The Valmet IQ Porosity Measurement (IQ Porosity) is a single-sided sensor for scanning or fixed-point measurement that delivers accurate online measurements comparable to standard laboratory measurements.
Improved porosity positively influences not only sheet strength and coating pickup, but many other qualities as well. Air permeability, for instance, is one of the key variables for sack, filter and other special papers. The accurate machine direction trend and high-resolution porosity profiles measured by Valmet IQ Porosity provide a solid foundation for producing uniform porosity.
The advanced measurement technology of the Valmet IQ Porosity is not affected by dust or humidity and eliminates the need for vulnerable air flow measurement and vacuum control. The Valmet IQ Porosity provides excellent measurement performance even in positions and applications where online porosity gauges couldn’t be used before.
With the Valmet IQ Porosity, you get instant online responses to porosity changes in a wide operating range with very high sampling rate. This helps you quickly react to changes caused by, for example, refining, wet end, press or calender operations, so you reach on-spec quality faster and reduce start-up waste.
The Valmet IQ Porosity can be installed in an IQ Scanner or in a fixed-point platform. The sensor is equipped with a sheet stabilization plate to ensure air does not leak between the sheet and sensor. There are no filters involved, so operation is essentially maintenance fee. Long-term accuracy and dirt build-up are compensated by scheduled standardization checks
The sensor head vertical position can be adjusted by a stepping motor to eliminate impact of sheet fluttering. The Valmet IQ Porosity is equipped also with a programmable air blast function to remove accumulated dust from pipelines and sensor surfaces.