WIT’s sensors were first developed in 2004 by a team of scientists and engineers from UC Berkeley. Today, our sensors are designed andfabricated by tweaking the original plans to meet the individual needs of our clients. This model allows WIT to produce a customizable yet reliable monitoring system for our clients.
An example of our sensors is the one developed for measuring current in the individual anodes of the pots of an aluminum smelter. There are typically more than twenty anodes per cell (pot) and the distribution of the current among the anodes both affects pot performance and is a diagnostic for performance. Each anode carries ~ 10,000 amps and generates a strong magnetic field proportional to the current. Hence by measuring the fields we are able to determine each anode current; a patented aspect of the measurements is one allowing for the interference caused by magnetic fields produced by currents in other nearby anodes and conductors. Magnetic field measurement is done using Hall effect sensors and multiple sensors are mounted on a “slave” mounted near each rod carrying current to an anode.
The use of multiple sensors allows the interference to be nearly eliminated. Further elimination of interference is achieved using a mathematical model. Slaves are “daisy chained” by a cable running along the pot to a “master” at the end of the pot. The cable serves to both send data and power the slaves. Each pot has two masters receiving data from slaves and relaying it wirelessly to a “manager” computer which stores and processes the data for onward transmission (e.g. by Ethernet) to the customer and/or WIT. Other sensors/systems have been developed by WIT for measuring temperatures, heat fluxes, gas flow rates and bridge position in the aluminum industry. In the copper industry, sensors have been developed for measuring currents, voltages and electrolyte temperatures.
A Unique ApproachWhat makes WIT’s sensors unique in the market?
- Wireless connectivity
In today’s aluminum smelters, safety and practicality dictate the use of wireless over hard-wired systems. WIT meets this need through the use of innovative wireless technology installed in each sensor and receiving device.
- Energy scavenging
The WIT wireless devices have been developed to be “energy scavenging,” that is to operate off adventitious energy, rather than batteries or plug power. Energy scavenging (from waste heat, vibrations etc.) is seen as an important facilitator for application of wireless devices throughout industry and beyond.