Design and Prototype Test of 9FQM1000 Branch and Straw Hammer Mill

[Objectives]To better design and test 9FQM1000 branch and straw hammer mill in view of the problems of large output,low utilization rate,traditional incineration and easily polluting environment of the new agricultural economic organization's straw and waste branches.[Methods]This hammer mill adopts dual-channel feeding method.It adopts the basic working principle of disc shredding and hammer crushing.Besides,it makes design of the structure and driving system of the branch and straw hammer mill.9FQM1000 type branch and straw hammer mill can finely crush the branches and straws.Finally,it makes a trial production of 9FQM1000 type branch and straw hammer mill.[Results]The prototype test showed that the combined crushing structure of 9FQM1000 type branch and straw hammer mill is reliable,and the production capacity is 3000 kg/h.[Conclusions]The automatic feeder makes the crushing operation more stable,the labor intensity is reduced,the structure is simple,and it can be moved by traction.It is environmentally friendly and pollution-free.It has the characteristics of high safety,automation and high production efficiency.Also,crushed materials can be used as edible fungus culture medium,animal feed,organic fertilizer,etc.,and can be further compressed into biomass fuel,and the crushed branches can also be returned to the field.

A Comparative Technique for Performance Evaluation of Hammer Mill and Disk Mill in Yam Flour Processing

Grinding (Particle size reduction) of biomass is an age-long operation that is performed during the preparation process of certain food products. Among the grinding mill machines mostly used for this operation are hammer mill and disk mill. Being that the nature of biomass affects the performance and choice of grinding-mill machine to be adopted, it is imperative to compare and select appropriate grinding mill machine that is efficient and effective. In this paper, a comparative technique to evaluate and select appropriate grinding mill machine for particle size reduction of dried white yam (Dioscorea rotundata) is proposed. Hammer mill and disk mill machines were selected for consideration. Two white yam species (Benue and Delta Yam) were prepared into dried chips and ground using the selected mills. Among the attribute (performance parameters) considered are crushing time, particle size distribution and energy consumed. A measure of performance (Index I) based on the comparative technique was formulated and used in evaluating the performance of the two mills. In the hammer mill, index I recorded 2721.2 and 3719.82 par/kWh for Benue Yam chips at screen size 4 and 6 mm, respectively, while 2647.89 and 3472.01 par/kWh was recorded for Delta yam chips at screen size 4 and 6 mm, respectively. Index I values for the Disk mill were 2536.25 and 2433.42 par/kWh at 1.2 mm clearance distance for Benue Yam chips and Delta Yam chips, respectively. The results indicated that hammer mill performed better overall than the disk mill. The comparative technique was found suitable in the evaluation of the performance of the mills. It is recommended that hammer mill be adopted.

Digital monitoring of rotary-percussive drilling with down-the-hole hammer for profiling weathered granitic ground

Rock and geotechnical engineering investigations involve drilling holes in ground with or without retrieving soil and rock samples to construct the subsurface ground profile.On the basis of an actual soil nailing drilling for a slope stability project in Hong Kong,this paper further develops the drilling process monitoring(DPM)method for digitally profiling the subsurface geomaterials of weathered granitic rocks using a compressed airflow driven percussive-rotary drilling machine with down-the-hole(DTH)hammer.Seven transducers are installed on the drilling machine and record the chuck displacement,DTH rotational speed,and five pressures from five compressed airflows in real-time series.The mechanism and operations of the drilling machine are elaborated in detail,which is essential for understanding and evaluating the drilling data.A MATLAB program is developed to automatically filter the recorded drilling data in time series and classify them into different drilling processes in sub-time series.These processes include penetration,push-in with or without rod,pull-back with or without rod,rod-tightening and rod-untightening.The drilling data are further reconstructed to plot the curve of drill-bit depth versus the net drilling time along each of the six drillholes.Each curve is found to contain multiple linear segments with a constant penetration rate,which implies a zone of homogenous geomaterial with different weathering grades.The effect from fluctuation of the applied pressures is evaluated quantitatively.Detailed analyses are presented for accurately assess and verify the underground profiling and strength in weathered granitic rock,which provided the basis of using DPM method to confidently assess drilling measurements to interpret the subsurface profile in real time.

基于Bently-Hammer软件的长距离输水管道水锤防护模拟

基于Bently-Hammer软件对某实际工程中长距离输水系统进行建模,通过实际运行中的不同工况,模拟突发事件在管道与水泵间产生的水锤影响,同时针对系统内突发事件增加液压气动罐、缓闭止回阀等水锤消除措施加以改进,为实际工程提供有效抑制水锤破坏的技术保障。

基于Bentley Hammer的长距离有压管道输水工程的水锤防护研究

【目的】在长距离有压管道输水工程中,因管道内部水流条件复杂而容易产生水锤现象,不仅会影响水流正常输送,还可能导致管道破裂。因此,有必要进行长距离有压管道输水工程的水锤防护研究。【方法】基于台前县城乡供水一体化南水北调配套工程,通过Bentley Hammer软件,在最不利工况下分别建立三种数值模拟模型:无防护措施、加装复合式高速进排气阀水锤防护、气囊式空气罐和复合式高速进排气阀,进行联合水锤防护,对以上三种情况进行水力过渡过程数值模拟分析,研究复合式高速进排气阀与气囊式空气罐联合防护时的水锤防护效果以及气囊式空气罐的防护能力与预设压力和罐体体积之间的关系。【结果】结果表明:复合式高速进排气阀和气囊式空气罐可以很好地消除管道内水锤带来的危害,气囊式空气罐防护能力随着罐体体积和预设压力的增大而增强,罐体体积对其防护能力影响更显著。【结论】选择合理的罐体体积和预设压力可以使水锺防护发挥最好的防护效果,最大化输水工程的经济性。

Bentley Hammer V8i软件在城乡一体化供水管道水锤计算中的应用

应用Bentley Hammer V8i软件模拟城乡统筹供水工程中输水和配水管道的稳态工况与事故断电工况的水锤安全性,可以清楚地展示管内水流压力的变化趋势。本文以新和县城乡一体化实际供水工程为研究对象,评估其供水管网水锤安全性。模拟结果显示,虽然该工程在稳态工况与事故断电情况下管道内压力会有剧烈波动,但仍在管道的承载能力之内,可以通过优化关阀时间及相关操作来确保供水的安全稳定。本应用可供类似城乡一体化供水工程管道设计参考。

Water hammer protection for diversion systems in front of pumps in long-distance water supply projects

For a water supply system with long-distance diversion pipelines, in addition to the water hammer problems that occur beyond pumps, the safety of the water diversion pipeline in front of pumps also deserves attention. In this study, a water hammer protection scheme combined with an overflow surge tank and a regulating valve was developed. A mathematical model of the overflow surge tank was developed, and an analytical formula for the height of the overflow surge tank was derived. Furthermore, a practical water supply project was used to evaluate the feasibility of the combined protection scheme and analyze the sensitivity of valve regulation rules. The results showed that the combined protection scheme effectively reduced the height of the surge tank, lessened the difficulties related to construction, and reduced the necessary financial investment for the project. The two-stage closing rule articulated as fast first and then slow could minimize the overflow volume of the surge tank when the power failure occurred, while the two-stage opening rule articulated as slow first and then fast could be more conducive to the safety of the water supply system when the pump started up.

Performance of large-diameter pneumatic down-the-hole (DTH) hammers: A focus on influences of the hammer structure

Pneumatic down-the-hole (DTH) hammer has been extensively used in air drillings through hard and ultra-hard geological formations. Numerical modeling can offer close observation on the working behaviors by visualizing internal pressure status as well as provide reliable performance predictions for large-diameter DTH hammers to which conventional empirical and experimental approaches cannot be applied. In this study, CFD simulations coupled with dynamic meshing are utilized to simulate the air flow and piston movement inside the large-diameter DTH hammers. The numerical modeling scheme is verified against a theoretical model published in literature. Effects of structural parameters on hammer performance, including piston mass, piston upper-end diameter, piston groove diameter, and lengths of intake and exhaust stroke in both front and rear chambers, are analyzed in detail by virtue of sets of numerical simulations. The simulations suggest that changing the intake stroke of front chamber has a negligible influence on hammer performance while increasing the piston groove would lower all the four indicators of hammer performance, including impact energy, impact frequency, maximum stroke, and air consumption rate. Changing the other structural parameters demonstrates mixed effects on the performance indicators. Based on the numerical simulations, a large GQ-400 DTH hammer has been designed for reduced air consumption rate and tested in a field drilling practice. The air drilling test with the designed hammer provided a penetration rate 1.7 times faster than that of conventional mud drilling.

Research on Breeze Vibration Law and Modal Identification Method of Conductor Considering Anti-Vibration Hammer Damage

In the harsh environment,the structural health of the anti-vibration hammer,which suffers from the coupled effects of corrosion and fatigue damage,is significantly reduced.As part of the conductor structure,the anti-vibration hammer is rigidly attached to the conductor,effectively suppressing conductor vibration.The conductor’s breeze vibration law and natural modal frequency are altered damage to the anti-vibration hammer structure.Through built a vibration experiment platform to simulate multiple faults such as anti-vibration hammer head drop off and position slippage,which to obtained the vibration acceleration signal of the conductor.The acceleration vibration signal is processed and analyzed in the time and frequency domains.The results are used to derive the breeze vibration law of the conductor under multiple faults and propose an anti-vibration hammer damage online monitoring technology.The results show that the vibration acceleration value and vibration intensity of the conductor are significantly increased after the anti-vibration hammer damage.The natural frequency increases for each order,with an absolute change ranging from 0.15 to 6.49 Hz.The anti-vibration hammer slipped due to a loose connection,the 1st natural frequency increases from 8.18 to 16.62 Hz.Therefore,in engineering applications,there can be no contact to determine the anti-vibration hammer damage situation by monitoring the modal natural frequency of the conductor.This is even a tiny damage that cannot be seen.This method will prevent the further expansion of the damage that can cause accidents.

基于Bentley Hammer的泵站输水系统管道优化前后的水力过渡过程研究

为了研究泵站输水系统管道优化前后事故停泵的水力过渡过程的特性,基于实际工程,运用Bentley Hammer软件,建立泵站输水系统双泵并联机组数学模型,研究两阶段不同关阀方案下管道优化前后对水锤压力、机组转速等最不利水锤参数的影响。结果表明,管道优化后最大水锤压力降低了3.76%~8.85%,最小水锤压力提升了4.89%~8.85%,最大倒转速度提高了1.47%~81.35%;快关时间对最不利水锤参数有显著影响,管道优化后泵站输水系统最不利水锤参数均比优化前提前发生。表明管道优化有效改善了泵站输水系统的水锤特性,提高了泵站输水系统的安全性。

基于BP神经网络算法的粉碎机自适应控制系统设计

针对饲料加工行业中锤片式粉碎机控制系统存在启动时间长、响应速度慢及负载变化时出现的稳定性差等问题,提出了一种基于BP神经网络算法PID控制方法。首先,建立变频器和饲料粉碎机驱动电机组合系统传递函数的参考模型,并对其进行稳定性分析。然后在分析常规PID和模糊PID控制算法的基础上,将自适应神经网络算法PID应用到饲料粉碎机驱动系统的控制过程当中。通过搭建饲料粉碎机控制电机的仿真模型,利用MATLAB软件中的Simulink图形化编程功能对其进行仿真分析,并基于LABVIEW软件搭建了粉碎机测控系统试验平台进行实验测试分析。结果表明:对于饲料粉碎系统所给定的速度参考模型,设计的BP神经网络PID控制器能够实现较好的自适应追踪,对阶跃信号的响应更加迅速、超调更小,抗干扰能力更强。设计的自适应控制器能够根据工况变化自动调节PID参数,吨料电耗平均降低5.16%、生产率平均提高2.08%,对粉碎机主轴转速的控制更加精确,误差更小,兼具了较高的控制精度和较强的鲁棒性,满足饲料粉碎机驱动系统的自适应控制要求。

基于Hammer积分的三维地面磁共振高精度正演方法

为满足三维地面磁共振正演计算的精度要求,本文提出了基于非结构不均匀四面体网格的Hammer积分算法。首先利用有限元方法实现了对地下空间的三维磁场计算,完成了地面磁共振灵敏度核函数表达式的推导。针对现有地面磁共振正演方法中常规网格尺寸大、计算精度差、细化网格尺寸小、但是数量大的问题,应用Hammer积分在常规网格中完成核函数的高精度计算。三维核函数和3个含水模型的正演仿真实验表明:基于Hammer积分的地面磁共振正演方法具有网格少、计算节点少、积分精度高的特点,能够高效解决核函数的正演计算问题。

饲料粉碎过程工艺参数多目标优化设计

试验旨在对饲料粉碎过程工艺参数进行优化设计,以提高粉碎机工作性能。试验以生产率、吨料电耗为优化目标,以主轴转速、筛网孔径、物料含水率、喂料量和回料管直径为优化变量,采用响应面试验原理(BBD)设计试验并构建数据集;基于反向传播神经网络算法(BPNN)和粒子群优化算法(PSO-BPNN)建立饲料粉碎过程工艺参数的多目标优化综合模型;结合快速精英多目标遗传算法(NSGA-Ⅱ)进行多目标寻优,得到Pareto解集;通过CRITIC-TOPSIS评价模型对符合实际生产要求的Pareto解集筛选。结果发现,经过PSO优化的BP神经网络算法误差指标更小、预测精度更高,粉碎机的生产率、吨料电耗、粒度的平均优化幅度分别达到了61.07%、38.58%、54.31%;目标寻优后粉碎机最佳工艺参数组合为主轴转速2 697 r/min、筛网孔径5.8 mm、物料含水率10%、喂料量19.3 kg/min、回料管直径67 mm。研究表明,经优化设计后,粉碎机生产率增加了5.92%,吨料电耗降低了2.29%。

锤片式粉碎机工作参数优化试验研究

为解决锤片式粉碎机工作效率低、能耗高等问题,对其工作参数进行响应面优化设计。首先进行粉碎机最佳工作参数组合的优化试验,分析主轴速度、回料管直径、喂料速率、筛网孔径及物料含水率对生产率、电耗和粒度的影响规律。然后对试验数据进行响应面设计分析,求解出最优组合并进行试验验证。试验结果表明,粉碎机的最优工作参数组合为:主轴转速2700 r/min、回料管直径57 mm、喂料速率0.25 kg/s、物料含水率10%和筛网孔径6 mm。对比单因素最优的评价指标,生产率提高4.36%,电耗下降3.23%,粒度减小23.21%。

有限元方法的Gauss积分和Hammer积分方案

研究了一致网格剖分下矩形单元的Gauss数值积分和三角形单元的Hammer数值积分;再利用有限元方法求解偏微分方程,且通过非奇异问题和奇异问题的数值算例观察解的l2范数误差;进而研究单元数值积分对有限元解的精度的影响,并给出了有效且经济的数值积分方案。

重型燃机叶片周向圆弧锤足型榫头加工及检测技术

重型燃机叶片周向圆弧锤足型榫头具有盆背径向大平面、大直径复杂转接圆弧曲面、复杂设计基准和关联尺寸等特点,该类型叶片榫头面临铣削加工难度大以及三坐标检测重复性差等问题。本研究采用创新工艺方法突破技术瓶颈的限制,开发周向圆弧锤足型榫头卧式加工中心集成铣削及其三坐标检测技术,满足了周向圆弧锤足型榫头叶片的表面质量、尺寸精度、加工效率及外观要求。

Aseismic performances of constrained damping lining structures made of rubber-sand-concrete

Flexible damping technology considering aseismic materials and aseismic structures seems be a good solution for engineering structures.In this study,a constrained damping structure for underground tunnel lining,using a rubber-sand-concrete(RSC)as the aseismic material,is proposed.The aseismic performances of constrained damping structure were investigated by a series of hammer impact tests.The damping layer thickness and shape effects on the aseismic performance such as effective duration and acceleration amplitude of time-domain analysis,composite loss factor and damping ratio of the transfer function analysis,and total vibration level of octave spectrum analysis were discussed.The hammer impact tests revealed that the relationship between the aseismic performance and damping layer thickness was not linear,and that the hollow damping layer had a better aseismic performance than the flat damping layer one.The aseismic performances of constrained damping structure under different seismicity magnitudes and geological conditions were investigated.The effects of the peak ground acceleration(PGA)and tunnel overburden depth on the aseismic performances such as the maximum principal stress and equivalent plastic strain(PEEQ)were discussed.The numerical results show the constrained damping structure proposed in this paper has a good aseismic performance,with PGA in the range(0.2-1.2)g and tunnel overburden depth in the range of 0-300 m.

基于HAMMER的长距离输水管道水力过渡分析研究

在长距离输水管线发生事故停泵的时候,产生的水力过渡破坏对管线输水安全有重要的影响。本文研究以HAMMER软件作为平台,通过对输水管线的运行和事故停泵工况进行模拟研究,为确定管线最大升压和真空破坏的位置和解决方案提出建议。

Bentley Hammer软件在泵站水锤防护中的应用

通过工程实例,采用Bentley Hammer软件对乌兹别克Besharyk泵站项目进行建模,对停泵水锤进行分析与计算,针对其计算结果,提出了停泵水锤防护措施。并根据所提出的两阶段关闭止回阀和空气阀,采用Bentley Hammer软件对泵站模型进行了重新计算和分析,证明该防护措施是有效的。

RESEARCH ON THE ENERGY ECONOMIZATION OF ELECTRO-HYDRAULIC HAMMER

The research on the driving principle and economization of energy of electro-hydraulic hammer is discussed. By means of the balance chart of energy, the method and formulas to calculate every level efficiency and the total efficiency of steam drived hammer are formed.With the aid of actual data of plants,the actual efficiency of steam drived hammer is got. The working principle and the driving system of electro-hydraulic hammer are introduced. The procedure of energy energy of this hammer is analyzed. The utilization ratio of energy of this type of hammer is got. It is shown that the efficiency of electro-hydraulic hammer is 7 times as much as that of steam drived hammer.