ATI - Model Q45H/62-63 - Residual Chlorine Monitor
From Water Monitors
ATI Models Q45H62 and Q45H63 are reagentless and designed for on-line monitoring and control of chlorination systems. It is available in two versions: a free chlorine monitor for drinking water and cooling water, and a combined chlorine monitor ideally suited for “chloraminated” drinking water. The combined chlorine system can also be used in wastewater effluents where sufficient ammonia is present prior to chlorination to result in a predominantly monochloramine residual. 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.
The residual chlorine sensors are available in two configurations: flowcell and submersion. The Free Chlorine sensor should always be used in the flowcell configuration. The Constant-Head Flowcell is used to maintain a constant flow rate and pressure at the face of the sensor. The only requirement is that the sample inlet flow rate be at least 7 gallons per hour. A Low Volume Flowcell is available for clean water application with a flow rate of 1-3 gallons per hour. The Combined Chlorine sensor can be used in either the Flowcell or Submersion configuration. The submersion sensors require flow velocities of at least 0.4 ft/sec for proper operation.
When the pH of the water stream varies regularly, a significant error in free chlorine concentration is introduced. With the simple addition of an optional pH sensor, the Q45H will automatically correct for these changes up to a pH of 9. With AC version, this option provides a second analog output that can be assigned to pH or temperature, converting the chlorine monitor into a dual parameter system. Both Free and Combined Chlorine monitors can be converted to dual output monitors.
This line of microprocessor based instrumentation allows for easy implementation as a loop-powered transmitter, line powered analyzer, or portable battery powered unit within the same instrument.
On-line Chlorine Monitors shall be provided to continuously measure (specify free or combined chlorine residual) at the (Specify Locations). Each Chlorine Monitor shall consist of a direct measuring chlorine 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 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 to diffuse into the sensor where it shall react with the sensing electrode, generating a signal that is linearly proportional to chlorine concentration. The sensor assembly shall also contain a precision RTD temperature sensor to continuously measure sample temperature to allow temperature compensation of the measured chlorine value. The chlorine sensor shall be constructed with a quick disconnect receptacle to allow easy sensor servicing or exchange. Chlorine sensors shall be supplied complete with at least 10 spare membranes, 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 monitor shall be supplied with a pH sensor. The pH sensor shall allow free chlorine monitors to automatically correct the chlorine value for changes in sample pH to maintain measurement accuracy over wide pH swings from pH 7 to pH 9.5. The pH sensor shall fit into the inlet chamber of the chlorine sensor flowcell. The pH value shall be available for display on the second line of the monitor display. For AC powered units, one analog output shall be assignable as a pH output.
The Chlorine Monitor electronic assembly shall be: (select one version below)
- A loop-powered 2-wire instrument providing an isolated 4-20 mA output proportional to chlorine into a maximum load of 500 ohms.
- 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, pH temperature, or PID control. Analog outputs shall be both ground isolated and isolated from each other. AC powered chlorine monitors shall also contain two SPDT relays.
- 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 monitor electronic assembly shall provide a variety of functions as follows.
- Provide user selectable display of PPM chlorine, 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.
- 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.
- Provide automatic pH correction of the measured free chlorine level based on input from an optional pH sensor. The pH compensation may be enabled or disabled by the user, and the pH value at which the correction factor is disabled (comp. stop value) may also be programmed by the user.
- 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.
- 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 free chlorine and pH.
- Provide output hold and output simulate functions to allow for testing or remote receiving devices or to allow maintenance without disturbing control systems.
- 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.
- 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.
- When operated from a 9 VDC battery, provide data logging of chlorine and temperature or chlorine 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 monitor shall be supplied with spare parts and accessories for up to 2 years of operation. A minimum of 10 replacement membranes shall be supplied for the sensor.
- The complete Chlorine Monitor shall be Series Q45H-62/63 as manufactured by Analytical Technology, Inc. or approved equal.