ATI’s Model Q45H/65 Residual Chlorine Dioxide Monitor is designed for on-line monitoring and control of industrial disinfection systems. Chlorine dioxide is a powerful disinfecting agent used for treating potable water, cooling water, and food processing wash water. To ensure proper disinfection while minimizing disinfection by-products, the concentration of chlorine dioxide must be precisely maintained.

Unlike on-line colorimetric and most amperometric monitors, Q45H systems utilize a membrane-covered polarographic sensor that does not require the addition of chemical reagents.  The Q45H system has no moving parts, so there are no pumps or motors that burn out or tubing breaks that create maintenance nightmares. All normal maintenance items are included with each system.

Installation is simple and you can be up and running in a few hours.  All that’s needed is a constant flow of water across the face of the sensor, and this is provided by a simple constant-head flowcell. The sample water is unaffected by the measurement and can be safely discharged back into the process.

The ATI Model Q45H/65 Residual Chlorine Dioxide system responds to chlorine dioxide with minimal interference from any residual chlorine that may be present.

Available in loop-powered transmitter, AC operated analyzer, or battery operated portable versions, the Q45H/65 is well suited for almost any chlorine dioxide measurement requirement. Even a portable data-logging version is available for temporary installation or process studies. And for even more flexibility, the instrument is available with an optional pH sensor input that allows a single unit to provide both chlorine dioxide and pH analog outputs.

On-line Monitors shall be provided to continuously measure chlorine dioxide concentration at the                                             (Specify Locations). Each Chlorine Dioxide Monitor shall consist of a direct measuring chlorine dioxide sensor, a clear constant-head flowcell, 25 feet of sensor interconnect cable with quick disconnect plug, and an electronic monitor housed in a NEMA 4X enclosure suitable for wall, pipe, or panel mounting.

The chlorine dioxide sensor shall be a direct measuring polarographic sensor utilizing a special polymeric membrane to isolate the sensing electrodes from the sample and eliminate the potential for electrode contamination. The membrane shall allow chlorine dioxide to diffuse into the sensor where it shall react with the sensing electrode, generating a signal that is linearly proportional to chlorine dioxide concentration. The sensor assembly shall also contain a precision RTD temperature sensor to continuously measure sample temperature to allow temperature compensation of the measured value. The sensor shall be constructed with a quick disconnect receptacle to allow easy sensor servicing or exchange. Chlorine dioxide sensors shall be supplied complete with at least 10 spare membranes, or membrane cap assemblies, electrolyte, and a spare parts kit that includes all o-rings and special hardware.

The flowcell assembly supplied with the monitor shall be constructed of clear material allowing the condition of the sensor membrane to be inspected without removal of the sensor. The sensor shall slide easily into the side of the flowcell, with a double o-ring seal to prevent water leakage. Flow to the sensor shall be regulated automatically through a constant-head overflow arrangement. Hose barbs for sample inlet (1/4" I.D. tubing) and drain (1/2" I.D. tubing) shall be supplied as part of the flowcell.

OPTIONAL:  The chlorine dioxide monitor shall be supplied with a pH sensor. The pH sensor shall allow the monitor to measure both chlorine dioxide and pH simultaneously, and display both variables on the LCD display. AC powered monitors shall have the capability of providing 4-20 mA outputs proportional to both chlorine dioxide and pH. The pH sensor shall fit into the inlet chamber of the chlorine dioxide sensor flowcell. The pH value shall be available for display on the second line of the monitor display.

The Chlorine dioxide Monitor electronic assembly shall be: (select one version below)

A. A loop-powered 2-wire instrument providing an isolated 4-20 mA output proportional to chlorine dioxide into a maximum load of 500 ohms.

B. An AC powered instrument for operation on (specify either 115 VAC or 230 VAC) single-phase line power. The monitor shall provide two isolated 4-20 mA outputs configurable for chlorine dioxide, pH temperature, or PID control. Analog outputs shall be both ground isolated and isolated from each other. AC powered chlorine dioxide monitors shall also contain two SPDT relays.

C. A battery operated data logging monitor capable of operating from an internal 9 VDC battery. The monitor shall provide two 0-2.5 VDC outputs suitable for use by the internal data logger. The monitor shall operate for up to 4 days continuously on an alkaline battery and up to 10 days on a lithium battery.

The chlorine dioxide monitor electronic assembly shall provide a variety of functions as follows.

1. Provide user selectable display of PPM chlorine dioxide, process temperature, or PID % output on the main display. Main display variable shall be indicated with a minimum character height of 0.75” to allow easy readability up to 20 feet away.

2. Allow selection of operating ranges of 0-200 PPB, 0-2 PPM, 0-20 PPM, or 0-200 PPM. Display ranges shall be configurable by operators, or the monitor may be configured for Auto-Ranging. The auto-ranging function shall automatically switch to the display range that provides the best resolution for any given operating level.

3. Provide for simultaneous measurement of both chlorine dioxide and pH based on input from an optional pH sensor.

4. Provide the ability to use the 4-20 mA output for PID control. Proportional, Integral, and Derivative functions shall be user adjustable, and also provide for output hold when needed.

5. When operated on AC power, provide two isolated 4-20 mA outputs, with output spans programmable by the user for any segment of a display range. When supplied with a pH sensor input, one 4-20 mA output may be assignable to the pH measurement to allow simultaneous output of both chlorine dioxide and pH.

6. Provide output hold and output simulate functions to allow for testing or remote receiving devices or to allow maintenance without disturbing control systems.

7. When operated on AC power, provide two SPDT relays.  Relays shall be programmable for either control or alarm function, or relays may be assigned to diagnostic functions for use in indicating trouble conditions at a remote location.

8. Diagnostic functions shall be incorporated into the transmitter.  The 4-20 mA output shall be capable of being assigned to safely rise to 20 mA, fall to 4 mA, or be left alone, during diagnostic failures.  Diagnostic error messages shall be displayed in clear language; no confusing error codes shall be displayed.

9. When operated from a 9 VDC battery, provide data logging of  chlorine dioxide and temperature or  chlorine dioxide and pH over programmable time intervals. Provide software with the data logger for easy data download to standard computers, with graphical and tabular viewing of data. Software shall allow export of data to standard spreadsheet programs.

The complete Chlorine Dioxide Monitor shall be Series Q45H-65 as manufactured by Analytical Technology, Inc. or approved equal.