Steam loco boiler

    Howdy,
A friend quizzed me, he wants to attach a manual blowoff/ drain valve to a small steam loco boiler. It's a small loco, about 15-17 inch guage. The
age is (I'm guessing) about 50 or 60 years old. There never was a bottom fitting on this boiler. There are rivets on it, but it appears they're *applied* as a decoration. Actual construction appears to be welded. But nothing has been ground or wirebrushed to verify anything.
My first selection would be 7018. This isn't anything urgent, but does anyone have any suggestions? Position shouldn't be a big problem, I'm pretty sure we can flip it over. Boiler is approx. 20 inch dia X 36 inch long.
Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sat, 10 Jan 2004 05:06:38 -0600, Greg M

That's a _big_ loco. Here in the UK you'd never get a boiler certificate or insurance for it, unless it was built with adequate washout plugs around the firebox foundation ring.
I doubt if you can weld a blowdown valve to the boiler shell. The place where you need to put it is at the worst possible place for corrosion and scale buildup and this is going to be a nightmare job if it's other than brand new and unsteamed. Just look at the trouble that repairs in this area cause, and that's usually on a boiler that's stripped right out to work on.
What you can do though is to replace a washout plug with a plug that contains a valve. The plugs are oval, held in place by steam pressure and clamped lightly from the outside by a bridge clamp (a bit like a pressure cooker). It wouldn't be that hard to make one up with a valve attached.
I'm also puzzled as to why it _needs_ a blowdown valve. They're not that useful, and they're hard for thermal stressing the firebox. Although they might have their place for rapid-turnaround expresses (along with asbestos suits for the ashpan cleaners), it's easier just to wait for things to cool down, then drop the plugs and get in there with a hose.
-- Smert' spamionam
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Andy, thank you.
It's a toy type loco, amusement park sort of size. But I will pass all of your post on to my friend. I'm not that knowledgable as far as boilers, although I have maintained a few, much larger, in an industrial setting.
The basic sizes I posted may be a little inaccurate, but we both understand that steam is steam is power.
If (perhaps) a couple of years ago, you heard of a steam farm engine blowing up, at a county fair in Ohio, USA, killed several and injured, more than several..(?) That was about a 45 minute drive. There was plenty of finger pointing, but the gentleman who owned it (and died) did not have a sterling reputation. The errors were all his as far as I understand.
Ohio's steam standards were extensively revised after that. I think that steam display was completely halted for about a year. Thanks again.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
A few things:
What make of locomotive/boiler? Drawing are available for most of the commercial models (Eg: Cagney, Crow Metal, etc) going back to the turn of the century.
The construction may be riveted, welded, of a combination of both. Cagney, for example, buitl boilers of single-lap, single butt, and I think double butt; riveted, riveted with seal weld, and riveted/welded.
What is the heating surface? (surface exposed to hot gasses: firebox above the grate line, tubes, door ring, etc., nut not the flue sheet at the smokebox end) Some of htese count as minature boilers (less than 10 Sq feet of heating surf, as I recall) which simplifies the requirements, some don't.
The NBIC _REQUIRES_ a blowdown at the lowest point of the water side for fire tube (loco type included) boilers. This should be under the throat sheet just above the mud ring. Minatures are NOT excepted. No blowdown is DANGEROUS.
Modifications to the boiler design are tightly regulated. There is a reason for this.
I can give you more info if you need it, until your ears pop off.
e
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I'm all ears and have saved all the posts in this hread. The loco is in another building, stored, right now. So any info gathering will wait for a bit.
It may be a Cagney but I'm not certain.
IIRC the *corners* are welded.
I agree with a proper blowdown also. If nothing else- you remove sediments and scales- et cetera.
enl snipped-for-privacy@yahoo.com (e) spluttered in wrote:

--
"The true man wants two things: danger and play.
For that reason he wants woman, as the most
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.