JPS55146299A - Electric blower - Google Patents

Abstract

PURPOSE: To reduce abnormal noises caused by high frequency by a method wherein the volute wall of an air guide is formed by guide vanes A and B provided on the same curved line with the intermediaries of gaps and thereby the exfoliation of air near the inside and outside of the volute wall is reduced.

CONSTITUTION: The air pushed out to the outer periphery of an impeller 11 turns to be compressional waves divided in accordance with the number of sheets of blades 11a and runs against a volute tongue 9. After that, the air, not flowing along the volute wall 8, gives rise to the exfoliation near the outside of the wall when its flow rate is high, thus generating strange noises of high frequency. In this case, by forming the volute wall 8 of guide vanes A8a and B8b, air is supplied from the inside of the wall 8 through an aperture 17 at the time of its high flow rate, thereby the exfoliation of air near the outside of the wall 8 being reduced, while at the time of low flow rate the exfoliation near the inside being reduced, thus the occurrence of the abnormal noises of high frequency being also reduced.

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