DOUBLE-WALLED CENTRIFUGAL FAN SCROLL

摘要

A hot gas centrifugal fan is constructed with a scroll part comprising spaced-apart walls 16 and 18 to define a hot gas passage 22 therebetween to which hot gas is conveyed when the fan is in a non-operating condition to hold the fan temperature sufficiently high to avoid unacceptable vibration brought on by thermal distortion of the fan wheel upon a re-start of the fan.