I have this optimus 111 T, that has something that looks like the top of the pipe inside the burner has started to melt. (The pipe inside the flame spreader ) What has happened here?
You most likely had what is called "Underburn". It is when the flame is under the burner instead of outside the burner. It can get hot and melt metal. It usually has a loud, and different, sound when burning. Ken
Under burn, flame is on the underside of the burner instead of out the top thru the caps. I've seen that on one, gave it to a friend. Duane
Definately underburn, I have a similar casualty that will require surgery. A cheap purchase so not an issue till I get around to dismantling.
It is caused usually, if the stove is in working order, by lighting the stove improperly. Best to light the silent burner after the priming flame has gone out. There are also various defects that can cause it, even if the stove is lit properly. Ken
At Optimus we used to call underburning "The China Syndrome". The term borrowed from the film with the same name that describes a nuclear meltdown.
@Lumberjack Sorry to hear that your stove may had a problem. Any chance you could post a picture of the damage? In addition to satisfying the curious side of some of us, a few folks here might be able to evaluate the seriousness and maybe recommend a repair.
@Lumberjack That looks very much like underburn damage. Are your inner and outer burner caps ok? If you cleaned up the rough bits of the damage (smooth them off), your burner might still operate properly. A silent burner should hiss, if it rumbles or roars, you have underburn. Tony
I'd have to check but mine has almost a third of the tube missing, you should be ok with what damage you've shown., just needs a tidy up. Even if the caps are shot they are readily available.
It burns quite Nice now. So it probbably works fine with the damages. But i have another burner i can use instead of that one But the flame spreader was broken and had some missing parts. Has it been too hot, or just bad metal on that?
Glad it works and excellent job with the pictures. By "spreader" I assume you are referring to the burner caps? If those looked damaged it was almost certainly due to underburn but hard to know for sure. Probably not a materials problem but there can be subtle variations in shape and other little design differences, some of which may be more prone to underburn. I get the feeling that, in the absence of a bonified original inner and outer cap, it can be a trial and error process finding a good set for a particular stove. It sounds like you are good with your current set up.
Look not too bad This is a model without ho!es on the tube. Maybe someone can explain why the model after has holes and differences on caps.
Hi @JP2 from an old post: “However, you will also note from the photos that there are some other small differences, for example, the inner silent cap the Primus regulated burner has holes on top.There are also holes in the centre up-stand of the corresponding silent burner body. I believe this to be subject of a Primus patent, claimed to prevent or reduce the incidence of under-burn. These perforated inner caps also turn up on certain conventional, non-regulated, silent burners. I have found that the burner operates with un-perforated caps just as well, so perhaps they are not critical in normal operation.” From this thread: Regulated Burners I have known. Best Regards, Kerophile.
Hi @JP2 The British stove manufacturer, Valor, also had a 1946 British Patent on additional holes in parts of the silent burner to prevent under-burn: From this thread: New Stove - Valor Best Regards, Kerophile.
The one I had was damaged, yours looks more like crud. Mine had some of the tube burnt away and missing, still worked. Duane
