ECVT Permittivity Chart

Non-Invasive. Non-Destructive. 3D Imaging.

Electrical Capacitance Volume Tomography (ECVT) allows us to re-create a digital 3D model of whatever materials happen to be within the sensing region of our sensors without inserting any kind of probes or diverting material flow through any alternative piping systems.

Diverse Material Applications

Traditional capacitance sensing technologies do not work with conductive or polar materials such as water. Our patented 4RD ECVT system works with a wide variety of dielectric materials from air to oil to water and can image materials in any phase – solid, liquid, or gas.

How does this work?

Tech4Imaging’s patented ECVT system uses sensors designed with multiple conductive plates arranged around the surface we want to image. Each of these individual plates can be paired with another plate to create a “plate pair” or a “channel”. Each plate pair consists of one excite plate and one receive plate. The excite plate emits a signal to excite the space between the plates. The space in between changes the signal as it passes through. Exactly how that signal is changed depends on what material or combination of materials is between the plates. The receive plate then reads the new signal that has been modified by traveling through the materials. By analyzing the difference between the original and modified signals, we can determine what is between those two plates. If we combine hundreds of these channels together, we can create an entire 3D image of an object or volume.

Advanced Data Analytics

Although ECVT is traditionally an imaging technology for reconstructing only two materials at a time, we couldn’t stop there! Through rigorous research, development, testing, and design, we have expanded ECVT technology to include many more capabilities.

Multi-Phase Velocity

Dispersed and continuous phase velocity profiles can allow powerful insight into important flow properties.

Volume Fraction

Know how much of each phase is in your process in real time.

Interactive 3D Models

Rotate, cut, slice, zoom, and explore your process like never before.

Expert Customization

To experience the power of this new and wonderful technology, please contact us to tell us about your problem and we will work side by side with you to develop a fully integrated ECVT solution.

ECVT Resources

Electrical Capacitance Volume Tomography: Design and Applications

This article reports recent advances and progress in the field of electrical capacitance volume tomography (ECVT). ECVT, developed from the two-dimensional electrical capacitance tomography (ECT), is a promising non-intrusive imaging technology that can provide real-time three-dimensional images of the sensing domain. Images are reconstructed from capacitance measurements acquired by electrodes placed on the outside boundary of the testing vessel. In this article, a review of progress on capacitance sensor design and applications to multi-phase flows is presented. The sensor shape, electrode configuration, and the number of electrodes that comprise three key elements of three dimensional capacitance sensors are illustrated. The article also highlights applications of ECVT sensors on vessels of various sizes from 1 to 60 inches with complex geometries. Case studies are used to show the capability and validity of ECVT. The studies provide qualitative and quantitative real-time three-dimensional information of the measuring domain under study. Advantages of ECVT render it a favorable tool to be utilized for industrial applications and fundamental multi-phase flow research.

Bubbling fluidized bed characterization using Electrical Capacitance Volume Tomography (ECVT)

Understanding the fundamentals of gas–solid fluidized beds and, in general, multiphase flows has been a significant task since the conception of gas–solid fluidization and fluid particle systems. Various measurement techniques have been applied in an attempt to better understand the fundamentals of the complex gas–solid flow structures that form in fluidized beds. This information may potentially provide a better design, scale-up, and operation of these systems as well as lead to accurate performance predictions of multiphase flow systems. Electrical Capacitance Volume Tomography (ECVT) has now reached a point of development where these multiphase flow structures can be imaged accurately and reliably in three dimensions at good resolutions and sampling rates to provide significant insight into the internal gas–solid flow structures. A 10 cm ECVT sensor was used in order to investigate the bubble behavior of a 10 cm diameter bubbling fluidized bed (BFB) of 185 micron glass beads at various fluidization velocities. Three dimensional images of gas–solid flow structures as well as time average vertical and radial solid fraction profiles are presented in this paper, and average bubble diameter and bubble frequency are discussed and compared to various correlations available in the published literature.

ECVT Imaging of 3-D Flow Structures and Solids concentration distributions in a riser and a bend of a gas-solid circulating fluidized bed

Electrical Capacitance Volume Tomography (ECVT) is a newly developed imaging technique that can quantify 3-D multiphase flows in a complex, geometric flow field. In this study, the 3-D phase distribution images inside a gas-solid circulating fluidized bed (CFB) are obtained using the ECVT. Specifically, measurements are made at a riser section and a 90o bendshape riser exit section of the CFB. Inside the vertical riser, a symmetric core-annulus structure with a low solids holdup in the riser center along with a high solids holdup near the riser wall is observed. The average volume solids holdup and the thickness of the annulus decrease with the superficial gas velocity. A core-annulus flow structure is formed both in the vertical and horizontal parts of the bend. The annulus structure is non-centro-symmetric in the horizontal part of the bend. The solids holdup in the annulus near the top wall area in the bend is higher than that in other locations of the annulus. At a higher superficial gas velocity in the riser, the centrifugal acceleration increases due to high solids velocity in the bend, and more solids are separated to the outside of the bend from the main stream. A “reversed-S” shape solids holdup distribution along the diagonal line is also observed. The solids holdup increases and then decreases from the outer corner to the center of the bend, which indicates that a relatively dilute region is formed near the outer corner of the bend.

Electrical capacitance volume tomography for imaging of pulsating flows in a trickle bed

Experimental results of the air–water pulsating flows in a trickle bed column were obtained using the electrical capacitance volume tomography (ECVT) system. Detailed 3-D pulse structures in both the fully developed and the transient conditions were illustrated. Pulse frequency, pulse traveling velocity, average liquid holdup and liquid holdup inside the gas-rich and liquid-rich regions, respectively, were measured. Based on a simplified model, the linear liquid velocities inside the gas-rich and liquid-rich regions were estimated. The results revealed that the gas flow rate was the most important parameter in controlling the pulsating flow properties. Discussion on the physical nature of the pulsating flow was also given.

Adaptive Electrical Capacitance Volume Tomography

Electrical Capacitance Volume Tomography (ECVT) has shown to be an effective low-cost and high-speed imaging technique suitable for many applications, including 3D reconstruction of multiphase flow systems. In this paper, we introduce the concept of adaptive ECVT based upon the combination of a large number of small individual sensor segments to comprise synthetic capacitance “plates” of different (and possibly noncontiguous) shapes while still satisfying a minimum plate area criterion set by a given SNR. The response from different segments is combined electronically in a reconfigurable fashion. The proposed adaptive concept paves the way for ECVT to be applicable in scenarios requiring higher resolution and dynamic imaging reconstruction.

A Multimodal Tomography System Based on ECT Sensors

A new noninvasive system for multimodal electrical tomography based on electrical capacitance tomography (ECT) sensor hardware is proposed. Quasistatic electromagnetic fields are produced by ECT sensors and used for interrogating the sensing domain. The new system is noninvasive and based on capacitance measurements for permittivity and power balance measurements for conductivity (impedance) imaging. A dual sensitivity map of perturbations in permittivity and conductivity is constructed. The measured data along with the sensitivity matrix are used for the actual image reconstruction. The new multimodal tomography system has the advantage of using already established reconstruction techniques, and the potential for combination with new reconstruction techniques by taking advantage of combined conductivity/permittivity data. Moreover, it does not require direct contact between the sensor and the region of interest. The system performance has been tested on representative data, producing good results.

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