Gravimat FMX

Measurement of basis weight (mass per unit area) / thickness

Backscattering of X-rays

The weight monitoring and control system measures the weight continuously, without contact, destruction-free and on moving product. The X-ray radiation from an X-ray tube is directed towards the product, from which it is partially scattered back.

The greatest part of the radiation passes through the product and is absorbed by a beam dump or steel facing roller installed there. This backscattered portion is an indication of the weight of the product.

Principle of operation

The Gravimat FMX sensor consists of a compact X-ray tube and its high-voltage power supply as well as special, modern X-ray detectors with the electronics for data acquisition.It is completely insensitive to environmental effects such as temperature and relative humidity.
This new measuring principle is used with the proven Mahlo components for data recording and processing, and is therefore fully compatible with other products of the Qualiscan QMS family.
The manner in which X-rays interact with mass allows for the measurement of a very wide range of web basis weights using a single sensor, from 50-20,000 g/m2 with the web against a steel roller or in free air!

Product highlights

  • Single-sided measurement requiring a minimum of space; easy to integrate into existing systems
  • Measuring device works with an X-ray tube that can be turned off, and has no radioactive isotope emitter
  • Insensitive to distancerelated variations due to patented detection system

Customer benefits

  • Can be installed without having to modify the processing range and existing web guiding arrangement
  • Easy to certify, and a minimum of radiation safety requirements; X-rays can be turned off
  • Highly accurate and virtually insensitive to product composition
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Extrusion 2019

Conference for all extrusion processing
17 - 19 Sept 2019
Chicago, USA



International Trade Fair for Plastic and Rubbery Machines
16 - 23 Oct 2019
Düsseldorf, Germany
Visit us at stand 10G21


Hofer Vliesstofftage

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Conference for fleece
06 - 07 Nov 2019
Hof, Germany
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Exhibition for Textile Machines
25 - 28 Nov 2019
Shanghai, China
Visit us at booth W2 D17!

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Exhibition for Nonwovens
11 - 13 Dec 2019
Shanghai, China
Visit us at booth 1A26!


Mahlo GmbH + Co. KG • Donaustraße 12 • 93342 Saal /Donau
Tel.: +49-9441-601-0 •