Michael Kon Yew Hughes

High efficiency coupling devices for guided wave radar-based level sensors

In this work we present novel coupling devices, in terms of feed-throughs and launchers, which are able to increase the efficiency of the electromagnetic power transmission along the propagation chain of guided wave radar (GWR) transmitters for level and interface measurement. The novel concepts are validated by 2D 1COMSOL® axisymmetric simulations which prove that the innovative design improvements are able to increase the electromagnetic efficiency by at least 6 dB. Such novel GWR level transmitters can improve the accuracy and the measurement range of the next generation of GWR level transmitters.

Two-sided laser device for online paper caliper measurement and control

Strong demand exists for a non-contacting paper caliper measurement which can be used as an input to a paper thickness control system. Caliper sensors requiring sheet contact suffer from errors related to dirt or coating build up and from high maintenance costs related to wear. These sensors can also damage the product by picking holes and marking sheets. Details of an on-line measurement device which employs two opposed laser displacement sensors and an inductive displacement sensor are presented. The sheet is held perpendicularly to the sensors with a Coanda air clamp. Dust and temperature control features which enable the sensor to operate reliably in an industrial environment are discussed. Results of production trials of this sensor are presented. Sub-micron profile agreement to lab and contacting caliper measurements has been demonstrated on light sheets. Results are presented of measurements on a wide range of paper grades from coated and uncoated light sheets to coated board.