Pipe to Pipe welded Joint in a reactor shaft-blade assembly
Pipe to Pipe welded Joint in a reactor shaft-blade assembly
(OP)
I've seen some Glass Lined Reactors where the agitator shaft & blades are all fabricated from what seems to be heavy steel pipes (they avoid sharp turning radii where the glass coating will crack). Which are finally coated with the protective glass & baked etc.
My question is about the blade-to-shaft joint. Essentially they had to weld a small diameter pipe (blade) to a large diameter pipe (the shaft) at right angles. Would this lead to one continuous hollow cavity or would the blades be a separate cavity.
My engineering sense says the metal wall of the shaft would still remain as a barrier but just wondering whether for fabricablity etc. one may prefer to gouge out the wall area underneath where the blade will be welded to?
From the drawing I have it isn't obvious how that welded connection would be.
My question is about the blade-to-shaft joint. Essentially they had to weld a small diameter pipe (blade) to a large diameter pipe (the shaft) at right angles. Would this lead to one continuous hollow cavity or would the blades be a separate cavity.
My engineering sense says the metal wall of the shaft would still remain as a barrier but just wondering whether for fabricablity etc. one may prefer to gouge out the wall area underneath where the blade will be welded to?
From the drawing I have it isn't obvious how that welded connection would be.





RE: Pipe to Pipe welded Joint in a reactor shaft-blade assembly
Unless something very weird happens, the answer to that question is no.
RE: Pipe to Pipe welded Joint in a reactor shaft-blade assembly
Yes. You interpreted correctly about the " leaving a hole connecting the internal volumes of the two parts"
That's exactly what I want to know.
OTOH, melting is one possibility but I was more thinking about whether there'd be some fabricablity / welding reason to do a perimeter weld after removing the intersecting part of the larger pipe on purpose. i.e. In the same way you'd gas cut out the portion say if this was a pipe-tee for liquid transport applications.
RE: Pipe to Pipe welded Joint in a reactor shaft-blade assembly
My question is the same: Would the blade + shaft be one connected cavity? Or separate ones.
RE: Pipe to Pipe welded Joint in a reactor shaft-blade assembly
RE: Pipe to Pipe welded Joint in a reactor shaft-blade assembly
Regards
r6155
RE: Pipe to Pipe welded Joint in a reactor shaft-blade assembly
No. Drilling or cutting holes in the central shaft tube does not make the fabrication easier, faster, or cheaper- just the opposite, it will add significant cost and time.
Are you asking this question because these rotors are produced so that the internal volumes of all sections are linked in the way you describe, or because you're looking for improvements?
RE: Pipe to Pipe welded Joint in a reactor shaft-blade assembly
Context is that we are wondering if there's a corroded spot on one blade whether material can travel and damage other blades straight without any restriction. Or if there will be a barrier (at least temporarily)
RE: Pipe to Pipe welded Joint in a reactor shaft-blade assembly
Unless you have evidence of this I would put the probability of significant corrosion on the inside of a fully sealed, welded, and glass coated assembly as very very low. Even if there is loose material inside the tubes, it's going to be transported to the tips of the fins by centrifugal force. The likelihood that it would ever touch the wall of the central shaft, let alone enough contact to wear a hole into the internal volume of the central shaft, is very very very low.
RE: Pipe to Pipe welded Joint in a reactor shaft-blade assembly
RE: Pipe to Pipe welded Joint in a reactor shaft-blade assembly
Ah! A vent hole! That's the most plausible explanation. Makes total sense.
Just out of curiosity: Why do we need to vent the blade cavity to the shaft cavity? What's the reason?
RE: Pipe to Pipe welded Joint in a reactor shaft-blade assembly
RE: Pipe to Pipe welded Joint in a reactor shaft-blade assembly
Makes a lot of sense. I think you have figured out the exact answer to my puzzle. Thanks!