Beta gauge

The concentrations monitored by these instruments range from a few milligrams to 4000 mg/m A flow diagram of a beta gauge particulate monitor is shown in Fig. 13.41. 

FIGURE 13.41 Flow diagram of beta gauge particulate monitor. ... 

IB.Vcrewa F-904-K. Extractive Beta Gauge Particulate Monitor. Principle of Operation, Ham burg Umwelt-iind ProzeBmeBtechnile GmbH (1998). 

If machine direction thickness uniformity is a problem, it can best be remedied with the use of a gauge detector (beta gauge) that is part of a control system adjusting the speed of the take-up device, to correct for thickness nonuniformities. Small period variations are very difficult to remedy in this fashion. 

The requirement for continuous production at speed implies that there must be convenient equipment for assessing weight and so ensuring uniformity. Almost always the instrument used for this work is the beta gauge, which records the attenuation of a beam of electrons from a weak radio-active source as it is passed through the coated web. The gauge can be calibrated with samples of known composition and weight, and the results are expressed in terms of mass per unit area . 

Composition of bulk particulate matter Beta gauge Filtration followed hy attenuation of heta rays +... 

Fibers and base resins are supplied against certificates of conformance and often property test certificates. On-line control during the manufacture of prepreg revolves around the correct ratio of fiber to resin. This is done by a traversing Beta-gauge, which scans the dry fiber (either unidirectional of fabric) and then the impregnated fiber and provides a continuous real-time plot of the ratio across the width of the material. This can be linked back to the resin system application point for continuous adjustment. 

The amount of compound deposited onto a fabric or steel cord is determined by the distance between rollers and is monitored by Beta Gauges. Each cord is insulated on all sides with rubber. The finished treatment or calendared steel cord sheet is cut to length and angle for tire building. Key compound requirements in calendaring operations are minimum shrinkage, optimum tack... 

Film thickness is usually monitored during the process. A beta gauge detects the passage of beta rays through the film bubble, while capacitance gauges measure the increase in thickness as increased capacitance. Blown film lines may also include corona or flame treatment to improve adhesion, sealing operations for bags, and slitters. 

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