PROCESS AND DEVICE FOR NON-CONTACT DETERMINATION OF THE MASS PER UNIT AREA OF THIN MATERIALS

摘要

PCT No. PCT/DE93/01041 Sec. 371 Date Apr. 26, 1995 Sec. 102(e) Date Apr. 26, 1995 PCT Filed Oct. 28, 1993 PCT Pub. No. WO94/10533 PCT Pub. Date May 11, 1994A method and apparatus for non-contact determination of the weight per unit area and the thickness of thin materials. This involves directing an ultrasonic wave at the material and measuring the proportion of sound energy that passes through the material. The process is distinguished by the fact that the time intervals between the ultrasonic pulses are greater than the propagation time. At the receiver only the signals that exceed a certain amount and are shorter in duration than the propagation time are evaluated.