Optical tomography imaging in pneumatic conveyor

Abstract

This paper describes the development of a tomographic system by employing optical sensors using low cost approach. The final aim of this project is achieving real-time monitoring of solid particles having low concentration flow when conveyed in vertical pneumatic conveyor. The developed tomography system consists of 32 pairs of Light Emitting Diode (LED) and silicon PIN photodiode. These sensors are used to monitor the emitted radiation for fluctuations caused by particles interfering with the beam when passing through it. A good design of sensor fixture may increase the collimating of light beam from a light source that passes through a flow regime. The obtained information from sensors provided the cross-sectional material distribution in conveyor. By using this information, the relationships between particle distribution and light attenuation effects are investigated by using computer programming to reconstruct the image. The results obtained from this investigation shows that the low cost optical sensors are suitable for monitoring low and medium concentration flowing materials. Optical sensors provide an opportunity to design sensors with a very wide bandwidth, thus enabling the measurement of high speed flowing particles or droplets.