b'MICROWAVE TECHNOLOGY APPLICATIONSReduce costs and process variation with microwave instrumentationBy Frank Cunnane, Product Specialist, Cristini NAINTRODUCTIONSince the introduction of planar!e r +e rmicrowave technology, new!Massapplications continue to be found for this investigative tool. Starting first in!Othersthe forming section, it replaced older gamma gauge tools which require federal licensing, extensive record keeping, and the need for a RadiationPaperstockOfficer on site. This technology wentMW-IN MW-OUT Formingfabricforward into the press section, initially to measure felt moisture, then laterFoilto measure felt and sheet moisture,!Resonance(F ris )and now to measurement of the Foil!Reec:ons/Lossessheet consistency itself in open draw configurations.!OthersFigure 1. New planar sensor operates without a resonance chamber.In the past year these tools have been expanded to help control sheet properties as well as a new applicationA new generation of instruments hasanywhere that the roughly 10 x 12 cm for the TAD segment of the tissuebeen developed using microwavehead can fit.Since the instrument industry, the fastest growing segment intechnology. These units generate lessdoes not see the machine framing in the paper industry.Data is shown thatradiation than a cell phone and are safeits measurements, tight fitting spaces allows predictable sheet consistencyto the touch. can be accommodated between table in the heart of the process. Work iselements.ongoing to predict sheet consistency inFigure 1 demonstrates that a fabric or Unorun sections.The results from thata fabric/sheet passing over the headFORMING SECTION MICROWAVE MOISTURE-application will be published soon. will cause a change in theflux of theA newMEASURING microwave field set up between thegeneration ofIn tissue manufacturing, most forming THE INSTRUMENTS incoming source (antenna) and theinstrumentssections allow little or no access for A. Principles of Operation receiver.The fact that microwaveshas beenmeasurement of water content, so we Older technology relied upon nuclearcause resonance in water moleculesdevelopedwill focus on applications in the press radiation from so-called back-scatterabove the sensor, means that all theusingsection and in TAD manufacturing.gauges.There were numerous issuessensor perceives is the water itself, notmicrowave with nuclear technology, not the leastthe fiber, the fabric, or the surroundingtechnology.PRESS SECTION MOISTURE MEASUREMENT of which were inherent radiation risk,machinery. These units In the press section, there are two governmental regulation, having agenerateinstruments that can be used. The separate radiation officer, and disposalB. The Instruments Themselves less radiationfirst, the PresScan (Figure 2), is used of the radioactive source material afterIn the forming section thethan a cellto measure felt moisture, and felt/its useful life. FiberScanOnLine can be mountedphone! sheet moisture combined. Standard 68 WORLD PULP&PAPER'