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6. Operating Controls and Components
1.
Chlorine Gas Temperature Thermocouple: The chlorine gas outlet temperature is monitored
by a K-type thermocouple through the top flange of the chlorine pressure chamber. For added
corrosion protection it is installed with a Hastelloy-C thermowell. Its main function is to provide
visual indication of the chlorine gas outlet temperature, and together with the chlorine gas pressure
transmitter, is used to calculate and then display the superheat value. Should the amount of
superheat go below the alarm level, an alarm will be activated to shut down the pressure reducing
valve, and thereby prevent liquid chlorine from flooding through the vaporizer.
2.
Chlorine Gas Pressure Transmitter: The chlorine gas outlet pressure is monitored by a
diaphragm protected pressure transmitter. The scale of the transmitter is 0-300 psig. Its main use
is to provide visual indication of the chlorine gas pressure in the chlorine pressure chamber, and
together with the chlorine gas temperature thermocouple, is used to calculate and then display the
superheat value. The operating pressure of the vaporizer should be between 38-210 psig. Should
the pressure go outside this range corrective action must be taken (see Troubleshooting).
3.
Water Tank Temperature: The water tank temperature is controlled and monitored by two
K-type thermocouples. One thermocouple is at the heater inlet/bottom of the water tank (aux water
temp) and the other at the heater outlet/top of the water tank (control water temp). The control
water temperature thermocouple is used for the PID control of the heater to maintain a stable water
tank inlet temperature of 180˚F (82˚C). It is also the thermocouple that provides the measurements
for the low water temperature alarm and high water temperature alarm. The temperature sensor at
the heater inlet (aux water temp) is used as a reference for measuring the amount of heat transfer.
4.
Water Level Control: Water level in the water tank can be controlled both automatically and/or
manually. For automatic control, there are four conductive level sensors in the water tank (one low
level, one low fill, one high fill, and one overfill alarm). Each alarm is then used in conjunction
with the water re-fill solenoid to open or close the solenoid and maintain the water level. For
manual control, there is a clear glass sight tube on the front panel for the user to determine the
operating level. When the sight glass is below
1
⁄
3
full, water should be added. When the water is
above
2
⁄
3
full water should be stopped. Water may be manually refilled using the 3" through hole
on the collar plate, or piping into the existing ½" water re-fill solenoid slot.
5.
Water Re-Fill Solenoid: The water re-fill solenoid is used for automatic control of the water
level. It is 2-way, normally closed, Nema 4x rated, with stainless steel housing and is available in
either 120 VAC or 240 VAC. Inlet and outlet connections are ½" FNPT. Water supply pressure
must be at least 10 psi and less than 60 psi.
6.
Cathodic Protection System: Corrosion protection of the chlorine pressure chamber, water tank,
water tank piping and all other components is provided by the use of four (4) sacrificial magnesium
anodes. The amount of protection provided is adjustable by using the potentiometer next to the
ammeter. The amount of current provided should be in the range of 50-250 mA. Any more will
unnecessarily consume the anodes and any less will provide insufficient cathodic protection. A
¼ lb. of sodium sulphate should be added if this amount of current cannot be regularly supplied.
Based on normal operating conditions these anodes will be consumed in about one (1) year, and
should be replaced yearly. During initial operation little to no current may appear on the controller
due to the electrical insulation provided by the enamel painting. This is normal and may take up to
6 months until a reading appears. The vaporizer is still being protected during this period.
