filling a hot boiler

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aopagary
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Location: San Diego

Re: filling a hot boiler

Post by aopagary »

i have an ashpan that slopes down to a lever operated dumping hatch. i remove the grates after a few runs to really clean it out, but i have to remove the firebox door to grab them and pull them out. before i run, there are typically only a handful of unburnt coal pieces that didn't fall through the grates or clinkers that are easy to remove through the door.

i doubt i would consider actually blowing a jet of any sort of air onto a live fire. the coldness might be the least of my problems. i was thinking more about well away from the firebox door inside the cab making the air being drawn in a lot less O2 rich.
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cbrew
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Re: filling a hot boiler

Post by cbrew »

aopagary wrote: Tue Nov 29, 2022 8:57 am i might add... the boiler is coal fired. with oil or propane i imagine it would have cooled faster. i turned off the blower immediately but it probably took a good 30 minutes or so before the embers died out completely. much different than when i come off the track, i was firing up so the firebox was packed with coal. i add water through the pop valve openings and the first thing the water hits is the firebox crown sheet.
I see you are in San Diego, member or CVLS? if so, talk to Scotty,, he showed me a trick that will kill any solid fuel fire right now... in short plug the stack, and turn up the blower, this will back feed steam into the firebox, displaying O2 and fire is dead.
If it is not live steam. its not worth it.
Pontiacguy1
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Re: filling a hot boiler

Post by Pontiacguy1 »

If you cap the stack with a rag or block..and then put on the blower. The steam will travel back to the firebox and instantly extinguish the fire.
I was taught this trick back years ago. Do this if you find that you need to immediately extinguish the fire: roll up your gloves, stuff them into the stack, and then crank the blower up. It will blow saturated steam back through the tubes and put your fire out, and it will also keep the tubes cooled down so they don't get damaged. You can do this anywhere on the track you happen to be and you don't have to look around to find something. I've only had to do it once, and it was on someone else's locomotive that was having trouble. Didn't want to take chances with that copper boiler getting damaged. Worked like a champ.
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aopagary
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Re: filling a hot boiler

Post by aopagary »

i'm not disparaging the tips about extinguishing a fire, but we seemed to have strayed from the topic of cold water into a hot boiler.

i can't help but think about a line a flight instructor once told me... under normal situations, there's no such thing as an emergency takeoff. ten years ago my boiler cost me about $7k... i have a feeling it would be considerably more today.
JKreider
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Location: Redlands, CA

Re: filling a hot boiler

Post by JKreider »

I’m glad aopagary posted this question on this forum as this venue has a very broad and knowledgeable bass among its members. This would certainly be the place to ascertain the correct technical info and allow one to come to the right decision.
With that being said, let me admit upfront that I do have an interest in this discussion, and particularly arriving at the proper conclusions, since the boiler in question is of my design and construction, and I even had a hand in designing the blowdown valve. The blowdown valve in question is a model of the Wilson type in which the pressure holds the valve plug against the seat. My experience has shown that the leakage has a tendency to decrease as the pressure rises because of course, there is more pressure against the valve plug. This is also characteristic of the prototype. In all fairness to aopagary, the valve did have fairly good leak at 50 psi consisting of a steady stream of drops, but nothing I felt would inhibit operation or in keeping the water level where it should be.
The boiler is of welded construction, 3/8” thick on the outer sheets and ¼” on the firebox and tube sheets. There is an abundance of 1/2” stays in the water legs and wrapper sheet. Tubes are steel, ½” ID with a 3/32” wall, welded in both the front and rear tube sheets.
At 50 psi, the temperature of the water would have been about 300 degrees and I have had similar situations where, after a couple of hours, I have filled the boiler with water out of the hose with no adverse effects. The water is probably slightly above ambient in that it does go through a water softener before it gets to the steaming bay. So guys, what’s the consensus. If it is one thing I have finally learned getting to my old age is that you are never too old to learn, so I’m all ears.
I do realize however, that the engine is aopagary’s property, and the decision he made to save running for another day is without a doubt, the safest decision he could have made.
Jim Kreider
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Bill Shields
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Re: filling a hot boiler

Post by Bill Shields »

aopagary wrote: Tue Nov 29, 2022 5:51 pm i'm not disparaging the tips about extinguishing a fire, but we seemed to have strayed from the topic of cold water into a hot boiler.

i can't help but think about a line a flight instructor once told me... under normal situations, there's no such thing as an emergency takeoff. ten years ago my boiler cost me about $7k... i have a feeling it would be considerably more today.
Takeoffs are optional...landings not so...
Too many things going on to bother listing them.
pat1027
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Re: filling a hot boiler

Post by pat1027 »

JKreider wrote: Tue Nov 29, 2022 6:07 pm This is also characteristic of the prototype. In all fairness to aopagary, the valve did have fairly good leak at 50 psi consisting of a steady stream of drops, but nothing I felt would inhibit operation or in keeping the water level where it should be.
I have a pair of Super Scale blowdowns and they will do the same thing. They may or may not slowly drip cold at atmospheric pressure. If dripping increases as pressure comes up a wiggle back and forth usually seals them. I once had the steady running water and steam that wouldn't clear up and got worse with wiggling. The water level was going to drop from the glass before pressure was sufficient for the injector to pick up. So I killed the fire and blew it down. Keeping them clean and a couple drops of light oil in the outlet seems to help them seal up better on the next fire up.
James Powell
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Re: filling a hot boiler

Post by James Powell »

To go back to the original question- I'd be a bit hesitant to refill a boiler that the steel is say, warmer than you can touch, until it's somewhere like what you can hold your hand on for a couple of seconds. Which generally should happen fairly quickly with the boiler if the fire is pulled. If you still have a fire burning, it can take hours to get to where the boiler drops in temperature.

-removable fire bars are important. How you get them back in might be a bit more difficult. I was warned that if I ever pull the pin and drop the bars out of the Britannia, the quickest way to put the bars back in is to take the boiler off the frames. I think that's the most awkward one we've had. I choose to not remove bars often, but they ARE removable.
Marty_Knox
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Re: filling a hot boiler

Post by Marty_Knox »

aopagary wrote: Tue Nov 29, 2022 8:00 am i had to blow down shortly after firing up the other day due to a leaking blowdown valve. i capped the valve, but now i had an empty very hot boiler. i was getting different opinions on how to proceed, but i chose the safe alternative by calling it a day. about 2 hours later the boiler jacket was still too hot to touch. did i make the right call?
My opinion is that you did not make the right call. The right call would have been to leave the water in the boiler until it had cooled down.
Berkman
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Re: filling a hot boiler

Post by Berkman »

Exactly... there was no real need to blow it down. just leave it and let it cool.
JKreider
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Re: filling a hot boiler

Post by JKreider »

Blowdown-1.jpg
Blowdown-1.jpg (38.47 KiB) Viewed 2764 times
I agree with Marty and Berkman. Dropping the firebed would not have even been part of my methodology for the situation at hand.
I would have brought the engine up to full pressure to see what the offending blowoff cock did. Those blowoff cocks leak, by design, when there is no or little pressure on them and tend to seal better when the pressure gets up. We have experienced that on the prototype a lot.
If the blowoff cock was still leaking to an unacceptable level at full pressure, then I would have turned the blower off and turned an injector on to reduce pressure until the injector quit which would probably been about 40-50 psi (doing that would only have reduced the water temp by about 30 degrees). Then I would have walked away until the pressure was down to 0 or very near it and replaced the blowoff cock with the plug while wearing the appropriate gloves of course.
Then of course I would have fired up and ran. I would have not removed the water from the boiler until I blew down at the end of the day.
Jim Kreider
joe.joseph
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Re: filling a hot boiler

Post by joe.joseph »

aopagary wrote: Tue Nov 29, 2022 10:46 am another note... i have no way of dropping the fire. i actually carry a emergency tire inflation gizmo that uses a CO2 cylinder, but like i said, i had a few minutes to let the fire die. the amount of glowing coal was simply a bit more than an end-of-the-day fire. i poked around a bit and some bits fell through the grate, but it more of a controlled situation than an operating emergency.
Can you elaborate, and maybe post a picture of your gizmo, and provide info on where it might be purchased? Your idea sounds good, and I'd like to look at it as another back up system. Dropping the fire is not the easiest thing to do. I have a plug that I put in the smokestack and then put the blower on to assist in blowing out the fire. I also installed an electric water pump to assist in filling the boiler for such emergencies.

Thanks
Joe

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