[Steam-engine] Boilers / Repairs

Dave Merchant nesys_com at ameritech.net
Thu Jul 15 12:06:49 PDT 2004


My understanding of the problem is that the tension across the seam is 
diagonal,
rather than the straight pull you'd get from a pair of butt straps.
Thus, you get a bending of the sheets near the lap seam.

Every time pressure goes up or down, the lap seam is flexing rotationally.
This would presumably cause metal fatigue.

Dave Merchant


At 10:39 AM 7/15/2004, you wrote:
>I'm curious as to the failure of lap seam boilers.  From an engineering 
>standpoint they are inferior to the butt strap and welded joint, but are 
>there documented failures of the lap seam boilers on traction engines or 
>is all the concern a preventative measure?  I'm told that the problem is 
>getting to the inside part of the lap seam for inspection but I'm not 
>aware of any cases where a traction engine boiler failed at this point.
> >
> > From: "Dan Donaldson" <ddonaldson at tampatank.com>
> > Date: 2004/07/15 Thu AM 07:09:05 EDT
> > To: "Steam-engine mailing list" <steam-engine at lists.stationary-engine.com>
> > Subject: Re: [Steam-engine] Boilers / Repairs
> >
> > Thanks Ken,
> >
> >     That is the type of information and advice I was looking for. The 
> barrel
> > is actually in great shape and does not need to be replaced. I was merely
> > trying to determine if it would be an advantage to eliminate the lap seam
> > because many states are putting such harsh restrictions on them.
> >     You have brought up a good point about checking material thickness. How
> > can I go about checking plate thickness on a boiler I may be interested in
> > buying? Will I need an ultra sound machine? If so how would I go about
> > getting use of one of those?
> >
> > Thanks,
> > Dan
> >
> >
> > ----- Original Message -----
> > From: "Ken Majeski" <fuller_johnson1 at msn.com>
> > To: <steam-engine at lists.stationary-engine.com>
> > Sent: Wednesday, July 14, 2004 7:18 PM
> > Subject: Re: [Steam-engine] Boilers / Repairs
> >
> >
> > > Well, Dan you asked for opinions so Here is one.
> > >
> > > In many states you can not alter the construction of a pressure vessel
> > > without a bunch of High Tech Expensive paperwork... They can  make you
> > > recalculate everything... This is the reason some people have actually
> > made
> > > new barrels of Butt Strap construction. I have seen one of these and 
> it is
> > a
> > > work of art.
> > >
> > > The second problem is if your state or the one you are going to has or
> > will
> > > adopt NBIC appendix C the stayed surface area will get you long 
> before the
> > > barrel will. In short if the barrel needs replacing the rest of the 
> boiler
> > > is not too far behind. For example if the stayed surface is .300 and the
> > > staybolts measure 4 1/2 you will get 128 PSI... with a safety factor 
> of 4.
> > > So there goes your 150 right there. States can set their own safety 
> factor
> > > as long as it is not less that 4. At a SF of 5 you will get 103 PSI.
> > >
> > > I have seen engines that have good looking staybolts and nice looking
> > > straight firebox sheets that check at about .200 in the firebox area. At
> > > .200 you will get about 57 PSI with a spacing of 4 1/2.
> > >
> > > This is the reason engines and shows seem to be jumping state lines a lot
> > in
> > > recent years. I believe you will see a lot of ASME all welded boilers in
> > the
> > > next few years on the few engines that are still running.
> > >
> > > A guy near here spent about 8,000 on a 15/45 Case a few years ago... New
> > > front flue sheet, Riveted in, Fill the pits on the barrel, all new flues.
> > > And Now... he has a firebox that is in the .100 range with a leak in the
> > > middle of the crown sheet... :( 8,000 would have been a pretty good
> > > downpayment on a new boiler....  So my Uneducated opinion is if you are
> > > thinking of extensive boiler repair look the rest of it over Pretty Darn
> > > Good first... And try to second geuss what your state will think up
> > Next....
> > > I wish you Good Luck...
> > >
> > >
> > >
> > > Ken Majeski, Ellsworth Wis. Case Steam Engine, Minneapolis Steam Engine,
> > > Rumely Oilpulls H, F, & R. Website, Http://www.pressenter.com/~kmajeski/
> >
> >
> > _______________________________________________
> > Steam-engine mailing list
> > http://www.stationary-engine.com/mailman/listinfo/steam-engine
> >
>
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Dave Merchant
kosh at nesys.com
nesys_com at ameritech.net

http://www.nesys.com
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