Electrostatic devices related to pneumatic conveying of powders. A short literature review

Pneumatic conveying is one of the industrial processes that give the most electrical charge to divided solids. This electrical charge is generally a nuisance that can, for example, influence the flowability, create discharges or even explosions in the ducts. In order to counteract these tribocharging phenomena, which are not well apprehended, several authors designed and implemented different measurement devices for the measurement of powder tribocharging in pneumatic conveying. In this article, we present an overview of four such devices. The first one has been based on a loop operation principle using Teflon particles convoyed with azote. According to the process of powder coating, a second was elaborated. A third was developed to confront several parameters that influence tribocharging in pneumatic conveying. The latest apparatuses presented here have been improved to carry out more reliable tests.