Wallace & Tiernan SERIES V-2000, Manual

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WT.025.000.001.UA.IM.0614
CHLORINE HANDLING MANUAL
PAGE 10
EVOQUA W3T98244
If the source of gas is one or more ton containers connected
to a manifold, install a drip leg of 1.0-inch schedule 80 seam-
less steel pipe approximately 18 inches long in a tee in the
manifold with the lower end capped. Locate the drip leg
immediately downstream of the last container connection
to intercept the liquid that comes from the ton containers’
gas eduction tubes when initially opened.
Gas may be withdrawn from two or more containers simulta-
neously provided all containers are at the same temperature.
Refer to Paragraph 3.1.
The installation of chlorine gas strainers in pipe lines up-
stream from pressure reducing valves or vacuum regulators
is a common practice. These strainers can also serve as traps
for a small amount of liquid chlorine. Figure 12 illustrates
a typical strainer.
4.3 LIQUID PIPING INSTALLATION REQUIREMENTS
It is important to avoid conditions that will encourage
vaporization. Thus it is important to keep liquid chlorine
lines as cool as, or cooler than, the containers themselves
by eliminating restrictive fittings and always operating with
fully opened line valves. Avoid running liquid chlorine lines
through overheated areas where gasification is likely.
Valves in liquid chlorine lines should be kept to a minimum.
It is particularly important to avoid situations where it is
easy to close two valves in a line thus trapping liquid that,
upon an increase in temperature, will expand and develop
higher than acceptable pressures.
A liquid line pressure relief system (which includes a rupture
disc and an expansion chamber) is required where liquid
may be trapped in the line or where it is necessary to run
lines a considerable distance. The relief system is detailed
in Figure 13.
The expansion chamber provides an area for expansion in the
event that valves at both ends of the line are closed. Relief
system placement must be based not only on length of line
but also placement of valves.
4.4 PRESSURE RELIEF AND VENT PIPING REQUIRE-
MENTS
All pressure relief vent line systems must be treated as though
they contain chlorine. Use the same materials for pressure
relief vent lines as used for chlorine gas piping, unless the
vent line is a combination pressure relief/vacuum relief line
in which case the material must be suitable for moist chlorine
gas (PVC or polyethylene tubing).
Vent lines must be run in such a way that moisture collecting
traps are avoided. A continuous gradient is preferred. The
end of all vent lines must be turned down and screened.
Manifolding of vent lines is an acceptable practice provided
only like vents are manifolded (i.e., evaporator water vapor
vents must be separate from gas pressure reducing valve
pressure vents, etc.). The interior cross sectioned area of
a common vent or pressure relief line should be approxi-
mately equal to the sum of the cross sectional areas of the
individual vent lines.
Figure 12 – Chlorine Gas Strainer
Figure 13 – Liquid Line Pressure Relief System
D I U Q I L F O H T G N E L
R E P D E T C E T O R P E N I L
R E B M A H C N O I S N A P X E
M E T S Y S
E P I P
E Z I S E N I R O L H C
" 1 ' 5 7 3
" 4 / 3 ' 5 2 6