Help ID the Mystery Centrifugal Supercharger!

I'm a little confused, then--by two things. One, the serpentine pulley. I can't think of any other application of this thing that would require a serpentine system. Secondly, even if it is a centrifugal pump, shouldn't the theory of it be the same as that of a centrifugal supercharger? Blade orientation aside, whatever moves through the thing is going to go in through the [larger] axial hole and hit the impeller then divert through the [smaller] downstream hole and flow some amount of increased pressure. The opposite wouldn't make sense.
I'm not trying to hold onto some hope that it is a special old supercharger or anything, but regardless of its origins shouldn't its design have inherent pressurizing capabilities?