SMOKE EVACUATING FAN Russian patent published in 2000 - IPC

FIELD: mechanical engineering; fans. SUBSTANCE: invention relates to fans designed for evacuation of smoke and can be used in designing fans for operation at higher ambient temperatures. Owing to the fact that rear wall of housing is made with step, flow of hot medium to shaft zone and to front part of electric drive is reduced, and ring enclosing the impeller and impeller proper accelerate flow of cooling air through clearances in impeller spaces. Through key slots provide additional cooling of shaft and bushings. All required relationships are given in description of invention. EFFECT: enhanced efficiency of heat protection of electric drive. 2 cl, 2 dwg