TEOM

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A TEOM (abbreviation of English T apered E lement O scillating M icrobalance ) is a measuring instrument for the determination of airborne dust . The measuring principle is based on the fact that the natural frequency of a vibrating system is mass-dependent.

Structure and procedure

A filter through which the gas to be sampled is passed is placed in a conical glass tube . The upper part of the glass tube is covered with an electrically conductive layer, which is located between two flat electrodes that maintain a constant electric field . An oscillating current flowing through the conductive layer causes the glass tube to vibrate. In the equilibrium state, the electrical oscillation frequency corresponds to the mechanical natural frequency of the conical glass tube. The natural frequency is mass-dependent and therefore also dependent on the filter loading.

Measuring devices that work according to the TEOM principle can be used for both immission and workplace measurements. They can also be used to record diffuse emissions . They are offered for both stationary and personal use.

With a TEOM, dust concentrations can be output directly. Corresponding pre-separators allow the PM 10 , PM 2.5 and PM 1 fractions to be measured . In order to avoid the condensation of water vapor, the system is kept at a temperature of 50 ° C. This means that it is not possible to measure volatile particles.

literature

  • DIN 33899-1: 2014-02 Exposure at the workplace - Guidelines for the use of direct display devices for monitoring aerosols - Part 1: Selection of the monitor for special applications. Beuth Verlag, Berlin.

Individual evidence

  1. ↑ a b Stephan Pannek, Traugott Kilgus, Abdreas Müllauer: PM 10 monitor comparison: TEOM FDMS / SHARP / airpointer PM modules. In: Hazardous substances - cleanliness. Air . 67, No. 10, 2007, ISSN  0949-8036 , pp. 439-443.
  2. ↑ a b James H. Vincent: Aerosol Sampling - Science, Standards, Instrumentation and Applications . John Wiley & Sons, Chichester 2007, ISBN 978-0-470-02725-7 , p. 381.
  3. ↑ VDI 4285 sheet 3: 2015-11 Metrological determination of emissions from diffuse sources; Quantification of diffusive emissions by measurements - Quantification of diffusive emissions of fine dust from industrial plants including agricultural sources. Beuth Verlag, Berlin. P. 38.
  4. ↑ Carsten Möhlmann, Johannes Pelzer, Albert Hellmann, Jens Niklas: Metrological determination of ultrafine and nanoparticles in mechanical processing of nanomaterials and their composites. In: Hazardous substances - cleanliness. Air. 72, No. 11/12, 2012, ISSN  0949-8036 , pp. 463-465.