Modeling Temperature Fields in Glass Articles in Annealing

Methods for the calculation of temperature fields in flat and cylindrical glass articles are considered. The advantages of numerical methods compared to analytical methods for the calculation of temperature fields in complex shapes of articles and heat-exchange processes are demonstrated.     

Modelling Annealing Lehrs for Flat Glass

Computer simulation of heat transfer in annealing lehrs for flat glass is combined with a method developed earlier for the calculation of stresses in glass. With this combined model one can predict stresses produced by annealing schedules that are readily realized in practice. Implications for the design, operation, and energy economy of lehrs are discussed.     

Optimum Schedule for Annealing Flat Glass

This paper formulates and solves the problem of optimum annealing of glass in which one seeks to minimize either residual stress or annealing time. An approximate analysis shows that residual stress is a weighted integral of cooling rates and that an optimum schedule is obtained when the cooling rate is inversely proportional to the square root of the weighting function. Several multibreak annealing schedules are investigated. It is found that a practical and nearly optimum schedule in this class is a two-break schedule that cools glass most slowly in a 65°CC interval and most rapidly outside this interval. It yields an optimum stress significantly lower than that of a constant-rate annealing schedule. Furthermore, the optimum is not very sensitive to minor changes in the schedule.     

Lead-Free Paint Coatings for Glass Articles

The effect of binders on the quality of paint coatings based on lead-free enamels and meeting the requirements of standard TU RB 100029049.030 is considered. It is established that enamel compositions can be prepared using 20% solution of oxyterpene resin in turpentine and 2% alcoholic solution of Na-carboxymethyl cellulose of grade 7MF. The use of an aqueous solution of dextrin as a binder deteriorates the quality of enamel coatings: it produces color modifications, loss of luster, and formation of crackle.     

Nonlinear Annealing of Glass

Transient as well as residual stresses were measured in laboratory experiments on annealing by nonlinear cooling schedules. The data on transient stresses, in particular, were incompatible with a classical view of annealing but they could be explained by a more recent model of annealing, in which account is taken of structural as well as stress relaxation. The potential utility of nonlinear annealing schedules is also discussed briefly.     

Lead-Free Enamels for Decoration of Glass Articles

The optimum compositions of lead-free fluxes and enamels based on them are determined; their physiochemical properties are analyzed. The quantitative transformation of the enamel coating into solutions depending on the duration of the reactant effect is determined.     

Nondestructive Heat-Treatment Regimes for Glass and Ceramic Plates

Unilateral heating of a glass or ceramic plate freely fixed along its contour by a surface source is considered in the context of a quasistatic non-coupled problem. An analytical relationship is obtained, which is a criterion of thermal strength of the plate and allows for identifying nondestructive treatment regimes. It is shown that for many materials there is a range of Fourier number variations in which the plate under treatment can be destroyed by thermoelastic stresses.     

Erosion Regimes Characterization of Soda-Lime Glass

Silicon - In this work, a semi-empirical relationship between sandblasting times and the surface roughness is presented. The derived relation is valid for the case where the erosion process does...     

玻璃熔窑刚架结构设计计算

以某千吨级大型浮法玻璃熔窑为例,介绍了熔窑横向钢结构采用刚架结构体系的设计计算方法。     

Fine Annealing of Optical Glass

Since the most important characteristic of optical glass is the uniformity of its refractive index, which is itself a function of fictive temperature, any fine annealing treatment must be such as to bring about substantial uniformity in fictive temperature. Methods of accomplishing this are reviewed. In terms of total required time in the annealing process, the most efficient method consists of soaking the glass for a short time at a temperature near the annealing point and cooling at a constant rate to a temperature below the annealing range and at an increased rate to room temperature. Formulas are given for specifying the parameters in the annealing schedule in terms of the final condition of the glass as to stress and index. The several outstanding advantages of this method of annealing are discussed.     

热煤气用于玻璃制品的退火

通过对热煤气进行简单除尘、除焦,采取特定管道加压、加热,保证热煤气的远距离持续供应,用于玻璃制品退火是可行的。     

薄玻璃的退火

简要分析和探讨了薄玻璃板生产过程中的退火问题,为薄玻璃板的生产提供一定的指导作用。     

Technological Aspects of Using Granulators for Molten Glass in the Production of Different Glass Articles

Glass and Ceramics - Different designs of granulators for molten glass which are used in the production of glass containers and other glass products are considered. The basic advantages and...     

浅谈浮法厚玻璃的退火

以12mm浮法玻璃为例,对浮法厚玻璃生产中的一些常见问题进行了分析并提出了解决的办法。     

浅论特种玻璃退火窑的传动

特种玻璃退火窑的传动有其特殊性,高温区的辊子材质采用陶瓷辊,其传动方式有三种,对特种玻璃退火窑传动的一些体会与大家探讨。