evaporator should be replaced when the evaporator is taken apart for cleaning and
inspection. Follow these steps to clean the evaporator:
Dismantle and remove the chlorine vessel from the evaporator.
Flush the chlorine vessel with cold water to remove corrosion
products from the inside.
Visually inspect the interior for pitting. If pitting is severe, replace
the chlorine vessel.
Remove all flushing water and reassemble the evaporator.
Fill the water bath and heat it to 180F (82C). Attach an aspirator
so that a vacuum can be exerted on the inside of the chlorine vessel. The vacuum
should be about 25 inches (635 mm) of mercury, and should be held for 24 hours with
the water bath at 180F (82C), to make sure that all moisture is removed from the
inside of the chlorine vessel.
Hypochlorite Solution Feeders
Hypochlorite solutions are highly alkaline. The reaction of this
alkaline material with the hardness in the makeup water results in carbonate scale
deposits in the pump head and tubing, and in the solution diffuser at the point of
application. Dilute (5 percent) hydrochloric (muriatic) acid solution can be pumped
through the hypochlorinator to remove this scale. Be sure to flush out the hypochlorite
solution with water first.
The diaphragm continually flexes. Inspect it to make sure it
Check valves and seats for corrosion, hardening, swelling, scale,
or foreign material that might prevent proper seating. Refer to solution-feeder
maintenance information in par. 11.8.7 for additional maintenance procedures.
Dry Chemical Feeders. Maintenance procedures for dry chemical feeders
are summarized in Table 44.