机电设备的电气自动化改造与维护探讨

采煤机为综采工作面关键设备,其生产能力及性能直接决定综采工作面的生产效率.实现采煤机生产的自动化水平和智能化能力,是提升工作面采煤效率的关键.采煤机在实际生产过程需根据工作面煤层、地质以及巷道等情况对采煤机截割滚筒的高度及截割头的转速等参数进行实时调整,以确保采煤机截割过程中的可靠性和稳定性.为此,需根据实际工况为采煤...     

滚筒结构参数对粉尘爆炸率的影响

通过假设与简化,建立了采煤工作面粉尘爆炸率与采煤机滚筒设计参数间关系的数学模型。以国产某型滚筒式采煤机为例,采用计算机模拟的方法得到了采煤机滚筒直径、螺旋叶片头数与粉尘爆炸率之间的关系曲线。通过分析,确定了各参数对粉尘爆炸率的影响,为预测不同结构滚筒参数的采煤机对粉尘爆炸率的影响,完善采煤机工作性能的评价体系,改进滚筒设计,减小采煤机的截割粉尘．降低粉尘爆炸率．提高煤炭生产的安全性提供理论依据．     

采煤机螺旋滚筒负荷的计算机模拟研究

本文对采煤机螺旋滚筒负荷的计算机模拟问题进行了研究。特别是对截齿负荷随机模拟的数学模型进行了深入探讨。目前,国外提出用瑞利随机过程模拟截齿负荷。本文提出,当模拟时间间隔较大时,可以采用Gamma分布模拟截齿负荷;否则,可以用x~2随机过程模拟截齿负荷。同时提出模拟截齿径向力的数学模型。此后,对螺旋滚筒上的负荷进行了研究,编制了滚筒随机负荷的模拟程序。并对某矿井采煤机的实际负荷进行了模拟和实测。最后,对此进行了分析与评价。     

镶铸截齿井下采煤试验

井下采煤试验是检验镶铸截齿工作性能的关键一步，本文通过井下采煤过程测试了镶铸截齿的综合性能，并着重论述了镶铸截齿的井下工作性能。     

基于改进RBF神经网络的采煤机截割煤岩性状智能识别

综采工作面煤岩分界面识别是采煤机滚筒高度自适应调节的关键和难点,为了在不增加额外设备的情况下准确识别综采工作面煤岩分界面,从采煤机滚筒分别截割煤层和岩层的表现性状出发,提出一种基于改进RBF神经网络的采煤机截割煤岩性状智能识别方法,使采煤机滚筒能够高速实时判别煤岩。该方法根据采煤机截割电流、牵引电流和摇臂调高液压缸阻力的变化,采用改进的萤火虫算法对RBF神经网络的基函数参数进行优化,并采用优化后的RBF神经网络模型对当前截割的煤岩性状进行识别。在耿村煤矿12150综采工作面实测数据的基础上开展试验,结果表明,基于改进RBF神经网络的煤岩性状识别模型对采煤机截割对象的识别准确率达到93.94%。利用该模型进行煤岩性状识别,无需加装额外探测设备,响应速度快、识别率高,有较好的工程应用潜力。     

采煤康拜因的块状碎煤工作机构及块状碎煤理论

采煤康拜因是在截煤机基础上发展起来的,他在煤矿工业中日益起着重要的作用,康拜因的工作机构一开始是应用截煤原理的链式工作机构的,这种康拜因应用特殊形状的截盘截链及破碎杆破碎盘来完成工作面的采煤工作,即先由截链上的截齿在煤层上掏槽将一大块煤与整中煤层分开,然后再由破碎装置将煤破碎成适宜于运输的块度,各种不同工作系统的链式工作机构如图1所示。     

滚筒式采煤机滚筒载荷谱的模拟分析与研究

根据单个截齿的受力模型和计算公式,建立了采煤机滚筒力矩模型和载荷波动模型。在此基础上,利用MATLAB编写了截割面积最大和波动系数最小时,转角与截齿力的关系程序和转角与力矩的关系程序,并对某型号采煤机滚筒进行了载荷模型的模拟和分析,分别得到了截割面积最大和波动系数最小时的滚筒转速;牵引速度和三向力的波动系数,为滚筒设计和实际使用提供理论依据。     

影响镶铸截齿工作性能的因素

截齿是采煤机工作时的重要零部件,它不但要有高的耐磨性,而且要有很高的抗冲击性能.镶铸复合金属材料截齿是将铬系耐磨合金与抗冲击性能好的低合金钢利用镶铸工艺一次浇铸成型,两金属复合界面在高温液态金属作用下形成冶金结合层,铬系耐磨合金与低合金钢组成的镶铸复合金属材料截齿在工作时两金属不分离,从而提高镶铸复合金属材料截齿的使用寿命.     

液压冲击截齿冲击煤岩的液压及电气系统设计

为改善采煤机煤岩截割过程中存在的截齿磨损严重、截割效率低等问题,对滚筒进行改装设计.以欲裂与截割联合破煤岩为设计方案,设计了一种液压冲击和截割联合的液压冲击截齿技术装置,并详细介绍了该装置的液压及电气系统.此设计方案对提高截割效率、增加截齿切削寿命方面具有一定的实践指导意义.     

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。     

Model test of the cutting properties of a shearer drum

According to similarity theory, we carded out a dimensional analysis of the shearer drum correlation parameters and built similarity criteria. Based on these, similarity models of shearer drums were developed. Simultaneously, based on an estab-lished cutting testbed of the coal and rock, cutting tests of different pick arrangements of the drum models were carried out, where the compressive strength of the analogous cutting material was 2.48 MPa and the drum rotary speed 67.5 r/min. The variance, the mean values, maxima and mean maxima of the torque load were analyzed for different type drum models. Moreover, the relation-ships between the type of pick arrangements and the cutting lump coal percentage were studied. The results indicate that the load fluctuation of the sequence drum is larger than that of the punnett square drum in the cutting process and the lump coal percentage and economic benefits of the sequence drum are inferior to the punnett square drum. We conclude that the punnett square drum is superior to the sequence drum.     

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。     

Suitable retention and recovery technology of floor coal at ends of fully mechanized face with great mining heights

Gateways at faces of great mining heights are mostly driven along the roof of coal seams. For gateway height restrictions, a 1-3 m floor coal is retained, leaving a triangular floor coal at the face ends, causing a loss of coal. In order to improve coal recovery rates and to ensure efficiency of equipment at coal mining faces, we investigated suitable retention methods and recovery technology of floor coal at face ends. The upper floor coal can directly be recovered by a shearer with floor dinting. The lower floor coal is recovered by shearer with floor dinting after advanced floor dinting and retaining a step for protecting coal sides in a haulage gateway. Field practice shows that this method can improve the coal recovery rates at fully mechanized working faces with great mining heights.     

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.     

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.     

液压支架与机采设备的约束关系及其控制模型

根据综采工作面的实际工况，分析了液压支架与采煤机以及液压支架与刮板输送机之间的运行约束关系，推导了液压支架与采煤机运行约束关系的数学表达式，建立了液压支架采煤机位置自动控制模型．制作并进行了10台控制器的联机试验，结果表明，模型实用，符合实际，为设计液压支架计算机电液控制系统提供了理论依据．     

Tests and error analysis of a self-positioning shearer operating at a manless working face

Self-positioning of a shearer is the key technology for mining with a man-less working face. In an underground coal mine all radio navigation; satellite positioning or celestial navigation methods have their limitations. We analyzed an inertial navigation system intended to guide the movement a shearer and designed a self-positioning device for the shearer. Simulation tests were also performed on the system. We analyzed the errors observed in these tests to show that the main reason for the low precision of the self-positioning system is accumulated error in the inertial sensor. A Kalman filtering algorithm used in combination with the shearer motion model effectively reduces the measurement errors of the self-positioning system by compensating for gyroscopic drift. Finally, we built an error compensation model to reduce accumulated errors using continuous correction to provide self-positioning of the shearer within a certain range of accuracy.     

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.     

Longwall mining automation horizon control:Coal seam gradient identification using piecewise linear fittingOA

Horizon control, maintaining the alignment of the shearer’s exploitation gradient with the coal seam gradient, is a key technique in longwall mining automation. To identify the coal seam gradient, a geological model of the coal seam was constructed using in-seam seismic surveying technology. By synthesizing the control resolution of the range arm and the geometric characteristics of the coal seam, a gradient identification method based on piecewise linear representation(PLR) is proposed. To achi...