METAL STEM & Plug in bowls
Whilst not strictly speaking a replaceable bowl pipe, this pipe nonetheless has an intriguing metal stem and cooling device.
There are at least these four patterns of shaft cover, and various sizes and shape of bowls
The mouthpiece, I have learnt from experience, can be delicate, it is a push fit into the outer shaft, which is itself a push fit over the inner smoke tube/filter with neoprene ? sealing rings each end.
What appears to be a piece of thin pipe cleaner can be insert into holes at each end of this inner assembly to soak up tars etc and clean the inside of the cover when twisted.
The inner assembly is screwed into a metal collar which is attached to the bowl
US design patent D204,652 in 1964 inventor Hans Lowenthal, London, England assignor to Colibri Lighter Limited