At present, the convection heating of horizontal tempering furnaces is mainly reflected in the following aspects: ① The heating furnace is equipped with a heat balance tube (LandGlass glass tempering furnace). The direction of the heat balance tube is perpendicular to the direction of the heating furnace wire. Directly below each heating furnace wire, a 1mm small hole is opened in the heat balance tube. The adjacent holes are in opposite directions. The hole spacing is 120mm, which is equal to the spacing between adjacent furnace wires. The compressed air ejected from the hole passes through The upper heating element is heated and blown onto the upper surface of the glass to form convection heating. This has a very obvious effect on heating coated glass, especially Low-E glass. Since the surface of the coated glass film has high reflection and weak absorption of radiant heat, the lower surface heats faster than the upper surface, and the glass takes on a "concave" shape in the furnace. Deformation, only the middle part of the glass contacts the silicon roller, which is prone to optical deformation and other defects. The most effective way to solve this problem is to enhance the convection heating intensity of the upper surface of the glass to ensure uniform heating of the upper and lower surfaces of the glass. ② When the temperature in the heating furnace is uneven, the air flows from low temperature to high temperature. When the air temperature is higher than the glass temperature, the glass is heated. ③ Because the furnace door is opened or cold air enters from loosely sealed areas of the heating furnace, the cold air locally reduces the furnace temperature and glass temperature. In actual production, opening the furnace door has a greater impact on temperature, often before and after the heating furnace. Corner furnace wires are added to the upper and lower parts to balance the temperature. Because the rear furnace door is afraid of the cold air from the air grille blowing into the furnace, an air curtain is often used to isolate the exchange of hot and cold air. ④The convection and radiation hybrid heating (CONVIR) tempering furnace of Italian Yanhua Company mainly uses convection heating. The hot air is extracted from the heating furnace, and a small and high-temperature-resistant electric hair dryer blows the hot air through the pipe to the air hole or nozzle and blows it to the upper and lower sides of the glass. Therefore, the hot air circulates in a sealed manner, effectively preventing cold air from entering the furnace. Two independent convection heating systems are used on the upper and lower sides of the glass, so that the upper and lower surfaces of the glass can be heated simultaneously toward the center of the glass thickness at the same heating speed. The heating elements of radiant heating are arranged longitudinally in the furnace, and each heating element is independently controlled so that the heating can compile corresponding temperature curves according to different loading arrangements.