Here we have an early offering of the new 1896 patent 7225 pump arrangement on a stove made by Primus for the German market. The German market intent is shown by the special DRP73457-marked filler cap (this cap related to the original 1892 German registration of the Primus burner design): The new fixed, not detachable, pump design, however, must place this stove no earlier than late 1895 at the very earliest. There is no number nor indeed any other marking on the tank top other than the single word 'PATENT'. This again may well relate to the German market destination intended for this stove (as possibly in this case too): The crescent shaped tank base provenance mark is not known any later than 1897: One of the main features is the fixed pump assembly for which the patent was obtained in March 1896, although this does not preclude some manufacture having begun shortly before that: And the final very distinctive feature are the legs from which the pan support extensions have been removed: It is difficult to be sure whether this was done during initial manufacture or subsequently. But it is certain that some stoves were prepared in this way for dedicated use in certain types of cooking range apparatus as can be seen, for example, in these 2 contemporary adverts: Not having a contemporary range to fit the stove to here it is installed in a mid-C20th equivalent set up: And after a very necessary servicing and renewal of various seals, it has now been fired up after decades of disuse as can be seen in this sequence:
hm... as usual with respect... imo If Yours ALL CONCLUSIONS are TRUE its mean - tank stamping/production was 2 or 3 years before pump was mounted