提高砂磨机研磨效率的探讨

砂磨机占我国涂料研磨设备的40％以上。探讨了砂磨机类型、物料粘度及研磨介质同研磨效率的关系。卧式砂磨机的研磨效率比立式砂磨机高二倍左右,其填充量为70～90％,而立式砂磨机是45～50％。对于开启式砂磨机,物料标准粘度为～2D00厘泊,而密闭式是5000厘泊。提出了研磨介质的比重、硬度、抗压强度和化学稳定性的要求。     

研磨设备及参数对钙镁悬浮液性能影响的研究

研磨过程是悬浮肥生产前期准备过程中的关键环节。为提高生产效率，从球磨机、棒磨机、气流粉碎机、胶体磨机及砂磨机中找到适合钙镁盐的研磨设备，并对研磨过程中的工艺参数进行研究。结果表明：钙镁原料的最优研磨设备为砂磨机；原料预处理可以减小出料粒径；镁盐比钙盐更易研磨；固含量对粒径没有明显的影响，但结合目标悬浮体系的养分含量和流动性，选择初始固液质量比为5∶5；研磨时间优选50 min；添加助剂有利于提升研磨效果，助剂A与B的复配物在影响物料研磨细度以及抑制原料在冷、热储过程中粒径变大的情况有更好的效果。     

卧式砂磨机制备硫化包在乳胶行业的应用

乳胶行业分散体的研磨,基本采用单种分散体,立式研磨。但生产的混合硫化包粒径大,操作繁琐。利用卧式砂磨机采用高速锆珠研磨,细化胶乳硫化包(分散体)物质粒径,从而提高安全套等薄制品产品质量。同时比对市场售卖胶乳硫化包,从粒径,产品性能上比较,得出结论。     

研磨设备和工艺参数对氧化锆粉体粒度的影响

为了研究不同研磨设备及研磨工艺参数对粉体团聚体的解聚效果,以d50=1.355μm的氧化锆粉体为研究对象,研究了研磨设备和工艺参数对氧化锆料浆粒度的影响。首先,分别采用立式球磨机、立式珠磨机和卧式砂磨机为研磨设备,以φ2 mm的氧化锆球作为研磨介质,以m介质∶m物料=5∶1的介质物料比研磨15 h后,检测研磨后氧化锆料浆的粒度。结果表明,卧式砂磨机的研磨效果最优,研磨后氧化锆料浆的d50=0.303μm。然后,采用卧式砂磨机为研磨设备,以φ2 mm的氧化锆球作为研磨介质,选择介质物料比(m介质∶m物料)、料浆固含量(w)、线速度和研磨时间作为试验因素,进行四因素三水平(m介质∶m物料分别为4∶1、5∶1和6∶1,料浆固含量(w)分别为35%、45%和55%,线速度分别为5、10和15 m·s-1,研磨时间分别为20、25和30 h)正交试验,检测研磨后氧化锆料浆的粒度。结果表明:采用卧式砂磨机为研磨设备,当介质物料比(m介质∶m物料)为4∶1,料浆固含量(w)为45%,线速度为10 m·s-1,研磨时间为25 h时,研磨效果最佳,研磨后氧化锆料浆的d50约为0.3μm。     

浅谈卧式砂磨机在汽车涂料生产工艺过程中的应用

通过对汽车涂料生产过程中的关键设备——卧式砂磨机工作原理的研究,通过采用不同研磨工艺,在确保产品细度和外观质量、研磨遍数不超过工艺要求的前提下,通过考察不同研磨介质充填量、调整物料不同进料压力、可变出料等因素对砂磨机研磨效率的影响,指出常见问题的排查内容,并找出之间规律,结合数据分析以寻求出较为合理的设备工艺参数,制定卧式砂磨机生产操作工艺规程,有效保证汽车涂料在生产研磨分散过程中其综合性能达到配方设计要求。     

碳黑的研磨

在水溶性有机颜料的分散体系中,得到好的颗粒尺寸和窄的粒径分布很不容易。因此,要达到预想的粒径指标、稳定的分散体系,就必须充分利用砂磨机和化学物质。介绍了砂磨机钢球大小和分散剂对于难研磨碳黑粒径的影响。     

高性能砂磨机在颜料超细研磨中的应用

通过分析盘式砂磨机和棒销式砂磨机的工作原理,讨论了砂磨机在研磨颜料时,研磨介质密度和粒径、冷却水温度、物料的固含量及黏度对研磨工艺的影响.     

LME1000K卧式砂磨机在钛白生产中的应用

通过分析卧式砂磨机的工作原理和性能参数,确定其运行指标。讨论了研磨介质填充率、进料量和浆料黏度对卧式砂磨机运行指标的影响。针对本公司工艺情况,归纳出卧式砂磨机运行的最佳工艺参数,为表面处理包膜提供粒度分布和分散性良好的浆料。     

悬浮剂粒径分布及研磨工艺研究

悬浮剂制备中普遍使用砂磨机作为研磨设备。通过改变研磨介质的直径、珠料比以及砂磨时间等工艺参数,使用激光粒度仪测量了不同工艺参数下制备的百菌清及甲氨基阿维菌素苯甲酸盐悬浮剂的粒径分布,研究了不同工艺参数对悬浮剂粒径分布的影响。试验结果表明,砂磨机中使用锆珠作为砂磨介质时,选用粒径较小的锆珠、适当的珠料比和足够的砂磨时间均可以得到粒径分布较窄的悬浮剂产品。     

研磨设备的研磨效率与不同研磨方式对涂膜性能的影响

讨论了影响和提高研磨效率的因素，主要探讨了砂磨机和球磨机的研磨效率和不同研磨方式对涂膜性能的影响；着重研究了篮式砂磨机和球磨机这两种研磨方式在涂料耐磨性方面的差别，以及篮式砂磨机砂子填充量对研磨效率的影响。     

苏里格气田不同组合类型的复合砂体水平井采出程度研究

苏里格气田现有直井产能低、整个区块开发效率差,水平井开发是提高气田采出程度的有效方法。然而,水平井在不同砂组中布署的适应性问题尚不明确。本文依据沉积成因分析,剖面储量集中度分布特征,建立了三种砂体组合类型,即厚层块状孤立型、多期垂向叠置泛连通型和多期分散局部连通型。通过对不同类型砂组开展地质建模、数值模拟研究,分析了各自情形下水平井储量动用的程度。研究表明,厚层块状孤立型、多期垂向叠置泛连通型复合砂体采用水平井开发比直井开发采出程度可提高10％-15％,而多期分散局部连通型复合砂体则更适应采用直井开发。     

Influence of flow field on sedimentation efficiency in a circular settling tank with peripheral inflow and central effluent

The paper presents an experimental study of suspension flow patterns and velocity field inside a circular settling tank with continuous operation. Research was focused on the impact of a specific flow pattern on the sedimentation efficiency of the prototype settling tank. The latter differed from a common circular settling tank in that it was peripherally fed and had the central draw-off. Experiment was carried out on a settling tank section made of plexiglass and represented a radial slice of a prototype settling tank. The flow field and local suspension concentration was determined by computer-aided visualization. Sedimentation efficiency was assessed relatively by comparison of the amount of settled particles (sludge height measurements) between different types of flow in a certain time period of the settling tank operation. Results showed that there were two types of flow in the settling tank that were initiated by a horizontal or vertical inflow from the distribution ring. The type of inflow (horizontal or vertical) was a function of the suspension height in the settling tank. Significant differences in sedimentation efficiency were observed between both types of flow, particularly at lower inlet suspension concentrations. Horizontal inflow proved to be less efficient in terms of settling.     

A new method for the control of dilute suspension sedimentation by horizontal movement

This research addresses some factors that control the stability of dilute suspensions in sedimentation processes under a dynamic environment. Experimental and numerical studies were conducted about the sedimentation velocity control of dilute suspensions by horizontal movement for particle concentrations up to 8 wt.%. Nearly monodispersed particles were used as test particles. The effects of horizontal movement speed and amplitude on particle sedimentation process were investigated. Under stationary conditions, particles settle in only one vertical direction because of gravitational force. However, complicated particle motions arise under moving conditions due to circulation flow in horizontal moving conditions. The results show that horizontal movement can reduce the particle settling velocity or maintain the stability of the suspension.     

Characterization of media mills based on mechanical energy applied to particles

This paper deals with the evaluation of characteristics of media mills having a different milling mechanism based on the mechanical energy applied to the particles to be processed during a milling treatment. Spherical copper powder was used as a stress-sensitive material and the milling treatment of the copper powder was carried out under various operating conditions using three types of media mills, a horizontal tumbling ball mill, vertical agitating ball mill and bead mill. The size distributions of copper powder before and after the milling treatment were measured and the deformation of copper particles was determined experimentally. The net energy applied to the copper powder was estimated from the plastic deformation of copper particles. It has been clarified that the applied energy depends strongly on the motion of media in the mill. By introducing two dimensionless parameters, which express the energy transfer efficiency from the kinetic energy of media to the particles and the motion of media in the mill, respectively, the media mills could be characterized on a uniform scale based on the applied energy regardless of milling mechanism.     

Control of crude oil dilution in palm oil mills

This paper discusses the results of development work on the control of crude oil dilution in palm oil mills. The importance of crude oil dilution in palm oil mills is clearly shown by a simple cost-benefit analysis. Preliminary results from a three-phase decanter trial have shown that, besides a clarification system using horizontal or vertical clarifiers, dilution control is also important to a decanter system. A practical approach to the automatic control of crude oil dilution using a flow ratio control system is discussed in depth in this paper. Results obtained from the evaluation of Doppler and magnetic flowmeters have shown that the major obstacle in automatic control of crude oil dilution, i.e., the selection of a suitable flowmeter to measure crude oil flow, has been overcome.     

Fall velocities of saltating sand grains in air and their distribution laws

In a cloud of blowing sand, collisions between falling sand grains and the sand bed are an important process that is the main source of additional saltating sand grains, because the collision process transfers momentum to the sand bed and initiates the liftoff of new sand grains. The initial liftoff and fall velocities of saltating sand grains are key parameters in the collision process, but little information exists on the subsequent fall velocities of the saltating sand grains. One important reason for this lack is that the collision process is unclear. Based on experimental data from high-speed multi-flash photographic images obtained in a wind tunnel and on a motion model of saltating sand grains, this paper discusses the fall velocities of saltating sand grains and the corresponding velocity frequency distributions. The results demonstrate that fall angles are small (less than 20°), and decrease with increasing frictional wind velocity. The vertical component of fall velocity increases with increasing frictional wind velocity, and is consistent with the initial vertical liftoff velocity. The fall angle and vertical velocity both follow a gamma distribution. The horizontal fall velocity mainly determines the resultant fall velocity, and both increase with increasing frictional wind velocity. The horizontal and resultant fall velocities follow a Pearson IV distribution. These results improve our understanding of the collision process between falling sand grains and sand beds and will also help us to modify the splash function that connects the parameters of falling saltating sand grains and their initial liftoff parameters.     

新型耐磨耐蚀砂磨锅的研究

对化工研磨行业广泛应用的砂磨锅进行了失效分析、锅壁结构改进及选用新型耐磨耐蚀材料等方面的研究。提出了新型波纹形护板结构砂磨锅和采用ＭＳ５铸钢制造砂磨锅，并取得良好的效果。     

Cutting edge damage in grinding of cemented carbides micro end mills

Micro mills are widely applied in the micro manufacturing and mainly fabricated using the grinding method. Cutting edges have significant influences on the performance of micro mills such as the micro mill life and machining quality. In this paper, the cutting edge damage mechanisms in the grinding of cemented carbides micro mills are investigated. The micro end mills grinding experiments are carried out and the cutting edge maximum edge damage width and surface roughness of the end teeth flank are measured. The results show that the micro fractures and micro cracks are generated in the cutting edge following micro pits in the grinding surface. The grain size and composition of cemented carbides have significant impacts on the damage of the cutting edge. The maximum edge damage width increases with the increase of Co binder content and WC grain sizes. However, a better flank quality with less micro pits is obtained as the reduction of Co binder content and grain size of WC.     

THE EFFECT OF STATIC CHARGES ON DRAG REDUCTION IN DILUTE GAS-PARTICLE SUSPENSION FLOW

This is an experimental study on the drag reduction phenomenon in a gas-particle suspension two-phase flow system. The purpose of the research was to examine the effect of static charges carried by the conveyed particles on the drag reduction characteristics of a flowing suspension in horizontal and vertical tubes. A specifically designed experimental loop was used to perform simultaneous pressure drop and particle charge measurements. The charge on the particles flowing in the system was artificially increased using high voltage rod-in-cylinder Corona chargers mounted in the closed loop. The particle charge was measured in a Farraday cage sampling device and the effective current generated by particle impact on a specially designed spherical nickel probe mounted in the two-phase flow was also recorded.

It was found during the measurements that the pressure drop in the vertical test section was not significantly influenced by the charge build-up on the flowing particles, while the results obtained in the horizontal test section showed a significant effect on the drag due to charged particles. The electric charge on the particles was shown to have a negative contribution on the drag reduction: the higher the value of the effective charge, the higher the drag increase, i.e., the smaller the drag reduction.     

Design of Horizontal Vessels Operated as CSTR – Basic Mixing Tasks,RTD, Productivity

Agitator performance in standard vertical vessels with cylindrical shape, dished bottom and zero to four baffles has been the topic of numerous publications. In certain industries, however, horizontal cylindrical vessels with hemispherical ends, divided internally into multiple compartments, are preferred for continuous processes operating at high pressures. Use of standard correlations derived from vertical vessels may lead to incorrect performance predictions for these horizontal vessels, and hence unsatisfactory process results. A number of laboratory trials were undertaken to identify differences in behavior and potential means to improve design for horizontal vessels. Differences with respect to solids suspension, mixing time and residence time distribution were studied. CFD simulations were undertaken and validated against the experimental results.