backward-curved v.s. radial in scrubbers

[cokeguy]

Up to now, we have used radial type centrifugal fans in our scrubbers (blades extend from the hub straight out). We want to evaluate the use of backward-curved blades for our scrubber ID fans, could somebody point me some literature on the subject? I understand that radial fans are less prone to solids build-up, but I recently visited a plant whose scrubber uses backward-curved fans, and they are doing OK, with smaller fan motors for comparable applications.

Also, is there a rule of thumb for approximately how much less power you need on a particular application when using a backward-curved instead of radial fan? What about fan speeds, in general a backward would work faster or slower than a radial, for comparable sizes?

Last, any references of good fan suppliers for scrubbers or corrosive/abrasive environment applications?

Thanks a lot for your help.