Discriminating acoustic emission system

Also, the system offers either a display module which provides an accumulation of counts (as in Fig. 7), permitting the selection of any one of three types of counts (event, oscillation or amplitude) or a Lin-rate module which automatically plots the time-rate function of any one of the three types of counts available in this system. Trodyne Corpora-

tion, 39 Industrial Avenue, Teterboro, N.J. 07608, USA.

I m p r o v i n g the o p e r a t i o n

Fig. 6

Ultrasonic location of flaws is simplified with the use of this plotting scale

range and stand off distance reading used during ultrasonic testing to be transposed onto a beam plotting card which allows the size and location of any defect to be readily ascertained within the material cross section. Two sizes are available, 305 mm for weldments up to 127 mm thick and a 153 mm for weldments up to 75 mm thick. Complete operating instructions together with two spare beam plotting cards are supplied with each scale.

Midland Sonic Services, 1 Chapel Street, Spondon, Derby, England. D i s c r i m i n a t i n g acoustic emission system To meet the growing needs for an uncomplicated and compact acoustic emission system at a reasonable cost, Trodyne Corporation has developed a two-channel system that can be used in a wide range of ndt applications (see Fig. 7). Designated the RS System (Region-Selector), it features discrimination techniques used for establishing a basis for accepting or rejecting particular data. These techniques are extremely useful in, for example, reducing the effects of extraneous noise produced from holding fixtures, hydraulicactuated machines, environment and signals originating from irrelevant

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regions. Thus, the RS System provides the user with practical techniques which proh ibit the acceptance of signals from non-critical regions and eliminates confusing effects in important measurements In addition, data evaluation time in the determination of the integrity of a structure is reduced. The system includes a power-audio module which contains a highly regulated power supply and an audio monitor; the processor module which houses the individual or combined selections of discrimination techniques; and a dual AE amplifier module which has two independent amplifier channels, each having a selectable gain and plug-in filters."

Push button controls with associated memory stores provide automatic processing without operator adjustment n on the Betascope NC100 used for measuring coating thickness. The instrument (Fig. 8) is a development of Fischer Instrumentation (GB) Ltd's range of Betascopes and represents a conscious effort to make their use and presentation of results very much easier, Computer derived calibration

Fig. 8 Simplicity of design reflects the simplicity of use of this Betascopefor coating thickness measurement

curves or printed charts are provided with each instrument which remain valid for long periods of time. Thus the purchase of a desk-top computer is not immediately necessary, although provision is made for such a connection; this upgrades the instrument to a fully direCt-reading type with print-out for measurements. Reject and acceptance quality levels for quality control can also be accommodated. Fischer Fig. 7 Thisacoustic emissionsystem is able to reduce the effect of extraneous noise during ae testing

Instrumentation (GB) Ltd, Arnhem Road Industrial Estate, Newbury, Berks, RG 14 5RU, England.

NDT I N T E R N A T I O N A L . DECEMBER 1976