Refiner control

Refiner control

The gap sensor (TDC) was developed already in the 1970s with the aim of measuring the distance between the plates in refiners for pulp production. The goal was to enable steering of the gap between the grinding segments to control the quality in the process.

The sensors are manufactured with very high precision to meet the high demands on reliability placed in these harsh industrial environments.

A further development led to a complete system, today called GMS, which makes it possible, in addition to gaps, to also measure and display temperature, vibration and conductance inside the refiner among other things.

The system gives our customers the possibility of delivering high and consistent quality in production throughout the entire process.

Manufacture of an AGS sensor
TDC sensor
AGS sensor


What is the difference between TDC sensors and AGS sensors?

The TDC sensor’s measuring accuracy is determined by the fact that the calibration is performed in exactly the same way each time, at the same time as the plates are moving towards each other.

With an AGS sensor, the calibration is performed automatically by moving the sensor tip towards the rotor segment instead of moving the rotor towards the stator. This gives a safer calibration that becomes independent of the operator.

Note that the calibration can be performed with minimal risk of segment damage as the rotor and the stator are no longer moving towards each other during the calibration.

Depending on the conditions, it is also possible to calibrate the AGS sensor during production.

An AGS offers, in addition to gap and temperature measurement, also integrated vibration and conductance measurement.


RMS – Refiner Monitoring System

RMS is a measuring system that features several variants, each one of which is optimized for Valmet’s different types of refiners.


  • A system that is used for Valmet’s RGP-CD refiners.


  • A system that is used for Single Disc refiners such as the RGP-60 and the RGP-200 series.


  • For Double Disc refiners, type RGP-68DD. As of the year 2014, this is complemented with Dametric’s Service panel.


  • A system without TDC/AGS measurement that is delivered to Fiberboard refiners.


  • RMS-RS1 replaces the 35-year-old measuring system DCA-02. Unfortunately, outdated components mean that the DCA-02 can no longer be maintained.


  • RMS-RS2 replaces the 35-year-old measuring system DCA-DD-H for Double Disc refiners. The RS2 system is used together with Dametric’s Service panel.

Upgrading to AGS system

It takes about 8 hours of downtime to upgrade a standard RMS system to AGS performance. The package also includes a Service panel as a display with the Windows 10 IoT operating system for simplified handling of calibration and tip change.

GMS – Gap Monitoring System

The Andritz Twin-60 refiners represent an additional market for AGS sensors. These refiners can be equipped with a GMS measuring system and an AGS to ensure that the operator is given accurate information about the gaps between the rotor and the two stator sides.

The AGS sensor was originally developed for Twin-60 machines where it is difficult to get a touch point depending on the machine’s characteristics.

Feel free to contact us at Dametric for further information »

RMS system