Gravimat FMI

Control of basis weight / thickness


Transmission of beta rays

The weight monitoring and control system measures the weight continuously, without contact, destruction-free and on moving product. The measurement is based on the attenuation of rays from a radioactive isotope through the substrate located in the measuring gap. This attenuation in intensity is an indication of the weight of the product.

Product Highlights

  • Highest repeatability ofthe measured values
  • Non-contacting measurement
  • Digital signal processingTemperature compensation
  • Source ageing compensation
  • Gap compensation

Customer benefits

  • Material saving
  • Quality assurance
  • Increased production
  • Comprehensive quality documentation

SpecificationValueUnit
IsotopeKrypton-85 (Kr-85)Strontium-90 (Sr-90) 
Activity3,0 / 9,620,5GBq
Measuring range10 - 1400100 - 6000g/m²

  • Coating of textiles
  • Carpet coating

With the common basis weight measurement is based on the attenuation of radioactive rays through the substrate located in the measuring gap. This attenuation in intensity is an indication of the weight of the product. The basis weight is hereby determined without contact and continuously at high accuracy.

For very different weight ranges, such as pile carpeting or coated textile bases, different nuclides are available. Differential measurements with two measuring points are  normally made to control a coating process. The coating weight is continuously recorded in the process and the application or coating unit of the machine is automatically adjusted. This allows immediately responding even to short frequency  changes of the incoming basis weight.

The coating weight is continuously recorded in the process and the application or coating unit of the system is automatically readjusted. In this way, even short-frequency changes in the incoming basis weight are reacted to immediately.

  • Krypton-85
  • Strontium 90
  • Gap cleaning

  • Module of the process control Optipac VMC-15
  • Stand-alone device

Documents