Cold thickness gauge / cold thickness length width gauge

The CTG is a 3 - track thickness measurement gauge with adjustable track positions. Optional length and width measurement can be added (CTLWG). 

The system is typically positioned after both cold shears and suitable for plates with up to 100 mm thickness and up to 5500 mm width. The length of the plate ist not limited. 

LAP supplies two different concepts/combinations of mechanics and sensors depending on range for plate temperature less than 100 °C and between 100 °C and 
300 °C.

The main advantages of this concept are

  • One common measuring frame, incorporation all necessary sensors
  • Minimum space requirements in the line, simple installation
  • No measuring house necessary above the roller table
  • Very simple and rugged protective housing system for sensors and instrumental components (air cooling only, no water supply necessary, insulated housings)
  • Integrated software package with integrated visualization
  • Integrated interface to host system


Auxiliary systems for cooling and protection

The entire measurement system is designed as a turn-key measurement solution including the auxiliary equipment for maintaining constant conditions for the measurement sensors. This is primarily required for the differential thickness measurement, as the distance between the sensors will directly influence the thickness readings.

Constant temperature conditions are not mainly required for the sensors, but for the inner steel frame supporting the sensors to eliminate thermal expansion. Therefore the entire inner frame is insulated and air-conditioned. Conditioned air will be supplied by an independent air conditioning system sized correctly for the application. The air conditioner will use ambient air and contains the blower, air filter unit and an air/water heat exchanger. The cooling water will be supplied by a compressor type water rechiller using a closed-loop water circulation. These two systems will normally be located close to the measurement location on the same floor or in the basement level below the measuring frame.

Performance figures

The conditions for the validity of performance figures are:

  • Hot plate surfaces, typical rolled surface
  • Surface free of water or scale
  • Vertical movement of the plate maximum 50 mm
  • Length accuracy is valid on the measured track
  • Accuracy of thickness measurement is based on flat plates, virtual increase of thickness in case of unflat materials will directly influence the measured thickness
  • Reference measurement on certified calibration pieces under cold conditions


Thickness measurement

For plate temperature < 100 °C
Resolution: 0.01 mm
Repeatability: ± 0.04 mm
Accuracy: ± 0.05 mm (2σ; integration time 10ms at 100 measurements per second)

Length measurement

Resolution: 0.1 mm (length)
Accuracy: ± 0.1 % of measured length
Signal delay: < 5 ms (measured at the analogue output)
Signal acqui-
sition time:
typically 20 ms, depending on the signal quality

Width measurement

Resolution: 0.1 mm
Repeatability: ± 2 mm (under reproducible conditions)
Accuracy: ± 3 mm (2σ; integration time 10ms at 100 measurements per second, calibrated measuring system)



For plate temperature 100 °C < T < 300 °C
Resolution: 0.025 mm
Repeatability: ± 0.085 mm
Accuracy: ± 0.1 mm (2σ; integration time 10ms at 100 measurements per second)


Download Application report