I recently repaired a damaged burner No 4047 from a Primus 110. I got to see its interesting design. After unscrewing the nozzle, I didn’t notice any holes beneath the thread of the nozzle socket. As it turned out later, they were clogged with soot. To cut off the deformed part, I had to measure the depth of the “hollow tube.” I managed not to damage the perforated section beneath the nozzle socket. Now I had a complete picture of this interesting design. Thanks to this repair,and the diagram from this manual 4283 (very similar design) posted by Staffan Rönn https://classiccampstoves.com/threa...ing-instructions-from-1937-and-onwards.39635/ I was able to understand where the coke builds up and how to clean it. I managed to put everything together. I described the soldering process in this thread: A DIY Trick to Make 360-Degree Soldering Easier I made a similar skewer to unclog the holes. By the way, I have a question. Are these channels meant to help create the right conditions for good vaporization, or do they serve a different purpose? ...or perhaps they are used to trap impurities from the vaporized fuel before it reaches the nozzle?
@Knee, thank you. interesting. re your "Are these channels meant to help create the right conditions for good vaporization, or do they serve a different purpose? ...or perhaps they are used to trap impurities from the vaporized fuel before it reaches the nozzle?" as for the latter. the channels are dead-ends correct (no flow), nothing preventing impurities to flow (where all the flow is) straight to bottom of jet /nozzle. my guess, you're right "...meant to help create the right conditions for good vaporization..." During design, this same section of solid brass without channels (more brass, more thermal mass, slows priming): vaporization was maybe not the best. Just leaving it hollow could be a weak point like the portion you repaired. this same section of brass with channels (less brass, less thermal mass) MUCH stronger than hollow tube, should prime quicker and the channels also increase surface area of hot brass in direct contact w/vaporizing fuel. ^^^ "i'm jus guessing, maybe" i'm onto something with that ^^^ ----- This burner always has a valve below it... that was where my initial thought went but nothing occurred to me from that.
Thanks for your reply @OMC , Actually, the second part of my question seems a bit unfounded, because the channel openings are located right below the nozzle seat.... This burner is equipped with a nozzle cleaning mechanism . In the hexagonal base of the riser pipe, there is a spindle (not vatve) used to set the needle—mounted on a rod—in motion.
I have no doubt that the outer cap (4209) designed for this burner, with its 5 rows of holes, is the correct one. But... in this catalog https://classiccampstoves.com/threads/1930s-primus-burners-overview.21383/ , I noticed that the outer cap, designed for the burner, has four rows of holes. The illustrations here are extremely detailed, so I assume there isn’t likely to be any mistake. When I looked for information on this topic, almost everywhere mentions 5 rows of holes, as can be seen here in the photos from @kerophile I found only one example with 4 rows in our gallery: Primus 110 followed me home. Maybe someone has some insight on this? Given the above, can we assume that, for a certain period of time, external caps with four rows of holes were manufactured for this burner?
