We received an e-mail from steam friends in DesMoines alerting us to a steam traciton class at Forest City, Iowa on May 15 and 16. Take a look at the website for Heritage Park, and then CLICK HERE to register for the class. The class is limited to fifty students, and the remaining slots are bound to be filled quickly; don't delay! Forest City is about 120 miles north of DesMoines. Thanks for the tip, Barb!
3 comments:
Looks like fun! Wish I were a thousand mile closer.
That brings up a question I've always been curious about. How does the water in the tank get into the boiler? After all the tank is at low pressure (atmospheric plus some head pressure) and the boiler is at high pressure, after all that's it's job.
It seems an airlock type design (close off the boiler end, fill with water from the tank, then close the tank valve and open the boiler valve) would work. The syllabus suggests alternatives (simplex pumps, duplex pumps and injectors).
This is a subject for a post! A check valve is installed close to the boiler, and a pump or injector pushes water through the check valve into the boiler. The pumps are easy to understand, and if you look at some of my videos you will see crosshead pumps on some of the engines. There were also gear driven pumps, and steam driven pumps. Injectors seem like black magic when they are first shown to you. Steam comes out of the boiler, is shot through a venturi in the injector, is condensed in water which it then propels through the check valve and into the boiler. The energy given up by the steam when it returns to the liquid state provides kinetic energy to the stream to overcome the pressure in the boiler, which is, of course, equal where the steam came out, and where the water goes back in.
Take a look at Stack Talk on the left side of the page. You can see the crosshead pump, which is the thin cylinder below the steam cylinder. The piston is powered by the crosshead, thus the name.
You're welcome for the softball ;-) A post on the different types with advantages and disadvantages of each would be most welcome.
I can see how the Stack Talk cross head pump works, and I've seen positive displacement oil pumps inside my IC engines. Makes sense it could work for water as well. Seems both of these would have the advantage that they both are proportional type pumps... that is they will always replace the right amount of water to the boiler since they are driven at engine speeds. IOW, as the engine speeds up, more water escapes the boiler as steam and the pump replaces more water at the same time.
Now the injector does seem black magic. I have a venturi pump here at the SandCastle. Blow a fluid in one end, venturi forces a pressure drop (Thanks Bernoulli!).
But it only works with a pressure drop from one end to the other. If both ends are plugged into the boiler they are at equal pressure.... which means I'm missing something...
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