Evoqua Wallace&Tiernan 50-200 Series, Manual

Page: 41 / 111

WT.050.200.001.UA.IM.0814
50-200 EVAPORATOR FOR CHLORINE
30
EVOQUA W3T98237
WARNING: TO AVOID AN OVERPRESSURE CONDITION THAT MAY RESULT
IN A DISCHARGE OF GAS FROM THE GAS PRESSURE RELIEF SYSTEM, DO
NOT CLOSE ANY VALVE OR VALVES BETWEEN THE EVAPORATOR AND
THE CHLORINE SUPPLY WITHOUT FOLLOWING THE EVACUATION PRO-
CEDURE DESCRIBED IN STEP B, BELOW. LIQUID CHLORINE HAS A HIGH
COEFFICIENT OF THERMAL EXPANSION. DO NOT CLOSE VALVES IN SUCH
A WAY THAT LIQUID CHLORINE MAY BE TRAPPED, SINCE DANGEROUS
PRESSURES CAPABLE OF RUPTURING THE PIPING SYSTEM MAY BUILD
UP WITH A SMALL INCREASE IN TEMPERATURE.
d. Re-open the gas outlet valve to resume evaporator operation.
• Long-Term Shutdown.
a. Follow the instruction for Short-Term Shutdown, steps a, b, and c. If
the liquid can be safely pushed back to the supply container, shut the
evaporator outlet valve for a period of approximately 30 minutes.
Under these conditions, most of the liquid chlorine will be forced
back to the supply tank through the nipple and remaining liquid will
be evaporated by the heat of the water bath.
b. At the end of this period, shut the supply valve at the tank car or the
ton container; immediately open the evaporator outlet valve and run
the chlorinator to exhaust the gas in the evaporator and the gas and
liquid in the inlet line.
c. When the evaporator pressure gauge reads zero, the chlorine outlet
valve may be closed.
d. If the evaporator pressure gauge shows pressure after the outlet valve
has been closed for several minutes, repeat steps a through c until the
evaporator pressure gauge reads zero with outlet valve closed. Then
turn off power to the control box and alarm units.
e. If no standby evaporator is being used, shut down the chlorinator.
f. Drain the hot water tank by opening the drain valve at the back of the
unit.
g. Drain the heat exchanger by removing the 1/2-inch plug at the bottom
(underside) of the heat exchanger. A small container may be used to
capture the water (approximately 1/2 gallon) when the plug is removed.
WARNING: TO AVOID SEVERE PERSONAL INJURY WHEN HOT WATER
DRAINS OUT OF HEAT EXCHANGER, ALLOW WATER TO COOL BEFORE
REMOVING PLUG.
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