HLF Low Noise Francis wind chassis, built-in SWF (A) or SWF (B) series of high efficiency mixed flow fan, modular cabinet frame, muffler insulation panels, with a clear appearance, low noise, stable operation ﹑ easy installation (seat , the lifting can be), maintenance and simple, widely used in residential, commercial, industrial and other construction projects, low-noise ventilation applications. HLF Low Noise Francis wind chassis air intake plus set up filters, can be used for purifying air box.