Let's look at 17 a bit

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Let's look at 17 a bit

Post by DaveLathrop57 on Fri May 24, 2013 10:59 am

The 17 drawings are posted on the norser.net site as previously mentioned.

We've had some issues with 17 steaming and with the front end. I think it's a great example of the lower margin of Porta's "good enough" engineering in practice......the problems happen when fuel quality problems push it slightly below that margin. 17 has a normally located Van Boden burner located under the throat and a small squarish firebox and is drafted a little at the burner, most through the firepan, and a good secondary draft through a damper at the firedoor. The front end is a single petticoat pipe and no other hardware in the front end done according to the Vulcan drawing.

Some experimentation has been done moving the petticoat pipe up and down, but it doesn't help, so I think Vulcan knew what they were doing in designing a least common denominator solution for an oil fired switch engine - but she's a road engine now.

What's the progression we need to follow in order to start to design a good front end retrofit for 17? We have a water tube manometer we can use....

Dave

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old sketches for central waste oil burners

Post by DaveLathrop57 on Sat May 25, 2013 5:04 pm

http://i82.servimg.com/u/f82/18/31/23/40/burner11.jpg

http://i82.servimg.com/u/f82/18/31/23/40/scan0011.jpg

These were part of a thread on RyPN a long time ago. One is very like a Van Boden made into a circle...the other like one turned into a circle on its head. What if we built a Nigel style firepan with preheater tubes aiming the draft into a swirling pattern, and replaced the front mounter burner with one like this - or hopefully a better design one of you can envision? waste oil is the issue preventing a full on vaporizing burner.

Dave

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Lima style front end for 17 burning waste oil

Post by DaveLathrop57 on Sat May 25, 2013 5:09 pm

http://i82.servimg.com/u/f82/18/31/23/40/17lima10.jpg

This isn't as much engineered and compromised into the 17's existing dimensions from the design for an oil fired Shay with a similarly sized front end. I've done this sort of thing successfully a few times in the past with unmeasured by generally favorable and workable results. I have noi idea what the Lima formula for engineering it might be.

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Re: Let's look at 17 a bit

Post by Nigel Day on Tue May 28, 2013 4:11 am

Can it make smoke when worked hard regardless of weather it steams or not?

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Re: Let's look at 17 a bit

Post by JJG Koopmans on Tue May 28, 2013 10:15 am

Could you give the full webreference to the drawings?
I cannot find any!
Thanks,
Jos Koopmans

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Re: Let's look at 17 a bit

Post by DaveLathrop57 on Tue May 28, 2013 12:34 pm

Drawings can be found at: www.norser.net/prints

They aren't as clear as the 110 batch.

Yes, we can make black smoke, sometimes witholut making much steam in the process. What I've heard about last months vosot to Roanoke indicated she steamed OK there, so the oil was decent.

I think we can start with looking at the front end; we should second priority burner and firepan, I really like the idea of a central burner and a Nigel style firepan for 17; and, for the next overhaul, the valves and cylinders do need some work - the balancing plates and the piston rings for sure, and the rope packings.......it might even be fun to think about a piston valve / Walschaert gear conversion.

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Re: Let's look at 17 a bit

Post by Nigel Day on Tue May 28, 2013 1:18 pm

So it's a draughting problem. You will also find that the air flow at the rear is inadequate. The air pipes oshould equal about 80% of the gas flow area through the tubes. In the instance it is not then its probably proportional to the draughting. So you improve the draughting and then open the air openings to match. I repeat myself " for Ann oil burner you need a lempor or better to provide suficent gas flow because of the positive pressure in the fire box from the atomising steam." A lempor is defined as one where the nozzles are aimed at the mixing chamber wall at 7.25 degrees, if it dose not have this impingement then it's not a lempor type and will not produce the draught required. Period. At this point do not mess with the burners.

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Re: Let's look at 17 a bit

Post by JJG Koopmans on Tue May 28, 2013 2:27 pm

Checking the front-end drawings it amazes me that for a 1941 design they did not consult the publication of Everett Young on his front end tests at the University of Illinois in 1933.
Kind regards
Jos

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Re: Let's look at 17 a bit

Post by DaveLathrop57 on Tue May 28, 2013 2:53 pm

I think they consulted with the same shop drawings they had been using since 1918. Vulcan Iron Works built simple and solid industrial machinery, not as interested in pushing the envelope of what was possible through R&D....especially as diesel electrics were making themselves known and taking over the market. In our collection is an old Baldwin Lima Hamilton diesel electric with two Buda motors that was built for the same shipbuilding business that 17 was built for, but a few months older.....

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Re: Let's look at 17 a bit

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