Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · Sensors and measurement

Turbidity sensor

Also known as: Turbidimeter, Turbidity meter

German: Trübungssensor

In process analytics, a turbidity sensor is an optical sensor that measures the cloudiness of a liquid caused by suspended particles, usually by the light scattered at an angle or absorbed by the particles.

  • Sensors
  • Process industry

In one sentence

A turbidity sensor measures the cloudiness of a liquid from light scattered or absorbed by suspended particles, e.g. in water or beverages.

Example

A turbidity sensor at the outlet of a filter unit in a brewery detects filter breakthrough and switches the flow to recirculation.

How it applies

  • Engineering: Measurement methods differ in wavelength and scattering angle, and results depend on the method. Units such as NTU and FNU refer to specific methods, so values from different instruments are not always comparable.
  • Installation: Air bubbles, deposits and ambient light disturb the measurement. Choose installation position and cleaning systems accordingly.
  • Maintenance: Verify with reference standards and clean the optics at defined intervals.
  • Documentation: State the method and unit with each turbidity value in specifications and reports, and document the cleaning and verification procedure in the maintenance manual.

Turbidity vs. color

Turbidity is caused by suspended particles that scatter light. Color is caused by dissolved substances that absorb light. Some instruments measure both, but they are different quantities, and a clear but colored liquid can have low turbidity.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: AI TechDoc Knowledge editorial definition, based on process analytics practice

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

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