Refiner control

Refiner control

The disc clearance 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 distance 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 distance, 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 distance and temperature measurement, also integrated vibration and conductance measurement.


GMU – Gap Monitoring Unit

GMU is our new measuring and control system for refiners. It measures disc clearance, rotor position, vibration, temperature and pressure. It also contains electronics for stepping motor drive, and regulators for disc clearance control. GMU is available in several versions, adapted to different refiner types.

The future-proof GMU system replaces the old RMS systems. It can be mounted in the old RMS system’s place, using the same connections, which allows for very quick replacement. The GMU takes over all functions from the old RMS system and consists of fewer spare parts.

The GMU has a modern display on an attached Panel PC for mounting in the cabinet door. In addition to displaying current status, it helps with calibration procedures and troubleshooting. It contains a continuous trend logger and can be accessed remotely.

An affordable alternative for simpler refiners without TDC and with a 7” color display.

For SD refiners with AGS or TDC with a single grinding zone.

For CD refiners with AGS or TDC and with two grinding zones.

Replaces RMS-RS1/DCA-02 system. For refiners with AGS or TDC with one or two grinding zones.

Download the brochure on the GMU system »
(PDF file, © 2023 Valmet)

Feel free to contact us at Dametric for further information »

RMS system