Paul Campbell is a technology columnist, author and mechanical designer. He holds a degree in Applied Technology, and his technology columns currently appear in the U.S. and Singapore. He has spent the last nine years publishing work for industrial and consumer markets. He can be reached by e-mail at techpubs@ix.netcom.com.
Sealing sanitary and storm sewer piping is typically more difficult than sealing interior plumbing, mostly because of their construction, and typically because of their size.
A significant portion of the reason there isn't an even greater number of new technologies in current use in industry is because it isn't always easy for the consuming public to make the connection to the inventor's idea.