Temperature,°C Fig. 1, Temperature dependence of viscosity: 1) glass No. 7 2)glass No. 7A; 3)nonalkali aluminoborosilicate glass Fig. 2. Feeder bowl after improvements: 1)dispersing spout; 2)bushing: 3)front wall of bowl temperature dependence of viscosity is shown in Fig. 1. It is apparent that glass No 7A is of more tech nological value than glass No. 7. The fiber properties(strength, chemical durability)of glass No 7A are also somewhat better We also made selective additions to the batch to minimize the gas content in the glass and to elimi nate foaming of the glass balls in the glass melting furnace. For this purpose, we laboratory tested ammonium, alkali, and alkaline earth sulfates and nitrates both separately and in combination with arsenic trioxide. The most effective of these(sodium sulfate and calcium nitrate in combination with As2O3)was tested by melting glass in a tank gas-electric furnace. The change in the residual gas content and foaming temperature of the glasses were studied using VNITSPV methods [3, 4]. The results of analyzing the glasses for gas content for different additions to the bath in comparison with the technology of the glass for fiber forming is presented in Table 2 The addition of potassium nitrate to the batch enabled the total gas content in the glass to be reduced in comparison with the glass melted using sodium sulfate by a factor of more than two, the foaming tem- perature to be increased by 40-60%, and the quality of the glass spheres to be increased. The decrease in gas content produced an improvement in the fiber-forming process, and an increase in the productivity of fiber making by more than 35%. The increase in glass quality was associated not only with a reduction in the total gas content, but also with the fact that the amount of water and So dissolved in the glass was re- duced and the content of dissolved oxygen was increased, which verified the previously published data for aluminoborosilicate glass [4] the technological properties of the glass for drawing fiber to be considerably improved. However, the as Selection of the optimum chemical composition of the alkali glass and of the batch composition enabled tained results did not permit us to completely eliminate devitrification of the glass at the feeder bushing where the glass balls are formed For improving the mass exchange and the isothermal characteristics of TABLE 2 。Aw、mm uctivity of"~o 3,0 "" > ~ 2,5 ". o o ~0 llO0 "120g 1300 14"00 Temperature, * C I I / I : / 1 2 3 Fig. 1 Fig. 2 Fig. 1. Temperature dependence of viscosity: 1) glass No. 7; 2) glass No. 7A; 3) nonalkali aluminoborosilicate glass. Fig. 2. Feeder bowl after improvements: 1) dispersing spout; 2) bushing; 3) front wall of bowl. temperature dependence of viscosity iS shown in Fig. 1. It is apparent that glass No. 7A is of more tech￾nological value than glass No. 7. The fiber properties (strength, chemical durability) of glass No. 7A are also somewhat better. We also made selective additions to the batch to minimize the gas content in the glass and to elimi￾nate foaming of the glass bails in the glass melting furnace. For this purpose, we laboratory tested ammonium, alkali, and alkaline earth sulfates and nitrates both separately and in combination with arsenic trioxide. The most effective of these (sodium sulfate and calcium nitrate in combination with AszO~ ) was tested by melting glass in a tank gas-electric furnace. The change in the residual gas content and foaming temperature of the glasses were studied using VNIISPV methods [3, 4]. The results of analyzing the glasses for gas content for different additions to the bath in comparison with the technology of the glass for fiber forming is presented in Table 2. The addition of potassium nitrate to the batch enabled the total gas content in the glass to be reduced in comparison with the glass melted using sodium sulfate by a factor of more than two, the foaming tem￾perature to be increased by 40-60%, and the quality of the glass spheres to be increased. The decrease in gas content produced an improvement in the fiber-forming process, and an increase in the productivity of fiber making by more than 35%. The increase in glass quality was associated not only with a reduction in the total gas content, but also with the fact that the amount of water and SO.~ dissolved in the glass was re￾duced and the content of dissolved oxygen was increased, which verified the previously published data for aluminoborosiHcate glass [4]. Selection of the optimum chemical composition of the alkali glass and of the batch composition enabled the technological properties of the glass for drawing fiber to be considerably improved. However, the at￾tained results did not permit us to completely eliminate devitrification of the glass at the feeder bushing where the glass balls are formed. For improving the mass exchange and the isothermal characteristics of TABLE 2 lTypl of fin- 3ulfate 7A Sulfate with AsuOa Potassium nit￾rate with AhOs i r,..) [Gas content in ~ with reference to the ~ Itotal volume of a ~lass ball ~ ~ tTotal [ ,~ ~ Ivolumd H0o so, co, o, N2 o g igases 1120 1140 1180 291 141 307 173 190 100 14n 65 J 85 16,5 [ 49,5 55,6 15,7 I 21 41,7 10,0 2,0 67,5 10,5 1,0 1,6 65,5 7,5 Average daily pro￾ductivity of eiectrofur￾nace. kg /thickness os fiber 16.7 "rex" 37:1 39,2 57,4 60,2 42