Influence of the mechanical characteristics of harp screen material on screening process

The paper presents the results of studies on the influence of mechanical characteristics of harp screen material on the technological  parameters of screening. A mathematical model of the vibrational  process of harp screens is presented depending on the length of their  free areas, magnitude of technological load and characteristics of the screened material. Dependences of the relative vibrations amplitudes  of rubber and cable strips on the length of their free areas are determined for different values of process load. As a result of the researches, it was established that the amplitude of the relative vibration of  rubber strip under load decreases with increasing length of their free  areas and for steel cable strips it increases, reaching a maximum at  certain values of process load. It was also found that presence of the  load dramatically reduces the amplitude of relative vibration of rubber  strips, especially, in the area of dimensionless frequencies of the order of (0.6  –  1.4)g, while the vibrations amplitude of cable strips vary  slightly in this frequency range. The article presents information on  rubber-cable harp screening surfaces of mesh type: strips in the form  of steel cables, rubberized with rubber cover having lateral separation  projections. The use of rubber-cable strips as working elements of the  screening surface allows to increase the “open area” of the screen due  to the increase of distance between supports while maintaining high  and stable amplitude of strips vibrations. Optimization of mechanical characteristics of the working elements material of harp screens and  conditions of their fixation allows to intensify separation of screened  material into fractions by eliminating sticking of the screened surface  with clay particles and clogging of the material with “difficult” grains, and to improve significantly technical and economic indicators of the  screening process. Such screening surface passed successful industrial tests at a number of quarries producing construction aggregates for the separation of crushed stone and gravel. Economic efficiency of the rubber-cable harp screens is presented in comparison with the wire screens in technological schemes of processing of mineral raw materials.

1. Vaisberg L.A., Kartavyi A.N., Korovnikov A.N. Proseivayushchie poverkhnosti grokhotov. Konstruktsii, materialy, opyt primeneniya [Sifting surfaces of screens. Constructions, materials, experience of application]. Vaisberg L.A. ed. St. Petersburg: Izd-vo VSEGEI, 2005, 252 p. (In Russ.).

2. Trubetskoi K.N., Shapar’ A.G. Malootkhodnye i resursosberegayushchie tekhnologii pri otkrytoi razrabotke mestorozhdenii [Lowwaste and resource-saving technologies at the open mining]. Moscow: Nedra, 1993, 272 p. (In Russ.).

3. Bibikov P.Ya., Bardovskii A.D., Mitusov P.E., Kalakutskii A.V. Design of classifier-grinder for the processing of weak rocks. Gornyi informatsionno­analiticheskii byulleten’ (nauchno­tekhnicheskii zhurnal). 2015, no. 3, pp. 233–237. (In Russ.).

4. Bibikov P.Ya., Bardovskii A.D., Mitusov P.E. Kharitonov A.O. Unit for weak rocks processing. Gornoe oborudovanie i elektrotekhnika. 2014, no. 4, pp. 24–28. (In Russ.).

5. Il’in S.A., Kovalenko V.S., Pastikhin D.V. Raising the economic efficiency of opencast mining. Gornyi zhurnal. 2012, no. 6, pp. 56–65. (In Russ.).

6. Yanik K. Bucks for belts. Pit & Quarry. 2016, vol. 108, no. 12, pp. 16–18.

7. Butkevich G.R. The problems of the development of watered deposits of non-ore raw materials. Gornyi zhurnal. 2004, no. 5, pp. 27–32. (In Russ.).

8. Shlain I.B. Razrabotka mestorozhdenii nerudnogo syr’ya [Development of deposits of nonmetallic raw materials]. Moscow: Nedra, 1985, 345 p. (In Russ.).

9. Wasson C. Moving Mountains. Pit & Quarry. 2015, vol. 107, no. 9, pp. 56–59.

10. Sorensen L. Vulcan Materials Co. upgrades the Bucyrus-Erie King Midas dragline – a 25-yearold marvel. Pit & Quarry. 2014, vol. 107, no. 1, pp. 34–41.

11. Butkevich G.R. Experience of application of conveyor technology, mining in quarries for the extraction of non-metallic materials in 1950–1990 years: the way forward. Gornyi zhurnal. 2017, no. 2, pp. 98–102. (In Russ.).

12. Stoker J.J. Nonlinear vibrations in mechanical and electrical systems. New York, London: Wiley, 1950, 294 p. (Russ.ed.: Stoker J. Nelineinye kolebaniya v mekhanicheskikh i elektricheskikh sistemakh. Moscow: IL, 1952, 264 p.).

13. Keropyan A.M., Gerasimova A.A. Connection of the temperature in contact area of the wheel-rail system with the railway slope of industrial railway transport. Izvestiya VUZov. Chernaya metallurgiya = Izvestiya. Ferrous Metallurgy. 2017, vol. 60, no. 5, pp. 355–363. (In Russ.).

14. Tikhonov A.N., Samarskii A.A. Uravneniya matematicheskoi fiziki: ucheb.posobie [Equations of mathematical physics: Tutorial]. Moscow: Izd-vo MGU, 1999, 735p. (In Russ.).

15. Lidin G.D., Voronina L.D., Kaplunov D.R. etc. Gornoe delo: Terminologicheskii slovar’ [Mining: Terminological dictionary]. Moscow: Nedra, 1990, 649 p. (In Russ.).

16. Kartavyi N.G., Bardovskii A.D. Influence of the parameters of the rubber- cable strip screen on technological indicators of screening. Izv. vuz. Gornyi zhurnal. 1985, no. 4, pp. 88–93. (In Russ.).

17. Panovka Ya.G. Osnovy prikladnoi teorii kolebanii i udara [Fundamentals of applied theory of vibrations and shock]. Leningrad: Mashinostroenie, 1976, 320 p. (In Russ.).

18. Kartavyi N.G., Bardovskii A.D. Prospects for the development of highly effective classification and shredding equipment for nonwaste production of non-metallic building materials. In: Problemy kompleksnogo osvoeniya mestorozhdenii tverdykh poleznykh iskopaemykh: Sb. nauchn. tr. MGI [Problems of integrated development of deposits of solid minerals: Coll. of MGI sci. papers]. Moscow: Nedra, 1989, pp. 115–128. (In Russ.).

19. Bardovskii A.D., Bibikov P.Ya., Verzhanskii P.M., Voronin B.V. Efficiency of dry vibration screening of waste of non-ore quarries on the sifting surfaces of various designs. Gornyi informatsionnoanali ticheskii byulleten’ (nauchno­tekhnicheskii zhurnal). 2015, no. 6, pp. 182–189. (In Russ.).

20. Keropyan A. M. Features of interaction of the traction wheels of a electric locomotive and a diesel locomotive with rails in the conditions of open mountain works. Journal of Friction and Wear. 2016, vol. 37, no. 1, pp. 78–84.