Regarding coal as fuel, RH efficient hot-air furnace can match with various kinds of drying equipment. It is widely applied to mine, chemistry, dyeing, medicine and othe biological agents. It is a kind of new energy-saving and low-pollution air supporting equipment. 

Compostion and main features of RH series of hot-air furnace
RH series of hot-air furnace is composed of RSL series of solid fuel efficient combustion furnace (patent product), heat exchanger (advanced HRQ efficient heat exchanger), flue gas draft fan, flue gas duct and auxiliary machine.
1. Host part
This furnace is composed of fire grate and combustion chamber. Fire grate adopts chain grate or horizontal reciprocating grate. Fire grate is driven by speed controller and reducer to control coal supplied speed. The thickness of coal layer is adjusted manually in order to guarantee the best state of coal supplied . Combustion chamber is built by heat insulating materials and refactory materials. Two combustion chambers are set in furnace. There are two poking doors on right and left side of primary combustion chamber. There is fire retention wall, ash removal chamber and peep door. Hot flue gas will be burnt fully in secondary combustion chamber. Afte primary dustfall, flue gas will enter heat exchanger and air distribution chamber.
2. Heat exchanging device
Heat exchanging device is composed of efficient heat exchanger, air distributor,, dustfall chamber and outer maintenance. By changing the design of heat exchanging duct of heat exchanger, hot air source with various temperature and heat can be produced. After combining with injection pipe and plug pipe, the temperature of air exchanger can reach 380 to 580 degree centigrade. Low and middle-heat exchanger adopts plug pipes. After heat exchanging, the temperature of air is 100 to 380 degree centigrade.

A. Injection heat exchanging pipe is composed of outer pipe and inner pipe. Preheated air will be injected on wall of outer pipe by holes on inner pipe. Owing to vertical injection to wall of pipe, air flow adhesion layer will be damaged. Then, convection heat is strengthened. Coefficient of heat exchange is increased. Meanwhile, temperature of pipe wall is reletively reduced, which is beneficial for expanding the service span of heat exchanger. According to the temperature and cleaness after heat exchanging, users can choose inner and outer pipes made from various materials.

B. Plug heat exchanger is insert thread plug piece in seamless pipe, which makes air swirl rapidly and reduces resistance to pipe wall. Accordingly, heat transfer coefficient of heat exchanger is improved.
C. Air distribution room can not only arrange much hot flue gas on the front end of heat exchanger, but also can plays a dustfall role. Ash cleaning door is set in air distribution room and dustfall room.
3. Coal feeder, slag discharger, temeperature controller and electrical control cabinet are set in this whole series of equipment.
 

Main performance and technical specification of RH series of hot-air furnace
RH series of hot-air furnace arranges heat exchange and combustion separately, which solves the conflict existing between incineration and combustion of integral hot-air furnace. This series of equipment can guarantee complete combustion and full heat exchange.
Thermal efficiency is higer than 70%. Temperature output reaches to over 550 degree centigrade. Blackness of flue gas is lower than the first class of ringelman blackness. The emission amount of flue gas and dust is lower than 150mg/Nm3.