It is to use fuel direct combustion, through high purification process to form hot air, and direct contact with the material heating drying or baking. This method USES about the same amount of fuel as steam or other indirect heaters
Reduce it by about half. Therefore, in the case that does not affect the quality of drying products, can use direct high purification hot air.
Fuel can be divided into:
Solid fuels, such as coal and coke.
Liquid fuel, such as diesel, heavy oil, alcohol - based fuel
Gaseous fuels, such as gas, natural gas, liquid gas.
The high temperature combustion gas obtained by the fuel after combustion reaction further contacts with the outside air, after mixing to a certain temperature directly into the drying chamber or baking room, and the drying material contact, heating, steaming
Hair moisture, thereby obtaining dry products. In order to utilize the heat of combustion reaction of these fuels, a fuel combustion device must be added. Such as: coal burner, oil burner, gas burner, etc.
This type of direct heating hot air furnace can not be used for breeding and other heating.
Indirect hot air furnace
It is mainly used for drying materials which are not allowed to be contaminated, or for drying heat sensitive materials with low temperature. Such as: milk powder, pharmaceutical, synthetic resin, fine chemical and so on. Such a heating device is
Steam, heat conduction oil, flue gas and so on as the carrier, through various forms of heat exchanger to heat the air.
The most essential problem of indirect hot air furnace is heat exchange. The larger the heat exchange area, the higher the heat conversion rate, the better the energy saving effect of hot air furnace, the longer the life of furnace and heat exchanger. Instead, heat is exchanged
The size of the area can also be identified from the flue gas temperature. The lower the smoke temperature, the higher the heat conversion rate, the larger the heat exchange area.
After the separation of fuel and heating source, it can be used for human heating.
Working principle can be divided into two kinds of heat storage and heat transfer
Regenerative type, according to the regenerative body inside the hot air furnace divided into ball type hot air furnace (referred to as ball furnace) and the use of lattice brick hot air furnace, according to the combustion mode can be divided into top combustion type, internal combustion type, external combustion type and so on. Such as
How to improve the wind temperature, is the direction of long-term research. Commonly used method is mixed burn high calorific value gas, or increase the heat transfer area of hot air furnace lattice brick, or change the material quality of lattice brick, density, or
Change the shape of the regenerator (such as the regenerator ball) and preheat the gas and combustion air by various means.
Advantages: high heat transfer temperature, high heat utilization.
Sun fule hot air furnace (3) disadvantages: large size, large floor area, hot air temperature is not stable, more switching mechanism, easy to problem, heat storage short life, high maintenance cost, high purchase cost.
Heat transfer type, the main use of the use of high temperature heat exchanger as the core component, this component can not use ceramic hot air furnace
Metal material heat exchanger, can only use heat resistant ceramic heat exchanger, gas gas in the combustion chamber full combustion, burning the hot air, after the heat exchanger, the heat to the fresh air, can make
The temperature of fresh air surpasses 1000 degrees.
Advantages: high heat transfer temperature, high heat utilization rate, small size, stable hot air temperature, no switching mechanism, long life, high maintenance cost, low purchase cost.
Disadvantages: heat transfer temperature is not as high as the heat storage, appeared late, not widely used.
Related products:
Hot Air Furnace Classification
Direct And Indirect Heating Hot Air Furnace Difference Between
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