Evanescently coupled dewpoint sensor based on a silicon waveguide

Stoddart, Paul R.; Pearce, Joshua; Mazzolini, Alexander P.

doi:10.1016/j.sna.2006.01.033

Cited by 7 publications

(3 citation statements)

References 18 publications

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“…The developed QCM dew/frost sensor has measurement errors of < ±0.2 • C at temperatures greater than −60 • C, as compared with ±0.2 • C for optical dew-point hygrometers [25] and ±0.3 • C ∼ ±0.5 • C for other types of dewpoint detectors, e.g. laser dew-point hygrometers [27,28], impedance dew-point detectors [29] and evanescent field detection techniques [30]. This demonstrates that the QCM dew/frost-point sensor has similar accuracy to other dewpoint sensors for temperatures greater than −60 • C. In contrast, while optical dew-point hygrometers exhibit poor performance, low sensitivity due to the optical detection limit and long response time, etc, at dew/frost points below −70 • C (even though some commercial optical chilled mirror hygrometers show good accuracy of ± 0.1 • C in the range below −70 • C), the QCM dew/frost-point sensor we have developed maintains reasonable accuracy even for very low dew/frost points with errors in the range ±0.…”

Section: Dew/frost-point Measurementmentioning

confidence: 99%

Accurate dew-point measurement over a wide temperature range using a quartz crystal microbalance dew-point sensor

Kwon¹,

Kim²,

Choi³

2008

Meas. Sci. Technol.

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Quartz crystal microbalance (QCM) dew-point sensors are based on frequency measurement, and so have fast response time, high sensitivity and high accuracy. Recently, we have reported that they have the very convenient attribute of being able to distinguish between supercooled dew and frost from a single scan through the resonant frequency of the quartz resonator as a function of the temperature. In addition to these advantages, by using three different types of heat sinks, we have developed a QCM dew/frost-point sensor with a very wide working temperature range (−90 • C to 15 • C). The temperature of the quartz surface can be obtained effectively by measuring the temperature of the quartz crystal holder and using temperature compensation curves (which showed a high level of repeatability and reproducibility). The measured dew/frost points showed very good agreement with reference values and were within ±0.1 • C over the whole temperature range.

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Section: Dew/frost-point Measurementmentioning

confidence: 99%

Accurate dew-point measurement over a wide temperature range using a quartz crystal microbalance dew-point sensor

Kwon¹,

Kim²,

Choi³

2008

Meas. Sci. Technol.

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“…A condensation-principle hygrometer operates by detecting the formation of condensed water or ice on a temperaturecontrolled surface. Previous studies [15,16] have shown that the initial condensate typically forms a uniform layer of droplets that are a few micrometres in size. In this section we consider the effect of surface droplets on the frequencies f TM 1n and f TE 1n , and hence derive a formula for estimating the volume of water on the internal surface of a QSR from the ratio f TM 1n / f TE 1n .…”

Section: Effect Of a Surface Condensate On The Resonance Frequencies ...mentioning

confidence: 99%

A microwave resonance dew-point hygrometer

Underwood

Cuccaro

Bell

et al. 2012

Meas. Sci. Technol.

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We report the first measurements of a quasi-spherical microwave resonator used as a dew-point hygrometer. In conventional dew-point hygrometers, the condensation of water from humid gas flowing over a mirror is detected optically, and the mirror surface is then temperature-controlled to yield a stable condensed layer. In our experiments we flowed moist air from a humidity generator through a quasi-spherical resonator and detected the onset of condensation by measuring the frequency ratio of selected microwave modes. We verified the basic operation of the device over the dew-point range 9.5–13.5 °C by comparison with calibrated chilled-mirror hygrometers. These tests indicate that the microwave method may allow a quantitative estimation of the volume and thickness of the water layer which is condensed on the inner surface of the resonator. The experiments reported here are preliminary due to the limited time available for the work, but show the potential of the method for detecting not only water but a variety of other liquid or solid condensates. The robust all-metal construction should make the device appropriate for use in industrial applications over a wide range of temperatures and pressures.

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“…So there is a strong demand for a sensor able to accurately detect a high humidity or dew condensation state. Different dew point hygrometers reported to date are based on resistive [2], capacitive [3], gravimetric [4], surface acoustic wave [5] or optical [6]- [10] technologies. Optical fibers are used to launch and collect optical signal from the condensation surface of chilled mirror hygrometers [9], [10].…”

Section: Introductionmentioning

confidence: 99%

Photonic crystal fiber interferometer for dew detection

Mathew¹,

Semenova²,

Rajan³

et al. 2011

SPIE Proceedings

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Abstract-A novel method for dew detection based on photonic crystal fiber (PCF) interferometer that operates in reflection mode is presented in this paper. The fabrication of the sensor head is simple since it only involves cleaving and fusion splicing. The sensor shows good sensitivity to dew formation with a large wavelength peak shift of the interference pattern at the onset of dew formation. The device's response to ambient humidity and temperature are also studied and reported in this paper. From our experiment it is also concluded that by attaching a thermoelectric cooler with temperature feedback, the sensor head demonstrated can be used as a miniature dew point hygrometer.Index Terms-Dew sensor, humidity measurement, modal interferometer, optical fiber devices, photonics crystal fiber.

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Evanescently coupled dewpoint sensor based on a silicon waveguide

Cited by 7 publications

References 18 publications

Accurate dew-point measurement over a wide temperature range using a quartz crystal microbalance dew-point sensor

Accurate dew-point measurement over a wide temperature range using a quartz crystal microbalance dew-point sensor

A microwave resonance dew-point hygrometer

Photonic crystal fiber interferometer for dew detection

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