help identify strange pipe with metal bowl insert

i found this strange pipe at a thrift store. it has a vulcanite stem with a threaded tenon, but more importantly it has a metal bowl that inserts from the bottom. the top of the pipe body is closed. the bowl insert appears to be aluminum and has a channel that lines up with the draft hole and goes up to the tobacco chamber. there is no writing or makers marks on the pipe, but the metal bowl has "Patent Applied For" etched on the bottom near what i take for the draw hole. i have been searching the web for a few weeks and still have no clue what this may be.



edit: changed pic 03

on the second pic (above) you can see that the metal bowl has a channel running around it horizontally and another that goes vertical. the draft hole from the shank enters about where it would if the pipe was normal and the horizontal channel should line up with it when the bowl is in. when i assembled it to test the draw i line up the vertical with the draft hole and it draws well. the metal is thin and pretty smooth on the inside, except where the channels are, with no coils or anything. the chamber in the briar is smooth and the bowl pressure fits into it. it fits pretty tight and does not go in all the way to the shoulder at the bottom of the metal and i haven't wanted to force it. note the residual pry marks from past owners...
the metal bowl from the top down inside:


inside of the pipe body from the bottom up:

i haven't tried smoking it yet. the stem is still kinda funky smelling even though i have polished out the exterior. it was powdery brown and green when i got it. i was hoping to replace it with something acrylic before i tried it and keep the old one for best but the threaded tenon will be hard to match.

as far as lighting, i assumed i would pack it as normal and use a very low flame up through the draw hole in the bottom. it would have some advantages when smoking a wetter tobacco but will probably drip.