Bring the sample to a stable temperature before the analyser.
ABB Continuous Water Analysis
Silica · Navigator AW641
Silica breakthrough and carryover are key indicators of steam and water cycle quality. AW641 is designed for continuous low-level colorimetric measurement.
Navigator 600
AW641 Silica
Continuous colorimetric analyser for high-purity water and the steam/water cycle. It uses the molybdenum blue method, automatic zeroing, cleaning and calibration, and can handle up to 6 sample streams.
0–5000 ppbSiO₂
0–50 ppbMinimum range
1–6 streamsConfigurations
<15 minAnalyser T90
When to use it / when to consider alternatives
Practical guidance
A good fit when
- demineralisation plants: anion and mixed-bed breakthrough
- boiler drums and steam purity
- condensate polishing
- multi-stream SWAS with several analytical points
Consider carefully when
- samples without cooling or pressure control
- sample lines with dead volume and excessive delay
- expired or contaminated reagents
- drainage with variable backpressure
Best practice
Installation and maintenance
Reduce pressure in a controlled manner, avoiding unwanted flashing or degassing.
Reduce transport delay when the measurement point is distant.
Manage replacement and storage according to the ABB procedure.
Check sequencing and timing: more streams mean a lower update frequency at each individual point.
Use the manual sampling point for verification without disturbing continuous measurement.
SWAS/SCS integration
For high-pressure or high-temperature sampling points, we can integrate sample conditioning, cooling, pressure reduction, flow control and the analyser on the same panel.
Explore integrationBest to know
Useful technical details
True auto-zero
Compensates for sample colour, turbidity and background silica in the reagents.
Maintenance
ABB specifies very low annual maintenance and up to approximately 3 months of unattended operation between reagent/solution changes.
Communications
Data logging, audit trail, SD storage and network functions support traceability and remote supervision.
SWAS integration
Silica measurement is well suited to integrating sample cooling, backpressure regulation, flow control and multi-stream distribution into one system.
Models and installed base
Models we support
AW641Navigator 600 Silica
ABB documentation
ABB datasheets and manuals
Download the documents for your model. Shared manuals, protocols and versions are identified in each document card.
AW641 · Navigator 600 Silica
Separate operating manuals for single- and multi-stream versions.
Request a quotation
Silica · Navigator AW641
Technical FAQ
Frequently asked questions
Where is silica measured in a power plant?
Typically at anion/mixed-bed outlets, in boiler drum water, in saturated steam/carryover and in condensate polishing, depending on the plant’s chemistry strategy.
Why is silica critical for the turbine?
Carryover can deposit silica on turbine blades and reduce efficiency and availability.
Can AW641 handle multiple streams?
Yes. ABB offers 1-, 2-, 4- and 6-stream configurations.
Which method does AW641 use?
Molybdenum blue colorimetry, with automatic zeroing, cleaning and calibration.
How quickly does it respond?
ABB specifies T90 below 15 minutes; in the installed system, sample-line transport delay must be added.