分阶段质调节下供热循环水泵最优运行方式的确定

针对闭式供暖系统采用分阶段经济流量比质调节问题,提出了在该流量小于单台循环水泵能够提供最大流量时,两台并联水泵可能有的多种运行方案;通过算例得出各个运行方案能耗大小的排序,并经过综合分析给出最优运行方式;强调了若将该最优运行方案应用于开式系统时并不一定是最优的结果。     

Rotary Ultrasonic Machining: A Review

Rotary ultrasonic machining (RUM) is a mechanical type of nontraditional hybrid machining process that has been utilized potentially to machine a wide range of latest and difficult-to-machine materials, including ductile, hard and brittle, ceramics, composites, etc. In RUM, the basic material removal phenomenon of ultrasonic machining (USM) and conventional diamond grinding amalgamates together and results in higher material removal rate (MRR), improved hole accuracy with superior surface finish. In the current article, several investigations carried out in the domain of RUM for enormous materials have been critically reviewed and reported. It also highlights several experimental and theoretical ensues of RUM to improve the process outcomes and it is reported that process performance can be substantially improved by making the right selection of machine, diamond tooling, material and operating parameters. In recent years, various investigators have explored umpteen ways to enhance the RUM process performance by probing the different factors that influence the quality attributes. Among the various accessible modifications in RUM as employed in industries, rotary ultrasonic drilling is more strongly established compared to other versions such as rotary ultrasonic side milling, face milling, grinding, surface texturing, etc. The micro machining applications of RUM have also been discussed briefly. The final section of this paper discusses RUM developments and outlines the aspects for future research.     

Recovery of Polycyclic Aromatic Hydrocarbons During Solvent Evaporation with a Rotary Evaporator

Analytical behavior of dichloromethane solutions containing polycyclic aromatic hydrocarbons (PAHs) was systematically studied through evaporation in a rotary evaporator. Starting sample concentration levels for each PAH were 0.167 w g/mL (concentrated) and 0.0167 w g/mL (diluted). Solvent reductions from 300 mL to final volumes of 30, 10, 3, and 1 mL (concentrated) and from 300 mL to 3 and 1 mL (diluted) were evaluated and each sample analyzed using gas chromatography-flame ionization detection (GC-FID). Factors affecting the percentage of analyte recovery include boiling point of analyte, the final sample volume, and starting sample concentration. When concentrated solutions were reduced from 300 mL to 1 mL, PAH recoveries were nearly all higher than 90%, except for naphthalene, acenaphthylene, and acenaphthene. However, when diluted solutions were evaporated to 1 mL, recoveries of all analytes dropped to 64.5% (naphthalene) ～ 89.2% (benzo[ ghi ]perylene). For evaporation to a final volume of 3 mL, recovery of PAHs in both concentrated and diluted solutions was higher than 90%. This implies that no significant losses of semivolatile analytes were found during evaporation of methylene chloride by rotary evaporation, regardless of boiling point or concentration level, until or unless the final volume was below 3 mL. Results of comparison of rotary evaporation and nitrogen blowdown showed that both concentration techniques provide qualitative recovery but rotary evaporation was more time effective.     

Investigation of the rotary swaging and heat treatment on the behavior of W- and γ-phases in PM 92.5W–5Ni–2.5Fe–0.26Co heavy alloy

The effects of rotary swaging and different heat treatment procedures on the W- and γ-phases behavior of PM 92.5W–5Ni–2.5Fe (wt.%) heavy alloy microalloyed with cobalt have been studied. The investigation was performed on sintered and cold rotary swaged samples deformed with area reduction from 5 to 30%. One batch of swaged samples was annealed in vacuum at 1473 K for 7.2 ks and then furnace-cooled to the room temperature, whereas another batch of swaged samples was previously deformed 30% and strain aged in argon and nitrogen in the temperature range between 473 and 1123 K for 3.6 ks. Strengthening of W- and γ-phases was investigated by applying microhardness measurements. Effects of the degree of deformation, parameters of heat treatment and strain aging on microstructural changes have been studied. Mechanical properties, hardness and microhardness of phases as a function of the degree of deformation and heat treatment were analyzed by applying statistical modeling. A correlation between deformation behavior of phases, effect of heat treatment and alloy properties was also discussed.     

熟料窑运行状态检测应用研究

阐述了对回转窑运行轴线进行监测的重要性 ;介绍了一种回转窑运行轴线监测的研究成果 ,该方法采用 15°方向键相法测量窑体截面的回转中心 ,通过对窑各挡支承轮带两侧的截面测量而获得运行轴线 ;研制的监测系统结构简单 ,运行可靠 ,监测精度高 ,操作、使用、维护方便 ,并成功地应用于实际生产中     

数控碾铆机的开发

介绍了自主开发的数控碾铆机的基本结构和组成，重点讨论了采用运动控制单元、PLC以及图示操作终端组建碾铆机数控系统的方法及技术关键，开发出一种经济性好、效率高、质量及可靠性高的数控碾铆机。     

降低114m^2立盘过滤机滤饼附液率的改进措施

针对立盘过滤机滤饼附液率较高的问题，主要从年心轴、分配头、扇形板及滤布选用等方面进行了深入探讨，分析了反吹风、进料分配器、滤液的排放方式等对立盘过滤机滤饼附液率的影响，提出了相应的改进措施。     

Improving hole exit quality in rotary ultrasonic machining of ceramic matrix composites using a compound step-taper drill

Mechanical-machining-induced tearing defects at hole exits restrict the application of C/SiC composites. Rotary ultrasonic machining (RUM) is suitable for hole manufacture in brittle composites, providing reduced tearing size as compared with conventional grinding. Even so, substantial tearing defects at the hole exit remain with RUM. In this study, a novel compound step-taper diamond core drill for RUM of C/SiC was developed to further improve the hole exit quality. Contrastive machining tests were conducted to evaluate the effectiveness of the new type drill. Experimental results show that the compound drill can help reduce the tearing size by 30% on average. Results of variance analysis indicate that there is little dependency of tearing size on processing variables with the compound drill, whereas the common drill shows substantial dependence. Detailed observation of the thrust force reveals that the tearing size reduction using the compound drill is due to the reprocessing effects of its taper face. In the reprocessing process of the taper face, the thrust force gradually decreases at the hole exit. Increasing the ultrasonic amplitude can help further improve the hole exit quality when using our compound drill.     

General solution to kiln support reactions and multi-objective fuzzy optimization of kiln axis alignment

Based on the analyses of the mechanical features of rotary kiln with multi-supports, a general mechanical model for indeterminate kiln with variable bending rigidities, arbitrary supports and complex loads is established. From this model, the equations of the rotational angle and the deformation are deduced, the general matrix and procedure are developed. The correlation between the roller forces and axis deflections of no. 2 rotary kiln is derived. To improve kiln performance by kiln axis alignment, taking roller forces equilibrium and relative axis deflection minimum as the optimization goal, considering the fuzzy constraints of axis alignment, the fuzzy optimization model of kiln axis alignment is set up. The optimization model is solved with the max–min approach. The results show that fuzzy optimization alignment of rotary kiln can make kiln axis as straight as possible and can distribute kiln loads equally.     

奥-贝球铁的研制及其在水泵零件上的应用

试制的奥－贝球铁，具有优良的机械性能和较高的性能／价格比，满足了水泵部分零件的性能要求，扩宽了奥贝球铁的应用领域。