On Oct 30, 9:49*am, RicodJour wrote:
On Oct 30, 9:29*am, lj wrote:





On Oct 30, 4:57*am, harry wrote:

On Oct 29, 11:53*pm, mike wrote:

Just because I'm sick of seeing the liquids-outrunning-solids-on-steep-
slopes myth on the net....

http://www.pmmag.com/CDA/Archives/83...M100000f932a8c...

"A few years later I took a college course that we nicknamed Sewer
101. You got it; the course was on the design of sewers and sewage
treatment facilities. The professor was explaining the installation of
sewers in steep terrain. He was suggesting that we change piping
materials for sewers that were pitched more than 30 degrees.

I raised my hand wondering about the problems that would be
encountered. My mind was abuzz with whether my father was right, or
the plumbing inspector was right. I asked, "If you pitch the pipe too
much, won't the liquids run away from the solids, resulting in an
increased amount of stoppages?"

The professor started laughing as I tried to disappear under my desk.
He said, "You're a plumber, right?" He already knew I was because we
had talked about it many times. "Yeah," is all I could say.

"I don't know why they always teach plumbers that myth. Maybe it is
because they want them to install perfectly aligned sewers."

Of course, I found out that the professor was setting me up. This lead
to the presentation of a new equation. The equation calculated the
minimum flow rate to keep solids in suspension in a sewer system. The
inverse of the equation calculated the maximum pitch before the
liquids ran away from the solids. Of course, the answer to the maximum
pitch was infinity. In other words, you could never reach that point.