AB Förgasningsapparater - Genius Silent Burner

This is a reference photos post to show an incomplete example of an AB Förgasningsapparater "Genius" silent burner. This burner is one of 2 shown in an advert (here), which dates from no later than 1921. The other shown in that advert is a roarer burner version called the "Ideal".

The only things that can be said for certain are, first, that the main body is a substantial lump of cast iron, and, secondly, that, despite the standard 1/5 size burner outer dimensions, this unit would seem only to be designed to accommodate a roughly 'No.4' equivalent size burner cap:




Needless to say the spirit ring, or rather, in this case 'spirit tray', is also quite idiosyncratic too:



The old advert gives some hints as to the original burner cap arrangement:



This may be able to be replicated using a Radius UFO cap, combined with a bespoke inner (two side shelf tangs on which this would be located can be seen clearly in the 6th detailed body photo above).

The old advert, and indeed the burner now in hand, do also suggest this burner may be a development of this earlier Trässman and Pettersson's patent unit:

(credit @Nicola Francesco Elia)



@optipri

 

A remarkable survivor. It would be interesting to return it to operation, not least to discover how difficult (or otherwise) it is to prime- but I suspect both indoors and draught-free are requirements.

Amusing claims regarding fuel savings and intense heat- vapourised paraffin is vapourised paraffin!

 

@igh371 a super find!

Nicola

 

Thank you, @igh371.

Tony

 

Dang...just when you thought you've seen it all.

Ben

 

Many thanks @igh371 .I've never seen before this burner
Stanisław

 

Out of the fire ... ?

The silent burner cap shown in the literature must have been both remarkably small and yet also quite a tight fit to have been housed as suggested entirely within the cast iron bell. This missing silent cap being now utterly unobtainable, there is also no even vaguely obvious substitute.

What follows is an attempt at firing the Genius burner up using a small Radius UFO burner. First a method of mounting this within the bell was constructed as illustrated here:


Mounted it fits as so:


The heavy cast assembly requires a substantial pre-heat from the large unique priming tray. Here it is mounted on a Svea No.16 for test purposes:


The first firing attempt using the original jet proved massively over-rich:


With a first change of jet the improvement was marginal:


A second NOS jet carefully chosen for having the tightest bore proved just on the limits of tolerability and managed to boil a kettle in reasonable time:


Clearly there are significant issues here. The redness of the flame may be linked with operating within a cast iron bell. But the need for sustained high pressure within the tank, and a quick reversion to obvious rich running if pressure is reduced is clearly not right. This may be due to the demands of keeping the bell at a high enough temperature to promote efficient vaporisation. But whether lowering the height of the UFO cap would make things better of worse I'm not sure, or is this a lost cause?


@Nicola Francesco Elia @kerophile

 

Ian, I beg to differ. I don't believe either of the pieces of literature show the burner with the cap in place. They seem to show the roarer version with a simple spreader plate in a position which would likely work in terms of combustion. The depiction of the silent cap is described as a 'Silent burning insert' alongside the roarer-equipped burner.

The illustration on the left surely cannot be the silent cap shoved well down inside the casting- the flame outlet holes would be right up against the iron! One possibility is that the pronounced lip meant the holes began above the rim of the cast bell- this would make the cap huge. An alternative is that the bottom of the silent cap descended some way into the cast bell, but still protruded enough to provide clearance for combustion. It doesn't help that at least the left hand image looks to be a doctored cut out photo and unlikely to be the same scale as the cap illustration!

(Dodgy Google translation)

 

More questions than answers here. The literature showing the ('Ideal') roarer version gives no clue as to the set up of a roarer spreader plate, though logically it must have had one (see here). Equally the "silent burner insert" must itself have had some sort of mounting; but again no details are provided.


@Blackdog

 

Surely the object within the burner casting in both documents is a roarer burner plate? And the advert for the 'Genius' shows the silent converter cap alongside?

 

Ah, if you mean in the sectional diagram view, that is a section not across the centre of the burner, but through the rear tubes casting, side to side.

 

I'm (probably not too clearly) speaking of the left hand illustrations- that can't be the top of the silent burner cap, proportion-wise the outer diameter of cap wouldn't quite fit inside the casting, and if it could there would be no room for the flames produced...

 

Next bit of experimentation. How would it look in an approximation of the 'Ideal' format, i.e. roarer. Two different set ups tried, both utilising a standard '96' cast flame plate.

Set up no.1 was with a semi enclosed base plate and unrestricted bell interior. Looked promising, but proved rather lacking in top end power:


Set up no.2 utilised a closed base plate holding a short riser inside the bell to give more direction to the vapour stream. Result!


And with the extra power, signs, at long last, of some real heat transfer to the cast bell:




Conclusion, for the moment at least roarer format seems to be the way to go to make a user out of this burner. Obviously that will mean modifying a '96' burner plate to make it more stable in situ, and adjusting the height of the riser to suite, but neither of those tweaks is in any way problematic.

On the other hand what modifications could be made to a UFO silent burner set up to achieve an acceptable result in that format remains an open question ...


@Nicola Francesco Elia @Blackdog

 

@igh371 great job Ian, it’s very promising. The roarer solution looks very good. For the radius UFO I suspect it sits too high, the flame should go against the cast body for a better heat transfer. Also a reduced orifice jet could be appropriate, 0.26 maybe like on most of lipstick burners.

Keep it up!

Nicola

 

Additionally, not even the Technical Museum in Stockholm has a complete Genius burner, so already having one that can produce some good flame is a great result

Nicola

 

True it seems; but there does seem to exist at least one complete 'Ideal' roarer version, as @multi-cho revealed 3 years ago (here). The photo gives a tantalising glimpse of the top, complete with name ('IDEAL) and hints of the mounting frame:

 

Never seen one like that before. Very interesting.

 

@igh371 yes, that’s also a beautiful burner. I like the Ideal flame pattern, that must be a full circle without interruptions. I can barely see a support below… I would be curious to see if the below support would interrupt anyway the flame shape or a beautiful blue ring could be obtained

Nicola

 

@Nicola Francesco Elia There are two supports visible in the photo (arrowed), the positioning of which suggests there were three in total so the flame ring would have been split into three. The supports are most likely part of the flame plate casting. Whether it's just flame plate and supports, or more internal parts to alter the gas flow as in Ian's experiments though...?



I've added the advert pages alongside, to my eye both of the complete burner illustrations look to have this 'Ideal' roarer flame plate in place.

 

Today I am finally happy with the 'roarer 'Ideal' format reconstruction. One of Juliand's repro '96 flame plates sacrificed and remodelled to give a snug fit at the right height. Works satisfactorily and at full throttle gives a power output equivalent to a perfectly functioning '96'. That is the good part. The less satisfactory aspect, from a regular user point of view, is the extent of pre-heat required to fire up, and the necessity to keep tank pressure as high as possible in sustained use. Would that ever have made it an attractive alternative to the conventional burner options?

Worth noting that the pre-heat seems to work best with the priming tray turned round the back of the burner, so the priming flame is concentrated on the feed pipes and rear top section of the bell. At first sight that looks wrong, but in practice it makes sense. The jet in use is still the 0.23 small jet put in earlier at the second change of jet with the silent burner experimentation. That seems to be essential to keeping signs of rich running at bay.