Air cirsulation heater is a kind of heater which is widely used. We call it air heater. In fact, it can be divided into many kinds according to the different heating gases. The common ones are air heater and hydrogen heater. These can also be called pipeline gas heaters. *Especially at present, due to the need of epidemic prevention and control, the demand for masks and other medical protective articles has increased dramatically, and the pipeline air heater has been widely used in the production of melt blown non-woven fabric by a large number of manufacturers. Pipeline heater has been widely used in many scientific research and production laboratories, such as aerospace, weapon industry, chemical industry and colleges and universities. It is especially suitable for automatic temperature control and large flow high temperature combined system and accessory test. The electric air heater can be used in a wide range: it can heat any gas. The hot air produced is dry, non-conductive, non combustible, non explosive, non chemical corrosive, non polluting, safe and reliable, and the heated space can be heated quickly (controllable).