AIR HEATER Russian patent published in 1998 - IPC

FIELD: air heating systems. SUBSTANCE: air heater includes shell 1 with screened inlet 2 and outlet 3 and casing 4 forming heat-shielding cavity 5 together with shell 1. Air heater is also provided with axial-flow fan 7 with electric motor 8 mounted inside shell on uprights 6, first and second thermal electric heating elements coaxial relative to fan and made in form of spirals 9 and 10 secured on brackets 11 and 12 mounted in circular heat-shielding cavity 5 where control system 13 is also located. Control system is provided with keys-switches 14, 15 and 16 for electric connection of electric motor 8 of fan 7 and heating elements 9 and 10 with power supply source. Keys 15 and 16 cannot be placed in ON position when key 14 is in OFF position. Brackets 11 and 12 are shifted over datum surface forming radial clearance between heating elements 9 and 10 no more than 0.25 of inner diameter of shell. EFFECT: uniform heating of air in section of flow. 2 cl, 2 dwg