The NIR-Sensor is a device for the online diagnostic of thermal HVOF- and plasma spraying processes. It can be used for the online monitoring of the process parameters for the quality management and the optimization of the process parameters during the process development.

Single particles in the particle stream are detected and the average velocity and surface temperature are measured. The velocity of every particle is determined by a measurement of the flight time using a laser optic. The measur-ing range is between 100 and 1000 m/s. The determination of the surface temperature (between 900°C and 3000°C) is done by a two channel meas-urement of the emission in the NIR spectral range between 800nm and 2600nm.

Particles passing the measurement focus are illuminated by a pulsed laser emitting in the infrared wavelength range. signalsThe Signal originating from particle reflections in the beam is measured. Its duration is inversely proportional to the particle velocity; based on the known width of the illuminated area, the particle velocity of the individual particles is calculated.

Heat radiation emitted by particles passing the measurement focus is analyzed with the respect to the intensity in two different wavelength ranges; the superimposed modulated laser signal in the short wavelength branch is separated by a band pass filter. The ratio of intensities in the two different wavelength ranges is the base for the calculation of the individual particle surface temperature by means of two color pyrometry.

Besides average particle velocities and surface temperatures, the particle detection rate and the distribution functions of the single measurements result are also displayed graphically in the PaCT-Software menu of the GTV NIR-Sensor.

+++ The NIR sensor is exclusively available at GTV Verschleißschutz GmbH. +++

Specifications are subject to change without notice.