Measurement & Control Systems

Acoustic measurement of gas temperatures

The efficiency of many pro­cess­es in chem­i­cal, ther­mal and pro­cess en­gi­neer­ing is de­ter­mined by gas tem­per­a­tures. In order to optimise these pro­cess­es by means of closed-loop con­trols, the gas tem­per­a­ture needs to be mea­sured prompt­ly and pre­cise­ly. The “classical” thermo cou­ple meth­od reaches ther­mal equi­lib­ri­um with the gas to be mea­sured with a long delay and is interferred by heat radiating surfaces.

In con­trast, the speed of sound in gases de­pends on the gas tem­per­a­ture only. The new­ly de­vel­oped ce­ram­ic sens­ing el­e­ment mea­sures the speed of sound in gas quick­ly and very pre­cise­ly, and thus di­rect­ly de­ter­mines the gas tem­per­a­ture with the same ac­cu­ra­cy and high speed (500—1 000 msec).

Gas Temp’s features in detail:

Hire precision – The measuring accuracy of < 3oC is the basis for optimised process control.

Short Response Times – Acoustic measurement allows short response times of < 1 sec.

Large Measuring Range – The large measuring range of 0 – 900oC (larger on request) permits the use in a wide variety of applications. One device – many application areas.

Robust Material – The use of modern, chemically inert ceramics ensures safe application in difficult atmosphere and prevents the sensor element from corrosion.

No Interference by Heat Radiation – The special measurement method eliminates any interference by radiating heat. GasTemp determines the actual gas temperature.

Easy Connection – Coming with an industrial standard 4-20mA interface the system can be connected to the PLC or other process interfaces easily.

Application examples

• secondary air
• tertiary air
• clinker cooler
• exhaust
• calciner