Wilmington & Western 98 Gets a New Blast Pipe

philip.marshall · **Posted:** Sun Jan 17, 2016 6:29 pm

Dave wrote:

Can't lay hands on my red Devil right now, but I think this was something known as a Kordina...... Seems mysterious to me and I'd like to know more.

Yes indeed.

From my copy of Red Devil, page 153:

Quote:

Ideally, some of the great amount of energy in the release steam could be used to create an ejector pump action on the exhaust from the opposite cylinder, lowering the back pressure in this cylinder, even to below atmospheric pressure.

The original idea to use the release steam for this purpose was credited to the German engineer Stumpf but its practical application was due to the Russian Kordina, after whom the device was named. Although a sound and simple idea, it did not find favour with normal exhausts because the blast nozzle tip, and hence the Kordina section, was generally so small that undesirable throttling would have taken place at and downstream of the Kordina. With improved exhausts having larger blast nozzles the severity of this restriction was reduced... [text continues with some discussion of experiments by Porta on the Rio Turbio]

-Philip Marshall

thunda · **Joined:** Tue Jan 22, 2013 6:49 am **Posts:** 21

The kordina is also about getting the steam flow from each cylinders exhaust passage flowing parallel to the other/s before it reaches the nozzles/blast pipe cap. Along the lines of extractors for a sports car.

On a lot of designs in the past, the flow of steam often intersected at anywhere from 20-30 degrees all the way to 180 deg out, eg both cylinders exhausted into a straight pipe running between them with a T piece leading up to the blast pipe cap. The exhaust steam flows hitting each other head on before turning a right angle to escape!

On a loco we are currently looking at modifying with a lempor/lemprex design, we are having to choose between just bolting on a 14" section that reduces the exhaust passage from 10" down to the correct size for the nozzles but does nothing to improve the exhaust steam flows meeting at 45 degrees, all the way thru to rebuilding the complete exhaust passages from the cylinders up al la Nigel Day in this thread.

viewtopic.php?f=1&t=33788

For us, it's really going to come down to costs in the short term. Not much cash around at the moment, we know that the improvements will pay for themselves long term but that doesn't help getting them built in the short term.......
Cheers, Al.

JJG Koopmans · **Joined:** Sat Oct 22, 2011 5:07 am **Posts:** 82

On page 429 of The Red Devil a Kordina is defined as "a longitudinal dividing wall extending from the base of the blast pipe to the end of each leg separating the steam flows". So what is the difference between Goss' "bridge" of 1896 and a Kordina? Just semantics!
For those interested in a "Kordina", in the Engineer of Jan 20 1888 page 46 it is explained.It shows clearly how frivolous "Kordina" is misused.
http://www.gracesguide.co.uk/The_Engineer_1888/01/20

Kind regards
Jos Koopmans