An innovative method for the measurement of liquid level of a conducting liquid
01 Dec 2016-pp 1-5
TL;DR: In this article, an accurate noncontact capacitance type technique is described, where measurement errors due to stray capacities effect atmospheric effect, parasitic effect, perpendicular plate capacitance effect etc. observed in conventional capacitive techniques are eliminated.
Abstract: Accurate measurement of liquid level in a storage tank is an essential requirement of any process plant. Various conducting liquids like tape water, acid solution alkali solution etc. are stored in storage tanks. Measurement of liquid level in these tanks may be done by various techniques such as float type, displacer type, capacitance type etc. In the present paper an accurate non-contact capacitance type technique is described. In this technique measurement errors due to stray capacities effect atmospheric effect, parasitic effect, perpendicular plate capacitance effect etc. observed in conventional capacitive techniques are eliminated. Due to these effects, the conventional capacitance type level transducers require frequent recalibration. This difficulty is avoided in the proposed technique. From the experimental study of the proposed transducer. it is found to have a linear characteristic with minimum measurement error.
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29 Nov 2018
TL;DR: A system which uses a ultrasonic sensor, NodeMCU and a progressive web app to collect the water usage data from the user and using the collected data with multiple linear regression it is possible to predict the water required for the next month for the user.
Abstract: Water is the key for life to sustain and to guarantees people’s quality of life. The water resource management plays an important role in checking the unnecessary wastage of water. In water resource management the demand forecasting plays the key feature in the planning of the distribution of water. There are traditional methods for forecasting the demand, but these methods lack in accuracy. To predict the demand it is possible to use the multiple linear regression, which offers more accuracy than the traditional method. In this paper, we propose a system which uses a ultrasonic sensor, NodeMCU and a progressive web app to collect the water usage data from the user. The NodeMCU and the ultrasonic sensor constitutes the hardware of the system which is a IoT Level 3 system. Using the collected data with multiple linear regression it is possible to predict the water required for the next month for the user. The proposed system was evaluated for 10 data sets and the results were comparable.
2 citations
01 Mar 2019
TL;DR: In this paper, an opto-mechanical technique suitable for measurement of liquid level with a very high resolution was presented and repeated experimental observations show that the proposed technique has good resolution, very small nonlinearity, high repeatability and negligible hysteresis error.
Abstract: In this paper, we present an opto-mechanical technique suitable for measurement of liquid level with a very high resolution. In the propose technique, the change in the liquid level in the cylindrical container, attached to the bottom of a vertically suspended helical extension spring, causes corresponding change in the elongation length of the spring. The change in the elongation length eventually changes the distance between a diverging light source and a photoresistor. The repeated experimental observations show that the proposed technique has good resolution, very small non-linearity, high repeatability and negligible hysteresis error.
2 citations
Cites background from "An innovative method for the measur..."
...Capacitive liquid level sensing methods, reported in [11]-[14], are quite economical and suitable for conducting as well as non-conducting liquids....
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References
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TL;DR: A water level measurement using an interdigital capacitive sensor with low-cost, low-energy, good repeatability, high linearity, and ease of installation is proposed with a support of experimental results.
Abstract: A water level measurement using an interdigital capacitive sensor with low-cost, low-energy, good repeatability, high linearity, and ease of installation is proposed with a support of experimental results. This sensor comprises a printed circuit board (PCB) with configuration of two interpenetrating comb electrodes. The comb electrode is 70–80 mm width, 300 mm height with 1–2 mm spacing between each comb. This configuration of electrode causes the capacitance between comb electrodes to vary by the water level. Microcontroller is used to calculate the capacitance between comb electrodes in terms of a discharge time correlated to the water level. A practical water level measurement technique using two comb electrodes designated as level and reference sensors is presented. This technique can directly be applied to water with different conditions without recalibration. This sensor is able to measure absolute levels of water with 0.2 cm resolution over 30 cm range. In addition, it is also sensitive enough to trace the variability of water level. A flood monitoring simulation is carried out in wave flume where this sensor is used to detect the rising wave.
128 citations
TL;DR: A new capacitive method is presented, based on the measurements of capacitances of three parallel plate capacitive structures, which are designated as level, reference, and air sensors, which gives the accurate reading of the liquid level in the tank.
Abstract: The liquid level in a tank should be measured for most applications. In this paper, a new capacitive method is presented to detect the liquid level. Existing methods are generally approximations based on the large difference between the dielectric constants of the liquids and the air. The method proposed here eliminates the effect of air and gives the accurate reading of the liquid level in the tank. The main advantage of the method is that it can directly be applied to any kind of nonconductive liquid without calibration. The method is based on the measurements of capacitances of three parallel plate capacitive structures, which are designated as level, reference, and air sensors. It is mathematically proven that the method completely eliminates different factors, which affect the readings, such as air and temperature. The capacitance measurements are performed using a capacitance-to-digital converter integrated circuit, which can measure very small capacitances up to plusmn4 fF error. The result of a computer simulation, which demonstrates the performance and limitations of the proposed structure, is also provided.
126 citations
TL;DR: An attempt has been made to design a low-cost noncontact capacitance-type level sensor for a conducting liquid that is found to have good linearity and repeatability within acceptable limits.
Abstract: In this paper, an attempt has been made to design a low-cost noncontact capacitance-type level sensor for a conducting liquid. The sensor is in the form of a uniform circular cylinder made of insulating material like glass, ceramic, plastic, etc. The sensor is connected with the metallic- or nonmetallic-type liquid storage tank, in which the conducting liquid column is taken as one electrode, and a noninductively wound short-circuited outside coil is taken as the other electrode of a variable capacitor. The change in capacitance due to the change of liquid level is measured by a modified linear operational-amplifier-based De' Sauty bridge network with adjustable bridge sensitivity. The bridge output after amplification and rectification may be used to drive a direct current indicator calibrated in level. The studies have been made with high-density polyethylene and glass tube sensors separately in both metallic and nonmetallic storage tanks with tap water as the conducting liquid, and the experimental results of the static characteristics of the level sensors with percentage error from linearity are presented in the paper. These results are found to have good linearity and repeatability within acceptable limits
99 citations
Additional excerpts
...Similarly, from (5), (9) and (11) we have,...
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TL;DR: In this paper, a liquid-level measurement system based on a grounded cylindrical capacitive sensor for conductive liquids is presented, where the inner conductor of the shielded cable is connected to ground and the outer conductor is used to measure the liquid level.
Abstract: This paper presents the design and fabrication of a liquid-level measurement system based on a grounded cylindrical capacitive sensor for conductive liquids. Fabrication of the cylindrical capacitive sensor is performed with a novel approach of shielded cable. The inner conductor of shielded cable is connected to ground and the outer conductor is used to measure the liquid level. The relationship between the capacitance value of the cylindrical capacitive sensor and the liquid level is deduced by the analysis and calculation of physical parameters. Moreover, a backward difference calculation is adopted in order to offset the effects of the parasitic capacitance. The performance of the system has been experimentally tested in both grounded metallic and plastic containers. The experimental results show that the nonlinear error is smaller than 5 mm over a range of 90 cm. Over a wide measuring range of 200 cm, the liquid-level measurement system has a nonlinear error smaller than 1.35 cm.
60 citations
"An innovative method for the measur..." refers methods in this paper
...1) First step: a) sensing capacitors 0 0( ) ( ) ( ) , & xh l h l air h air C C C+ measured by digital LCR meter at different liquid level in both ascending and diminishing manners and then ∆C1, ∆C2 and ∆C calculated b) static characteristic curves, % age deviation curves and standard deviation curve are drawn as shown in Figs....
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...a) sensor terminals connected to the bridge circuit and bridge output at different levels measured in both ascending and diminishing manners. b) static characteristic curves, % age deviation curves and standard deviation curve are drawn as shown in Figs....
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...0 ( ) ( ) ( ) x x x h l air h l air p h h C C C + + − ′ = + (3) or, 0 ( ) 1 0 0 ( ) x h l air p x p p C K K h K h C K + = − + + + (4)...
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...digital LCR meter at different liquid level in both ascending and diminishing manners and then ∆C1, ∆C2 and ∆C calculated b) static characteristic curves, % age deviation curves and standard deviation curve are drawn as shown in Figs.(3-5)...
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TL;DR: In this paper, a millimeter-wave Doppler sensor is developed to measure the liquid level on the basis of the absorption of millimeter waves in liquid and a piezoelectric vibrator enables accurate measurement by reflecting a limited portion of the spread beam and modulating it in frequency.
Abstract: A novel contactless method for measuring liquid level through an opaque container is proposed. A millimeter-wave Doppler sensor is developed to “see” (i.e., sense) through a target container and measure the liquid level on the basis of the absorption of millimeter waves in liquid. One of the challenges is to accurately measure liquid level (within sub-millimeter error) despite the inherently large beam diameter of the millimeter wave due to diffraction. A piezoelectric vibrator enables accurate measurement by reflecting a limited portion of the spread beam and modulating it in frequency to distinguish it from the other portion of the beam. A prototype measurement system is fabricated and evaluated. The feasibility of our proposed method for clearly detecting an air-liquid interface concealed in an opaque container is confirmed experimentally. The nonlinearity error of the measured liquid level is within ±0.5 mm .
47 citations