Non-destructive Evaluation of Flexible Sachet Seal Integrity Using a Capacitive Proximity Sensor

Flexible retort pouches or sachets are extensively used to package contents on a large scale in food and beverage fast-moving consumer goods (FMCG) industries. High-speed sealing of such packages causes poor sealing (e.g. air leaks) and/or trapped contents (e.g. powder, liquid, etc.), which affects product containment. Presently, seal integrity testing is performed using offline, slow, expensive and invasive methods (e.g. leak test). Herein, a capacitive proximity sensor is used for sachet seal integrity testing to detect powder trapped in seals based on the differences in the dielectric properties of the seal and the trapped powder in the capacitive field. The sensor showed a fast response (100 ms) and a low detection limit (∼9.09 mg) for detection of powder trapped in seals, which is suitable for high throughput inline seal inspection.