TDC – True Disc Clearance

TDC – True Disc Clearance

The TDC sensor has been designed to measure the gap between the grinding plates in high yield pulp refiners. The sensor is a market leading product in continual development and improvement.

Buy TDC sensors from us

The TDC sensor is available in several models for the different refiner types used by pulp and paper manufacturers all over the world, functioning on Valmet refiners as well as on Andritz refiners. The sensors can be purchased either from your local sales agent or directly from Dametric.

The development of the TDC sensor

The TDC sensor has been used in refiners from Valmet since the 1970s and we have further enhanced the product over the subsequent years. Today the sensor can be considered as very solid and stable.

The sensor withholds a temperature element for indication of the process temperature, the purpose of which is to protect the sensor from overheating (>225 °C). The sensor’s temperature range goes up to 220 °C, which is necessary for some high pressure processes.

As time progressed, we introduced complete welding of the sensor to increase the strength and improve the tightness. As a result of this, the sensor is entirely protected from the chemicals of the pulp process, which contributes to longer life and higher stability.

Technical specifications

Sensor principle Reluctance sensor
Measuring range 0-3 mm
Response time 500 ms
Accuracy ± 0.03 mm plus ± 1 % of current value
Resolution 0.01 mm
Temperature range 0-220 ºC
Materials Stainless steel and bronze, aluminum in the socket
Mechanical dimensions Depending on model
Diameter of the holder 45-55 mm
Diameter of the measuring tip 27 mm
Distance to supporting edge 23 mm
Total length 97-476 mm
Weight 0.5-5.3 kg