Plumbing in water gauge questions

[zimirken]

I have some questions about plumbing in a water gauge to a boiler. My specific application is a 1-2 gallon water/steam tank for a forced circulation boiler. I'm trying to figure out the requirements for it as far as number/position of ports. It's unfired and there's no crown sheet, so there's no real risk if the gauge glass is temporarily off. In my last boiler, I just used a single electric water level sensor about 3/4ths of the way up the tank, and had that drive an electric feed pump every ten seconds or so. It worked okay, but on this boiler I'd like to have a real gauge glass, for the novelty factor if nothing else. With that in mind:

Say you don't have two dedicated ports at the right perfect heights on your boiler for a gauge glass. What are the requirements for plumbing in a gauge glass?

I'm assuming you can't attach the top connection to the same port that goes to the engine, as when you open the throttle the water level will jump up due to the pressure reduction. So I'm guessing that it must be attached to a dedicated port above the water line.

As far as the bottom connection goes, could I attach that to the feedwater inlet manifold? Depending on the resistance of the various paths and plumbings, I suppose the gauge glass might read high, but only when pumping feedwater in.

How short do the gauge glass connections need to be? My interface might be like a foot from the tank, could I run tubing to it, assuming it's in the same spot vertically?

edit: I'm also looking to source a water gauge. My original intention was to just buy this one: https://www.ebay.com/itm/115253896812. However if there's a cheaper or easier way, I'm interested. Could I possibly hold a gauge glass with an off the shelf compression fitting, but with o-rings instead of the brass bushing? If that would fit, but wouldn't hold structurally, perhaps I could make a couple brackets to go on the fittings for the rods that hold the gauge together?

[James Powell]

1. Why do you need to add water to an unfired boiler?

I suspect there is more sus to this than I want to answer questions about...if you can't figure out the how's and the why's, then you probably shouldn't be doing it...

Amount of energy in 1 lb water @ 100 PSI- 855 986 ft-lbf
Amount of energy in a 30.06 bullet- 2,656 ft⋅lbf

...

[rmac]

I suspect there is more sus to this ...

I'm guessing this is a silly typo, but I can't decipher it. What's "sus"?

-- Russell Mac

[hoppercar]

With no pictures,, or other construction information, it's hard to visualize what your doing here ?????

[zimirken]

A forced circulation boiler or "lamont" boiler has an unfired water/steam drum and coils of fired tubing. Water is continuously pumped from the tank, through the tubing where some of it boils, and back into the tank where the steam separates out. It combines many of the advantages of a monotube boiler and a tank style boiler like a firetube, at the cost of requiring a powered circulation pump capable of pumping boiler water at temperature and pressure. As far as safety goes, it's much safer than a firetube. The only thing under fire is copper or steel tubing. The water level in the tank has to drop all the way to the circulation pump inlet at the bottom before the coils run dry. Then the coil just goes pop like a monotube inside the firebox.

I've already built a smaller one several years ago, which worked, but the tank was much too small. It made water level management fickle, and it lost pressure much too quickly. I want to make or acquire a larger tank, so the water level is more stable and I have more steam reserve. This will also help when using solid fuel.

This is not my first steam rodeohttps://www.youtube.com/watch?v=FUXyZdWM_YA, so please don't patronize me. Several years ago I was much into steam power, but I had some setbacks and lost interest. Mostly due to the lack of machining and welding capabilities at the time. My interest has been rekindled, but now I have a welder and a large HAAS cnc machine that is basically my personal toy at work. My goal is to build a "trackless locomotive", similar in size and concept to the rideable locomotives here. The main differences are that it will have tires and steering, and I won't be using a classic firetube boiler. However, I would like it to look and act like a locomotive. So I plan on using wheel mounted direct drive cylinders with hackworth valvegear, and I will be disguising my boiler as a firetube by hiding it in a steel drum or something. While I won't be trying to replicate any particular full size locomotive, I want it to look like a generic steam loco. I would also ideally like it to be solid fueled, but I can always shove a propane turkey fryer burner in the firebox if I need to.

My new boiler will ideally be rated for 60-100psi, with a goal of around 5sqft of heating surface. This seems low, but 1-2.5sqft per horsepower is common for a lamont boiler, as the forced circulation greatly increases heat transfer.

On topic, I really want to try to use a gauge glass, even if I use a sensor as a backup. Between the circulation pump and the electric feed pump, I won't escape electricity yet, but a gauge glass would give me more information than a couple water level sensors, and captures the locomotive feel better too.

My tank will be about 1-2 gallons, perhaps 6-10 inches in diameter, vertically oriented cylinder. The water level in it can vary from 25-75%, since I'll be pulling circulation water from the bottom or near it.

[James Powell]

Don't patronize you ?

You are claiming that an Lamont boiler is a unfired boiler. Here, I'll quote you chapter and verse, and you can see what a UNFIRED boiler is- it sure isn't a boiler with forced circulation over a fire...

""boiler" means a vessel in which, by the application of heat,

(a)gas, steam or vapour is capable of being generated and pressurized, or

(b)a liquid is capable of being pressurized or heated

and includes fittings and boiler external piping associated with the vessel;

""

""
"unfired boiler" means a pressure vessel in which gas, steam or vapour may be generated for use external to the boiler by the application of heat resulting from something other than the combustion of fuel;

"unfired plant" means a plant where heat from gas, steam or vapour or other heating medium is supplied to heat exchangers or used directly for the purpose of heating a facility or a process without combustion of a solid, liquid or gaseous fuel taking place on the premises;

""

Right from my province's boiler codes. (BC, in case you are wondering)

So, what you propose to build is a boiler. Period. If you don't have the knowledge as to the risks involved, then you don't have the knowledge of how to safely build your own. You popped out with this being your first post, and asked "how do I build a boiler ?"...well, I'd suggest start by reading a series on building a pot boiler- I'd go with "The Generating Game" by the late Jack Weldon, in Model Railway Constructor ~1985, or similar. Once you have some idea of what you are playing with, then start asking questions. The answers are there- look at the amount of energy that you are talking about- 850x lethal energy in a lb of water or more...

Yes, a Lamont or any water tube boiler is safer than a firetube boiler. No, that doesn't make it "safe". I'd hazard that those of us who have been around the block here once or twice, and have answered the same sort of question are a little careful about how we answer it, because otherwise you get stupid people doing stupid things.

https://www.stationroadsteam.com/lethal ... ck-warmer/

and

https://www.dli.mn.gov/workers/boiler-e ... edina-ohio

(that one ended with 5 dead...)

For our other forum members- sus= suspicious.

James

[zimirken]

I did my college thesis on steam engines but thanks for the introductory lesson on what a boiler is.

If you had bothered to read, I never said the boiler was unfired, I said the water/steam tank was unfired. I also never asked "how do I build a boiler?" I was asking specific questions about gauge glasses.

Thanks for helping me understand how it feels to be a female construction worker.

Can we get back to talking about gauge glasses?

[318J]

.

[Gra2472]

Since I am not a mechanical engineer, it is astounding how much one can learn just by reading these kind of threads. I feel like I should be taking notes. Is there a final exam?

G

[318J]

To follow up, upon reading more closely, I do know exactly the type of boiler you are describing. I did not catch it being called a Lamont at first... and then everything clicked. The steam drum on a LaMont is still directly connected without means of isolation to the steam generating coils in the combustion chamber. This makes it part of the boiler and the pressure vessel, even if it isn't the portion of the boiler that is directly fired. It's construction should be taken as seriously as if it were.

I would not put the sight glass water connection down by the pump manifold, upstream from the steam generation coils. Not knowing your boiler specifically (again, photos, sketches, ect would help) the coils (if running in vertical loops), will form traps when the circulation pump doesn't run. Every Lamont I've installed in the field has the sight glass and water level sensors connected directly to the steam drum. It's the most accurate and reliable way to see what's in the drum, without complicating the sight glass set up or opening up the sight glass to interfence from the circulation pump. If the connection is after the pump, the glass will fill with water as the pump not only circulates water into the coils but up through the sight glass and directly into the steam drum as well.

Attach the sight glass directly to the drum and only the drum with the most direct and simple plumbing possible. If you don't have the ports there to do that, I advise making them. Even if your Lamont boiler doesn't "need" a sight glass, it's a very good backup to verify your other sensors are working, which is why I think it should have one, and one that works well and accurately.

[zimirken]

Thank you. That's exactly the kind of advice I was looking for. I managed to find a copy of the asme power boiler code. It also says that they should be directly connected to the steam drum or a water column using straight piping of a minimum size without any bends that would allow water to collect.

I suppose my definition of "fired" was different than the proper one. I meant fired as in the part is directly exposed to fire or flue gases. That may not be the proper definition. Sorry for the misunderstanding.

As far as the design goes, I could probably draw up a piping schematic, but layout is kind of affected by these questions. I'm still sourcing the steam drum, but I'll have to make sure now that I can have a straight shot from it to the operating area somewhere in order to pipe in a gauge glass. Or I guess I could have it stick out the side.

I was given a ride in a steam car once that had the gauge sticking out the side, and you looked through a mirror down by your foot to check it. Interestingly enough mirrors for this are mentioned in the boiler code.

[Pontiacguy1]

Make sure you have some valves on it so that you can turn it off and also blow the glass down to make sure it is kept clean. From what I'm reading, it should operate like a locomotive gauge glass, but you would be attaching it to your steam drum. Make sure that you put the lowest reading point (bottom) of the gauge glass a safe distance above the inlet for your pump so that if you can see water at all in the glass, you know your pump won't cavitate and cause issues.

Sounds to me like you could have a much bigger drum. A bigger drum would take a lot longer to fire up and get up to pressure, but would hold that pressure longer and be more forgiving and easier to deal with after it was fired up. Always a trade off.