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Evaluating transmitters for quantifying respiratory airflow in the breathing mechanism

Barański Robert, Nitkiewicz Szymon, Zając Andrzej, Kukwa Andrzej, Stano Łukasz, Szawarc Sebastian

Diagnostyka

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2024

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Vol. 25, No. 1

art. no. 2024105

EN

Techniques for measuring fluid flow have been known since the 19th century. The first solutions based on the use of pressure only allowed relatively slow changes to be observed. It was not until measurement techniques based on the use of electronic components and the phenomenon of thermo-transfer, combined with a method enabling fast signal recording (A/C converters), that it became possible to analyse the flow of a medium (e.g. air) in detail. Although flow sensors based on measuring changes in resistance have been known for many years, new solutions are still being developed. This paper presents the results of a study using three sensors. Their response to laminar airflow was investigated for different velocities (1.2 - 2.6 m/s). The flow forcing was implemented using an axial fan and the signals were measured simultaneously for all the sensors tested. The results showed which sensors had the smallest dispersion of results (PAN and WA sensors) and confirmed that for the investigated velocity variations (0.14 m/s pitch) the results are unambiguously interpretable.. It should be noted that sensor research is related to the need to develop a device to measure flow as accurately as possible, while at the same time ensuring the comfort of the test person during the measurements. Therefore, the search was for a sensor that is small in size and at the same time resistant to damage and operation in a harsh humid environment.

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Magnetic Coupling of Two Coils Due to Flow of Pure Water Inside Them – Double Coil Volumetric Flow Sensor

Al Jarrah Asem Mohammad, Aljabarin Nader

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 3

47--53

EN

In this work a simple new type of flow sensors was developed; the double coil flow sensor. In this sensor two coils are magnetically coupled due to the flow of pure water inside them. The first coil, the primary coil, was supplied by AC voltage in the frequency range 0.5-1 MHz which is the coupling range of frequency for water. The voltage in the second coil, was found to be directly proportional with the volumetric flow rate of the water flowing inside the coils. The two coils can only be coupled in the laminar flow region. In the turbulent region, due to the turbulent chaos and fluctuation the two coils cannot be effectively coupled, and therefore the sensor cannot be used. The temperature of the water was found to have a negligible effect on the coupling, which add a good advantage to the simplicity of the double coil sensor. The working fluid used in this work was pure water. Other fluids are believed to be working as well, most probably at different frequency range, and this will be the subject of future work.

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Koncepcja czujnika termoanemometrycznego wykorzystującego zjawisko Peltiera

Durnaś M., Papliński J.

Elektronika : konstrukcje, technologie, zastosowania

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2008

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Vol. 49, nr 2

19-21

PL

W pracy przedstawiono koncepcję czujnika termoanemometrycznego, wykorzystującego zjawisko Peltiera, Joulea i Seebecka, wraz z układem do pomiaru prędkości przepływu nieprzewodzących gazów i cieczy. Zaproponowany układ pozwala na stabilizację różnicy temperatur pomiędzy punktem występowania zjawiska Peltiera, a przepływającym medium. Charakterystyka statyczna i właściwości dynamiczne czujnika mogą być kształtowane przez nieliniowe ujemne sprzężenie zwrotne.

EN

The system and design variants of hot-wire anemometric sensor for measuring of flow velocity of non-condueting gases and liquids have been presented in the paper. The operation of presented sensors is based on simultaneous using of Joule's, Peltier's and Seebeck's phenomena. The sensor design allows to stabilize the difference of temperatures between junetion of two condueting materials and surroundings. Furthermore, the temperature of junetion can be simultaneously measured. Due to application of speedy non-linear control system in feedback loop conneeting elements of sensor one can change sensor static characteristies and its dynamic properties.