Environmental Engineering Reference
In-Depth Information
turbulent flow results from momentum exchanges occurring as a result
of motion of fluid particles from one layer to another (McGhee 1991).
Normally, flow inside tubing is laminar; however, if the inner wall of
the tubing has any irregularities (dents, scratches, or bumps), the fluid
will be forced across the otherwise smooth surface at different veloci-
ties which causes turbulence. Iron piping has more irregularities along
its inner walls. This inner-wall surface roughness produces turbulence
in the fluid flowing along the conduit. Ultimately, this turbulence can
reduce the delivery rate of the piping system considerably.
4.10.2.2 Chemical Advantages of Tubing
The major chemical advantage in tubing as compared to piping
comes from the corrosion-resistant properties of the metals used to
make the tubing. Against some corrosive fluids, most tubing materials
do very well. Some metals perform better than others, though, depend-
ing on the metal and the corrosive nature of the fluid. It is important
to also point out that tubing must be compatible with the fluid it is
conveying. When conveying a liquid stream from one point to another,
the last thing we want is to add contamination from the tubing. Many
tubing conveyance systems are designed for use in food-processing
operations. If we were conveying raw milk to or from a unit process, for
example, we certainly would not want to contaminate the milk. To avoid
such contamination, where conditions of particular sanitation are nec-
essary, stainless steel, aluminum, or appropriate plastic tubing must
be used.
4.10.3 Connecting Tubing
The skill required to properly connect metal or nonmetallic tubing
can be learned by just about anyone; however, significant practice and
experience are required to ensure that the tubing is properly connected.
Moreover, certain tools are required for connecting sections of tubing.
The tools used to make either a soldered connection or a compression
connection (where joint sections are pressed together) include:
•
Hacksaw
•
Tube cutter
•
Scraper
•
Flat file•
•
Burring tool
•
Flaring tool
•
Presetting tool for flareless fittings•
•
Assorted wrenches
•
Hammer
•
Tube bender
