Post
by Pontiacguy1 » Mon Oct 02, 2017 7:27 am
On our models, I don't worry nearly as much with efficiency as I do with reliability. A small loss in thermal efficiency on our models will be unnoticeable, whereas on the full size with the thing running thousands of hours per year, it would be a big deal. When you run your locomotive dozens of hours per year, the efficiency really isn't that important as long as it can make enough steam to do the work it is being asked to do.
That being said, I think that a good axle pump is one of the most reliable pumping methods out there. Some say they are useless/worthless, but I know of too many of them that have been reliable for decades, and on many different locomotive sizes. The do not have that many intricate mechanisms, are actually quite simple, and most will last for decades with nothing more than lubricating a couple of times per day and the occasional change of the sealing o-ring. I also think that a good injector that is plumbed in properly and has a suction line strainer to keep debris out of it is an excellent method and probably the most thermally efficient in our scales.
Again, I go back to reliability, and that really means that you need to have more than one method. Some use a couple of injectors, I use an axle pump plus an injector. A good duplex pump will keep your water up and is interesting to watch run, however, a lot of those tend to be temperamental, and like was mentioned before, without a feedwater heater, I don't think they are too thermally efficient.
Just my two cents' worth: Worry more about reliability than efficiency.