Study on pick arrangement of shearer drum based on load fluctuation

According to the coal or rock cutting theory, a mechanical model and computing formula for a pick and the drum load fluctuation model were established in order to obtain relationships between pick arrangements and drum fluctuation loads, drum rotary speeds and haulage speeds. Based on a minimum load fluctuation, an optimal mathematical model was established for drum pick arrangements. The effects of pick arrangements (including punnett square, sequence, aberrance Ⅰ and Ⅱ) on the drum load fluctuation coefficient are discussed. The relationships between the pick arrangements of the drum with different start vanes and the cutting load fluctuation coefficient, the drum rotary speed and haulage speed were also studied. The results indicate that the punnett square arrangement has a smaller cutting load fluctuation coefficient than other forms of arrangement and the drum with the 4-start vanes has the smallest coefficient. The drum rotary speed and haulage speed are affected not only by pick arrangements, but also by the number of vanes.     

采煤机螺旋滚筒截齿排列的研究

设计制造螺旋滚筒式采煤机时,不可能具体针对某一地区某一工作面,这样在用采煤机组采煤时,会发现由于截齿排列安装的状况不适宜本工作面煤层地质条件而造成截齿的磨损严重,冲击载荷增大,时时有将截齿上合金片打掉的现象发生。为解决这一问题,在现场进行了一系列"采煤机截齿排列"的实验及分析研究。     

采煤机螺旋滚筒结构参数的模糊优化设计

运用模糊理论对采煤机螺旋滚筒结构参数进行了优化设计。选择螺旋滚筒装煤生产率作为优化设计的目标,建立了其数学模型并确定了设计变量。通过选取煤壁破碎模式、滚筒工作转速、叶片螺旋升角等作为约束条件,讨论了其隶属函数。运用最优化水平截集法将采煤机滚筒结构参数的模糊优化问题转化为非模糊优化问题,建立了非模糊优化数学模型,再按普通的优化设计问题进行求解,使滚筒参数的设计结果更能符合工作实际,从而提高采煤机的工作效率。     

采煤机滚筒不均匀运动时截齿瞬时切削厚度的算法

给出了采煤机螺旋滚筒不均匀运动时截齿瞬时切削厚度计算的数学模型和程序框图。本算法逻辑性强、结构紧凑，可在微机上实现。     

Rock excavation using surface miners: An overview of some design and operational aspects

Surface miner, a continuous mining machine, is being manufactured in India and abroad owing to enhanced demand of production in various mining industries like coal, limestone, gypsum, bauxite etc. Different types of surface miners are manufactured today based on cutting drum placement and design specifications. Selective mining without drilling and blasting, high production and small size products are some of the prominent attractive features obtained with these moving marvels. This machine can be used with good efficiency in soft to medium hard rock (100–120 MPa). This paper synthesizes the different applications, equipment models, features offered, operating methods, cutting performance assessment models as well as typical production performance of surface miner in coal and limestone mines of India. Engine hour metre reading, diesel and pick consumptions are linearly influenced by production. The emphasis for future research is also brought out.     

采煤机切割时作用力的分析与探讨

采煤机切割机理的研究是当今非常重要的课题,对提高采煤机生产率,降低能耗,减少刀齿损耗都具有重要意义。本文对煤炭切割过程、切割机理进行了分析。对于截齿切割时的影响因素进行了分析与研究。提出了采煤机单齿的受力状况及计算公式。     

基于双滚筒优化模型的采煤机运动参数优化

目前大多数学者在研究采煤机运动参数优化问题时,普遍采用仅包含一个牵引速度和一个滚筒转速的单滚筒优化模型,但由于双滚筒采煤机两侧滚筒受力情况及截割状态不完全相同,由单滚筒模型所得结果并不完全适用于双滚筒采煤机。本文以某型双滚筒采煤机为研究对象,以牵引速度和左、右滚筒转速三个运动参数作为设计变量,建立了双滚筒运动参数优化模型;利用遗传算法(GA)对双滚筒采煤机运动参数进行优化,并将最优参数下的截割性能与工业参数下的截割性能进行了对比,结果表明最优运动参数下的截割性能更优;对单、双滚筒两种优化模型下的优化结果进行了对比分析,结果显示双滚筒模型优化后的综合截割性能较单滚筒模型优化提高了16.35%,表明双滚筒优化模型下的截割表现更优。     

Developing selective mining capability for longwall shearers using thermal infrared-based seam tracking

Longwall mining continues to remain the most efficient method for underground coal recovery. A key aspect in achieving safe and productive longwall mining is to ensure that the shearer is always correctly positioned within the coal seam. At present, this machine positioning task is the role of longwall personnel who must simultaneously monitor the longwall coal face and the shearer’s cutting drum position to infer the geological trends of the coal seam. This is a labour intensive task which has negative impacts on the consistency and quality of coal production. As a solution to this problem, this paper presents a sensing method to automatically track geological coal seam features on the longwall face, known as marker bands, using thermal infrared imaging. These non-visible marker bands are geological features that link strongly to the horizontal trends present in layered coal seams. Tracking these line-like features allows the generation of a vertical datum that can be used to maintain the shearer in a position for optimal coal extraction. Details on the theory of thermal infrared imaging are given, as well as practical aspects associated with machine-based implementation underground. The feature detection and tracking tasks are given with real measurements to demonstrate the efficacy of the approach. The outcome is important as it represents a new selective mining capability to help address a long-standing limitation in longwall mining operations.     

采煤机滚筒模化实验研究

本文利用人造模拟截割材料,在液压刨床和专用截割实验台上完成了单齿和滚筒截割系统的模化实验.根据相似准则函数理论,对实验结果进行定量分析,并进行了滚筒载荷的计算机模拟和一系列概率统计分析.研究表明,模化实验是一种经济和有效的研究采煤机滚筒的方法.     

Modeling and simulation of ocean mining subsystem based on virtual prototyping technology

1　INTRODUCTIONThe study of ocean mining system is a greatconcern in international ocean resources research.The system is related to many subjects, such as o cean re connoitering, mining, mechatronics, mate rial, environment and so on . It is considered thatthe first commercial mining system will be possiblymade up of mining subsystem, lifting subsystem,remote measuring and controlling subsystem andsurface supporting system. The mining subsystemis used to crush and collec…     

综放面多尘源粉尘分布规律数值模拟及实测

为解决综放工作面粉尘浓度高的问题,掌握各作业工序粉尘浓度空间分布规律,有效指导粉尘控制工作,依据气固两相流理论,运用Fluent软件对综放工作面割煤、移架、放顶煤、转载各工序单独及同时作业时的粉尘分布规律进行数值模拟,并与现场实测数据进行对比分析.结果表明:割煤作业粉尘沿采煤机机道扩散的同时向人行道空间扩散,需在滚筒尘源处控尘,并在采煤机外侧采取水幕帘除尘措施;移架作业时人行道粉尘浓度高于机道粉尘浓度,需在机道空间和人行道空间均设置架间喷雾;放煤作业粉尘沿人行道空间分布较大,需在放煤口采取隔尘措施;转载点局部风速大,粉尘影响范围较广,应采取密封等措施.还应在放煤和割煤作业之间增加全断面喷雾降尘装置.     

横向截割头切屑图人机界面系统的设计与模拟研究

建立了以截齿崩落线方程和交点坐标方程为代表的切屑图的数学模型,基于MATLAB／GUI设计了横轴式掘进机截割头切屑图的人机界面系统。利用该系统,通过在界面上输入截割头的相应参数,就能模拟掘进机截割不同煤岩时、不同工况参数下的横轴式掘进机的切削过程和切屑图。通过以国产某型掘进机为例进行模拟,获得了该掘进机在不同参数下的切屑图,根据切屑图比较分析了截齿的受力状态、切屑厚度与截割粉尘量以及截割阻力的大小,为提高截割头设计水平、研究横轴式掘进机的截割过程,改善该型掘进机的截割性能奠定了基础。     

拉刀切削刃表面微结构对拉削性能的影响

为了研究拉刀切削刃表面微结构对拉削加工的影响,搭建拉削加工实验台,设计5种表面微结构数量不同的拉刀,进行实际拉削负载、工件振动特性和切屑蜷曲半径的对比实验. 实验结果表明,当刀具型号从2/3型变为6/7型时,拉削负载呈现先减小后增大的趋势;使用4/5型拉刀时的拉削负载最低,与使用2/3型拉刀和6/7型拉刀时相比,负载分别降低420、647 N. 拉刀切削刃表面微结构槽数量越多,对工件振动特性的抑制效果越好;使用6/7型拉刀时的工件微振动均方根振幅和刀齿切入频率对应的幅值相对于使用2/3型拉刀时分别降低38%、63%. 随着拉刀切削刃微结构槽数量的增多,切屑的蜷曲半径（即切屑变形难易程度）呈现先减小后增大的趋势,当使用4/5型拉刀时切屑的蜷曲半径达到最小值（654 μm）. 增加切削刃表面微结构的数量可以提高拉削性能,但是数量并不是越多越好,而是存在最优值.     

Method to determine installing angle of conical point attack pick

In order to obtain the determining method of the installing angle and decrease the performance indices (cutting force and wearing rate) of the pick, the relationships among the installing angles (impact angle, inclination angle and the skew angle) were studied, and the static model of installing angles of the pick was built. The relationships among the impact angle, the tip angle of pick and the kinematics parameters of the pick were built, too. Moreover, the mechanic models of the maximum clearance angle and the wearing angle of the pick were set up. To research the relationships of the installing angles and the change law of the wearing angle along with the kinematics parameters, the simulation was done. In order to verify the correctness of the models, the cutting experiments were done by employing two picks with different pick tip angles. The results indicate that, the cutting force is the smallest when the direction of the resultant force of pick follows its axis, and the relationship derived among the installing angles should be satisfied. In addition, to decrease the cutting force and the wearing of the pick, the tip angle of pick should not be larger than the half of the difference between the minimum wearing angle and the impact angle of the pick, and the clearance angle must not be less than zero.     

Modeling and simulation of crushing process of spiral mining head

1 INTRODUCTIONThe research of mining deep seabed cobalt-richcrust is a hotspot of international oceanology[1].Based on the mining manganese nodule ,lots of re-searches on mining cobalt crust have been madedeeply and many kinds of methods ,such as thei m-proved CLB, mining vehicle +lifting system +surface supporting ship have been put forward.Mining vehicle consists of collecting machine ,tracked treading machine and spiral mininghead[2 ,3].The first step of mining cobalt crust is tocrush…     

New Respirable Dust Suppression Systems for Coal Mines

Dust suppression in coal mines is a worldwide problem which has not been solved effectively. The application of negative pressure secondary dust removal （NPSDR） is a breakthrough in the coal mine safety field. In this paper, NPSDR technology and ultrasonic dust suppression systems are introduced. High pressure water is supplied to the NPSDR device which is mounted on the shearer. A negative pressure field is formed in the device. At the same time, the dusty air around the shearer drum will be sucked into, and purged from, the NPSDR device by the negative pressure field. An ultrasonic dust suppression system uses water and compressed air to produce micron sized droplets which suppress respirable coal dust effectively. The NPSDR technology can be used for shearer dust suppression while ultrasonic dust suppression can be applied in areas such as the transportation positions. These dust suppression methods have the following advantages： high efficiency, wide applicability, simple structure, high reliability and low cost.     

综采工作面割煤时煤尘污染状况的现场实测研究

在对平沟煤矿综采工作面采煤机割煤时煤尘浓度和分散度现场实测和分析的基础上,得出了综采工作面采煤机割煤时煤尘的污染特征.在一定风速条件下采煤机割煤时,距底板和煤壁较近处煤尘的总粉尘浓度沿程分布曲线出现2个极大值,然后随着煤尘运移距离的增加,煤尘的总粉尘浓度沿程分布曲线趋向于1个稳定值;距顶板和液压支架较近处煤尘的总粉尘浓度沿程分布曲线仅出现1个极大值,然后随着煤尘运移距离的增加,煤尘的总粉尘浓度沿程分布曲线也趋于1个稳定值.     

采煤机滚筒优化设计

基于模型试验原理 ,作者对采煤滚筒参数进行了优化 ,并开发了用于手煤机滚筒优化设计的软件。将模型试验与优化理论结合 ,使采煤滚筒的分析、设计更为有效。     

Preparation and properties of a new cutting pick of coal shearers

Reliability and wear resistance of cutting picks play a significant role in coal mine exploitation with coal shearers.Tool bit separation,blade breaking,severe erosion of the cutting body and fatigue fractures are the main reasons for failure of cutting picks.We carried out carburization on a 30CrMnMo alloy to synthesize a new cutting pick material with improved mechanical properties and high wear resistance.The results indicated that carburization can effectively strengthen the surface of the30CrMnMo alloy by forming a thick carburized layer and thus significantly improve the surface hardness and wear resistance.In addition,the excellent toughness of 30CrMnMo alloy as a substrate of cutting picks can prevent brittle ruptures and fatigue fractures under high impact stress conditions.The significant decrease in both frictional coefficient and rate of erosion of this carburized 30CrMnMo alloy suggests that this alloy is a potential material for cutting picks of coal shearers after rational carburization.     

同态滤波在扭矩载荷识别中的应用

通过理论分析和实验验证,证明了采用同态滤波的方法识别机器扭矩载荷的可行性。同时提出了根据时序模型的Green函数来判定窗函数宽度的方法,减少了选取窗函数宽度的盲目性。作为应用实例,给出了采煤机扭矩的识别结果。