Acoustic Sensor (For closures with no measurable deflection)

Acoustic technology is used to measure pressure or vacuum in containers with metal closures that do not have a measurable lid deflection. The sensor works by applying a “tap” to the top of each container lid using an electromagnetic pulse which excites the closure. The lid vibrates at a natural resonant frequency “tone” based on internal pressure or vacuum. The resultant “tone” signal is sensed by a microphone. The Digital Signal Processor (DSP) produces a real-time signal spectrum and calculates the resultant frequency of the “tone” for that lid. The frequency is then compared to user set limits. Containers with a frequency outside these limits are rejected.