[Steam-engine] lap seam boiler pressure

[Lawrence Swanz]

Chas,

To answer a few of your questions, here in Minnesota it is assumed that the boiler plate is 55,000 tensile strength, unless stamped otherwise (refer to TS in the formula layout I sent yesterday).  As for figuring the "Diameter of rivet after driving", it is nothing more than knowing or making an educated guess of the original thickness of material after ultra sound readings are taken.  Then simply look the plate thickness up in the chart and match to the number given on the right.  According to your earlier email, you stated that your boiler was .375" thick and has an inside dia. of 24".  With knowing the plate thickness the chart gives you a driven rivet size of .8125".  Some of the gray areas that you have left are, what is the pitch between rivets at the joint?, The 24" inside dia., is this the firebox?  If so, what is the inside diameter of the barrel?

Keep in mind, so far we have been talking about the barrel.  What is the spacing of the staybolts in the firebox?  What is the thickness readings of the firebox material?

Without seeing your boiler, assuming that it is in fairly good shape, I would say that the boiler shouldn't have any problems obtaining a certification.  However, I know from a friends experience, he had to have a coupling welded to a flue for a fusible plug location that wasn't present during inspection.  So don't be surprised if this is required of you.  Even though on earlier engines, the fusible plug was threaded directly to the flue casing.

I hope that the information I have given you will help.

Lawrence

-----Original Message-----
From: steam-engine-bounces at lists.stationary-engine.com
[mailto:steam-engine-bounces at lists.stationary-engine.com]On Behalf Of
CopperheadMarine at aol.com
Sent: Thursday, July 07, 2005 9:05 PM
To: steam-engine at lists.stationary-engine.com
Subject: Re: [Steam-engine] lap seam boiler preshure


Well'
 
   The boiler had a 100lb. safety when I got it and I am assuming  that that 
is design pressure I have hydroed it and it didn't leak at 200lbs. No  bad 
pits.
 
No fusible plug or even a hand hole fore one.
 
 Titusville boiler made for Fairbanks Morse.
 
Lap seam double row of staggered rivets.
 
safety is 800 lbs/hour @ 100 psi
 
Not sure how to check the diameter of a rivet?
 
Not sure how to get the tensile strength? Rockwell test?
 
The boiler works good and has for years. hopefully the introduction of  
inspections here won't cause it to be unsafe?  I had a woman on the DHEC  board 
tell me once that even though we had had no incidence of hazardous waste  at our 
facility in 25 years that the introduction of the new hazardous waste  ruling 
would increase our chances that we would get some. I told her that if the  law 
would increase the risk then we should drop the law to reduce the risk. She  
looked up and to the left for a long time as she thought about that one!
 
Chas F
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