Infrared sensors

Infrared transmission / reflection – Measurement of moisture, basis weight, thickness

By means of optical evaluation of the reflected light energy in the near-infrared range (NIR), important product-specific parameters such as moisture (water), coating weight, thickness, and organic components in the web can be measured during the manufacturing process.

Its non-nuclear measurement technique is very selective and offers an accurate and cost-effective measurement solution that can be supplied in either single-sided reflection, or dual-sided transmission modes.

Infralot IMF

Measurement of moisture / organic compound

Absorption/reflexion of infrared light

Infralot IMF uses optical evaluation of the absorbed/reflected light energy in the near-infrared range to continuously measure and control material moisture on-line.

Product Highlights

  • Non-radioactive
  • Static simultaneous filter – simultaneous measurement of all wavelengths
  • High spectral resolution
  • Insensitive to product flutter and soiling

Customer benefits

  • Non-destructive, continuous determination of various parameters of product webs
  • Same-spot measurement dry/wet – optimized measuring accuracy
  • No moving parts - wear-free and low-maintenance
  • Broad range of applications through use of various measuring wavelengths

Light-specific wavelengths can excite the atomic bonds of certainmolecules to oscillate. These amount to a multiple of the basic resonance of the molecules. A large part of the incident light energy is absorbed by the material being measured.

If the light energy reflected or transmitted by the material to be measured is examined separately for each wavelength, a relationship is established between the degree of absorption of this resonance wavelength and the number of absorbing  molecules. Dependent on the moisture content in the product, the light energy absorbed alters significantly at the resonance wavelength of the water molecule.

For stable measurements in practice, the measured light energy of the resonance wavelength is compared with other reference wavelengths at which no absorption occurs.

IMF-R (Reflexion)For one-sided measurement of coatings and light-weight products
IMF-T (Transmission)For measurement of the product's overall thickness and composition

ParameterBasis weight & Moisture 
TypeIMF-R (Reflexion)IMF-T (Transmission) 

Measuring range
Basis weight 1

Paper~ 10 - 30~ 10 - 200g/m²
Nonwoven~ 10 - 60~ 10 - 500g/m²
Measuring range Moisture 1~ 0,2 - 15~ 0,2 - 15% H2O
~ 0,2 - 10~ 0,2 - 30g/m²
Measuring range Coating 10,2 - 200-g/m²

1) Measuring range and measuring accuracy depending on the material (analysis of material sample necessary)