I do like to think things through and to understand how and why things happen, that said I do also try not to overthink things. To my mind we are using the gases own pressure to eject it from a container, the rate at which its ejected is in theory controlled by the size of the opening in the nozzle/jet. I also believe that hot gases burn more easily or combust more completely than cold gas. The question being raised is does the gas break down at high temperatures and cause issues with deposits in the jet? So what temperatures is this burner operating at and how hot is it making the gas?
The first clue is that the steel tube of the burner on occasion reaches a glowing red colour, so the tip of the burner is in the range of 550C to 750C - this then is probably the maximum temperature that any part near to the gas reaches. A quick internet search reveals butane and propane are very stable and only degrade in the presence of a catalyst in very controlled conditions in the range of 700 - 900C.
We know the copper pipe carrying the gas is not in direct contact with the steel and that the gas has a cooling effect. We also know that the silver soldered joints are not being affected so the temperature in the gas pipeline is definitely lower than 700C, at no point have we seen the gas lines copper pipe glowing red, so we can safely say the temperature is below 500C.
We also know that other people successfully use this system without problems. We also know and experience blocked gas jets from dirty gas or tanks when using gas in the usual way. So my conclusion is that using gas from the liquid phase is unlikely to be any more prone to gas jet blockages than using lag from the gaseous phase.
I am not an expert but I am experimenting and trying to learn, I now have more experience than I did a couple of months ago and have much to thank friends for that continue to help and support me on my journey of discovery.
What I have realised from my tests is that I have been trying to get the burner to work at the maximum rate - having tested the gas consumption I know it to be 360g/hr or 6g per minute - From this I know the burner will provide more heat than I need so I can now concentrate on operating the burner at a lower rate so aim to set it up at 75% max and for it to be consistent and reliable.
Despite being an engineer, I do not know those numbers by heart, so I had to look them up...
Not being pedantic, I just found information differing from yours.
According to my AI buddy on the web, Propane and Butane start decomposing around about 480 deg C, literal statement was: "at the auto-ignition point, 480 degrees".
According to Wiki, the auto-ignition temperature is around 280 degrees, and that usually is the temperature where molecules become unstable, because they show a strong tendency to react with other molecules without external provocation. So now we have three values, appr 280 deg, appr 480 deg, and "above 700 deg in presence of a catalyst.
Given that the gas is pressurized throughout the entire fuel circuit until either nozzle or control valve, whichever of the values turns out correct, that critical temperature could be significantly lower.
Personally, I still think the chances of dirt being formed in the evaporator being higher than the dirt being carried from the bottle to the tank to the burner, and given that it happens also on vapourfeed installations, I would not be surprised if the dirt is being formed at the tip of the nozzle even...
On the bolded, I have a question: those that experience gas blockages in vapour fed installations, how intensively do they operate their equipment, and what consumption rates are we talking about?
Because here is why I can't grasp the concept of there being dirt in the gas:
-IF the blockages are being caused by dirt, it would be fair to assume, this dirt has certain dimensions, no? The gas as we buy it being filtered and all should suggest a certain max possible particle size.
-If above assumption is valid, it would also be fair to assume, that "trouble-interval" would be depending on nozzle size, no? A smaller nozzle would block sooner than a wider nozzle, if particles are the reason, because the smaller particles would pass a wider nozzle unhindered, but might get stuck in a smaller nozzle...
Reason I am pushing this subject a little, is that I an fairly certain that not many people run their set 80+ hours in a single year. Most people I talk to, speak of maybe 5 hours per year, if that...
But that is the kind of runtimes I am getting. I have a relatively small burner (max about 90 grammes per hour, average 60), meaning my burner has seen roughly 5 kilos of fuel and all of it throught that one single tiny nozzle. If dirt would be a problem, I run no filter and my burner has a relatively small nozzle, I would expect to have seen trouble allready...
I have anyway a very hard time imagining how dirt particles, once on the bottom of the fuel tank, would be carried away by the vapours above the liquid surface. I just don't see the mechanism... I could see that happening in liquid feed installations, but not in vapour feed systems.
Again, if this comes across as pedantic, I apologize once more, that really is not my intention. I see things that do not add up, and being a bit autistic, that does not go down easy.