Vaisala K-PATENTS® SAFE-DRIVE Process Refractometer PR-23-SD for fiberline

Vaisala K-PATENTS SAFE-DRIVE Process Refractometer PR-23-SD for brown stock total dissolved solids (TDS) control and optimization 

Depending on the installation point requirements of the fiber line, there are two types of SAFE-DRIVE Process Refractometer PR-23-SD systems specifically designed for reliability and easy installation directly in the process pipeline:

  • SAFE-DRIVE™ Process Refractometer PR-23-SD with steam prism wash for filtrates and weak black liquor lines
  • SAFE-DRIVE™ Process Refractometer PR-23-SD with special isolation valve and installation plate for the blow line and the pulp stock line.

Performance features of SAFE-DRIVE Process refractometer in the BSW application

  • Indicates total dissolved solids (TDS) in solution
  • Suitable for measuring washing efficiency, because it accounts for both organic and inorganic fractions.
  • Suitable for all concentrations
  • Measures the precise concentration of washable liquid substances
  • Detects organic materials with a large molecular size, such as lignin
  • Not influenced by chemical oxygen demand (COD) caused by methanol
  • In-line real-time measurement, immediate response time, suitable control
  • Mounted directly onto the pulp line
  • Low operating costs, maintenance-free

The measurement range covers 0-100 % by weight. The accuracy is typically ±0.1 % b.w. and the measurement is automatically temperature compensated. Low and high concentration alarms can be configured. Because of the digital sensing technology, even large amounts of suspended solids, bubbles, or color changes do not affect the measurement or the accuracy.

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Key Benefits

Refractive index technology
Our refractive index measurement technology has become an industry standard – it is widely used to measure black liquor dry solids and green liquor density in Kraft chemical recovery processes worldwide.

The technology addresses the critical factors required for measuring TDS in all types of brown stock washers and washing processes. Continuous in-line measurement enables a quick response to changes in the process.
Easy to install and operate
The SAFE-DRIVE Process Refractometer PR-23-SD Sensor is very easy to install by welding to any vertical or horizontal pipeline with 2 inch or larger diameter. The need for separate spool pieces or pipe sections is minimized. A welding stencil guides the correct welding.

The refractometer has no lamps or moving parts requiring regular maintenance or recalibration. Users can simply 'install-and-forget', getting a low total cost of ownership.
Accurate and reliable
The SAFE-DRIVE Process Refractometer PR-23-SD measurement is based on unique technology utilizing solid-state optics and a CCD-camera to provide a digital measurement of refractive index.

The measurement accuracy is ±0.0002 RI (which corresponds to ± 0.1% by weight). Because of its unique design, measurements are not affected by suspended solids, bubbles or fibers, which make it possible to install the refractometers directly to the pulp or filtrate lines. Our refractometers are not influenced by vibration, temperature shocks or pressure peaks.