ventilateur à deux étages

OBS: Two-stage; double-stage: à deux étages.

CONT: Single-stage, vaneaxial fans may be operated at pressures as high as 6 or 8 inches of water. Double-stage fans are capable of much higher pressures, but since the system requirements for most applications seldom exceed the range of the single-stage fan, the double-stage design has little or no usefulness in the industrial exhaust field.