C4.2 - Electrical Capacitance Tomography for Level Measurements of Separated Liquid Stacks
- Event
- SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
Nürnberg - Band
- Proceedings SENSOR 2011
- Chapter
- C4 - Sensor Electronic I
- Author(s)
- M. Neumayer, H. Zangl - Graz University of Technology (Austria)
- Pages
- 433 - 438
- DOI
- 10.5162/sensor11/c4.2
- ISBN
- 978-3-9810993-9-3
- Price
- free
Abstract
The determination of liquid levels in industrial vessels of process plants or tanks in automotive applications is an important measurement task in a number of today’s applications. Traditional level sensors are mechanical devices like floaters, hydrostatic pressure sensors, capacitive tubular sensors or ultrasound/radar based time of flight sensors. In a number of industrial processes the used fluids are mixtures or emulsions of different media. In tanks this emulsions separate due to the different densities of the components. In this case traditional sensors fail. Typically, noninvasive capacitive level sensors which utilize single receiver electrode and several transmitter electrodes take use of the almost linear signal trend obtained by the different sensor segments when the liquid level is
crossing the specific segment. Hence, the methods are not applicable for stacked liquid layers. In fact, the signal trends exhibit strong nonlinear coupling effects with increasing distance to the specific segment. Due to the complex signal trends, the application of more powerful model based algorithms to obtain phase boundaries between different immiscible fluids seems suitable. In this paper we investigate the potential use of methods based on electrical capacitance tomography for noninvasive capacitive level sensors. The properties of different electrode layouts are investigated with respect to different tanks and different fluids, i.e. water and oil. The benefits of the use of several receiver electrodes to provide measurements from different coupling capacitances is demonstrated.