Arvid Böhlmark Nya Excelsior 1893-1904 Circa

Hello,

today I have completed the restoration of a beautiful stove that has been on my pile for some months… a fantastic Nya Excelsior by Arvid Böhlmark, datable from 1893 circa (when the burner was patented https://classiccampstoves.com/threads/arvid-böhlmark-improved-roarer-burner-patent-1893.35614/) up to 1904/5 when the production ended, as stated by @Christer Carlsson into another discussion.

The Nya Excelsior came after the 1892 predecessor Excelsior (Nya means new) and probably lasted for the entire Böhlmark production with the later releases of the silent variants Orbis, Jupiter and Sirius.

This stove came to me without legs and the original hinged cast iron flame plate, a very decorative element, that we have seen only on a stove that resides in South Korea, thanks to a photo shared by the friend @multi-cho I will add the photo in this post as well.

I recycled some legs donated by a broken Primus stove, that I modified to match the Böhlmark shape. The flame plate I used is a Juwel 6A style plate, a perfect match for this stove, with same proportions of the original, so the flame pattern will be realistic.

To have it back to work I just renewed the pump leather cup and back washer for the pump, filler cap gasket and I cleaned the jet and a little the burner from the side access visible on the burner details photos.

To note the jet threads are not standard, so fortunately the original jet was in acceptable conditions.

The soldering of the legs fortunately came out well, clean and with correct orientation and height at first attempt

Well, here it is the stove completed:



Next a detail of the perfect match of the flame plate:



In the next detail we see the hinge housing of the original flame plate:



The stove finally burning:



The original flame plate:



The as found conditions:



Enjoy,

Nicola

 

great job! very nice..haha

 

A fantastic looking stove. Very ornate. Nice work.

 

Thank you for the detailed post.

Cheers

Tony

 

Great job on an interesting old survivor.

 

Superb presentation Nicola, and an impressively imaginative and successful solution to the burner head plate challenge

Thinking back at the far-from-original wreck I posted back in 2017 (here), I wonder if you would be in position from this restoration to answer 3 questions about the Nya Excelsior which were asked but left unanswered back then?

One was what configuration of NRV was used on the original detachable pump? Do you have photos of this?

Similarly can you add a photo of the tank base? Does it have the same peculiar fixed centre plug? And did you find/see anything in the course of your restoration to help explain what the purpose of the plug may have been?

Finally, were you able to discern what size and form the original burner/riser joint threads were? What I had found appeared to be something midway between 'normal ' No.0 and No.1 sizes, but it may have been damaged, worn or modified.

All the best,
Ian

 

Beautiful uncommon stove, fantastically restored and presented. Thanks for sharing.
Stanisław

 

The tank shape and inscriptions are a thing of beauty. What a pity economics and competition meant they were not viable longer term.

And the burner design with plugs for easy cleanout- another example of the ideal but ultimately uneconomical.

 

@igh371 thanks Ian, I knew you would have asked these questions.

1: Unfortunately these oldies are so well made that the pump valve was perfectly functional, so I didn’t need to mess with the pump tube fortunately (still can’t find a proper tool for these). I am sure the NRV will be similar to pre 1896 Primus and Aetna, but, as soon as I receive my endoscope, I will take some shots of the internals

2: Yea, there is the central plug as on other Nya Excelsior… endoscope will reveal its use as well, but I am sure it’s a bottom plate reinforcement.



3: Regarding the burner, I accessed from side plug and cleaned the central tube. That’s the purpose of that plug as explained on the patent:



I didn’t try force to remove the burner to protect the stove as much as possible, having the burner a round fitting. Clearly the cleaning of jet and central tube was successful and granted a good flame, so the removal of the burner was not necessary, as for the pump tube. At the moment I can’t answer about threads size.

Cheers,

Nicola

 

@Stanisław Grajewski thanks

@Blackdog I agree. After the first test the burner was clearly clogged by carbon. So I removed the plug and the central horizontal tube was full of it. Once cleaned that portion of the burner it started to work very well with good flame. So I need to understand if this design allows the carbon to be formed all there (relatively obviously) to be easily cleaned.

Nicola

 

My observation of conventional 'roarer' burners is that most carbon is deposited in the initial burner tubes and a small amount in the burner head, suggesting vaporisation occurs very early on in the passage of fuel through the burner.

There's a lot less mass in this Böhlmark burner than the conventional design with a heavy cast head, so it's quite possible vaporisation and deposition of carbon occur later, i.e. closer to the nipple, allowing easy cleanout. It would be fascinating* to find out what the deposits are like in the initial two tubes if you ever do remove the burner.

*to me, even if nobody else on this planet

 

@Blackdog will come the day I will check the initial tubes.

For now, considering the quantity of carbon inside the central tube and how free is the burner after the cleaning I suspect little carbon at the initial section of tubing.

Nicola

 

Well the flame photos look superb

 

A short video of the stove burning:



Nicola

 

@Nicola Francesco Elia
@igh371
I think - there must be a cork block used in NRV as a pip ( like in early Primus before 1896 ). No other material would stand such time.
Stanisław

 

@Stanisław Grajewski yes exactly, cork for sure!

Nicola

 

The hinged flame plate is a brilliant idea. It keeps in connected to the stove. I don' know how many stoves I've seen with missing flame plates.

Ben

 

@z1ulike Hello Ben, yes a brilliant idea. Unfortunately the rule is confirmed, flame plate lost ahah

These cast iron plates probably suffered of some fragility. You can see also on the Korean one a crack at hinge position:



The same hinge bit rest was found in mine:



Nicola

 

Hi @Nicola Francesco Elia .
Congratulations!
A very nice, old and very rare stove.
Beautiful presentation.
Nice to see that you were able to get it up and running with minimal effort.
This is indicative of solid workmanship.

I hope you will share here the pictures of the inside you will make with the endoscope.

 

@Knee thanks Stanisław! Sure I will share the internal photos, I have many more stoves to inspect as well ahah

Nicola