Nirupama Mandal

A Review on Capacitive-Type Sensor for Measurement of Height of Liquid Level:

The capacitive sensors are used in a variety of industrial and automotive application. A capacitive sensor converts a change in position, or properties of dielectric material into an electrical signal. These properties of capacitor can be used to measure the liquid level in storage tanks. The various aspects and configurations of capacitive liquid level measurement have been described. Here, review is also done on the several types of liquid level measurement techniques using capacitive sensor, for conducting and non-conducting liquid.

Design and Implementation of Real-Time Flow Measurement System Using Hall Probe Sensor and PC-Based SCADA

A rotameter is a variable-area-type flow rate measuring instrument in which the position of a metallic float in a transparent conical tube is taken as a flow rate indicator. It has the disadvantage that it is a local indicating type instrument and special type of transducer is used for its remote indication. In this paper, a noncontact flow rate measurement technique using Hall probe sensor and rotameter is designed, developed, and tested. In this design, a float carrying a thin circular permanent magnet is used, and a Hall probe sensor placed outside the rotameter tube has been used to sense the variation of magnetic field of the magnet with the variation of float position. A signal conditioner unit has been used to convert the Hall probe sensor output into 1-5 V dc signal. This dc signal output of the signal conditioner has been sent to a PC-based flow indicator through optoisolator and analog input channel of a data acquisition system (DAS) card. The PC-based flow indicator has been designed using the Lab Tech Note Book Pro software and the PC-based supervisory control and DAS. A theoretical equation has been derived to explain the operation of the system. The performance of the system has been tested experimentally, and the experimental results are reported in this paper. A very good repeatability and linearity of results has been observed.

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

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, such as glass, PVC, nylon, and teflon. 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. Furthermore, 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 this 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.

Design of a Flow Transmitter Using an Improved Inductance Bridge Network and Rotameter as Sensor

A rotameter is a variable area type flow sensor. It is generally used as a local indicator and display unit. Hence, a special technique is needed to transmit and to display the reading of a rotameter at a remote distance. In this paper, an improved inductance bridge-type technique has been developed to convert the float movement of the rotameter into an electrical current signal, which can be transmitted to a remote indicator. A straight ferromagnetic wire attached to the float of the rotameter acts as a sensing element of the proposed rotameter transducer. The movement of the wire as a result of fluid flow variations inside an inductive pickup coil changes the self-inductance of the coil with the changes in flow rate. An improved inductance bridge network has been used to measure the self-inductance of the coil. It has been observed that the variation of the self-inductance of the pickup coil as well as the variation of the transducer and transmitter outputs with flow rate has a very good linearity and repeatability. The necessary theoretical equations, along with the experimental results, are reported in this paper.

Review on transit time ultrasonic flowmeter

Ultrasonic technology is evolving rapidly due to the significant improvements of the flow measurement in continuous industrial process. It is a widely used technology among the non-contact type of flow measurement for its high resolution, low pressure loss, less interference of noise on output. Ultrasonic flowmeters gained the debate, mainly due to measurement ability in custody transfer of natural gas, accurate measurement of the flow of slurries and impurity liquids, works for wide range of nominal diameters. This paper contains review on some important developments of transit time ultrasonic flowmeters particularly to improve the accuracy.

Design and development of an eletro-optic type flow transmitter using Mach-Zehnder Interferometer

The Rotameter is a variable area, local indicator type flow sensor. Hence to transmit reading of Rotameter at a remote distance, some special technique is needed. The transmission of electrical signal is dangerous for inflammable industry. In this paper, an electro-optic type flow transmitter has been proposed. The float movement of Rotameter is converted into an electrical signal with the help of inductive pickup coil and Maxwell Bridge. This electrical signal is applied in electro-optic Mach-zehnder Interferometer, which gives the optical signal for transmitting to remote location. The necessary theoretical equations, along with the experimental results are reported in this paper.

Design and Analysis of Hall Effect Probe-Based Pressure Transmitter Using Bellows as Sensor

Bellows is an elastic-type pressure sensor used as a local indicator in industry. Transmission of bellows reading to a remote location in control room is very important in pressure measurement and control system in industry. In this paper, the design of a noncontact pressure transducer along with a transmitting unit using bellows as the primary sensing element and a Hall sensor as secondary sensing element has been described. The theoretical equations describing the operation of the proposed transducer and transmitter have been derived. The function of the transducer and transmitter has been experimentally tested and the experimental results are reported in the paper. Both transducer and transmitter characteristics have been found to be linear with good repeatability.

A modified design of a flow transmitter using rotameter as a primary sensor and LVDT as a transducer

Rotameter is one type of the variable area flow meter in which the height of the float is linearly related to the flow rate of liquid. It is generally used for measurement of flow rate of liquid and for display. The Rotameter gives the information about flow rate locally. In this paper an attempt has been made to transmit the information to a remote receiver. Float variation according to flow rate has been converted to an electrical voltage signal, the voltage signal amplified and transmitted to remote indicator. For generation of voltage a non-magnetic straight thin cylindrical rod has been taken whose one end is connected to float of Rotameter and the other end connects with the core of an LVDT. When float varied according to the flow rate of the liquid then core of LVDT also varied and generated voltage. It has been observed that movement of float as well as core and variation of LVDT output voltage has good linearity and repeatability. The necessary theoretical equations, along with the experimental results, are reported and compared in this paper.

Calibration of electrode polarization impedance type flow meter using neural network

In Electrode Polarization Impedance type Flow meter the relationship between the conductivity coefficient and the voltage output of the flow meter is nonlinear. This paper mainly focusses on nonlinear calibration of electrode polarization impedance type flow meter using Artificial Neural Network. The operation and the method of calibration of electrode polarization impedance type flow meter are discussed in detail. The testing results show that the calibration method is efficient.

Design and Development of an Electro-Optic Type-Flow Transmitter Using Mach–Zehnder Interferometer

The rotameter, the widely used flow meter, is generally used as a local indicator. Therefore, for industrial use, some necessary technique is required to transmit float displacement to remote location. Direct transmission of electrical signal through connecting wires is generally prohibited in an inflammable region. In this paper, an electro-optic system is developed using a modified inductive-type rotameter, which produces an electrical signal according to float movement of the rotameter. The electrical signal is then converted into an optical signal using the Mach-Zhender interferometer. Necessary equations along with the developed theory of operation are presented in this paper. An experiment is performed on the proposed transmitter and the experimental and simulation results are reported in this paper. Very good linearity and repeatability with a very small uncertainty in the measurement of the transducer characteristic have been observed. The graphical abstract is shown.