Yazar "Hekimoglu, OZ" seçeneğine göre listele

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    Effect of angle of wrap on cutting performance of drum shearers and continuous miners
    (Taylor & Francis Ltd, 2004) Hekimoglu, OZ; Ozdemir, L
    The significance of angle of wrap in tool-lacing has, to date, been investigated in detail on the loading efficiency of shearer drums only; no comprehensive work on the cutting efficiency has, however, been found. This paper is concerned with the effects of angle of wrap on the cutting performance of rock and coal cutting picks fitted on drum shearers and continuous miners. A series of laboratory trials was carried out at full-scale, to simulate the actual cutting position of the picks in a cutting sequence at varying angular positions, which correspond to the angle of wrap. The results showed that the tool forces varied remarkably with the changes in the angular position, in such a way that all exhibited a minimum at 10degrees angle, being more pronounced for the sideways force components. It was also inferred that cutting drums, which operate at higher advance per revolutions, might experience poor performance due to higher tool forces if greater angle of wraps are employed.
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    Laboratory and in situ investigations of tracking cutters for computer-aided design of shearer drums
    (Canadian Inst Mining Metallurgy Petroleum, 2003) Hekimoglu, OZ; Ayhan, M; Tiryaki, B
    This paper discusses the aspects of tracking cutters related to the computer-aided design of shearer drums. A comprehensive computer analysis of drum dynamic parameters for multi-tracking tool arrangement is not presently available, as the current computer programs mainly consider the aspects of single tracking. Despite the fact that the single-tracking arrangement is recommended for efficient cutting, some major drum manufacturers have been seen to persistently adhere to multi-track-ing, probably due to a lack of information. Further studies in this field are believed to contribute greatly to the current understanding of the computer-aided design of shearer drums. A number of laboratory simulation trials and long-term underground investigations were carried out in detail on tracking cutter arrangement, and an equation required for a computer program was derived. The results obtained from computer assessment of dynamic parameters for drums with multi-tracking arrangement were found to be in accordance with those of the underground trials, indicating the validity of the equations. The procedure adopted for the computer appraisal of the shearer drums designed with a multi-tracking concept, as described in this study, Is therefore recommended to be considered in the currently employed computer programs.
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    Reducing respirable dusts and fines through shearer drum design in coal mines
    (Canadian Inst Mining Metallurgy Petroleum, 2002) Hekimoglu, OZ; Tiryaki, B; Ayhan, M
    Coal shearers are one of the major sources of dust and fines in underground coal mines. Despite considerable research investigations, no comprehensive in situ investigations coupled with extensive laboratory studies on the effects of drum design on generation of dust and fines have been found. It may be for this reason that many major shearer drum manufacturers persistently employ a certain drum-lacing pattern on current coal shearers, which is believed to cause excessive dust and fines in coal mines. This paper shows how respirable dust and fines are minimized under near-identical conditions when the drum lacing pattern was changed from a triple-tracking to a single tracking arrangement. A series of laboratory trials simulating in full scale the practical cutting action of tools was followed by extensive long-term underground trials during production operations in OAL (Cayirhan) Lignite mine in Turkey. The results are presented and discussed, and recommendations for proper drum-lacing in terms of respirable dust and fines are made.