In electrostatic powder spraying, curing furnace is the key equipment, the quality of paint film and curing furnace temperature has a very important relationship.In the powder curing furnace, the heating mode can be divided into two categories: one is the hot air circulation type, and the other is the infrared radiation heating mode.
Hot air circulation heating can be divided into direct heating and indirect heating.There are two kinds of heat sources for direct heating, electric heating spiral fin and gas heating.Direct electric heating spiral fin type advantage is uniform temperature in the furnace, workpiece adaptability: the use of solid state relay PID regulation temperature, temperature deviation in the furnace is small.Disadvantages are slow heating time, equipment power.Because is USES the hot air circulation heating, therefore solidifies the process easy to cause the dust second pollution.The stove covers a large area.
Gas type heating mode directly heating speed, the advantages of high heat energy conversion rate, furnace temperature control using proportional control control, temperature in furnace temperature control deviation is small, because is the direct combustion burner flame in the combustion chamber, so the curing process is easy to cause secondary pollution, dust and waste gases design in the indoor heating with high temperature resistant filter, so the fan on the choice of circulation fan pressure should be taken into account, all other indoor heating plate must be used stainless steel plate, the two relative increase equipment cost, covers an area of a big stove.
Indirect heating means two kinds of fuel gas which are divided into fuel oil and indirect heating means.The characteristics of indirect burning heating mode, should have a heat exchange unit, inline term heat exchanger, burner flame burning in the hearth in the heat exchanger, so the material of the heat exchanger should choose heat resistant stainless steel material (generally using SUS310S material thickness not less than 5 mm), indirect heating mode of advantages, because the burner flame burn in the heat exchanger, it won't cause dust and gas in curing process secondary pollution, uniform temperature, temperature control can be controlled by two pieces of fire control and proportional control.Temperature control is more accurate.The disadvantage of indirect heating is that, because heat is transferred through a heat exchanger, the thermal efficiency is lower, the installation cost is relatively high, and the furnace covers a large area.Infrared direct heating can be divided into far infrared and high infrared two.Far-infrared heating has been known to the world, when the radiation spectrum of far-infrared heating body and the absorption spectrum of the heated workpiece at the same time, the thermal efficiency is the highest, so as to achieve energy saving.The advantage of the far infrared heating method is that the radiation spectrum directly absorbed by the powder during the heating process makes the powder on the surface of the workpiece solidify rapidly.The furnace covers a small area, but the far infrared heating mode of furnace temperature uniformity is not good, so the current design is used in the way of circulating fan agitation.
When high infrared heating, the radiation spectrum of the heater is absorbed by the workpiece and powder at the same time, so that the workpiece and powder are heated at the same time, so that the speed of powder curing is faster, thus saving energy.General high infrared heating products are made of glass, easy to damage when installed, the life of high infrared heater is short, its working life is about 5000 hours to 8000 hours.