Induction heater or a specialty soldering iron for pipes, maybe? Edit: Probably not enough "support circuitry" for an induction heater on second thought. Still think the soldering iron idea might be possible.
Edit: Yes, it would be size-specific if that happens to be correct. I would reply to RTM on this, but it seems insubstantial so I'm just editing in my agreement on that.
Edit 2: Maybe a pipe "welder" for plastic pipes? Whether for soldering or plastic welding, it does look crude, but old tools often do. That said, I might not even be close on this. Who knows.