NEMA 4X instrument Front
Flow proportioning control
Residual control
Compound loop flow pacing control
Dechlorination with sulfur dioxide
Feed forward/feedback control
Available in new Field Mount case
The 555 1/4 DIN Chlorination Controller provides the water
and wastewater treatment industry an automatic and accurate
means to control chlorine in potable and wastewater applications.
The 555 can be easily set up to handle flow proportional
control, residual control, compound loop control with
lag times, and dechlorination with sulfur dioxide.
Flow paced (or flow-proportioning) control positions a
chlorine or sulfur dioxide valve in direct proportion
to the water flow rate. For chlorine, a user-defined "dosage-setting"
from 0% to 400% (the percentage of gas flow to water flow)
increases or decreases the rate of gas feed dependent
on water flow rate. Flow paced is well suited where the
water flow rate varies but the disinfection/oxidation
demand remains constant.
Residual control positions a chlorine valve based on chlorine
residual measurement. With a user defined residual setpoint,
the 555 increases or decreases the gas feed dependent
on deviation from setpoint. Residual control is ideal
for applications where the water flow rate is constant
but the disinfection/oxidation demand varies.
Compound loop control positions a chlorine valve based
on chlorine residual measurement and water flow measurement.
The residual control signal trims the valve position signal
generated by flow proportional control. Compound loop
control is ideal for applications where water flow rate
and disinfection/oxidation demand vary, or where tight
control is required.
Feed forward dechlorination control positions a valve
(typically sulfur dioxide) in direct proportion to the
water flow rate and residual level. With a user-defined
"dosage-setting" from 0% to 400% (the percentage of gas
flow to water flow) the 555 increases or decreases the
rate of gas feed dependent on changes in residual level
or water flow rate.
