My friend Michael Guy has been working on a new front end arrangement for Essex Terminal #9, a 1923 vintage 0-6-0 at the Waterloo Central Railway. I asked him if this was a lempor type exhaust, he replied
"No, it looks similar but is different. Lempor theory includes a mixing chamber which is not necessary and also includes in its calculation secondary gas mass flow from the boiler tubes which has been shown conclusively to be an error. Koopmans has updated the whole thing and has been able to take historic test data and match it to the recorded test results something the engineers of the day were unable to do."
He went on to say,
"In response to feedback asking exactly what the heck we did to loco #9 exhaust on WCR: We removed the 1923 single blast nozzle and the double petticoat pipe above it and replaced it with a 4-nozzle exhaust correctly located just below the stack inlet flare. The calculations to size and place the nozzles were done by Dr. JJG Koopmans in The Netherlands; I drew up the new arrangement and added the blower. Construction work was split between my Elmira shop and the WCR St Jacobs shop. The relevant theory is that short, fat exhaust ejectors don't work as well as long, thinner ones. This arrangement breaks the single stack up into four smaller ones, essentially four separate chimneys with the unnecessary intervening walls removed. The benefit is that the vacuum developed in the smokebox is higher and the draft through the firebed is correspondingly greater than that developed by the old arrangement. A secondary benefit is the total exhaust area can be larger than before realizing a decrease in cylinder back pressure and a corresponding increase in tractive effort by the engine. The only other steam locomotive in existence with this front end design is King 6023 in the UK. Testing of #9 is in early stages but we are very pleased with our success so far."

In case you were wondering, this is how she looks on the outside :-)

Interesting. What brought about this change? Has the engine worked under load for any distance? Can it be easily reversed if not proven to be successful?

Interesting. So what's in the box? Is there a baffle/splitter arrangement of some sort? Got pics? And with the top of the nozzle just below the stack inlet, the goal for the gasses is to meet at about two thirds stack height, or just below the top? The nozzle pipes are machined - outward taper or just roughed up to break up the stream?

News page on the #6023 mentioned above. The similar exhaust installed on it is working well in testing:

http://www.6023.co.uk/news/news.htm

I've asked Michael for pictures or drawings to show the arrangement, this is what he has given me so far...
"The box is just a means of getting steam from the old blast stand to the new nozzles. It does have a square cone inside to split the flow towards the nozzles. Nozzles outward taper matches the stack if you draw flow centrelines from each quadrant at choke and stack top. Easier to draw than explain."

Here is a picture from Michael of the internals before being welded together...

Apparently the quest was for better drafting and better efficiency also. On Victoria Day in Canada she pulled 5 passenger cars and a caboose to see how it all worked. The results were apparently encouraging.

4 bolts only between new blast pipe and old nozzle. Old double petticoat just bolts back up to the smokebox shell with 3 bolts. Easy swap. 7 bolts total. Old blower would have to be replaced too. No big deal.

Only half way through reading J.J.G. Koopmans book "The Fire Burns Much Better" and found the book fascinating so far. These threads and articles on front end modifications are awesome. Reading the history of development is as rewarding. Thank the OP for posting this and the wonderful pictures so one can "see" the work.

The Polson #2 had modified nozzles but I did not look at the finished product after it got closed up. Sure wish I did so I could of got pictures of the modification. Being still in break in, not being a fireman past or present nor running it I can't say how it is working first hand. I do know it is doing well once hot and running, but from the point of "improved" nozzles I don't really know. Gary can you comment on this? Not trying to drift from the original threads locomotive but it is related to exhaust modifications and on a smaller 70 Ton locomotive. Again thank you Finderskeepers for starting this thread.

Regards, John.

[/quote] Apparently the quest was for better drafting and better efficiency also. On Victoria Day in Canada she pulled 5 passenger cars and a caboose to see how it all worked. The results were apparently encouraging.[/quote]

Glad to hear it appears to be a success. If there is a fuel saving that would be a benefit considering the expense involved with steam engines. What is SOLRS paying for coal now? Does it come by rail or road? There ought to be considerable savings if you can afford to buy hopper carload of coal. I believe 22 tons is maximum load for tractor trailer on Ontario roads.

Number 9 ought to be able to pull twice or triple that tonnage on the flat land it runs on.
124 could pull 5 coaches.

Congratulations on the first advanced front end in Canada. I am curious, it's hard to see in the photos but it looks like the blast orifices are very close to the base of the stack, dispensing with the petticoat (mixing chamber) entirely. This seems to go against the common idea of having the blast nozzle as low as possible making the entire exhaust system as tall (long) as possible. I really must finish reading Dr. Koopmans book, it's on the toilet cistern right now.
Pat

RLK - I may be wrong (and someone please say so if I am), but IIRC Canada banned coal years ago and all engines are liquid fueled there now, so they wouldn't be concerned with coal.


And as a general question, if I'm correct about the above, how much improved draft do you need for an oil fire? I can see wanting reduced back pressure and improved TE, but the benefits of adding air are/were, in more modern builds, provided by adding combustion air above the fire bed, so it seems like adding draft would only be a benefit as far as it provided movement to mix the added air to the burning gas. Increasing draft beyond what's necessary for proper mixing only sucks the heat up the stack before it's used. Most oil burners I've seen have adequate vents at the 'grate level' for adjusting air intake, muting that benefit here. Of course the other variable in question is whether the equipped engines have combustion chambers.

Hope to see some testing results for this project posted here in the future.

Those common ideas have very little footing in fluid dynamics, which is the common problem with exhaust systems. Mostly they are simply fairy tales. The distance from the orifice to the throat of the chimney has an optimum. Larger or smaller distances give a diminished vacuum.
In #9 the 4 orifices are positioned at the optimal distance and use each 1/4 of the cross area. As a consequence this system acts as a system with 4 chimneys which is the equivalent of a double length chimney with 1 orifice.
You can verify this in Young's tests at Illinois University of 1933, his report is on the web these days: https://www.ideals.illinois.edu/handle/2142/4435
Look at fig. 28 Pepperbox vs double length
Kind regards
Jos Koopmans

RLK - I may be wrong (and someone please say so if I am), but IIRC Canada banned coal years ago and all engines are liquid fueled there now, so they wouldn't be concerned with coal [quote]

I live in Canada and I've never heard this, last summer I shovelled coal all day into Essex Terminal #9. CP 136 and 1057 also burn coal at the South Simcoe, and there are plenty of coal burning boilers at the steam shows I attend. All of these engines have a common denominator for me as they were at one time or another stored, repaired or operated by my late uncle, Sherwood Hume.