Ultrasonic density sensor—analysis of errors due to thin layers of deposits on the sensor surface

Püttmer, A.; Hoppe, N.; Henning, Bernd; Hauptmann, P.

doi:10.1016/s0924-4247(98)00365-3

Cited by 16 publications

(23 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…(9) any buffer material can be used to determine the density using the reflection coefficient. But, as shown in Table 1, only materials of acoustic impedance comparable to the impedance of the sample medium possess an acceptable sensitivity for small density variations Püttmer et al, 2000;Greenwood et al, 1999). The same holds true for the ARM; increasing angular difference to the normal incidence even decreases the RC difference.…”

Section: The Choice Of Materialsmentioning

confidence: 88%

“…The RRM based on one pulse, as applied in McClements and Fairly (1991), Papadakis et al (1973), , Püttmer et al ( , 2000 and Saggin and Coupland (2001), uses the ratio of any detectable buffer reflection of a sample medium and the corresponding buffer reflection of a reference medium, e.g. A r1 (sample) and A r1 (reference):…”

Section: Reference Reflection Methods (Rrm)mentioning

confidence: 99%

“…But using two different transducers probably generates other systematic errors due to misalignment or differing transducer properties. A special case of this method is presented by and Püttmer et al ( , 2000, who used an additional delay line that is connected to the reverse side of the piezoceramic to determine signals from a reference interface. In this way a similar excitation pulse can be guaranteed for reference and sample measurement by using one transducer only.…”

Section: Reference Reflection Methods (Rrm)mentioning

confidence: 99%

“…Additional requirements for the buffer materials are good chemical resistance, reasonable temperature stability and a low sound attenuation Püttmer et al, 2000). If special liquids are analysed, e.g.…”

Section: The Choice Of Materialsmentioning

confidence: 99%

“…The equations presented so far represent the time domain approach and refer to the signal amplitude, but do not state which pulse amplitude is used in the end. In Greenwood and Bamberger (2002), Greenwood et al (1999), and Püttmer et al ( , 2000, the maximum peak-to-peak amplitude within a certain time window has been examined:…”

Section: Signal Processingmentioning

confidence: 99%

See 4 more Smart Citations

Ultrasound-based density determination via buffer rod techniques: a review

Hoche¹,

Hussein²,

Becker³

2013

J. Sens. Sens. Syst.

View full text Add to dashboard Cite

Abstract. The review presents the fundamental ideas, assumptions and methods of non-invasive density measurements via ultrasound at solid-liquid interface. Since the first investigations in the 1970s there has been steady progress with regard to both the technological and methodical aspects. In particular, the technology in electronics has reached such a high level that industrial applications come within reach. In contrast, the accuracies have increased slowly from 1-2 % to 0.15 % for constant temperatures and to 0.4 % for dynamic temperature changes. The actual work reviews all methodical aspects, and highlights the lack of clarity in major parts of the measurement principle: simplifications in the physical basics, signal generation and signal processing. With respect to process application the accuracy of the temperature measurement and the presence of temperature gradients have been identified as a major source of uncertainty. In terms of analytics the main source of uncertainty is the reflection coefficient, and as a consequence of this, the amplitude accuracy in time or frequency domain.

show abstract

Section: The Choice Of Materialsmentioning

confidence: 88%

Section: Reference Reflection Methods (Rrm)mentioning

confidence: 99%

Section: Reference Reflection Methods (Rrm)mentioning

confidence: 99%

Section: The Choice Of Materialsmentioning

confidence: 99%

Section: Signal Processingmentioning

confidence: 99%

See 3 more Smart Citations

Ultrasound-based density determination via buffer rod techniques: a review

Hoche¹,

Hussein²,

Becker³

2013

J. Sens. Sens. Syst.

View full text Add to dashboard Cite

show abstract

Time‐of‐flight prediction for fermentation process monitoring

Hoche

Hussein

et al. 2011

Engineering in Life Sciences

View full text Add to dashboard Cite

This work presents an ultrasound‐based inline sensor system, which is used to monitor the alcoholic yeast fermentation. The pulse‐echo method is used to determine ultrasound velocity (USV) of the sample medium. The major aim of the paper is to highlight the importance of an accurate time‐of‐flight (TOF) estimation for accurate concentration determination and to present method immanent strategies to fulfill the requirements. An algorithm aiming at a stable and highly accurate TOF estimation in time domain was developed. The basic methods of the algorithm are a frame‐wise signal analysis based on the sensor dimensions, cross‐correlation to find complementary impulses and root estimation via polynomial fit to calculate the TOF in time domain. The analysis results of laboratory‐scale validation trials (demineralized, vented water) and of real process data (yeast propagation) are presented. In spite of the stable algorithm performance in the lab scale, the algorithm fails in a few cases of real process signals. The relevant signals and corresponding causes for failure were analyzed and future strategies for algorithm enhancement are discussed. Reviewing the results, the aimed USV accuracy of 0.075 m/s can be achieved. The maximum USV error of the used principles and applied methods in the investigated temperature range is ±0.02%.

show abstract

Sensors in Disposable Bioreactors Status and Trends

Glindkamp

Riechers

Rehbock

et al. 2009

Disposable Bioreactors

View full text Add to dashboard Cite

For better control of productivity and product quality, detailed monitoring of various parameters is required. Since disposable bioreactors become more and more important for biotechnological applications, adequate sensors for this type of reactor are necessary. The required properties of sensors used in disposable reactors differ from those of sensors for multiuse reactors. For example, sensors which are in direct contact with the medium must be inexpensive, but do not need a long life-time, since they can be used only once.This chapter gives an overview on the state of the art and future trends in the field of sensors suited for use in disposable bioreactors. The main focus here is on in situ sensors, which can be based on optical, semiconductor and ultrasonic technologies, but current concepts for disposable sampling units are also reviewed.

show abstract

Ultrasonic density sensor—analysis of errors due to thin layers of deposits on the sensor surface

Cited by 16 publications

References 3 publications

Ultrasound-based density determination via buffer rod techniques: a review

Ultrasound-based density determination via buffer rod techniques: a review

Time‐of‐flight prediction for fermentation process monitoring

Sensors in Disposable Bioreactors Status and Trends

Contact Info

Product

Resources

About