ABB AC221 Insertion-Type Stainless Steel Conductivity Electrode

Overview

The ABB AC221 is an insertion-type conductivity electrode built with stainless steel sensing elements, designed for 2-electrode contacting conductivity measurement in industrial process water. It is supplied in two cell-constant variants – 0.01 and 0.10 – so the same electrode design can be matched to the conductivity range of the application, from ultrapure condensate to more concentrated process streams.

Seven Star LLC supplies the ABB AC221 to power generation, water treatment, and semiconductor operators across Oman and the wider GCC. Units are supplied with manufacturer documentation and backed locally with guidance on selecting the correct cell constant and pairing the electrode with the right ABB transmitter.

Operating Principle

The AC221 measures conductivity by applying an AC signal across its two contacting electrodes and measuring the resulting current, which is proportional to the ionic concentration of the process fluid; the cell constant (0.01 or 0.10) determines the effective measurement range, with the lower constant suited to very low-conductivity ultrapure water and the higher constant suited to more concentrated streams. An integral Pt100 temperature sensor provides automatic temperature compensation with a response time (T90) of under 30 seconds, keeping readings accurate as process temperature shifts.

The stainless steel electrodes resist polarization – a common source of drift in contacting conductivity cells – and require virtually no routine maintenance under normal operating conditions. This low-maintenance characteristic is a key reason the AC221 remains a standard choice for continuous, unattended conductivity monitoring in critical water/steam cycle applications.

Engineering Design of the ABB AC221

The AC221 mounts directly into pipelines, vessels, or process sample lines using an insertion fitting, with a detachable connector that eliminates incorrect wiring during installation and simplifies field replacement. With ABB’s high-temperature cable option, the cell can operate at up to 200°C (392°F) and withstand pressures up to 20 bar (290 psi), giving it the thermal and pressure headroom needed for demanding power-plant water/steam service.

The two-variant cell-constant design lets a single electrode family cover a wide span of applications without requiring an entirely different sensor for each conductivity range, simplifying spare-parts stocking for facilities that operate multiple conductivity measurement points across different process conditions.

Key Features

• 2-electrode contacting conductivity measurement, stainless steel sensing elements
• Two cell-constant variants (0.01 and 0.10) for different conductivity ranges
• Integral Pt100 for automatic temperature compensation, T90 under 30 seconds
• Polarization-resistant electrodes, virtually maintenance-free
• Detachable connector eliminates incorrect wiring during installation
• Operates up to 200°C with high-temperature cable option
• Pressure rating up to 20 bar (290 psi)
• Insertion mounting into pipelines, vessels, or sample lines

Industrial Applications

The AC221 is widely used in power plant water/steam cycles, ion-exchange demineralization trains, reverse osmosis systems, and semiconductor chip-cleaning processes, where continuous, low-maintenance conductivity monitoring is critical to protecting boilers, turbines, and high-purity water systems from ionic contamination.

Across Oman’s power generation and desalination sectors, and throughout the wider GCC, Seven Star LLC supplies the AC221 to facilities in Muscat, Sohar, and Salalah that require dependable, factory-genuine conductivity electrodes with full local support.

Technical Specifications

Request a Quote for ABB AC221 Insertion-Type Stainless Steel Conductivity Electrode

Contact Seven Star LLC for a quotation on the ABB AC221 conductivity electrode, supplied with manufacturer documentation, and local support across Oman and the GCC.

Choosing the Cell Constant

The key choice when ordering the AC221 is the cell constant. The 0.01 version is intended for very low conductivity, such as condensate, boiler feedwater and demineralised water, while the 0.10 version suits higher-conductivity water further upstream in the treatment process. When replacing an installed electrode, read the model code on the label and confirm the cell constant set in the transmitter, since fitting a different cell without changing the configuration will give wrong readings. Also confirm the cable type and length, especially where the high-temperature cable option is needed.

Installation and Commissioning

Mount the ABB AC221 so that the electrodes are fully immersed in flowing liquid with no trapped air. In sample lines, a steady flow rate helps keep the reading stable and the temperature response fast. Tighten the insertion fitting to the specified torque and connect the detachable connector without twisting the cable. At the transmitter, enter the cell constant and confirm the temperature compensation mode for the application; ultrapure water often needs a different compensation setting from general process water. Then compare the reading with a calibrated reference instrument or a laboratory sample.

Maintenance and Troubleshooting

• Reading higher than expected: check for air leaks or CO2 pickup in the sample line and verify temperature compensation.
• Slow or unstable reading: check flow in the sample line and look for bubbles around the electrodes.
• Reading lower than expected: inspect the electrodes for deposits and clean them if needed.
• Temperature value wrong: check the Pt100 connection and cable before replacing the cell.

Supply from Seven Star LLC

Seven Star LLC supplies ABB conductivity electrodes and transmitters to power, desalination and water treatment plants in Oman and the GCC. Share the existing model code, cell constant and process conditions, and our team will check the match before issuing a quotation.

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