It's a drum roaster. I always wondered what one looked like.
Here's a link to the full Specialty Malts pdf at the AHA site.
http://www.ahaconference.org/wp-content/uploads/presentations/2010/Specialty_Malts-Kelly_Kuehl.pdf
Here's a link to another malting pdf at the AHA site too
http://www.ahaconference.org/wp-content/uploads/presentations/2010/Malt___The_Malting_Process-Kelly_Kuehl.pdf