Tube rupture
Tube rupture
(OP)
Dear All,
I have read a couple of books on boiler, but could not find an answer to a question. I hope to find the answer in this forum.
All books describe that scale, corrosion and embrittlement cause weakening of boiler tubes. This could cause cracks, leaks & rupture, and boiler failure. However the explanations are not very detailed.
I am wondering when cracks leads to a boiler failure / explosion and when not?
I understand the flash steam" mechanism: pressure drops when there is a rupture in the boiler. Water changes to steam and re-pressurize the boiler (1 to 1700), and it causes explosion.
What is not clear to me is the following: when do crack in tube lead to this flash steam? and when not? when does it cause explosion? Apparently not every crack leads to an explosion.
Does it depend on the size of the crack? Does it depend on the location of the crack (wall furnace vs boiler tube)?
Many thanks in advance.
Chris
I have read a couple of books on boiler, but could not find an answer to a question. I hope to find the answer in this forum.
All books describe that scale, corrosion and embrittlement cause weakening of boiler tubes. This could cause cracks, leaks & rupture, and boiler failure. However the explanations are not very detailed.
I am wondering when cracks leads to a boiler failure / explosion and when not?
I understand the flash steam" mechanism: pressure drops when there is a rupture in the boiler. Water changes to steam and re-pressurize the boiler (1 to 1700), and it causes explosion.
What is not clear to me is the following: when do crack in tube lead to this flash steam? and when not? when does it cause explosion? Apparently not every crack leads to an explosion.
Does it depend on the size of the crack? Does it depend on the location of the crack (wall furnace vs boiler tube)?
Many thanks in advance.
Chris





RE: Tube rupture
RE: Tube rupture
I have, thankfully, not witnessed a catastrophic tube rupture in a boiler; my understanding of one is that the expanding steam bubbles at and near the rupture will essentially throw large "slugs" of water into the boiler, potentially blowing out the tube sheet, collapsing the furnace, or even shift the entire boiler - depending on its operating saturation pressure at the time. It's these slugs that cause the damage, as the rapidly expanding steam itself has an exit path through the stack. Essentially, any crack is a bad day; the bigger the crack, the worse your day.
I'll also note that the more violent boiler failures I've heard about tend to revolve around fuel explosions - fuel-rich mixtures in the furnace and/or improper purge cycles.
Edited to add some clarification.
RE: Tube rupture
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P.E. Metallurgy, Plymouth Tube
RE: Tube rupture
RE: Tube rupture