Blackstaff boilers in copper.

[VANYA]

Can someone please tell me if ALL copper Blackstaff type boilers are allowed under the codes for large applications?

By all copper I mean copper mud drums, steam drum and water tube pipes? The whole works!

It may be allowable for model engineering sizes but not steamboat boiler due to degredation of strength of copper due to heating. Is this why steel drums are used?


Hayden

[fredrosse]

According to the Boiler Code used in the USA, (as well as many other countries), the ASME Boiler & Pressure Vessel Code, the use of copper in boiler construction is allowed for tubes as well as drums. HOWEVER..... Compliance with the code requires heavy wall thickness for copper, due to its low strength with increasing temperature. I recall looking at this several years ago, and to make an ASME Code compliant boiler out of copper is virtually prohibitive due to the very heavy wall thickness of tubes, drums, etc.

In the model railroad arena, several boilers (of the horizontal firetube type) are made with steel shells, and copper tubes. The heavy wall copper tubes (Type "K" in the USA), being either 5/8 inch or 7/8 inch outside diameter used for these locomotives have given generally satisfactory service, however they are not thick enough to meet the ASME Code requirements.

[VANYA]

Fredrosse.

Yes thankyou and comments noted . I see listed in the lastest SBA(UK) book two Blackstaffe boilers listed for sale and though it might be a good start. My friend tells me to ask first about this all copper assembly due to the heating. apparently a UK boiler maker went out of business and he made all copper marine boilers for steamboats. There were problems with them.

Anyway better for me to check first.

I would like a lower profile Blackstaff boiler in my boat but they are more difficult than a VFT to make. Back to the drawing board for me.

Thanks.

[Mike Cole]

Yes, there was a issue with copper boilers in the UK . I think now that new builds, using copper (for the SBA) are resticted to a max 100 psi working pressure.

[VANYA]

Mike.

Do you see or have you seen those items lists in "The Funnel"

Guess it would be a little difficult to keep the fire tamed in such a boiler?Sure the pressure can be released with an appropriate safety but obviously most of the generated steam would be wasted.

I guess this does then restrict this type of material/construction to " model engineering" size boilers too. I really would like something in between model size and full size for what I plan in the 16 foot size.

Is there a drawing of a "mini "Blackstaff boiler anyone knows of that is bigger than a model engineering size?

[Akitene]

Hi Vanya,

I'm considering to have a go at an all copper Blackstaffe boiler; I plan to build a boiler able to deliver 100 PSI + moderate superheating for compounding purpose. One of the most detailed and interesting example of an all copper boiler is the one designed and made by Al Dunlop (http://aldunlop.com/ for general info and http://aldunlop.com/boiler2011/pressure ... r2011.html for details about his boiler).

A few years ago, I've noticed another example of an all copper boiler, a true Blackstaffe design coupled to a compound engine. I can't find the URL anymore; if I get it back, I'll drop another post here.

Hope this helps.

Akitene