彩色显像管玻璃中的气泡

气泡是显像管玻璃生产中最主要的缺陷,本文主要论述了彩色显像管玻璃中气泡产生的原因,并对玻璃中气泡缺陷的分析、判定以及减少气泡缺陷的措施作了简要评述.     

液晶玻璃基板气泡缺陷分析与对策

基于液晶玻璃生产中气泡缺陷分析,就气泡缺陷的分类、产生原因及对策方法展开分析讨论,为液晶玻璃生产气泡缺陷分析对策提供思路,提高对策效率。     

泡沫玻璃气泡缺陷与解决方案

泡沫玻璃是一种具有均匀气泡结构的玻璃制品,具有隔热、吸声、防潮、防火等特点的轻质高强建筑材料和装饰材料。泡沫玻璃的生产过程中,经常会遇到气泡结构不均或大气泡等气泡缺陷。本文从气泡的产生机理分析入手,针对具体的气泡缺陷种类,分析产生原因,提出解决方案,更好地实现泡沫玻璃的内在和外观质量。     

用质谱分析判断气泡的形成

气泡是浮法玻璃生产中最常见的玻璃缺陷之一,由于它的尺寸、密度、位置的不确定性,增加了对气泡缺陷来源诊断的难度.通过测定气泡气体的组成含量,可以较准确、快速地判断该缺陷产生的根源,从而采取有效措施消除缺陷,提高产品质量和生产效率.     

气体成分分析判定浮法玻璃气泡来源

气泡是玻璃产品中最主要的缺陷之一,本文主要论述了通过分析玻璃气中的气体成分,判定并帮助解决了一起实际生产中的气泡缺陷.     

浮法玻璃气泡的产生与控制

气泡是浮法玻璃的主要缺陷之一,在浮法玻璃生产中,除退火以外,其他任何一个小环节的不稳定,都有可能产生气泡。总结气泡规律,利用岩相分析准确快速判断气泡来源,采取措施,尽快提高玻璃产量质量,成为生产过程中的一个重要课题。     

液晶玻璃基板气泡缺陷分析与对策

液晶显示平板对基板玻璃的外观品质和玻璃内部缺陷数量有着极高的要求,气泡作为液晶玻璃基板产品的主要缺陷之一,其形态和产生机理各有不同。根据液晶玻璃基板中常见的气泡缺陷进行分类,对不同的气泡缺陷的成因进行分析,并提出相应的解决对策。     

玻璃制品的气泡缺陷

气泡是玻璃制品的常见缺陷,阐述了玻璃中气泡的成分及形成机理,提出了去除气泡的机理,并详细说明了一次气泡、二次气泡及其他种类气泡的解决方法。     

格法玻璃气泡的产生与防治

分析了该厂格法玻璃生产中产生气泡缺陷的主要原因,提出了预防和治理措施。     

玻璃制品的气泡缺陷

气泡是玻璃制品的常见缺陷,阐述了玻璃中气泡的成分及形成机理,提出了去除气泡的机理,并详细说明了一次气泡、二次气泡及其他种类气泡的解决方法。     

挥发滴落物气泡的成因及防止

气泡是浮法玻璃中的主要缺陷,从来源上搞清气泡的分类,能为解决气泡问题提供科学依据.挥发滴落物气泡属于杂质气泡,可以从配合料参数的合理设定、稳定熔窑工艺制度、窑炉设计方面以及熔窑、流道等部位的彻底吹扫等方面进行改进与处理,从而解决该类气泡问题,稳定玻璃质量.     

Effect of bubble interaction on interphase mass transfer in gas fluidized beds

A non-interfering technique has been used to measure the concentration of ozone in pairs of bubbles injected into a bed of inactive 390 μm glass beads fluidized by ozone-free air. The transfer of the ozone tracer from the bubble phase to the dense phase is enhanced when compared to the transfer from isolated bubbles in the same particles and the same column. Bubble growth is also greater for the case where pairs of bubbles are introduced than when bubbles are present in isolation. Enhancement of interphase mass transfer for interacting bubbles in the present work and in previous studies incr with particle size and can be explained in terms of enhancement of the throughflow (or convective) component of transfer while the diffusive component unaltered. This mechanism leads to new equations for estimating interphase mass transfer in freely bubbling fluidized beds.     

Spontaneous Bubble Formation in Silicate Melts at High Temperatures

Heating previously melted glasses usually produces gas bubbles in the melt at constant pressure. Bubble formation generally occurs in a narrow temperature range; if experimental conditions are carefully controlled the temperature at which gas bubbles form and the characteristics of the bubbles can be reproduced with reasonable accuracy. Extensive measurements were made with binary silicates of lithia, soda, and potash. Significant bubble evolution occurred only when there was sulfur in the glass. Bubbles formed at quite high temperatures (1400° to 1500°C) in dry oxygen but did not form in reducing atmospheres and quite stable foams resulted. In dry reducing atmospheres some bubble formation was observed at lower temperatures (1200° to 1300°C). The behavior was considerably altered in atmospheres containing water vapor and by changes in base glass composition or sulfur content.     

Role of zirconia phase transformation,interface processes,and Ta2O5 doping on the blistering phenomenon of molten glass in contact with zirconia-based refractories

Bubble formation and removal within the molten glass is an important issue in glass industry. Various sources of bubbles have been identified in glass manufacturing: decomposition of the glass components, air trapping, oxidation/reduction reactions, precipitation resulting from insufficient refining, etc. It has been demonstrated in a previous paper that the blistering phenomenon at the interface between a molten glass and a zirconia-based refractory can be ascribed to the oxygen semipermeability through the zirconia phase. The objective of this study is to clarify the role of temperature on the blistering process, and especially, below and above the phase transition temperature of zirconia (monoclinic/tetragonal transformation) and to evaluate the role of zirconia doping on the blistering level. The influence of the kinetics of the surface processes at the glass/refractory interface is emphasized. Quantitative measurement of the slight blistering ascribed to the so-called “redox shock” is also given.     

The effect of bed materials on the solid/bubble motion in a fluidised bed

Gas fluidisation provides good mixing and contact of the gas and particle phases as well as good heat transfer. These attractive features are achieved by the high degree of bubble-induced particle circulation within the bed. Bubble and particle motion vary with bed materials and operating conditions, as investigated in the present study, by the use of the non-intrusive positron emission particle tracking (PEPT) technique. The selected materials were spherical polyethylene and glass particles.The data obtained by the PEPT technique are used to determine the particle velocities and circulation pattern. Bubble rise velocities and associated sizes can be inferred from the particle velocity data, since particles travel upwards mostly in the bubble wake. The results indicate that the flow structure and gas/solid motion within the fluidised beds were significantly different, even at the same value of the excess gas velocity, U-U_mf. The solid circulation pattern within the beds differ: if for glass beads, a typical UCDW-pattern existed (upwards in the centre of the bed, downwards near the wall), the pattern in the polyethylene bed is more complex combining a small zone of UWDC movement near the distributor and a typical UCDW-pattern higher up the bed. Transformed data demonstrate that at the same value of excess gas velocity, U-U_mf, the air bubbles in the polyethylene fluidised bed were smaller and rose more slowly than in the fluidised bed of glass beads, thus yielding a longer bubble residence time and improved gas/solid contact. For polyethylene beads, the size and rise velocity of air bubbles did not increase monotonically with vertical position in the bed as would be predicted by known empirical correlations, which however provide a fair fit for the glass beads data. Bubble sizes and solid circulation patterns are important parameters in the design of a fluidised bed reactor, and vary with the bed material used.     

Near‐surface vapour bubble layers in buoyant low stretch burning of polymethylmethacrylate

Large‐scale buoyant low stretch stagnation point diffusion flames over a solid fuel (polymethylmethacrylate) were studied for a range of aerodynamic stretch rates of 2–12 s⁻¹ which are of the same order as spacecraft ventilation‐ induced stretch in a microgravity environment. An extensive layer of polymer material above the glass transition temperature was observed. Unique phenomena associated with this extensive glass layer included substantial swelling of the burning surface, in‐depth bubble formation, and migration and/or elongation of the bubbles normal to the hot surface. The bubble layer acted to insulate the polymer surface by reducing the effective conductivity of the solid. The reduced in‐depth conduction stabilized the flame for longer than expected from theory neglecting the bubble layer. While buoyancy acts to move the bubbles deeper into the molten polymer, thermocapillary forces and surface regression both act to bring the bubbles to the burning surface. Bubble layers may thus be very important in low gravity (low stretch) burning materials. As bubbles reached the burning surface, monomer fuel vapours jetted from the surface, enhancing burning by entraining ambient air flow. Popping of these bubbles at the surface can expel burning droplets of the molten material, which may increase the fire propagation hazards at low stretch rates. Published in 1999 by John Wiley & Sons, Ltd.     

Bubble Splitting in a Pseudo‐2D Gas‐Solid Fluidized Bed for Geldart B‐Type Particles

Bubble splitting in 2D gas‐solid freely bubbling fluidized beds is experimentally investigated using digital image analysis. The quantitative results can be applied for the development of a new breakage model for bubbly fluidized beds, especially discrete bubble models. The variation of splitting frequency with bubble diameter, new resulting bubble volumes, positions, and also the assumptions of mass and momentum conservation for bubbles after breakage are studied in detail. Small bubbles are found to be more stable than large ones and nearly all mother bubbles split into two almost equally sized daughter bubbles. The momentum of gas bubbles in the vertical direction remains approximately constant after breakage, whereas that of bubbles in the horizontal direction changes with no clear trend. The effect of fluidizing gas velocity in breakage frequency is also examined.