Juwel 3B stove, current in 1903, a slightly earlier incarnation of what became the Juwel 6B by 1908. Some reference to this stove also appears in this gallery thread by multi-cho link. The only difference I can see between this and the later 6B is the 3B is the form of the leg sockets. The design of the pressure release also changes later to the one shown in most of these photos for operating reasons (i.e. getting a decent seal with the release key). This is the original pressure release cap minus original key, it is still with the stove: The pump tube caps I have also discovered are not interchangeable, the later ones being for a very slightly smaller diameter o/d thread. The legs in the photos are newly reproductions, the pan ring from a later date, and the burner caps from a Primus No.4 (but fit and work perfectly well with only an additional inner sleeve to aid positioning). But at least it is now in working order (just): No less than 4 brass mesh pellets are now inserted into the single riser tube to cure dreadful pulsing and flooding which had previously been extinguishing the burner within 20 seconds of lighting regardless of the amount of pre-heating. An over-size worn jet, now peened, had also been contributary to these problems. The burner is horridly bent too but I'm not going to tempt fate by doing anything more to it. This is never going to be a 'looker'!
Could You take a photo "what is the burner internal constructions" - just what is under the outer (and inner if exists) cap?
@gieorgijewski - there you go, inside views of the burner cap set up. Nothing special, just a very small bore original fixed feed tube, standard No.4 inner cap with sleeve added to locate over the fixed feed, and a standard No.4 outer. The original inner and outer would have been only very slightly smaller, but cone shaped.
The old Juwel out for a rare firing to make a coffee and try out slightly smaller diameter copper inner cap. Still can't decide if this has made any worthwhile difference to the burn or not. The distinctive tank and leg detail from a 1903 catalogue:
