On the subject of heat exchangers, I can give my own industrial experiance. The bulb or dome end generally is where your water in/out lines are hooked up. The other end is usually set up to provide 2 or more passes back thru the exchanger before sending the water back to the delivery point. Now, this is a basic exchanger for hydraulic fluid, but to pre-heat water would be the same. It's a rough sketch, but I think you can get the idea. Hope this helps Dan
Adding to what Dan posted, which was right on target, attached is a picture of a shell & tube heat exchanger from one of my chemical engineering textbooks. This is not an Elesco feedwater heater, but is a similar design. In the case of the Elesco FWH - the tube fluid is steam, the shell fluid is boiler feedwater. Note this exchanger pictured is set up for four steam passes - the steam passes through the tubes surrounded by the water four times. As it passes through the tubes, the steam condenses and its condensate is returned to the tender to be used again. The feedwater in the shell picks up all the latent heat released by the condensing steam, and perhaps some sensible heat as well, thus heating the feedwater. The steam used was relatively low pressure exhaust steam, thus its energy was recovered, raising the efficiency of the engine somewhat. Otherwise, this steam would just be among that exhausted up the stack to the atmosphere. I'm not sure how many steam passes occurred in an Elesco FWH. Anybody know? The Elesco FWH was manufactured by the Locomotive Superheater Company, i.e., LSCo, or "El eS Co". Get it? Corrections or added comments by our many steam locomotive mavens in frisco.org are welcome. Remember, I'm just a diesel guy! Ken
The Elsco FWH, Type H & Type K, had 4 steam passes. By 1930 approximately 4500 North American applications had been made. The manufacturer claimed fuel AND water savings of 10-15%. Note on the pic of the 1067 at the West Shops, the piping behind the coal bunker. This is part of the "return" in which "spent steam" (condensate) was returned to the tender to be used again as boiler feedwater. The condesate line had a filtering system which removed oil.
Chris, I am beginning to wonder if the 1067 didn't have two different FWH's during her career. Note that on the West Shops photo, the check valves are on the boiler top. In the Monett photos, the feedwater line from the injector still enters the boiler through a top-mounted check valve; the feedwater line from the FWH enters the boiler from a side-mounted check valve.
My two cents: If they had hung the bell on the smoke box, it would have come pretty close to the Southern PS-4 ... which I have always thought it to be a beautiful locomotive.
On pg. 94 of the Stagner book, a loco diagram describes the superheater as a Schmidt. This was applied to loco's 1060 - 1068 by Baldwin. I'll dig a bit to find out more about it. Dan found this info. http://en.wikipedia.org/wiki/Superheater
The superheater units are inside the boiler flues and nearly every engine since 1920 has been superheated. This is a feedwater heater system that's on the 1067 that was on none of the other 1060-1069 4-6-2s. The flat side/whatever are caps that fit over the ends and really don't do much other than protect cleanouts, etc.
Let me build on what Don posted by playing chemical engineer again. A superheater and a feedwater heater are two different things entirely. A superheater adds more energy to the saturated steam generated by the boiler, which results in the steam temperature and pressure increasing. This results in increased performance from the locomotive, i.e., more powerful. A feedwater heater takes some exhaust steam, that otherwise would be wasted up the stack, and heats up the cold boiler feedwater before the feedwater is introduced into the boiler. This recovers some of the energy that would otherwise be wasted, and raises the efficiency of the locomotive. Ken
I received the two Elesco FWS from Cal Scale that I purchased off eBay. I'm going to try the look on a few engines. If I like them, I'll probably equip more. I will more than likely hang them off the front of the smoke box like T&P engines.
Can anyone tell me if the Elesco on 1067 is sitting on top of the smoke box, or if the smoke box is indented, cradling the FWH? Thanks!
Good observation, Karl. Based on the visual evidence, I'd say you're right on the mark. It's these little subtle differences over time that I sometimes find frustrating, but at the same time I could never tire of them. Don, thanks for clarifying on the "caps." Best Regards,
