Analysis and Countermeasures of the Causes of the Edge Lines of Float Glass

0 Introduction In the past ten years, the domestic glass industry has developed extremely rapidly. The oversaturation of the market has resulted in increasingly fierce competition among enterprises. For glass original glass manufacturers, the control of quality and cost is the primary goal of maximizing their profits. This article analyzes the reasons for the problem that the edge line of the glass plate affects the total yield that has occurred with the commissioning of the domestic large-scale float production line in recent years, and proposes an improvement plan from the perspective of production, as well as from the perspective of design and construction. Recommendations accordingly. 1 Example of the influence of the side line on the total yield of glass production In one of the two 900t/d float production lines in China, there are formed glass plate edge lines on the left and right sides. If the width of the original glass plate is enlarged, the product quality is guaranteed not to be affected; if there is no edge line, the original plate width can be reduced by 50~150mm, so that the total yield can be improved without increasing the control level and investment 2 Causes of side lines There are two types of edge lines: one is that the liquid glass near the wall of the flow channel flows out of the lip brick and is partially folded, and flows back to the deformation line formed by the wet back brick, which is the so-called J-Line (J-Line); The second is the (upper) contour line of the molten glass (Vacano) after passing through the flow gate. The edge line is formed as shown in Figure 1. According to the theoretical forming conditions of float glass, the edge line is within the range of edge cutting. However, due to the design of domestic kilns and tin baths, the runners and launders are installed before the kiln, basically no expansion joints are reserved. At the same time, the thermal expansion control of the kiln and tin bath is lacking during the baking process. The runner is squeezed by the working part to move too much downstream, and the bottom shell of the tin bath moves a little upstream, resulting in two of the three key dimensions of the lip area of ??the tin bath. The distance between the eight-shaped bricks) deviates from the design requirements, the recirculation distance of the wet back zone becomes longer, and the distance between the projection point of the lip brick and the eight-shaped bricks increases, which causes the J-shaped line or contour line to move to the inner side of the glass plate. Because the glass ribbon at its location has a large optical distortion and is far away from the edge of the glass and cannot be cut during edge cutting, the width of the original plate must be enlarged to ensure product quality, which ultimately affects the t