Capacitive level meter for liquid hydrogen

Matsumoto, Koichí; Sobue, Masamitsu; Asamoto, Kai; Nishimura, Yoshiyuki; Abe, Satoshi; Numazawa, Takenori

doi:10.1016/j.cryogenics.2010.11.005

Cited by 12 publications

(6 citation statements)

References 8 publications

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“…The capacitive observability of a single gas-liquid phase boundary under cryogenic conditions has been demonstrated by Hennes and Barnard (1964) and Kügler et al (1984) with liquid nitrogen (LN 2 ) as the liquid; based on this, a fill-level resolution of ±1 mm was reached. Successful fill-level measurements have also been reported by Matsumoto et al (2011) with liquid hydrogen (LH 2 ). The earlier studies, of course, did not have access to modern electronics and thus had to limit themselves to very specific geometries and measurement purposes.…”

Section: Introductionmentioning

confidence: 77%

“…The earlier studies, of course, did not have access to modern electronics and thus had to limit themselves to very specific geometries and measurement purposes. But even the recent work in Matsumoto et al (2011) did not aim for a detailed investigation of the electrode geometry, its influence on the measurable capacitances, the information which may be extracted from these capacitances on quantities other than the fill level, and the possibly error-producing influence of the capacitance measurement hardware. We have designed and tested a capacitive system for gas-phase detection under cryogenic applications.…”

Section: Introductionmentioning

confidence: 99%

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Capacitive gas-phase detection in liquid nitrogen

Kandlbinder

Fischerauer

Mösch

et al. 2017

J. Sens. Sens. Syst.

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Abstract. The main and upper stages of heavy lift launchers for space applications are often fuelled by cryogenic liquids. In order to enable the re-ignition of a cryogenic upper stage for orbital changes, it is crucial to study the behaviour of these fluids in microgravity. As gaseous bubbles entering the fuel lines of the engine can cause the destruction of the engine, these bubbles are a risk for the functionality of the re-ignition mode. To measure an evolving gaseous phase and its volume, a capacitive measurement system for two-phase mixtures was realised. Its electrodes are arranged in such a way that phase changes inside a vessel can be detected without parasitic heating under cryogenic conditions. Two cases have been investigated: a fill-level measurement involving a large gas bubble above a homogenous liquid on the one hand, and the identification of a bubble stream inside a liquid on the other hand. The system concept was tested in a cryogenic environment allowing the controlled generation of bubble streams inside liquid nitrogen and of a contiguous gaseous volume above the liquid. The characteristics of the measurable capacitances of different pairs of electrodes were experimentally determined and compared with finite-element simulations (Ansys). In addition, the electrical flux density was computed to corroborate the simulated capacitance curves with theoretical statements. The experimental findings closely agree with the simulated results if possible disturbances due to the characteristics of the capacitance measurement hardware are properly taken into account. Thus, by measuring various capacitances, it was possible to determine the level up to which a receptacle inside a liquid-nitrogen tank was filled with liquid (the space above the liquid being taken up by gaseous nitrogen), to identify the existence of a bubble stream in the liquid nitrogen and to demonstrate that the capacitance measurement results enable one to differentiate between the two cases.

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Section: Introductionmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

Capacitive gas-phase detection in liquid nitrogen

Kandlbinder

Fischerauer

Mösch

et al. 2017

J. Sens. Sens. Syst.

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“…The capacitance-type water level gauge [5] converts the water level detection into the induction of capacitance parameters, and displays it on the meter through the current.…”

Section: Literature Reviewmentioning

confidence: 99%

Design of a Groundwater Level Monitoring System Based on Internet of Things and Image Recognition

Bo¹,

Cheng²

2021

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This paper designs an intelligent groundwater level monitoring system based on image recognition and Internet of things (IoT). Image recognition technology was employed to process the water level image, and determine the water level line. The IoT was adopted to transmit the collected multimedia data accurately to the monitoring end, thereby realizing the automatic remote monitoring of real-time water level. After analyzing the image recognition technology and the key algorithm of water level recognition, the authors designed the whole process of groundwater level monitoring with two modules: water level monitoring base station, and remote monitoring management center. The water level monitoring base station is embedded with a data acquisition module to periodically collect data, including water level, videos, and images. The collected data were sent to the remote monitoring management center through the cellular network. Then, flood or low water warning could be determined according to the historical data. Finally, the proposed groundwater level monitoring system was tested. The results show that the system not only solves the problem of measurement accuracy, but also improves the work efficiency.

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“…The sensor consists of a PCB with two comb electrodes where the capacitance between electrodes varies in steps with water [8] have described a non-contact liquid level measuring system by utilizing the principle of absorption of frequency modulated millimeter wave in a liquid. K. Matsumoto et al [9] have studied the application of a parallel plate capacitor at low temperature with ac capacitance bridges for measurement of level of liquid hydrogen, liquid nitrogen and liquid helium. J.E.A.…”

Section: Introductionmentioning

confidence: 99%

Study on Further Modification of Non-Contact Capacitance Type-Level Transducer for a Conducting Liquid

Chakraborty

Bera²,

Mandal

et al. 2015

IEEE Sensors J.

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A non-contact capacitance type liquid level transducer for a conducting liquid consists of a short circuited non-inductive coil wound on a uniform cylinder made of insulating material like glass, PVC, nylon, teflon etc. The cylinder is connected with a storage tank through a metallic connector and the capacitance between upper short circuited end of the coil and metallic connector varies linearly with liquid level measured from datum level. The capacitance at datum level depends on atmospheric condition and the fringe effect of other conductors. So the transducers require frequent recalibration depending on atmospheric and environmental conditions. In the present paper, this non-contact capacitive sensor has been further modified in order to minimize this defect of non-contact capacitive sensor. Moreover, all the conventional capacitance type level sensors are associated with a perpendicular plate capacitance between liquid and electrode which varies with the length of the electrode. In the present paper, the effect of this perpendicular capacitor on liquid level measured has been studied and its effect is minimized. The proposed modified transducer has been designed and developed and its theory of operation has been derived. The performance of the developed transducer has been experimentally studied and the experimental results are reported in the paper. A good linear performance characteristic of the transducer with very minimum parasitic capacitance effect has been observed.

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Capacitive level meter for liquid hydrogen

Cited by 12 publications

References 8 publications

Capacitive gas-phase detection in liquid nitrogen

Capacitive gas-phase detection in liquid nitrogen

Design of a Groundwater Level Monitoring System Based on Internet of Things and Image Recognition

Study on Further Modification of Non-Contact Capacitance Type-Level Transducer for a Conducting Liquid

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