Hi Ramon,
Yes, I am ok myself, thanks for your concern, but have had a rather upsetting family issue to get through so have been away for a while.
I will email you later.
I actually felt the burner was operating quite well apart from the excessive flame length, it just needs a few minor changes to optimise it
certainly the jet appears to be too large but you will soon get that sorted with your smaller drills... I would expect a total flame length of about 4"- 5" at the optimum... the slightly smaller jet should bring this closer.
It will, of course, alter in performance when inside the flu; so you will probably need to adjust it a bit more when installed.
Did you make the current jet? Or is it a modified commercial one?
The reason I ask is that the genuine Calorgas jets are counterbored at 2.6mm dia from the thread side to within 0.025 0.030 of the tip so as to form a converging jet
the actual jet hole only passes through the thin tip portion.
I also seal the thread using some gas sealant when fitting it to the jet carrier.
I would think that the 0.3mm (size 12) jet would be about right
you may even get away with a number 8 (0.25mm) as used in the 2 vertical burner (see attached PDF)
An 0.2mm (number 5) would be way too small for your burner/boiler.
No worries about the small clamp screw, I was just concerned that it passed through the mixer chamber wall so could possibly leak gas
as it is, any small leakage around the flange will not be an issue, since this will just be air and will supplement the secondary air slots.
Fitting a small diffuser inside the mixer chamber, in line with the jet tube, may help a little in mixing the gas and air it would certainly do no harm to add one.
I actually fit 2 of them on my 2 dia vertical boiler burners
the first one for just that reason
the second one (furthest from the jet tube) is only there to provide a second mounting point.
I did not add one to your design as it is just a larger version of my standard 3 ½ boiler centre flu burner and this did not need one
it is, however, a bit smaller in dia than yours, so perhaps I should have included one.
The orientation of the burner is not an issue
just mount it for best access to everything else.
If you do decide to fit one use the spacing from the jet tube as shown on the above PDF
the diffuser height needs to be just above the OD of the jet tube.
Steam drier
I would fit it down the flu, as is your preference, this will be the most effective
the only issue is, as you say, possible early failure due to heat exposure.
If you can use fittings with nuts and olives/cones then replacement would be easily possible should failure occur, however, if your fittings (tee etc) are of the soldering type then I would consider changing to a thin walled Stainless Steel tube for the drier.
The biggest problem will be when bringing the boiler up to steam, or when steam flow is shut off
the flu gasses are going to be of the order of 300deg 400deg C at that location and, without steam passing through it, a copper tube will deteriorate pretty rapidly
stainless will just sit there without issue.
Fitting an inner funnel liner can be beneficial in increasing gas velocity, which can help strip away boundary layers within the flu, but dont overdo it
you most certainly dont need to use a blower or any other form of forced draft
this would just draw excess secondary air through the flu, thus cooling the gasses
gas burners dont need this
coal fires do.
You can also fit the engine exhaust to pass up between the 2 skins rather than passing it up through the inner
this way you dont get variable draft but still get a good output of steam from the funnel.
I have no personal experience with using liquid gas
for the simple reason I have not yet found a system that works reliably.
Most fall into the trap of not being able to adequately control the gas pressure, which can quickly get out of control.
Gas pressure needs to be reasonably constant or your air/gas mix will go all over the place, leading to erratic burner performance; which is why I suggested a pressure regulator.
I am not sure if any of these would work adequately for use with liquid gas though... although you may be able to use one on the vaporized gas if you can find a way to keep the temperature above returning to liquid.
I am not really sure if you could fit the necessary vaporising coil to your burner without it being vulnerable to external influences, such as cold air drafts and the heat sinking effect of the main boiler full of water... I would think a different burner style (such as the blowtorch type) would be more suitable on this score.
The only possible place would be a tight coil around the outside of the mixer body; however, I would not be convinced that the temperature there would be constant enough
it would certainly take some time to reach a suitable temperature, let alone a stable one.
70/30 Butane/Propane mix has a vapour pressure of 35.8 psig at 60 deg F (15.5deg C)
100% Butane would only be at 11.6psig at that temperature.
If your burner is set up for 70/30 Butane/Propane then to get the same flow using just 100% Butane would mean increasing its temperature to approx 98deg F (36.6deg C)
At 100deg F (37.8deg C) Butane would reach 37.5 psig.
10 deg F more and it would rise to 46.1 psig.
Butane also requires more AIR than the mixed gas.
70/30 Butane/Propane requires approx 23.86 cu ft air per cu ft of gas.
100% Butane will require approx 31.02 cu ft air per cu ft of gas.
NOTE... the above is for the gas state... I am not sure how this relates to the liquid state, other than Butane boils at 32deg F at atmospheric pressure.
So
pressure control is going to be one of your biggest problem.
The other is timing the change over from gas to liquid
get it wrong and you have a bigger problem.
By all means experiment, thats what it is all about
just be very careful and consider how to control it adequately.
As for the Prop issue and the bent finger
ouch, I hated it when that happened
especially with a razor sharp racing prop
I still have some of the resultant scars... you have my sympathy.
Hope this is of some help.
Best regards.
Sandy.