No doubt this question has been asked and answered before, but the old hands around here are so obliging about sharing information that I'm going to ask anew rather than searching for a previous answer. Given that all "primus-type" brass pressure stoves use the same fuel, approximately the same jet size, and operate at about the same pressure, is their performance correspondingly about the same? Obviously, there are differences in aesthetics, workmanship, ease of use as relates to the location of pump, filler cap, etc., but how significant is the difference in heat output between any two properly-performing stoves? Obviously there are going to be small differences in efficiency as a result of various minor changes in burner design and so on. But it appears to me that the only real difference between my Svea 106 and my Primus 210--to give one example--is that the former holds a lot more fuel than the latter. What, if anything, am I not understanding?
Not a lot. The physically smaller burners (No.210 for example) put out a fraction less heat than the next size up (No.106 for example!). But they're all much of a muchness, apart from a few really low end shocking examples. Different stoves for different uses, that's all. Requirements up a mountain are different to the base camp or domestic kitchen.
!!! Well, a 0.23mm diameter jet ((Primus No.4, Primus/Optimus No.96, Primus/Optimus No.100 for example) has an equivalent cross-sectional area of approximately 0.04 square millimetres. The jet of those stoves with a jet orifice of 0.32mm diameter (most others, including Primus No.210, Primus/Optimus No.5) has a cross-sectional area of about 0.08 sq.mm. That equates to twice the output of vapourised fuel and air mixture to burn in stoves with the larger jet orifice, in theory. In practice, the extent to which the fuel is pressurised by pumping air into the space above the fuel, and how much fuel is in the tank for that matter add variables that make it less obvious a difference than the theory suggests.
