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Digox 602 Silica

Determination of dissolved silicic acid (orthosilicate) in steam is of great importance for the operation and safety of equipment in power plants. In addition to determining the orthosilicate in the steam (to prevent settling or crystallization inside the turbine), it is possible to detect an opening in the anion filter or in the exchanger.

Digox 602 silica is constantly evolving in accordance with the physico-chemical method of measurement according to the new VGB S-006 guidelines for the quantitative detection of dissolved silicic acid. A photometric procedure with a detection limit of 0.5 ppb is used, which is ideal for the determination of silicic acid in ultra-pure power plant water.

Technical Specification

Device Digox 602 Silica
Measuring range 0,5 - 5 000 ppb Si02
Photometer Accurate photometer with sample temperature regulation
Display Graphic display, measured value for each channel with time and operating conditions
Accuracy Max. {± 2% of the reading or ± 2 ppb} within the measuring range 0 - 100 ppb; Max {± 5% of the reading or ± 5 ppb} within the measuring range  > 100 ppb
Limit of determination 0,5 ppb
Repeatability Max. {± 2% of the reading or ± 2 ppb} within the measuring range 0 - 100 ppb; Max {± 5% of the reading or ± 5 ppb} within the measuring range  > 100 ppb
Calibration Three-point calibration is performed using micro-dosing pumps;  water deionized using an integrated ion exchanger for the zero point and standard
Agents 2 x 2.0 l and 2 x 1.0 l of the agent, 0.25 l of the standard solution
Data interface Profibus DP-V0 (optional)
Binary inputs 6x binary inputs for external (dry) contacts for hiding channels and for remote control
Relay outputs Two relays (1x for warning and 1x for alarms), 250 VAC / 3 A, max. 24 VDC / 3 A
Operation Password protection for two levels, entering threshold values, communication parameters and measuring cycles
Analogue outputs Up to 6 analogue outputs 4… 20 mA ± <0.025 mA, max. load resistance of 500 Ω; max. 2 analogue outputs, when the Profibus interface is installed
Duration of the analysis Max. 15 min. at sample temperature of  25 - 50 ° C
Ambient temperature +10 - +50 ° C, storage and transport 0 - 50 ° C, relative humidity 10 - 95%
Sample condition 1-6 input channels with the application for maintaining constant pressure, another laboratory sample, determination of the blind value using the filter
Power source 100 - 240 VAC 50/60 Hz, 70 VA, battery-free saving of parameters, no loss of data after power interruption, data stored in the memory
Standard compliance

In accordance with CE and CB according to EN 61010-1, EN 61326 -1 and -2 -3, EN 50581 air treatment

Protection system IP 65 (electronic unit)
Weight Max. 38 kg (6-channel device including all consumables)
Dimensions 850 x 450 x 250 mm (HxWxL)
Space required for assembly 1050 x 550 x 500 mm ((height x width x depth)

Main Functions

  • Very low reagent consumption, one set of reagents (approximately 3 liters) can withstand at least 5000 measurements or
  • 8 weeks at the highest measurement frequency
  • Automatic recalibration, adjustable measurement interval
  • Individually adjustable measurement sequence and frequency for each channel. The time frame can be adjusted from the minimum measurement time to a measurement interval of 96 hours
  • Short measuring sequence <15 min. (at the sample temperature of 25 - 50 ° C)
  • Determination of the actual value of the empty chemical while determining the zero point
  • Highly accurate sample temperature regulation
  • Galvanically isolated signal outputs
  • Pressure regulator and easy to clean channel pre-filter
  • Built-in sequencer for up to 6 sampling channels
  • Additional measurement of the "grab" sample in the bottle
  • Profibus DP interface (optional)
  • Possibility of remote control using 6 external binary contacts (calibration commands, channel selection, hide channel, grab sample)