New refractory materials for construction and overhaul of glass furances

Borovichi Refractories Combine Co. has developed and mastered production of a series of new kinds of refractory articles for construction and overhaul of glass furnaces: molded packing of the bucket type for glass furnace regenerators (chamotte, mullite-corundum and periclase-spinel compositions); chamotte light-weight brick with a density of 0.9, 1.0, and 1.3 g/cm³, with high strength; large-block articles for lining the bottom of glass furnaces; elements for the top structure, production channels, burners, and other elements of the glass furnace (based on customer plans) made of low-cement concretes. The articles have a high technical lifetime and are recommended for use in many glass works.     

METHOD FOR MEASURING FINING TIME OF GLASS*

A method is described for measuring the fining time of glass, and a formula is given for using the data obtained to estimate the tonnage-temperature schedules of continuous tank furnaces. Measurement of fining time at two and preferably three temperatures, in the range 1400° to 1500°C., is required to establish the fining characteristics of a glass. Data from fining-time measurements of four glasses show that fining is largely independent of the viscosity and probably also of the surface tension of glass. The use of fining-time measurements in accounting for differences in the melting efficiencies of tank furnaces and the value of systematic studies, involving fining agents and variations in composition, are suggested.     

Control of the thermal conditions of a tank furnace based on produced glass homogeneity

Mathematical models are constructed to describe the dependences of homogeneity, defects, and specific heat consumption on melting conditions. The efficiency of using daily variations in glass homogeneity and density to control the thermal regime of a tank glass-melting furnace is demonstrated.     

DESIGN OF A FURNACE FOR ANNEALING OPTICAL GLASS1

Design of a natural-gas furnace for annealing optical glass.—Most of the furnaces built for annealing regular glassware are unsuitable for optical glass due to irregularity and inequality of temperatures. Working drawings are given for a successful optical glass annealing furnace operated by natural gas. The design is novel in the placing of the flues and burners in such a manner as to supply the heat and remove it in a symmetrical manner, thus obtaining uniformity of temperature.     

小型水平全电熔窑上层空间的布置对生产的影响

研究了小型水平伞电熔窑上层空间的布置对生产的影响.介绍了通过长期生产一线的实践和观察,发现上层空间布置得合理与否,直接关系到电熔窑的生产成本、热效率的高低、窑炉的使用寿命和玻璃质量的好坏.通过试验与进一步的生产实践,最终得出当熔制不同品种的玻璃或电极布置方式不同时,电熔窑上层空间的布置也应相应不同.     

SEPARATION OF INHOMOGENEITIES IN BOTTLE GLASS BY DENSITY DIFFERENCES*

Cordy glass consisting of a mixture of fibers or laminations of various glasses of slightly differing compositions is separated in the form of powder by differences of density. These differences in general run parallel with differences of thermal expansion which produce the polariscopic appearance of cordiness. The separated fractions can be analyzed chemically, and therefore, perhaps, for the first time an estimate can be made of the chemical errors involved in the cords of the old polariscopic gradings, A, B, C. The most important features of the technique are (1) the elimination of moisture from the glass and the suspending liquid and (2) the use of a special centrifuge with accurate control of temperature.     

Refractories Quality Improvement for Glass Industry Upgrading

1 Glass Industry and Refractories Industry Closely Connect1.1 Glass Development Drives Refractories ProgressRefractories are indispensable to glass industry; the rapid development of glass industry drives the     

3D Simulation of Borosilicate Glass All‐Electric Melting Furnaces

Two all‐electric melting furnaces, 15t/d and 36t/d, were simulated and analyzed with the ANSYS FLUENT 14.0 software add‐on MHD module. The electric power density distribution, temperature distribution, and velocity field in the glass furnaces of these two models were analyzed. Electric power density and temperature are found to increase initially and then decrease from the center of the furnace to the side wall in a horizontal direction. Similar trend is observed from top to bottom in a vertical direction. The temperature distribution causes the internal and external circulations in the all‐electric melting furnaces. An unstable connectivity relation is proven to exist between the external circulation flow and the dog‐hole of the 15t/d all‐electric melting furnace. Experimental evidence of the relation is presented from the annular strip images of the corresponding glass pipe product samples. Our analysis revealed several design flaws in the working condition of the two types of furnaces. The simulation results of the two models were compared.     

玻纤熔窑在能源利用上的发展趋势

介绍了随着国际油价节节攀高,我国玻纤工业的飞速发展,各种火焰窑特别是烧油的火焰窑其成本将越来越高,而水电、核电、风电发展越来越多的社会现状,并提出为降低成本,提高经济效益,各种熔窑由原先以烧油烧气为主用电为辅的情况将会逐渐改为以用电为主烧油烧气为辅。今后电熔窑、电通路辅以烧油烧气或全电熔窑、电通路的生产线将是主要的发展趋势。     

THE MODULUS OF ELASTICITY AS AN INDICATION OF THE UNIFORMITY OF ELECTRICAL PORCELAIN1

An electrical porcelain body of the composition 30% H and G A1 china clay, 20% Dorset English ball clay, 20% Ottawa flint, and 30% Buckingham feldspar, fired to cone 11. showed a modulus of elasticity of 9.54 ± 0.02 × 10⁶ 1b. per sq. in. (mean of 164 measurements). A similar body with Kentucky special ball clay substituted for Dorset hall clay gave a value of 10.01 ± 0.02 × 10⁶ 1b. per sq. in. (mean of 69 measurements) The accuracy of the measurements was ± 1.5%. The use of the modulus as a measure on. the uniformity of electrical porcelain gave excellent results The variations were expressed in terms of statistical constants such ac: the standard deviation and the coefficient of variability.     

ANNEALING STRAINS IN GLASS AND THEIR DEGREE OF PERMANENCE*

A statistical comparison has been made of 13 sets of measurements of optical path difference, taken over a seven-year period, on 24 samples of the standardized disks distributed in 1938 to the manufacturers of glass containers. These data show that the original optical retardation of about 22.8 millimicrons has not changed by more than =1.3%, equivalent to =0.30 millimicron or =0.10° on the scale of the measuring instrument. Five tests were made in 1938, five in 1945, and three between. The standard deviation of the combined errors for each of the 13 averages of 24 measurements is =0.0338° and is composed of an accidental error of observation of =0.005° and an error of adjustment of the instrument of =0.0333°. The range of =1.3%, or =0.10°, beyond which the disks could not have changed over seven years, represents the 3-sigma probability limit of combined errors. While this possible change of =1.3% would be insignificant in relation to the utility of the standardized disks, it represents a possible experimental error too great to permit broad conclusions concerning the ultimate stability of birefringence in strained glass.     

THE DESIGN AND OPERATION OF GLASS HOUSE FURNACES*

Design and operation of glass house producer-gas furnaces.—After discussing the proper design of checker chambers, two inefficient designs are criticised. The gases being cooled should move downward and the gases being heated should move upward, and the dimensions should be based on actual working data. The location of the ports is important and heat insulation should be carefully considered. The reversing valve should be efficient and operated regularly; and the performance of the furnace should be constantly watched with the help of instruments such as draft recorders and thermocouples, and the waste gases should be analyzed frequently. With care in design and operation it should be possible to approach the performance of a certain furnace which gave 3 lbs. of glass for each pound of coal burned.     

玻璃熔制过程三维数学模拟的运用

采用所建立的玻璃的熔制过程的三维数值模型对彩色显微管玻璃熔窑进行模拟,详细研究了不同壁面散热和两通道引出量不对称条件对玻璃熔制过程的影响。三维数值模拟的结果可以真实地反映玻璃熔池实际运行过程,有助于加深对玻璃熔制机理的认识和指导实际生产。     

Estimator-Based LQR Control Model for Glass Fiber Furnace

Drawing of glass fibers is an important industrial process used for manufacture of a variety of materials. A variety of furnaces and machines exist for manufacture of glass fibers, but all share similar problems with control of the fiber diameter and breakage of the fibers during the extrusion process. In many cases, control systems are not configured to monitor the most critical process variable — temperature of molten glass in the furnace, but instead use only furnace crown temperature. This work seeks to develop an estimator-based LQR control model to monitor molten glass temperature and winder speed for good production quality. When a disturbance in ambient temperature and/or molten glass depth happens, the control system still performs as expected.     

Service of refractories in a glass-tank furnace producing glass fiber by the single-stage method

Conclusions Chromium oxide blocks developed by the Ukrainian Scientific-Research Institute of Refractories from fine-grained and coarse-grained compounds, like the chromium oxide refractories S-1215 material made by the Corhart company of the USA, ensure a high resistance in the linings of the tanks of glass furnaces producing glass fiber. Their wear occurs on account of chemical solution in the glass at temperatures above 1500°C.Magnesite-chromite refractories rapidly react with aluminoborosilicate glass and cannot be recommended for the second layer of the structure of the glass tanks.Mullite-corundum refractories are subjected to rapid wear in the crown of glass furnaces due to the interaction with vapors of the glass batch at high temperatures.In order to increase the length of the operation of fiber-producing furnaces we recommend that the first and second layers of the tank lining, the channel, and the feeder be made of chromium oxide refractories, and the suspension walls and roof of the furnace from corundum refractories. These recommendations are being used for building the furnace for a second campaign.Translated from Ogneupory, No. 1, pp. 5–12, January, 1980.     

Metal Corrosion and its Impact on Glass Tempering Furnace Design

A reliable well-designed tempering furnace is considered to be the cornerstone of any modern glass-processing facility. This paper addresses a series of engineering anomalies encountered during the commissioning of such a glass-processing furnace. Following the installation of a furnace in a European facility, small black deposits were noticed on both the silica-fused rollers used to transport the glass through the hearth of the furnace and on the processed glass surface itself. EDAX and scanning electron microscopy investigations indicated conclusively that the deposits were primarily constituted of sodium sulfate and trace elements consistent with stainless steel (chromium, iron, and nickel). Traditionally, high-density glass fiber was used to insulate the roof walls and side walls of tempering furnaces; however, it was noticed in this particular case that rolled stainless steel sheeting (SS316) was used. Chemical and X-ray diffraction analyses were used to pinpoint the origin of the deposits. It was determined that poor material selection choices taken during the design stage of the furnace in question were at fault. The combination of stainless steel and sulfur dioxide (SO₂ is used as a lubricant to prevent scuffing) at elevated temperatures (>650°C) generated droplets of sodium sulfate, which condensed due to the convectional flow of the heat currents within the oven. These droplets scorched the glass surface and destroyed the fused silica rollers. As a recommendation, the usage of stainless steel and other nonrefractory metals should be avoided in the design of any future glass tempering furnaces.     

模拟技术在新池窑设计中的实际应用

设计一个运行性能优良、可控性好的熔窑，是玻璃熔窑设计师追求的重要目标。单纯凭经验设计难以达到这一目标，借助于模拟技术有可能做到这一点。本文报道运用模拟技术设计玻璃池窑的一个实例。文中简要介绍了模拟技术本身必须的改进或发展以及模拟技术实施的步骤，图示了若干模拟结果。按照模拟技术提供的优化方案建成的玻璃池窑，经过近2年时间的运行，性能相当令人满意。该池窑具有滴料后调整时间短、可控性好、运行稳定、抗干扰能力强、熔制玻璃质量高等优点。     

SOME OBSERVATIONS OF SURFACE DEPOSITS FORMED IN GLASS FURNACE REGENERATORS1

Two high alumina refractory brick which had been used in glass furnace regenerators were examined with the petrographic microscope. The deposits formed on the surface of the brick through reaction with the dusts and gases of the furnace atmosphere were found to be composed principally of nephelite, carnegieite, and corundum. Nephelite and carnegieite probably can form only in those parts of glass furnaces where the temperature is considerably lower than that required to melt the glass, but corundum may be formed at melting temperatures.