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Re: [Phys-l] Heat transfer lab

One set of my grandparents had a one-pipe steam system. It was explained to me that the vent was to let the air out. This makes sense. When the system starts up, there is air at atmospheric pressure in the radiator. As the boiler begins to generate steam and the pressure begins to build, the only way for the steam to get to the radiator is diffusion through the air... unless you have a way to get the air out. If the air can escape through the vent, you eventually have the boiler, pipes, and radiators full of H2O (that is, no air in the system). This allows very efficient steam transport because the condensation of the steam in the radiator produces a partial vacuum there (that is, lower pressure than in the boiler). The higher-pressure steam from the boiler rushes into the lower-pressure radiator, but the pressure in the radiator remains at a steady lower pressure than boiler pressure because the new steam arriving at the radiator promptly begins to condense.


Michael D. Edmiston, Ph.D.
Professor of Chemistry and Physics
Chair, Division of Natural and Applied Sciences
Bluffton University
1 University Drive
Bluffton, OH 45817

419.358.3270 (office)
edmiston@bluffton.edu


--------------------------------------------------
From: "brian whatcott" <betwys1@sbcglobal.net>
Sent: Wednesday, November 17, 2010 6:31 PM
To: <phys-l@carnot.physics.buffalo.edu>
Subject: Re: [Phys-l] Heat transfer lab

I can even comprehend the possibility of a one pipe one port steam
radiator, where steam condenses, and runs back down the same pipe that
it entered, and the reduced volume is made good by an air vent allowing
air into the radiator.
I'm pretty sure this is just a creature of my imagination though: how
does a steam one pipe system really work, and what does the vent
actually do? Does it meter steam into the radiator, in fact?

Brian W
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