box properly.

Dynamic analysis and simulation of four-axis forced synchronizing banana vibrating screen of variable linear trajectory

https://cyberleninka.org/article/n/973135.pdf

Dynamic design theory and application of large vibrating screen

Analyzed large vibrating screen's dynamic characteristics of single channel and hyperstatic network structure and calculated natural frequency,natural mode of vibration and dynamic response based on finite element technology.Modification method was revealed to optimize the vibrating screen structure.The results show that the vibrating screen's structural strength is increased and the natural frequency of bending and torsional deformation is enhanced in virtue of the adoption of hyperstatic network structure.The mode frequency is far from working frequency(12.2 Hz) which means that the screen structure can avoid resonance effectively to reduce the damnification.The screen's lateral deformation is reduced from 0.428 mm to 0.126 mm by virtue of adding blocking plate and peripheral reinforcing rib.The use of hyperstatic network structure provides a big structure intensity and stiffness to meet large vibrating screen's needs in the design process.

Dynamic characteristics of large hyperstatic network structure vibrating screen

It was discovered that the shaker of the large-scale vibration screen vibrated abnormally and gave off peculiar sound during testing.In order to find out the primary cause of the faults and to provide the theory basis for eliminating the abnormal vibration and peculiar sound,the vibration test on the shaker of the large-scale screen were carried out and the long data was used to do FFT computation.With the spectral analysis,the primary fault causes were found,and the diagnosis conclusions were confirmed through disassembling and inspecting the shaker.

Vibration Test and Fault Analysis on Shaker of Large-scale Screen

Multiple frequencies constraints and analytical sensitivity methods were used in structural optimization design of stiffeners on the side plate of vibrating screen to lower the damage of side plate causing by high dynamic stress when the large vibrating screen works.The mass of side plate of vibrating screen was taken as object function,multiple frequencies were regarded as state parameters and an optimization criterion which is applicable to solve this kind of problem was given.Meanwhile,sensitivity characteristics of variable parameters were considered during the process of optimization.The results show that the optimization program with embedded analytical sensitivity calculation methods is of a higher solving precision and a more stable calculating process.After structure optimization,the mass of side plate is reduced by 8.27% and two elastic deformation frequencies are increased by 1.37% and 2.97%,respectively,and a better optimization effect is achieved.The analysis of the optimal vibrating screen presents that the mass of vibrating screen decreases by 2.35% and three elastic deformation frequencies which are close to the working frequency increase by 14.17%,12.29% and 23.01%,respectively.The natural frequencies of vibrating screen are improved and modal frequency is far from working frequency of the exciting motor and thus the structural stiffness and reliability of vibrating screen is enhanced.

Optimal design of large vibrating screen based on multiple frequencies constraints and analytical sensitivity methods

In this paper,we deeply analyzed the problem of screening in coal industrial.We look back a lot of issues and difficulties of research and application of coal screening in last few years.We show that there are two key problems which are blinding of deep screening and Reliability of large vibration screen.Firstly,we sump up the screening theory of probability screening,banana vibrating screening,probability-banana vibrating screening,flip-flow screening,elasticity screening,strong screening,and briefly introduce the grain kinematics and the progress of screening model.Secondly,we systemically expatiate the blocking of deep screening of moist coal and the development and application of the equipment of probability screen,strong screen,elastic bar screen,flip-flow screen,hydra screen and gas stream-screen classifier etc).We point out the necessity of research and application of deep screening equipment of moist coal.At last we point out that developing new screen theory,alleviating conglutinating of material,making use of dynamics analysis,creating new structure are main ways to solve the two key problems.

Zhang Cheng-yong

Papers

Dynamic design theory and application of large vibrating screen

Dynamic characteristics of large hyperstatic network structure vibrating screen

Vibration Test and Fault Analysis on Shaker of Large-scale Screen

Optimal design of large vibrating screen based on multiple frequencies constraints and analytical sensitivity methods

Progressing of Coal Screening Theory and Equipment