Size matters!

fixitguy

Am I correct in assuming that manufacturers such as riser & header sizes & header height are minimum suggested standards?

Bio

size

Yes, that's the minimum suggested, you can go above and beyond by doing a drop header, increasing header pipe size etc... to slow steam velocity and making a drier steam which in most cases pros will recomend

Jean-David Beyer

In the old days ...

when building steam locomotives, it was discovered that the drier the steam, the more efficiently the engines ran. So they took the steam from the steam dome and ran it through hairpin shaped tubes through the flues (fire tube boilers) on the way to the cylinders to dry out the steam. That way they could get more work from the steam pushing the pistons because it did not condense in the cylinders. They could cut off the steam early in the cycle and rely on the expansion to push the piston the rest of the way.



If drier steam in home heating is beneficial, why not install a superheater on a steam boiler. I imagine they do that in power plants with large turbines, to reheat the steam before running it through the low pressure part of the turbine. I do not know for sure.

Paul48

I

suppose if you were trying to move the house down the block, super-heating the steam might make it more efficient.My father use to talk about 10000 psi steam off a reactor. I had an engineer tell me it wasn't possible, until I told him it was off a reactor.

Jean-David Beyer

Superheating the steam.

I do not think superheating the steam raises the pressure any; it just evaporates any residual water and raises the temperature of the steam higher than the boiling point of the water in the boiler. So it would not move the house down the block. If you had a boiler in one house, and wanted to heat the house down the block, it might make sense. 



I do not know what the University of Buffalo did. They had a coal fired steam boiler plant near one corner of their campus, and underground steam mains went to all the other buildings. I believe they ran in underground tunnels. I know they seldom had to shovel the sidewalks on campus where the pipes ran under them. So maybe they superheated the steam; maybe they didn't.



So if you were running the boiler at 16 ounce pressure, the water temperature and the steam temperature in a non superheated boiler would be about 215F. With a superheater in the vent, assuming a perfect superheater (heat exchanger), and an exhaust temperature of 300F, you could probably get 300F steam temperature. I doubt the superheater would be that efficient, and I do not know what the exhaust temperature of a steam boiler is. You would not want to cool it down too far anyway, because that would mess up the draft.



I do not suppose it would be worth the trouble in a residential boiler. In locomotives, doing it saved on both coal and water, which was important to the railroads. It is my understanding that it is worth the trouble in steam power plants, where wet steam erodes the turbine blades.