提升薄煤层采煤机工作效率关键措施研究

针对薄煤层工作面采煤机工作效率低的问题,提出了采煤机大功率化、合理确定滚筒大小、明确滚筒旋转方向、缩短检修维护时间的解决措施。研究表明,优选大功率薄煤层采煤机、合理选择滚筒直径,可显著提升采煤机工作效率;明确滚筒旋转方向为内旋,可降低采煤机运行阻力,有利于提升工作效率;开发基于自润滑技术的铰接轴套和轴承,可减少检修时间,提高采煤机开机率,提升工作效率。

综采面无线采煤机截煤跟踪降尘系统的设计

为了有效地解决现有综采面采煤机截煤跟踪降尘系统各设备间由于有线连接的安装难度大、线路易扯断、维护繁琐等问题,设计了一种基于无线通信的采煤机截煤跟踪喷雾系统。阐述了系统的总体结构,介绍了采煤机定位发射器和定位接收器的设计原理,重点介绍了喷雾控制箱的硬件设计、软件设计以及低功耗设计过程。通过在实验室搭建模拟系统,进行了喷雾功能实验,结果表明:该系统各设备之间采用无线通信,减少了中间的线路连接,安装及维护简单,系统能够按照设定的系统喷雾参数,控制电动球阀的开启和关闭,实现采煤机滚筒附近的喷雾降尘。

基于矿鸿操作系统的采煤机控制系统架构研究

研究了基于矿鸿操作系统的采煤机控制系统架构。首先介绍了煤矿智能化发展背景和传统采煤机系统存在的问题,针对现有问题提供了解决思路。然后着重探讨了矿鸿操作系统架构设计和特性、矿鸿在采煤机控制系统架构中的应用,分析了矿鸿操作系统在采煤机领域的潜力和优势。最后展望了矿鸿在采煤机控制系统的应用前景、技术发展方向及存在的问题和挑战。

基于参数迁移的摇臂传动系统跨工况故障诊断算法

摇臂传动系统在采煤机中扮演着至关重要的角色,直接影响着煤炭生产的效率。针对跨工况迁移故障诊断难题,研究发现源域和目标域的故障数据特征分布相似。为此,提出了一种基于参数迁移的故障诊断模型。该模型采用全局均值池化的迁移卷积神经网络(TCNNG)模型,能够自动从源域工况数据中提取特征信息。通过参数迁移加微调的策略,将诊断知识参数从源域成功迁移到目标域,显著提高了模型在不同工况下的故障识别率和泛化性能。

高功率密度采煤机摇臂加载油温预测方法及试验

分析了高功率密度采煤机摇臂产热和散热因素及计算方法,建立了热平衡方程,根据热平衡方程预估了摇臂加载试验过程中的油温,通过计算和试验分别得到了摇臂空载和加载时在不同加油量下摇臂温升与时间的变化曲线。结果表明,齿轮的啮合、轴承摩擦及直齿轮搅油在摇臂产热中占据主导地位,而摇臂表面散热、内部件吸热及冷却水是散热的主要途径。设计过程中可以采取措施从上述几方面减少产热及扩大散热。该方法可预测采煤机摇臂加载油温并可推广应用。

恶劣综采工况条件下的采煤机摇臂散热设计研究

简述了在采煤机设计过程中对恶劣综采工况中工作倾角较大、煤岩硬度较硬、截割功率大且结构紧凑限制条件下的摇臂热功率的计算,分析了该工况中摇臂简化为复杂齿轮箱思路下的热功率计算、散热途径和热平衡点,提出了摇臂内部结构改进及增加外置冷却装置的散热设计方案,并验证了满载试验条件下摇臂截割热平衡温度不超过90℃的方案可行性。

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 navi-gation 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 preci-sion 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.

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.

Reliability modeling of hydraulic system of drum shearer machine

The hydraulic system plays an important role in supplying power and its transition to other working parts of a coal shearer machine. In this paper, the reliability of the hydraulic system of a drum shearer was analyzed. A case study was done in the Tabas Coal Mine in Iran for failure data collection. The results of the statistical analysis show that the time between failures （TBF） data of this system followed the 3-parameters Weibull distribution. There is about a 54% chance that the hydraulic system of the drum shearer will not fail for the first 50 h of operation. The developed model shows that the reliability of the hydraulic system reduces to a zero value after approximately 1 650 hours of operation. The failure rate of this system decreases when time increases. Therefore, corrective maintenance （run-to-t^ailure） was selected as the best maintenance strategy for it.

Control strategy for an intelligent shearer height adjusting system

An intelligent shearer height adjusting system is a key technology for mining at a man-less working face. A control strategy for a shearer height adjusting system based on a mathematical model of the height adjusting mechanism is proposed. It considers the non-linearity and time variations in the control process and uses Dynamic Fuzzy Neural Networks （D-FNN）. The inverse characteristics of the system are studied. An adaptive on-line learning and error compensation mechanism guarantees sys- tem real-time performance and reliability. Parameters from a German Eickhoff SL500 shearer were used with Maflab/Simulink to simulate a height adjusting control system. Simulation shows that the trace error of a D-FNN controller is smaller than that of a PID controller. Also, the D-FNN control scheme has good generalization and tracking performance, which allow it to satisfy the needs of a shearer height adjusting system.

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 the 30CrMnMo 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.

Reliability and maintainability analysis of electrical system of drum shearers

The reliability and maintainability of electrical system of drum shearer at Parvade. 1 Coal Mine in central Iran was analyzed. The maintenance and failure data were collected during 19 months of shearer operation. According to trend and serial correlation tests, the data were independent and identically distributed （iid） and therefore the statistical techniques were used for modeling. The data analysis show that the time between failures （TBF） and time to repair （TTR） data obey the lognormal and Weibull 3 parameters distribution respectively. Reliability-based preventive maintenance time intervals for electrical system of the drum shearer were calculated with regard to reliability plot. The reliability-based maintenance intervals for 90%, 80%, 70% and 50% reliability level are respectively 9.91, 17.96, 27.56 and 56.1 h. Also the calculations show that time to repair （TTR） of this system varies in range 0.17-4 h with 1.002 h as mean time to repair （MTTR）. There is a 80% chance that the electrical system of shearer of Parvade. 1 mine repair will be accomplished within 1.45 h.

Dynamic Simulation of Shearer with 3D Computer Graphics

Based on computer graphics principle, technology and 3D graphics software, this paper deals with the 3D part design, assembly and animation of shearer in longwall integrated mechanized coal mining. The matixes of kinetic and geometry relationships and 3 dimension space coordinate systems are built for the cut drums, arms and shearer body. The methods of 3D modeling, dynamic simulation and relative technique problems are discussed.

An experimental research of dynamic characteristics for long wall shearer cutting unit gearbox in oblique cutting

Oblique cutting is a working condition in fully mechanized mining whose function is making it possible for coal shearer to cut coal wall.Coal shearer often exhibit large vibration amplitudes in oblique cutting since the shearer is forced to be bent.In this study,dynamic behavior in oblique cutting for the coal shearer cutting unit gearbox(SCUG)is investigated experimentally based on National Coal Mining Equipment Laboratory of China.A new long wall mining test set-up consists of a test coal shearer and other auxiliary machines is developed for operating long wall coal mining process.Realistic oblique cutting process is developed,and vibration response will be more accurate since both cutting loads and test machine in this experiment are realistic.A data-acquisition system consisting of sensors,channel conditioner and computer is developed to capture three-dimensional vibratory accelerations.A test matrix which included various combinations of key cutting load parameters is executed under realistic oblique cutting loads within a wide parameter range to establish database.Experimental data is analyzed in time,domain and time-frequency domains for investigating the rules of dynamic behavior for SCUG.Beat vibration phenomenon and the coupling of gear mesh frequencies are found in experiment,resulting in local resonance and reduce fatigue life of SCUG.The influence of cutting load on beat phenomenon and frequency coupling is demonstrated at the end,and some conclusions are obtained.

Factors affecting thin coal seam shearer drum coal-loading performance by a model test method

To solve the problem of a low coal-loading rate being exhibited by the drum shearer on Chinese thin coal seams,systematic tests and research were performed to study the pivotal factors’influences on drum coal-loading rate using a model test method.The effects of the drum hub diameter,cutting depth,vane helix angle,drum rotation speed and hauling speed on drum coal-loading rate were determined under circumstances of coal-loading with drum ejection and pushing modes,and reasons for these phenomena were analyzed.The results indicate that the influence of the drum cutting depth on the drum coal-loading rate is the most significant.The parameters of hub diameter,drum rotation speed and hauling speed can influence the drum coal-loading rate by cutting the coals’filling rate in the drum.The parameters of vane helix angle and drum rotation speed can influence drum coal-loading rates by influencing the ratio of cutting coals’tangential and axial speed in the drum.The coal-loading rate with drum ejection is clearly higher than that observed with drum pushing.Research in this study can provide support to design the drum structure and select drum operational parameters for a thin coal seam shearer.

Analysis on vertical steering vibration of drum shearer cutting part

The impact of the load on the shearer is mainly transmitted through cutting part.In this paper,in order to get the vertical steering vibration characteristics of the cutting part of the drum shearer,the working condition of coal mining machine is simplified.A simplified vertical steering model and the simplified vibration model of the whole cutting part of shearer are established.The vertical steering vibration process of the cutting unit is simplified into a single freedom and one forced vibration system under harmonic excitation.The dynamic response of the cutting part under sine excitation is obtained by using Matlab/Simulink for modeling and simulation.The influence of the support rigidity and damping of the high oil cylinder on the vertical steering vibration characteristics of the cutting part is analyzed.The results show that the damping of the cylinder can reduce the vibration of the system and the stability of the swing process of cutting the part is improved.

Parameters analysis of shearer drum loading performance

Three drums with different helical angles （15°, 20°, and 25°） were developed to investigate improved loading performance of the shearer drum. Nine trials were performed at different drum rotation speeds （80, 100, and 120 r/min） and different haulage speeds （1.5, 2.0, and 2.5 m/min） in an orthogonal test design. Loaded coal quantity and cutting power of the drum were the responses measured under the dif- ferent conditions. The effect of the parameters was determined by means of the extreme difference method. The significance of the effects was determined by analysis of variance. The results indicate that the effect from changes in the helical vane on loading performance of the drum is the largest in magnitude. The haulage speed has the least affect on loading performance. The helical angle has the least affect on cutting power of the drum. Haulage speed has the largest affect on the cutting power of the drum. 2011 Published by Elsevier B.V. on behalf of China University of Mining ＆ Technology.

A preliminary study on selected methods of modeling the effect of shearer operation on methane propagation and ventilation at longwalls

Underground coal mining frequently uses longwalls.The occurrence of a potentially explosive mixture of methane and air is one of the most serious hazards.A large number of papers have applied numerical modeling of methane propagation in research aimed at this problem.To date,none of the CFD simulations has considered the movement of the shearer in the analyses.This paper proposes an adaptation of a method used for the description of the movement of trains in tunnels to a specific geometry of a longwall district.The flow of the air-methane mixture was calculated using the finite volume method,in particular the k-w SST and SAS turbulence models.Due to the movement of the shearer,moving and deforming meshes were used for simulation of unsteady flows.Examples of solutions for two hypothetical cases are presented.Finally,the drawbacks and advantages of presented methods are discussed.Further development with the application of either local mesh variability or overset meshes is outlined.

Nonlinear multi body dynamic modeling and vibration analysis of a double drum coal shearer

The double drum coal shearer is widely applied for the underground coal exploration in the mining industry.The vibration and noise control are significant factors for the stability design of the double drum coal shearer.In this paper,the vibration properties of a double drum coal shearer are firstly investigated.The horizontal,transverse and torsional vibrations of the motor body and the angle displacements of the rockers are taken into account.The walking units and the hydraulic units are modeled by the stiffness-damping systems.The nonlinear equation of motion of the double drum coal shearer is established by applying the Lagrange’s equation.The nonlinear vibration response of the system is calculated by using the Runge Kutta numerical method.The effects of the shearing loads,the equivalent damping and stiffness of the walking units,the inclination angels of the rockers and the equivalent damping and stiffness of the hydraulic units on the vibration properties of the system are discussed.

What can the changes in shield resistance tell us during the period of shearer's cutting and neighboring shields' advance?

In order to determine the influence of shearer's cutting and neighboring shields' advance on the support resistance variation, leg pressure data of all 235 shields in the panel LW61 of Cumberland coal mine were analyzed. The results show that the relationship between the leg pressure increment and the distance from shield to front drum of shearer is a quadratic function and that the higher leg pressure increment before shield advance tends to be related to adverse roof conditions. In addition, the three proposed leg pressure increment-related parameters and the three traditional parameters(time-weighted average pressure, setting pressure, and final pressure) of approximately 32000 shield supporting cycles were calculated by a self-developed software package to analyze the correlation between them. The results show that there is a powerful connection between them, and that the three proposed leg pressure increment-related parameters could be used as the indexes to evaluate the interaction between shields and the roof, and to identify the periodic weighting.