Wallace & Tiernan - Model Micro/2000 -Measurement Module

• High accuracy measurement of Chlorine, Chlorine Dioxide and Potassium Permanganate Residuals
• Ability to handle poor quality water sources without fouling
• Fast speed of response for control applications and monitoring rapid water quality changes
• Low sample flow cell design for economical reagent usage
• Wide choice of field selectable measurement ranges
• Separate flow cell and electronic packages for installation flexibility

• Measurement of disinfection residuals throughout the entire potable water treatment process
• Wastewater residual measurement
• Industrial process water and wastewater
• Cooling water

• Accurately measures free and total Chlorine, Chlorine Dioxide or Potassium Permanganate residuals at ranges from 0-0.1 to 0-50mg/L.
• Suitable for all poor quality water applications such as wastewater and cooling water (fresh or seawater source).
• Sensitivity and speed of response down to 1 ppb (0.001 mg/L utilizing 3 electrode measurement technology.)
• Bare electrode cell design provides high reliability, long term stability, low maintenance, and minimal chance of fouling.
• Unaffected by varying water quality, changes in turbidity or conductivity.
• Field proven in thousands of installations around the world in a wide variety of ambient conditions.

• Choice of peristaltic pump speed - for residual monitoring applications, a 1 rpm pump is used to minimize reagent usage; for use in a control loop, a 2 rpm pump is used to provide a quick response to a process change
• Sample line dosing - a biocide metering pump can be used with the integral control software to prevent biofouling of the sample line in wastewater applications
• Circular chart recorders - feature chart ranges scaled to match the selected range of the analyzer.

Modular Design
The Micro/2000 measurement module is used with either an SFC or MFC electronic package. The Micro/2000 measurement module consists of a separate flow cell enclosure for wall mounting and a plugin electronic module. Typically, the Micro/2000 enclosure is mounted adjacent to either the SFC or MFC electronics, but can be separated for a distance up to 2m (6 ft). The lift-off, removable cover provides quick access to the flow block, measuring cell and peristaltic sample/reagent pump. All liquid lines are piped to a common drain. When required, reagent bottles are mounted below the analyzer enclosure with the supplied brackets. Utilizing “plug and play” technology, the SFC or MFC automatically recognizes the Micro/2000 electronic module to display the correct information. The SFC or MFC electronics provide multiple alarm outputs, a 0/4-20 mA residual output signal and an RS 232 or RS 485 digital interface.

Three Electrode Measuring Cell
Utilizing universally accepted and time-proven amperometric measurement technology, the Micro/2000 measurement module uses an innovative 3-electrode measuring cell to provide direct measurement of residuals with a sensitivity of +/- 1 ppb (0.001 mg/L). With its bare electrode design, the Micro/2000 analyzer is not susceptible to the fouling typical in membrane probe analyzers, caused by bacteria, grease or turbidity. Also, unlike membrane probe analyzers, it measures all species of Chlorine residuals including dichloramine. The 3-electrode cell eliminates the need for the constant zero adjustment typical of other analyzers. Reliability and stability are vastly improved while maintenance is drastically reduced. The calibration and accuracy of the analyzer is not affected by changes in turbidity or conductivity, which can be a problem with some other analyzers on the market.

Unique Sample Flow System
The sample is delivered to the Micro/2000 measurement module at a rate of 4-8 l/m (1-2 US gpm) for potable water applications 11-19 l/m (3-5 US gpm) for wastewater applications via a suitable sample pump). A flushing Y-strainer in the sample line filters the sample and divides it into two streams. The larger excess sample stream is used to continuously flush the strainer screen. The smaller stream is throttled and flows to the analyzer.

Inside the Micro/2000 measurement module a valveless peristaltic pump is utilized to ensure a consistent sample reaches the analyzing cell for timely measurement in parallel with the actual process lag time. This pump eliminates the need for back-flushing and flow control orifices that could become fouled. The same pump, also delivers liquid reagents, where required, for pH buffering and total residual measurement, in a fixed proportion to the sample. The small volume of the sample flow, together with inexpensive reagents, dramatically reduces operating costs without sacrificing performance or reliability. A motor driven impeller in the analyzing cell maintains stable fluid velocity and provides constant grit bombardment for cleaning electrode surfaces, further reducing maintenance requirements.

Automatic Sample Line Dosing
The Micro/2000 measurement module is particularly well suited to wastewater applications. One of the inherent problems in this service is biological growth in the sample line, from the sample pump to the analyzer, due to very low Chlorine residuals. As an option, the analyzer can be supplied with a small dosing pump for metering a suitable biocide (typically sodium hypochlorite) to clean the sample line. The pump is activated by the analyzer software to automatically dose the sample line periodically. During dosing, the analyzer’s 4-20mA output is frozen to prevent upsets to the control or monitoring operations. Analyzer reliability is enhanced and maintenance is reduced.