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Method for detecting the critical flow state of gases

Country of Origin: Germany
Reference Number: TODE20190513002
Publication Date: 13 May 2019

Summary

A German research institute has developed a method for detecting the critical flow state of gases. Nozzles and diaphragms are used for flow measurements of gases. Above a suitable pressure ratio between inlet and outlet pressure at the nozzle, a critical state occurs in which the volume flow is independent of the pressure behind the nozzle. The offered sensor can detect this state to minimize the energy expenditure for the pressure generation. The research institute is looking for licensees.

Description

A German research institute, active in metrology, has developed a method for detecting the critical flow state of gases. Established on the market, critical nozzles are a long-term stable transfer standard for the calibration of flowmeters. The flow is measured with a suitable nozzle by increasing the pressure at the inlet until the critical operating state of the nozzle is reached. The aim here is to achieve the operating state with minimal energy expenditure.

The offered invention realizes this in the case of gaseous media because of an additional sensor system, which uses the influence of the critical flow on the spread of sound and light waves in the nozzle. The sound and light waves are directed along the flow direction to a detector and the signal is evaluated to detect the critical state.
Commercial relevance:
Critical nozzles allow a very accurate and reproducible measurement of flow rates. They are used in measuring instruments in calibration laboratories. Inadequate inflow and other confounding factors, however, result in unexpected break up of criticality and, therefore, to a falsification of the result of measurement. Up to now, this has been counteracted by the fact that a reliable "criticality" of the measurement setup is ensured by higher pressures with oversized pumps and the necessary increased energy input.
State of development:
A patent application is pending. The research institute is looking for licensees.
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Advantages and Innovations

The following advantages are offered:
- Optimized flow measurement
- Low operating costs
- Accurate determination of the critical state
- decreased energy input for pressure generation.

Stage Of Development

Concept stage

Requested partner

Type of partner sought: industry
- Specific area of activity of the partner: producers of measuring instruments and calibration laboratories
- Task to be performed by the partner sought: use the offered product as licensee in a defined region or for a defined application.

Cooperation offer is closed for requests