That looks like a turbocharger. I take it the "snail" is operated by a hand crank to pump air that stirs up the heat.
Yep, it drives a centrifugal fan via a step-up gearbox, so it's not necessary to crank it very hard to get a lot of air blast.
A night shot of it fired up;
![[Linked Image]](https://www.outdoorking-forum.com.au/forum/uploads/usergals/2017/03/full-5630-33581-forge_flash_pic.jpg)
Pic without use of the flash;
A pic of the finished tool [a fire rake], that's shown being heated in the pics above;