Sensing Configuration
Precision measuring instruments provide non-destructive testing for paper web strength and elastic modulus. Use of an air coupled ultrasonic transducer allows for the transmission of high frequency sound through a gas medium rather than a liquid or solid coupler. Contactless configurations maintain the integrity of delicate or coated surfaces by removing the risk of mechanical marking during the inspection phase.
Propagation Efficiency
Energy losses occurring at the boundary between air and solid material require specialized piezoelectric materials or capacitive membranes to maintain signal strength. The air coupled ultrasonic transducer operates at frequencies typically ranging from 50 kHz to several megahertz depending on the grammage and density of the substrate being evaluated. Attenuation must be managed through precise alignment and distance control to ensure the integrity of the data stream.
High performance units employ synthetic matching layers to minimize impedance mismatches that would otherwise degrade the measurement resolution. Effective reception depends on the sensitivity of the receiver to low amplitude signals after they pass through the paper.
Process Integration
Real time monitoring of stiffness and internal bond strength facilitates immediate adjustments to the refining process. Modern air coupled ultrasonic transducer technology provides the data needed to verify grade compliance before the reel reaches the finishing department.
