Noise Generation by Vacuum Cleaner Suction Units

Abstract

Among all household appliances, the vacuum cleaner is the most powerful source of noise. The built-in suction unit, consisting of an electric motor and a centrifugal blower, represents the main source of noise; this is partially aerodynamic, mechanical and electromagnetic in origin. The contribution of the particular origin of noise generation to the total noise level depends on the geometry of the suction unit and operating conditions. The aerodynamically generated noise within the blower mostly prevails in the total emitted noise at design and off-design operations, and is especially distinct at partial flow rates when rotating stall and surge appear. The vaned diffuser built into the blower has an important effect on the emitted noise, so on the airborne as well as on the structure-borne noise and their spectra. Detailed analyses of measurement results have shown that the built-in vaned diffuser has numerous disadvantages, including: increase in the tonal and turbulent noise, increase in production costs and reduction of the flow rate, therefore, it could be omitted or replaced by a vaneless one. In this paper, an overview of the effects of the vaned diffuser on the aerodynamic, mechanical and electromagnetic noise origins at different operating conditions is given.