Parallax PVDF Sensors

Application: Integrate Parallax PVDF surface-mount Piezo Thin Film Sensor “Vibra Tap” part number 605-00004 for data acquisition to facilitate optimization of an acoustically-driven cavitation system

The Challenge

Create and maintain inertial cavitation over a wide operating range with an automated acoustic drive system utilizing PVDF sensors and data acquisition.

Key concepts

Utilization of Parallax surface-mount polyvinylidene fluoride (PVDF) sensors, piezoelectric acoustic drivers, characterizing a cavitation system, 3-dimensional sonic landscape, destructive interference, frequency signature.

The Impulse Solution

Though standard, off the shelf piezoelectric drivers perform well in the majority of Impulse’s inertial cavitation applications, system operation under certain extreme conditions was compromised due to destructive interference patterns of the driver resonance with the overall system resonance.

In order to solve this problem, Impulse first needed to characterize the acoustic system across the complete operating regime to determine how and when the destructive interference occurs. Invasive investigation of the sound field was not possible in this particular application, so using an array of Parallax thin film polyvinylidene fluoride (PVDF) surface-mount sensors, computer automated data collection, and innovative graphical visualization, Impulse was able to map the acoustic signature of the system, and create a complete 3-dimensional sonic landscape. As system conditions such as temperature and pressure change, the Parallax PVDF surface-mount sensors track the pattern of destructive resonance interference allowing precise tuning of the system.

Impulse’s solution involved elements of standard piezoelectric drivers combined with custom components. This creative combination generates the required sonic profile needed for the extreme operating condition. By actively monitoring the Parallax PVDF sensors across all operating regimes, modifications to the acoustic drivers result in a specific frequency signature designed to avoid the destructive interference zones and allow cavitation across the complete range of desired system conditions. Impulse routinely utilizes Parallax thin film sensors to characterize cavitation performance and make required system modifications to create the appropriate frequency signature.

Our team of scientists and engineers has extensive experience in the implementation and interpretation of a wide range of acoustic monitoring systems, including the Parallax PVDF thin film sensors. Our expertise includes the design of custom impedance matching circuitry to ensure system functionality across the complete range of required operating conditions and the development of software resonance tracking algorithms to control the drive frequency so systems stay on resonance when conditions such as temperature or static pressure drift.

By successfully managing all the mechanical and electrical challenges, Impulse created a turnkey automated acoustic driver system to achieve extreme cavitation in our spherical resonators. We can use that expertise and knowledge to optimize acoustic performance in a variety of applications.

Look for our next Parallax story - we will be using their powerful and simple-to-use Propeller multi-core microcontroller to control a turn-key cavitation distillery application.