Noise in electromagnetic flowmeters

Wyatt, D G

doi:10.1007/bf02476151

Cited by 12 publications

(5 citation statements)

References 9 publications

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“…Square wave excitation is preferred over AC excitation schemes since the former gives a substantial amount of time for stabilizing the current flowing through the coil. The strength and uniformity of the magnetic field is a governing factor for getting high sensitive signals because the emf induced is directly proportional to it [13,14,23,24]. With an excitation current of 1 A and high quality electromagnetic core, the sensitivity achieved on a benchmark probe output signal is less than 40 mV/lpm.…”

Section: Low Signal To Noise Ratiomentioning

confidence: 99%

“…Kolin developed a method for adjusting the zero setting with minimum interruption to flow [12] but the technique was not the best option for clinical requirements. These inherent problems were extensively studied by Wyatt [13,14], and Hickman et al [1]. Wyatt demonstrated that the base line drift and noises were due to non-uniform magnetic fields, external magnetic interference, and magnetic interferences when excitation frequency coincides with its own harmonic frequencies [13].…”

Section: Review Of Existing Technologiesmentioning

confidence: 99%

See 1 more Smart Citation

Design of Electromagnetic Probe Having Reduced Base Line Drift for Blood Flow Measurement

Nair

Vinodkumar

Sreedevi

et al. 2015

IETE Journal of Research

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An improved design for electromagnetic probe for blood flow measurement is presented. The probe produces a magnetic field in the column of blood to induce a voltage as per Faraday's laws. The mechanical and electromagnetic structures are designed to reduce the effect of base line drift and signal variations with time which are very common in electromagnetic flow measurement systems. A signal with very less noise and drift is induced with a sensitivity of more than 80 mV/lpm. The signal has a linear variation with flow rates and need no frequent calibration. Signal variations with time are negligible and had less power signal interferences and noisy spikes.

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Section: Low Signal To Noise Ratiomentioning

confidence: 99%

Section: Review Of Existing Technologiesmentioning

confidence: 99%

Design of Electromagnetic Probe Having Reduced Base Line Drift for Blood Flow Measurement

Nair

Vinodkumar

Sreedevi

et al. 2015

IETE Journal of Research

View full text Add to dashboard Cite

show abstract

“…Currently, circuit compensation (hardware processing) and software filtering are mainly applied to eliminate interference in the field of EMF to improve measurement accuracy [26][27][28][29]. However, new interference is easily caused by circuit compensation.…”

Section: Analysis Of the Inter-electrode Interference Of The Electromagnetic Flowmetermentioning

confidence: 99%

Study on a New Electromagnetic Flow Measurement Technology Based on Differential Correlation Detection

Chen

Tian

et al. 2020

Sensors

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Under the conditions of low flow rate and strong noise, the current electromagnetic flowmeter (EMF) cannot satisfy the requirement for measurement or separate the actual flow signal and interference signal accurately. Correlation detection technology can reduce the bandwidth and suppress noise effectively using the periodic transmission of signal and noise randomness. As for the problem that the current anti-interference technology cannot suppress noise effectively, the noise and interference of the electromagnetic flowmeter were analyzed in this paper, and a design of the electromagnetic flowmeter based on differential correlation detection was proposed. Then, in order to verify the feasibility of the electromagnetic flow measurement system based on differential correlation, an experimental platform for the comparison between standard flow and measured flow was established and a verification experiment was carried out under special conditions and with flow calibration measurements. Finally, the data obtained in the experiment were analyzed. The research result showed that an electromagnetic flowmeter based on differential correlation detection satisfies the need for measurement completely. The lower limit of the flow rate of the electromagnetic flowmeter based on the differential correlation principle could reach 0.084 m/s. Under strong external interferences, the electromagnetic flowmeter based on differential correlation had a fluctuation range in output value of only 10 mV. This shows that the electromagnetic flowmeter based on the differential correlation principle has unique advantages in measurements taken under the conditions of strong noise, slurry flow, and low flow rate.

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“…Therefore, if the rectangular wave with the same frequency as the excitation wave is used as the reference signal, correlation detection technology can be used to remove the noise (including common mode interference, series mode interference and electrochemical interference) in the output signal of the electrodes effectively. If the traditional method [23] and correlation detection technology work together, complex situations of strong external interference, high solid particle content, and flow rate below 0.2m/s, can be treated more effectively.…”

Section: Correlation Detection Model Of Electromagnetic Flowmetermentioning

confidence: 99%

Electromagnetic Flow Detection Technology Based on Correlation Theory

Huang

et al. 2020

IEEE Access

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When the electromagnetic flowmeter (EMF) is applied to the industrial field, the effective flow signal of the electrode output is easily drowned out by the noise under the condition of strong noise and flow rate lower than 0.2 m/s. However the flow signal drowned out in strong noise cannot be measured accurately by traditional electromagnetic flow detection technology, which cannot separate signal and noise effectively. The correlation technology can be applied to select the reference signal with the same regularity as the target signal to separate the target signal and remove the noise. Firstly, researches on the correlation detection and the basic correlation theory of the electromagnetic flowmeter are carried out. Then, the design of the electromagnetic flow measurement system based on the theoretical research is completed. Finally, in order to verify the performance and accuracy of the designed flow measurement system, a test platform for electromagnetic flow detection is set up, and the verification experiments are implemented. The experiment results show that the electromagnetic flow measurement system based on the correlation theory can not only meet the requirements of traditional flow measurement but also have unique advantages in suppression of strong noise interference, slurry flow measurement, and low flow rate measurement.

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Noise in electromagnetic flowmeters

Cited by 12 publications

References 9 publications

Design of Electromagnetic Probe Having Reduced Base Line Drift for Blood Flow Measurement

Design of Electromagnetic Probe Having Reduced Base Line Drift for Blood Flow Measurement

Study on a New Electromagnetic Flow Measurement Technology Based on Differential Correlation Detection

Electromagnetic Flow Detection Technology Based on Correlation Theory

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