Dave Dickey Forum Moderator 246 Posts
Re: Pitched-blade impeller direction27 April 2007 at 1:29pmThe direction of a 60-degree pitched-blade impeller, or any angle axial flow impeller, should be downward by your definition. The impeller should be about one impeller diameter (typically between 0.5 and 1.25 impeller diameters depending on liquid levels) from the bottom dish of the reactor.
Material, especially settling solids, will not be lifted from the bottom is the impeller is facing upward (pumping upward). A pitched-blade impeller facing downward (pushing downward) will give proper mixing, suspend solids, and give proper motion from the bottom to the top of the reactor. Definitely do not install the impeller facing upward, regardless of the direction of rotation.