ASME IV and rectangular boiler

[Zdzislaw]

Hi,
I am looking for an answer how to calculate a rectangular fired heating boiler with waterway around? All sides are flat and stayed. Stays are angles welded to both internal and external shells. See attached picture. Any idea?
As I do not see any suitable paragraph to calculating the design I think only about using HG-500 Proof test to establish design pressure. I am going to use boiler steel so the test would be done per HG-501, HG-501.1a, HG-501.4 and HG-502.2.
What do you think?

Thanks in advance

 

[kwaliteitshenk]

High, Isn't it practical to use staybolts at a pitch depending on the plate thickness?

 

[Zdzislaw]

Hi,
No, it is just easier to use angles as stays. Easier to produce and less leaks after welding and the stays can work as water baffles to increase water flow time thru the boiler.
I found the answer for my question yesterday (mighty internet ). I got a report made by a US company for another US company about heating shell boilers rectangular in shape. Acc. to them there is no way to calculate this kind of boilers. Only a proof test can be used to test the design. Anyway I got a proof for my previous reflections on the code.
But of course I am open for all other opinions.
I hope there are some lads on this forum designing fired heating boilers. Not only power boilers
Thanks

 

[kwaliteitshenk]

Hi,

The mill I used to work for the last 47 years produces horizontal fire tube boilers up to 1200 BHp (+/-50 MBTU) acc to Section IV limited by the welddetails of HW to 30 psi. We also made locomotive like fluidised bed heating boilers fired with wood pellets or coal also acc. to Sect. IV. Those boiler are used to heat greenhouses for growing flowers or vegetables. For the staying of the flat parts we use staybolts.

 

[Zdzislaw]

Hi,
I think I was not clear a little bit. My boiler is an oil fired domestic one with a draught burner. And it is a shell boiler with a condensing unit to increase eficiency. It is not a drum or lokomotive boiler for solid fuel. That is why I cannot find any usefull formula in ASME code.
My stays work as baffle to make water flows thru the boiler like I want. And it has been working for 25 years in my company.
I do not know exactly why staybolts are still used. Probably there are good reasons for that.
I paste a link to the report mentioned before:

http://www.hearth.com/econtent/index.php/wiki/Boiler_Standards

Thanks