Resonant acoustic monitoring of damage in plug-screw feeders

Abstract

Plug-screw feeders are critical in many industrial processes for compressing slurry materials via a rotating plug-screw feeder. Over time, increasing plug-screw feeder wear will eventually lead to catastrophic mechanical failure. Early detection of the wear state can prevent unplanned catastrophic failures resulting in operational shut-downs, costly repairs, and most importantly the health and safety of workers. We present a theoretical basis for a noninvasive, in operando acoustic resonant technique to monitor the wear state of plug-screw feeders. The technique is based on tracking the resonant acoustic modes of the plug-screw feeder, which are sensitive to the plug-screw feeder geometry, material, and operating conditions. We implemented a multivariate polynomial model to estimate the plug-screw feeder wear state using multiple acoustic resonances by simulating the acoustic resonant modes for two categories of wear (tip and thread damage) that are common in plug-screw feeders. Fitting multiple resonances to the polynomial model, we demonstrate accurate estimation of the total mass loss, as well as characterization of the type of damage (i.e., tip vs. thread). Current approaches for monitoring plug-screw feeder wear rely on shutting down the operation and visually inspecting the plug-screw feeder. The presented acoustic technique offers a noninvasive, in operando measurement approach that mitigates unplanned catastrophic failures. The acoustic resonance technique presented in the paper has a broad range of industrial applications including the Pharmaceutical, Mining, Integrated Biorefineries (IBR), and Additive Manufacturing industries, to name a few.