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Q46H/65 Chlorine Dioxide Monitor

The Q46H/65 Chlorine Dioxide Monitor uses a polarographic membraned sensor to accurately measure ClO2 in water.


The Q46H/65 Chlorine Dioxide Monitor uses a polarographic membraned sensor to accurately measure ClO2 in water. It is particularly well suited for removing biofilms from the inside of piping systems. The sensor operates much like a battery, generating current that is linearly proportional to the concentration of chlorine dioxide in solution. A ClO2 permeable membrane isolates the sensor from the measured sample and insures that the measurement is interference free.

Two versions of the sensor are available, a sensor intended for installation in a flowcell and a sensor intended for submersion applications. Requiring minimal maintenance, sensors are easy to use and easy to maintain. an integral RTD provides temperature compensation and allows temperature to be displayed and transmitted from the monitor.

Chlorine Dioxide sensors require 2 to 4 hours of stabilization time when first installed or after membrane change. ATI offers a battery powered “polarizer” that can be used to stabilize a spare sensor so it is ready to run within a few minutes if installation. Polarizers simply plug into the sensor connector and require no adjustments.


  • pH Input Option
  • Programmable range options from 0-200 PPB up to 0-200 PPM provide maximum application flexibility
  • AC or DC Power Options
  • Analog Output Options
  • PID Output
  • Digital Communications. Available for either Profibus-DP, Modbus-RTU, or Ethernet-IP
  • Relay Contacts
  • Flexible Mounting
  • Back-lit large LCD display provides clear visibility in any lighting conditions. A scrolling second line on the display provides additional information and programming prompts

Chlorine Dioxide sensors require a steady flow of sample across the membrane at the tip of the sensing assembly. ATI offers a number of options for flowcells including the standard constant-head overflow system, a sealed flowcell for pressures up to 50 psi and a low-volume flowcell where low sample flow is important. a 1½” flow tee is also available for in-line applications with reliable constant flow and pressure conditions.

Specifications – Monitor

Display Range 0-200 ppb, 0-2.000 ppm, 0-20.00 ppm, or 0-200.0 ppm
Accuracy ±0.5% of selected range or 0.02 ppm
Repeatability ±0.3% of selected range of 0.01 ppm
Non-Linearity 0.1% of full scale
Temperature 0.01% of span/°C
Power 100-240 VAC, ±10%, 50/60 Hz, 10A maximum
12-24 VDC, 500 mA maximum
Analog Outputs Two isolated 4-20 mA, 500 Ω load maximum, 3rd output optional
Relays Three SPDT, 6A @ 250 VAC, 4A @ 24 VDC, 3 additional SPST non-isolated 1A#30 VDC optional
Display 4 digit, 0.75″ numeric LCD with 12 character second line, LED back light
Enclosure NEMA 4X, (IP-66) Polycarbonate, V-0 flammability
Operating Temperature -20 to 60°C
Weight 6 pounds
Zero Drift < 0.01 ppm/month

Specifications – Sensor

Ozone Sensor Membrane covered polarographic sensor
Temperature Sensor Internal Pt 100 RTD
Materials PVC and 316 stainless steel
Sensor Cable 25′ standard, 100′ maximum
Response Time 90% in 60 seconds
Temperature Limits 0-50°C
Pressure Limit 0-50 psig
Flowcell Material Clear Acrylic constant head overflow standard
Sealed acrylic flowcell optional
Sample Connections ¼” ID hose barb inlet, ½” ID hose barb drain for standard flowcell

Ordering Information

For pricing please call AFC International at 800-952-3293, 219-987-6825 or fax 219-987-6826 or email


Q46H/65 Chlorine Dioxide Monitor Literature

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