Valmet LC - Optical Low Cs%
High-resolution accuracy for low consistency
The Valmet Optical Low Consistency Measurement (Valmet LC) delivers extremely precise low consistency measurements for advanced control of critical processes.
Meet the demands of sustainability
As environmental regulations tighten, pulp and paper mills are striving to reduce water consumption and implement closed-loop processes. Better process management and reduced variability also contribute to improved runnability while reducing the impact on the environment.
Using Valmet Optical Low Consistency Measurement, you can better control paper machine disc filters and presses to reduce variations in the process. The Valmet LC solution works for feed consistency control, as well as measurement of filtrate quality. Customers often rely on the precision of Valmet LC to detect unwanted materials in purified circulation waters.
For headbox and white water applications, low consistency measurements are an essential element in wet end process management. On slower paper machines where the stock contains no ash or the ash percentage is relatively stable, the Valmet LC can be effectively used for total consistency measurement. In the growing molded pulp package industry, for example, the Valmet LC is a popular consistency measurement solution.
The Valmet LC is particularly well-suited for recycled pulp lines, for example. In screening control, maintaining the correct feed consistency results in uniform drainage and improves process operation, as well as end-product quality.
Continuous measurement of effluent also helps to steer and manage the mill’s wastewater system. The Valmet LC helps detect process disturbances immediately so that corrective action can be taken without delay.
Low maintenance, high accuracy
Using light polarization and attenuation, Valmet LC delivers reliable and accurate measurements independent of pulp color and brightness variations. The polarization method also minimizes the impact of ash fluctuations. For consistencies from 0 to 2%, the measurement readings are precise down to the thousandths.
Practically maintenance-free, the Valmet LC sensor has extremely durable sapphire glass windows. During the automatic flushing sequence, self-diagnostics routinely check the condition of the sensor and alert maintenance personnel if contaminant or blockage is detected.
Calibration is easy with just one lab sample. If needed, four different recipes can be calibrated and stored in the Valmet LC memory. The solution comes with HART® connectivity as standard and Profibus PA as optional.
SENSOR PART
Measurement:
- Measuring range: 0–1.5 % Cs
- Repeatability: ±0.005 % Cs
- Sensitivity: 0.001 % Cs
Materials:
- Enclosure: Aluminium
- Wetted parts: AISI 316 L
- Windows: Sapphire
Process condition:
- Temperature: +10–80 °C
- Flow: 4–30 l/min
- Pressure: max. 7 bar
Environment:
- Ambient temp.: +5–50 °C
- EMC test standards
- Radiated interference: IEC 61000-6-2
- Interference immunity: IEC 61000-6-4
- Weight: 6 kg
- Vibration: IG (10m/s2), 10–200 Hz
TCU
Connection to mill system:
- Analog output: 2 outputs (4–20 mA, passive)
- HART: 12–35 VDC
- Binary inputs: 2 inputs (galvanically isolated), 12–28 VDC / 10 mA
PROFIBUS PA slave (option)
IEC 61158-2
Connection to PC
- DTM: HART
- PC-connection: RS-232
Environment:
- Ambient temp.: Max. 50 °C
- Weight: 2 kg
- Vibration: 1G (10 m/s2), 10–2000 Hz
Supremely accurate low consistency - Measurement sensitivity to ±0.001%
Easy to use - Simple calibration and automatic self-diagnostics
Reliable technology - Automatic flushing keeps the measurement clean
