How to heat glass in glass tempering furnace
When glass is heated in a tempering furnace, if the electromagnetic wave radiated by the furnace passes through an object and is not absorbed, the object is said to be transparent. If the electromagnetic wave radiated by the furnace passes through completely, part of it is absorbed and part of it is reflected back, the object is called translucent to this light.
If the thermal radiation electromagnetic wave of glass tempering furnace is absorbed by the object, the object is opaque to the thermal radiation electromagnetic wave. Therefore, when setting the heating temperature, it is necessary to select the range in which the radiation wavelength of the heating element can be absorbed by the glass, which can shorten the heating time and improve the efficiency. The process of heat transfer from glass surface to center and from ceramic roller surface to glass surface.
The furnace of glass tempering furnace should reach a suitable heating temperature, heating should be rapid, the temperature distribution in the furnace should be balanced and symmetrical, and the difference of heating temperature on the glass surface should be less than 5%.
The suitable temperature for glass tempering is in a temperature range from brittle state to plastic state, i.e. close to the softening temperature of glass. In this region, the residual stress of glass can be rapidly and completely relaxed and eliminated, and the glass can obtain temperature gradient, tempering degree and tempering stress.
When the glass is first put into a small tempering furnace, the heating speed is very fast. This is because the temperature difference between the glass and the furnace is very big, and the heating speed is very fast. With the decrease of the temperature difference between the glass and the furnace, the heating speed is slowed down.