Economizer tube material

A special section just for steam engines and boilers, as without these you may as well fit a sail.
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TahoeSteam
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Re: Economizer tube material

Post by TahoeSteam » Sat Dec 09, 2017 5:54 pm

CB... have you any way to see what your flue gas temps are? You may be wasting a TON of heat up the stack! Tubulators would probably help you a lot by breaking up the boundary layer of hot gasses going up the flues... a stack damper too!

300lbs of firewood at a generous 7,000 BTUs/lb is 2,100,000 BTUs... 20lbs/hr is 140,000 BTUs/hr a lot of heat and energy is going somewhere, and I suspect it isn't into steam production... though how hard is your engine working during all of this? Is it linked-up? Do you have a superheater?

Your 3"×4" twin Toledo has a volume of approximately 113cu.in./ revolution for both cylinders combined. The HP cylinder of 5"x6" on the the Doty is approximately 235 cu.in/ revolution...
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Re: Economizer tube material

Post by cyberbadger » Sun Dec 10, 2017 3:32 am

I have some of those cheap magnetic biametalic spring gauges sold for stoves. I don't actually look at them because it depends on where you put them and I don't really know well enough exactly where to put them.

I could well believe that it's just going into the air. I need to improve my draft controls and put in a damper to play with.

This new nozzel I'm using for the exhaust in the bonnet/smokebox maybe too intense perhaps.

High-Volume Clog-Resistant Spray Nozzle
Full-Cone, Brass, 1/2 NPT, 0.44" Orifice Diameter - 60 degree model
McMaster Carr part number 3282K991
https://www.mcmaster.com/#3282K991
3282k153p1l.png
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-CB
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Re: Economizer tube material

Post by barts » Sun Dec 10, 2017 3:48 am

cyberbadger wrote: This new nozzel I'm using for the exhaust in the bonnet/smokebox maybe too intense perhaps.

High-Volume Clog-Resistant Spray Nozzle
Full-Cone, Brass, 1/2 NPT, 0.44" Orifice Diameter - 60 degree model
McMaster Carr part number 3282K991
https://www.mcmaster.com/#3282K991
3282k153p1l.png
-CB
If you're trying to force the exhaust through a .44 orifice, that's half the problem right there. Exhaust pipe should not be necked down at all from what's coming out of the engine.

- Bart
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Bart Smaalders http://smaalders.net/barts Lopez Island, WA
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Lopez Mike
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Re: Economizer tube material

Post by Lopez Mike » Sun Dec 10, 2017 4:03 am

There are a lot of opinions out there on hull drag but most (including many of mine) are based on guesses at best. I’ve used this following method to come up with repeatable numbers and the unknowns, or poorly knowns are obvious. It’s called a coasting test.

It’s based on one of Newton’s laws, to wit, Force equals Mass times Acceleration. F=MA.

Things you need in order to do this:

A way to measure your speed. On my sailboats, I’ve had knot meters. If you have a GPS that responds fast enough, that will do.

You need to know the mass of your boat. This can be hard to come up with but if you are more interested in changes rather than absolute numbers all you need to do is come close and know when the mass has changed for some reason like more people or less fuel. When you are going for absolute numbers, add about 4% for water that moves along with the boat.

It’s important to do the test where there is little or no wind and if you are using a GPS, do your testing where there is no current. With a knot meter, that doesn’t matter.

You’ll need a watch with a second hand and at least one helper to split the tasks with you.

Motor to your top speed and then stop your engine. As your knot meter passes whole numbers of knots, record the time. Do this down to one knot. Do this again perhaps five times. Don’t rock the boat or move the steering. That will mess up your data. If your numbers are all over the place, figure out why.

Record your data on graph paper. Record all of your tests on top of each other. This will let you spot bad data. Strike a curve through the good points.

Measure the slope of the deceleration curve at whole numbers of knots. The slope of the curve at a given point is your deceleration at that speed.

For each speed, multiply the deceleration (A) times the total mass (M) of the boat including crew. This will give a drag figure or force (F). F=MA again.

This test is sensitive enough on my sailboat to see the buildup of growth after new bottom paint or a scrub. I can see the changes after as little as a month. Making any change such a new condenser or any submerged appendage will affect the results. Changing the trim by moving masses including crew will show up.

It will occur to you that the slope of drag v.s. speed will be informative as to whether the drag goes up linearly, as the square or at some higher factor as the speed increases. If you wish, you can reverse engineer your “Hull Speed” as the point where you feel that the curve starts to shoot up alarmingly.

This test is covered nicely in Oceanography and Seamanship by Van Dorn. A recommended library addition.
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Re: Economizer tube material

Post by cyberbadger » Sun Dec 10, 2017 4:51 am

Mike,

I would like to test such things. It's hard to do everything you want to get done. Certainly got a lot of freshwater algae fouling accumulation this summer.

I will also say that my Dock partner pointed out I had a lot of junk that accrued over the summer in a very polite way, "You sure have a lot of gear on there".

Bart
The underlined red is the nozzel I got. I may want to look at one of the ones underlined in yellow instead. This was the first nozzel that let us operate consistently at 150-200psi, and it minimizes stack dribble by aerating it - so I don't want to give up on this design entirely - but it may be too agressive.
nozzel.png
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The 3/4" exhaust from the Toledo would have an ID with sched 40 of 0.824" or sched 80 0.742".

-CB
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Re: Economizer tube material

Post by barts » Sun Dec 10, 2017 5:27 am

Before changing anything, measure the back pressure on the engine exhaust.

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Re: Economizer tube material

Post by cyberbadger » Sun Dec 10, 2017 6:29 am

Well I recorded the course. This is one way, and it was better (sligthly faster) on the way back.

See if this works.

https://drive.google.com/open?id=1sWSGw ... sp=sharing

Or here you can see she found a happy spot around 4knots:
tobemus.png
GPS Speed vs Time
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-CB
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