WATER DRAINING OR AIR VENTILATING DEVICE OF VEHICLE PART

摘要

PURPOSE: To effectively prevent the passage of sound in a channeled device for removing water or air. CONSTITUTION: Helically surrounding webs 2 or lamellae starting from walls project and extend in the free cross section of a channel. The helically provided webs or lamellae prevent the transmission of sound from outside. The pitch of the helix is selected as nonuniform in order to prevent the formation of stationary sound waves.