1. Cooling section and homogenization section
Glass liquid in the process of flowing through the cooling and homogenization section, should make the glass liquid evenly cooled to a temperature suitable for molding, if no measures are taken, both sides of the forehearth heat dissipation more, the middle part of the heat dissipation less, will lead to the middle part of the glass and both sides of the temperature gradient is large, that is, the temperature of the same section of the glass liquid is uneven, so that the viscosity of the molten glass is inconsistent, directly affecting the quality of molding, in order to make the temperature of the liquid consistent, on the one hand, in the cooling section reserve cooling hole, by adjusting the opening of the cooling hole, to adjust the amount of heat dissipation in the middle part of the forehearth cooling sectionto make the temperature uniform; On the other hand, special silicon carbon rods are used to assist heating to achieve this.
Silicon carbon rods are generally evenly arranged above the glass liquid in the feeding shaft, kept a certain distance from the glass liquid, and radiated downward heating. In order to ensure that both sides of the forehearth are heated and the middle part is not heated, the five-section rod of silicon carbon rod for the glass forehearth industry (that is, the double heating element silicon carbon rod) is generally selected. It is welded by two identical heating elements and three cold ends using a special process, that is, the middle and indirect cold ends of the two heating elements, the total length of the three corresponds to the width of the forehearth (double-threaded silicon carbon rod is used in the imported forehearth) Because the middle part of the silicon carbon rod does not heat up or has less heat and heats up close to the side wall, coupled with a reasonable design, it can ensure that the temperature of the molten glass in the flow is uniformly reduced. In the forehearth design, some manufacturers also choose equal diameter silicon carbon rod (that is, three-section silicon carbon rod), which is welded by a heating element and two cold ends.
The forehearth uses three sections of silicon carbon rod silicon carbon rod to heat both the glass liquid and the walls on both sides, which can ensure the temperature of each section of the forehearth and supplement the heat dissipation of the side wall, but the homogenization effect is far less than that of the five-section silicon carbon rod. Regardless of whether a three-section rod or a five-section rod is selected, the homogenization effect is determined by the structure of the forehearth and the heating of the silicon-carbon rod, and the final temperature of each section of the forehearth is controlled by the control system.
2. Feed basin section
After the glass liquid flows through the homogenization section, the temperature uniformly drops to a certain suitable value, if the temperature at the basin is not controlled, it is still difficult to ensure that the droplets have a constant and uniform temperature, so that the temperature is too high or too low will affect the shape of the droplets, and ultimately affect the molding quality of the glass container. Therefore, the scientific method is to control the basin separately. Basin heating generally has the following two forms:
(A) Two gun-type silicon carbon rods and one three-section silicon carbon rod are used to heat around the basin.
(B) Two grooved silicon carbon rods and one three-section silicon carbon rod are distributed around the basin to heat the basin.