How to Select the Dryer Heat Carrier

Dryer (dryer) machine is a kind of commonly used drying apparatus whose operation is simple, the process amount is large. the decision of the heat carrier and the choice of its highest temperature depend primarily on its pollution tolerance ,the processed materials properties , and the other factors. The matters we need to note are mainly the following four points:
1, if the dry objects are not allowed to be contaminated, and does not allow air to dilute, the heat should go through the drum wall to enter, at this time, the drum should be loaded in the bricks indoors, the outer should be accessed the flue gas,we can also  set out barrel shelters pipe or tube these surface heat exchanging devices, The heating medium may be flue gas, steam, or electrical heating.  2, if the processing material is not allowed to be contaminated (like the materials be processed in the rotary kiln), and the necessary temperature gas is high, we can use the furnace for the heat carrier, this product is energy saving and environmental protection  ,the heat obey is high, the combustion gas through cleansing disposal penalty can be used again,  the gas stove in energy efficiency is energy-saving 20% than the burner ,and the manual costs are saved much.  Generally, the normal operation of   gas furnace only need one operator, in addition, this machine can use and stop un-continuously, it can does not work  as long as 10 days.3, if the processing solid materials are not afraid of high temperature, and not the non-final products, we allowed the processing materials to be slightly contaminated, the stove or flue gas can be used as the heat carrier, and we can  obtain a high volume rate of evaporation .For example, for drying the materials which contain higher water content , when using the gas inlet temperature of 300 degrees,  the dryer volume the evaporation rate is 5kg/M3/h ,heat obedience to 30% -50%; if the gas inlet temperature is 500 degrees, volume evaporation rate is 35kg/M3/h; thermal obedience is 50% -70%.  4  we can also use the direct heating,that is to say,  the heat is transferred from the metal wall to the dried materials, rather than rely on hot air and material directly contact, such as the external heating tumble dryer.
If the dryer (dryer) does not contain the heat carrier, we can imagin that the dried material contained moisture can not be carried out, the  dried materials can not be quickly dried. And the provision of heat carrier device is not random, we need to  determine it according to the nature of the material itself.