Center Trycock

A special section just for steam engines and boilers, as without these you may as well fit a sail.
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cyberbadger
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Center Trycock

Post by cyberbadger » Sat Sep 09, 2017 5:53 pm

So, finally after months of almost being on the work billet. Literally making it onto Nyitra's deck and then taken off - my 3x2x3 Worthington Duplex has finally is onboard, mounted on a piece of 4"x4" onto the deck.

Just to be clear - I do not need this - both injectors have been working quite well. Also this beast is a steam hog!

However I have a thing for steam pumps. The non rotary motion and the movement and there ruggedness warm the cockles of my heart.

At any rate - I have plumbed up the steam from the Center Trycock and want to give this setup a try.

I usually have opened up all my petcocks on the worthington before starting.

Are there any hints to running it like this?
I remember reading that it will just choke up on the water, and it should clear itself as the water level drops.

If I like this arrangement I will look at an economizer or preheater of some sort.

-CB
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Re: Center Trycock

Post by dhic001 » Sun Sep 10, 2017 10:30 am

Is it hooked up to another boiler you are towing on a barge that is bigger than your boat? Or are you hooking that pump up to a jet unit to push the boat and barge along?

Seriously, that pump may be nice, but it will be way way too big for what you are trying to do with it. I bought a Weir junior (single cylinder 2 * 2 *4 1/2) to add to Zeltic, but then I ran a much larger boiler with one on, that provided all the water needs to a couple of steam engines many times the size of Zeltic's engine. Even then it was only run every few minutes. I've bought a Southworth 12 inch pump as on Iron Chief instead.

Daniel
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cyberbadger
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Re: Center Trycock

Post by cyberbadger » Sun Sep 10, 2017 1:09 pm

You clearly haven't seen my old video with a smaller boiler then is on Nyitra..... :lol:

Listen to what I have to say at 15 seconds.


Seriously though - I have already made this decision. It is bolted to the deck and it's staying there for the forseeable future.

Lets please focus the discussion on technique of using the center trycock and and tricks to that arrangement, not that fact I have a problem with scale.

-CB
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Re: Center Trycock

Post by SL Ethel » Mon Sep 11, 2017 10:37 pm

I'm jealous that you have a boat with space and bouyancy to be able to have fun with neat machinery like your duplex pump out on the water. I think, though, that your issue of scale IS going to be one of your biggest operational challenges if you intend to use the pump for regular boiler feed.

What I mean is this - when Ron runs Iron Chief with a semi-waterlogged duplex pump for feed, it's a bit inefficient, but the losses are not huge compared to the engine. That pump, running waterlogged, is not doing much.

Your pump, on the other hand, will move a LOT of water, relative to the size of your boiler, even running very slowly while waterlogged. Running on steam, it would move the water level quite a bit with only a couple of strokes. My guess is that it will regulate the boiler level all right, but that it'll never fully clear and run normally on steam, because every time you start to get a little actual steam into the pump, one or two strokes will see the boiler level back up to where it's flooded.

Lots of boats used those duplex pumps as general purpose pumps, as well as for feed. You could plumb it so that in addition to feed, you could take water directly from the lake and discharge through a hose, and you'd have a great washdown/firefighting pump. You could also really show what it could do as a fire pump, since you won't be constrained by your boiler's very limited need for water, compared to its rather mighty output. Also good for fending off pirates.

Cheers,
Scott
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DetroiTug
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Re: Center Trycock

Post by DetroiTug » Mon Sep 11, 2017 11:46 pm

As my steam mentor says "Try it"

Iron Chief has five individual methods of getting water in the boiler, the engine driven mechanical ram water pumps are by far the most efficient. If I'm racing I use those.

The biggest issue with the steampump on the center trycock setup is that when the pump is taking boiler water from the center trycock, it's taking precious ready to expand to steam and convert to work water and throwing it away. Water you've expended fuel to heat and work at the pumps to get it there, that now has to be replaced/regenerated. Therein lies the inefficiency. The steam when present to run the pump is roughly 1600 times less costly to lose.

The setup works and I too love steampumps and am willing to live with a bit less efficiency and the otherwise annoying clacking sound they make. It's a real attractive show feature to any steam boat.

However, as the others have stated, with a pump that large the losses are going to be much greater. Will it work? Probably, but make sure to bring a lot of extra fuel, and don't be in a hurry to get anywhere. Throttling the pump is going to be necessary to limit the losses. And of course the pump discharge needs to go through an economizer.

Also, The steam and water going to the pump is very erratic, there is no set on/off as it would be with a stable land-based boiler, the simple rocking of the boat/changing level at the trycock is continually changing what the pump is running on.

It would be better to simply use it as a feed pump and shut it off when the water gets near the center trycock.

-Ron
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cyberbadger
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Re: Center Trycock

Post by cyberbadger » Tue Sep 12, 2017 1:48 am

DetroiTug wrote:Iron Chief has five individual methods of getting water in the boiler, the engine driven mechanical ram water pumps are by far the most efficient. If I'm racing I use those.
It would be interesting to see how you laid that out. I think about things for a time and then lay them out. Both physically and functionally I'm not always sure if I have the best arrangements Seen any good reference steam plant diagrams/guides?
DetroiTug wrote:he biggest issue with the steampump on the center trycock setup is that when the pump is taking boiler water from the center trycock, it's taking precious ready to expand to steam and convert to work water and throwing it away. Water you've expended fuel to heat and work at the pumps to get it there, that now has to be replaced/regenerated. Therein lies the inefficiency. The steam when present to run the pump is roughly 1600 times less costly to lose.
Ahh. I get it. Yeah, kind of throwing away a little bit of what we've been working so hard on. There are always tradeofs in engineering...
DetroiTug wrote: t would be better to simply use it as a feed pump and shut it off when the water gets near the center trycock.
-Ron
I made sure that I put in a T near the pump inlet so that I could add this an option later.

Is there any reason to put a valve+pipe between the water inlet and discharge, bypass?

-CB
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DetroiTug
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Re: Center Trycock

Post by DetroiTug » Tue Sep 12, 2017 1:19 pm

Multiple pumps are simple to implement. T's or a manifold on the water coming in going to each pump and then T's or a manifold on the feedwater going in and each pump system should have an isolation valve at the discharge so the other pumps don't try to feed back through them and their bypasses.

Not sure what is meant by a T near the steampump. Every pipe or line coming from the boiler should have an isolation valve and the pump can be controlled with that, no steam, no pump.

The little bit of loss while taking boiler water to the pump steam cylinder, in the case of that pump you're trying to use, is going to be a big loss, two or three strokes is probably going to be close to a gallon.

The bottom line is, it can be piped up and played with, but it is simply too big for the plant.

-Ron
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cyberbadger
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Re: Center Trycock

Post by cyberbadger » Tue Sep 12, 2017 4:47 pm

DetroiTug wrote:Not sure what is meant by a T near the steampump. Every pipe or line coming from the boiler should have an isolation valve and the pump can be controlled with that, no steam, no pump.
Correct.
I just put a T on the steam inlet 2 inches from the pump. It's got a plug. Right now t That way I could plumb in normal supply later. I actually have two valves right now. One right at the trycock, and one at the pump.
DetroiTug wrote: The bottom line is, it can be piped up and played with, but it is simply too big for the plant.
I've had folks say that about several things on my launch, only to find that are to my satisfaction once I implement them. No one is wrong, different folks have different expectations.

I don't disagree with that it's simply too big for the plant - I just don't care. It's purpose is to be amuse me and be a backup.

If you watch the video you will see me running it just fine on a smaller boiler then is on Nyitra- so this an improvement.

-CB
"We are already misguided, we have a hobby in obsolete technology"
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DetroiTug
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Re: Center Trycock

Post by DetroiTug » Tue Sep 12, 2017 5:11 pm

I wrote: "The bottom line is, it can be piped up and played with, but it is simply too big for the plant. "

Quote: "I've had folks say that about several things on my launch, only to find that are to my satisfaction once I implement them. No one is wrong, different folks have different expectations."

Exactly, it's going to work perfect. :)
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Re: Center Trycock

Post by fredrosse » Wed Sep 13, 2017 2:13 pm

Back in the 1960s the USACE had a derrick barge, built 1929, with an 8 ft diameter scotch boiler to run all the winches. A 2 inch duplex reciprocating steam feedwater pump was mounted on the boiler, taking steam off the boiler shell where the water level was desired. The pipe from boiler shell to steam pump was about 10 inches long.

The pump would choke up on water and nearly stop when the boiler level was high, and would work away properly when the connection was just getting steam. A good reliable feed regulating device, and pump combined. But the size was matched close to the steam generation rate, maybe 150% of the required feedwater flow while working.

With a pump that is capable of hundreds and hundreds % of your boiler output, I would not expect reasonable performance by tapping off the try cock connection.

For large reciprocating steam duplex pumps, they use about 300 PPH for 1 horsepower pumping duty. A good steam engine can get 1 horsepower with 30 PPH steam flow. I am sure smallish recip steam pumps use far more than the 300 PPH value.
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