ATI's versatile Q45P/R pH/ORP system is designed for use in all industrial and municipal applications. The sensors are engineered to function normally in applications where conventional sensors quickly fail.  Conventional pH/ORP sensors have an “open reference system,” which means the reference element and electrolyte are in contact with the process. This allows chemicals to diffuse into the reference chamber and alter the reference system. As the reference junction becomes contaminated, the reference potential shifts. As chemicals attack the silver reference wire, the reference potential shifts and the sensor no longer functions. When any of these problems occur, cleaning and calibration cycles increase and the sensors fail much faster, all of which costs you time and money.

The differential pH/ORP sensors utilize a “sealed reference system,” where the sensors are constructed with a second glass pH electrode as the reference element. The glass reference system protects the sensor from chemical poisons (sulfide, cyanide, chlorine, bisulfite, etc.) that destroy conventional pH sensors.  A large volume, dual junction saltbridge is used to maximize the in-service time of the sensor. Large electrolyte volume and dual junctions minimize contamination of the reference solution. The replaceable saltbridge allows for easy and inexpensive sensor regeneration.

The Q45P/R Auto-Clean System is designed to extend sensor cleaning intervals on pH and ORP sensors that are mounted in applications containing high levels of solids contamination. The Auto-Clean System uses high pressure air to remove contaminants from the face of the sensor automatically.  Our Auto-Clean System utilizes a self contained compressor and air cylinder to generate a series of high pressure air blasts.  Each cleaning cycle lasts approximately 2 minutes, during which the monitor outputs are placed in a HOLD condition to prevent false readings or alarms.  The concentration of solids in the process will determine the cleaning frequency of the system. The user can vary the cleaning cycle frequency from as often as once every two hours to as little as once a day.

pH Monitors shall be supplied for continuous monitoring of pH in _________ (Specify Application and Location). The pH monitoring system shall consist of an electronic monitor housed in a NEMA 4X enclosure suitable for wall, pipe, or panel mounting, a differential-style pH sensor, and accessories listed below. The pH Monitoring System shall be ATI Series Q45P/Q25P as described below.

The pH sensor shall be a 1" NPT, dual-electrode design. The reference electrode shall be fully sealed in a glass to prevent contamination of the reference element. The reference chamber of the sensor shall be fully serviceable by removal of the saltbridge and replacement of the reference chamber solution.

The sensor shall be constructed of molded PEEK (poly-ether-ether-keytone) components. These components include the saltbridge, body, all rear seal components, and all internal components. The body shall be hex shaped to facilitate quick connection to standard 1" NPT fittings.

The sensor shall include a titanium ground electrode to improve signal stability and enable electrode breakage diagnostic functions to be performed. The sensor shall include a Pt1000 RTD for high accuracy temperature measurements. The sensor shall include an integral preamplifier to provide a low impedance signal output capable of being driven 3000 feet with standard sensor cabling. The sensor preamplifier shall contain features to monitor for electrode breakage and sensor seal failure. The integral electronics shall be encapsulated into the sensor.

The sensor shall include a highly chemical resistant, cross-linked polyethylene jacketed cable. The sensor cable shall contain two foil shields for optimum electrical performance.

The sensor saltbridge shall be a high capacity, dual-junction, high capacity device. The saltbridge shall be completely replaceable.

The pH 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 pH 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 pH, temperature, or PID control. Analog outputs shall be both ground isolated and isolated from each other.  AC powered pH 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 pH monitor electronic assembly shall provide a variety of functions as follows.

1. Provide user selectable display of pH, 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. 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.

3. 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.

4. The transmitter shall allow the 4-20 mA output to be set to any two points within the measuring span of 0-14 pH, as long as the points are at least 2 pH units away from each other. The points may also be reversed. The transmitter shall allow the user to place a delay on the reaction time of the output and display.

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

6. 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.

7. The transmitter shall contain calibration functions for 1-point (sample or buffer) and 2-point calibration for pH. The user shall be able to easily override the automatic buffer recognition values and manually enter values if desired. Calibration stability monitors shall be provided to hold calibration status until stable buffer conditions have occurred.

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  pH and temperature 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 pH Monitor shall be an Analytical Technology Inc. Model Q45P/Q25P, or approved equivalent.