Worthington SA Feedwater Heater Booklet (1944)

The Worthington - and its handsome cousin, the Elesco - were different designs of feedwater heaters. These appliances were employed by any railway seeking to obtain greater fuel efficiency from its steam locomotives. 

These feedwater heaters were designed to scavenge energy from the 'used' steam ejected from the pistons. The force of this steam had traditionally performed the useful function of drafting the fire, but a lot of valuable energy was lost out of the smokestack in that familiar, photogenic steam/smoke plume.

In a cold climate such as Canada's, the extra installation and maintenance costs of feedwater heaters were generally seen as a reasonable expense ...

Seasonally, the sun spent half the year causing all of Canada's near-surface water molecules to move with increasing energy. Then, there were the other six months when water molecules became increasingly sluggish. Extra coal or bunker oil had to be unearthed, paid for, and transported all the way to the steam engine tender ... and had to be hurled, augered, or blown into the firebox just to compensate for this heat deficit.

• So, feedwater heaters reduced fuel costs because they made the cold tender water molecules jumpier using 'waste heat'.  

• They also saved the steam engine from all of the internal strains which came from taking water at a near-freezing temperature ... and forcing it into direct contact with an assembly of rivetted, crimped and welded metal parts which would otherwise be heated to the point of incandescence. 

Another benefit of feedwater heaters was that they gave the locomotive fireman something to do ... yet another motive power subsystem to learn about. And that's why Rolly Martin owned this booklet - because he had to know most of this information to be his very proficient self in his work as a fireman. No doubt, this booklet travelled many miles in his bag while he worked his steam era trips on the Heron Bay and Nipigon subdivisions.

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Above and below is a helpful 14-inch pre-gummed supplement included with the 5x7-inch booklet. The description, above, gives a plain-language overview. The diagram, below, shows the general layout and zooms in on the heater itself (1), the hot water pump (2), and the cold water pump (3).

Where the colours come together, just forward of the smokestack, is where the feedwater heater is located. As the heater illustration (1) shows, this is an 'open' feedwater heater in which the exhaust steam physically mixes with the cold water from the tender to effect the 'feedwater heating' work.

 

Getting back to the booklet, the only booklet illustration is the diagram below. While shop forces would need this information, it is not very helpful in explaining how the heater works.

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For contrast, here are a some illustrations of an Elesco Feedwater Pump - often seen on CNR engines.

Elesco Feedwater Heater

from: Locomotive Boiler-Feeding Devices; JW Harding; 1937; International Textbook Company.

The Elesco was a 'closed' feedwater heater in which the exhaust steam and cold water never came in direct contact with each other. 

You will probably notice that the design of the heater mimicked the design of a boiler. In this case, the cold fluid is in the tubes (tender water), surrounded by the hot fluid (exhaust steam) ... and the heat exchange takes place by conduction through the metal of the tubes.

In my quick research, I believe I read that the Worthington was more efficient as a water heater than the Elesco. Perhaps, some of this was due to the fact that the latent heat of condensation (released when changing some of the steam in the heater from a gas to a liquid) was more effectively exploited in the Worthington's open design.

... That is, the sluggish water molecules from the tender were more effective in directly converting and bringing along some steam molecules (grabbing their extra energy) for another trip through the boiler and pistons.

from: Locomotive Boiler-Feeding Devices; JW Harding; 1937; International Textbook Company.

from: Locomotive Boiler-Feeding Devices; JW Harding; 1937; International Textbook Company.

At (8) you'll notice a 2-phase, steam powered pump to run water through the whole system and to force the warmed feedwater into the boiler via a check valve at (11). 

End of Elesco section. 

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Back to the Worthington ...

On Page 12, above, notice the eternal Canadian winter challenge of ensuring that water does not freeze inside machinery. 

The fireman would need to be conversant with the operating procedures and principles above. As well, the need to clearly describe the exact problem encountered on the road was essential to ensure that roundhouse staff could find and correct the problem before the next trip. 

All of the complexities, investigations and remedies below can help us imagine the 'long term operating costs' (versus fuel cost saved) of having a feedwater heating system included when a locomotive was built.