How to set the temperature of automobile glass tempering furnace to be even
Glass is mainly divided into two categories: flat glass and deep processing glass, of which there are three main types of flat glass: lead-up method flat glass (divided into slotted / non grooved), flat pull flat glass and float glass. Deep processing glass is made of flat glass, which is widely used. If you want to know how to set the temperature of the automobile glass tempering furnace and how to control the internal temperature of the tempering furnace, let me have a look.
If the temperature of automobile glass tempering furnace wants to be uniform, its setting mode is as follows:
(1) 1-stage electric heating: that is, in the direction of glass operation, the electric heating body is arranged as one section, which is powered on at the same time and powered off at the same time. In order to solve the problem that the heat dissipation of the furnace side is faster than that of the middle part, the power distribution of each section of electric heating wire is larger at both ends and smaller in the middle (the power distribution is controlled by the density of electric heating spiral tube), It can replace the electric heating wire without stopping the furnace, but the disadvantages are obvious, that is, the accuracy of furnace temperature control is poor, and it is not easy to adjust when the temperature distribution in the furnace is uneven.
Automobile glass tempering furnace
(2) Multi stage electric heating: the heating body is vertically divided into 3 and 4 sections, and the whole furnace body is composed of about 8 continents and electric heating bodies. It is equivalent to dividing the furnace body into many small heating areas on the horizontal plane and arranged in matrix. Compared with the discharge section electric heating, the temperature control loops are significantly increased, which can meet the requirements of different glass specifications in the tempering batch, In order to adjust the furnace temperature more accurately and quickly, the furnace wire heating and glass uniform heat absorption can be synchronized. However, the disadvantage is that the furnace wire can not be replaced online, and the maintenance cost is high. Due to the many temperature control loops, the temperature setting of the temperature control point is relatively complicated, which needs many times of experience, Find out the reasonable control scheme.
(3) Adding preheating furnace or one furnace with two chambers can solve the problem of different heating temperature rise on the upper and lower surfaces of Low-E glass due to low radiation heat transfer efficiency at 300 ℃. In addition, increasing the automobile glass tempering furnace can reduce the waiting time and improve the production efficiency.
(4) According to the principle of heat transfer by convection, the external compressed air with certain pressure is blown to the upper and lower surfaces of the glass through the heat balance tube with longitudinal distribution, stirring the air, accelerating the heat transfer to the glass, and balancing the temperature difference between the upper and lower surfaces of the glass, The temperature of the upper, lower, left and right points of the glass should be consistent. However, the low temperature compressed air injected into the furnace will consume part of the heat energy in the furnace, which is not conducive to energy conservation and environmental protection.