Tinker & Rasor's Model PD and the Null Method have been recognized as being the fastest method to accurately locate points of electrical contact and insulating joints on coated underground piping systems. The Tinker & Rasor Model PD is unaffected by parallel lines, depths, 60 Hz or ground cover, the survey can often be, in part, conducted from a moving vehicle over the pipe. In brief, the Null Method follows the flow of impressed audio frequency current in a coated pipe; determines where it leaves. This method is quite practical, particularly as competent field personnel can interpret findings quickly and accurately. The Model PD is also an excellent device for pinpointing defects in coatings on buried pipelines. This unit is also highly accurate in locating breaks in cables such as anode leads on impressed current, cathodic protection systems.

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Recent Changes to the PD

 

You should be aware that we have made a few changes to the Model PD recently (08/30/04).

•    The Oscillator (PD-C) has been updated to include LED lights instead of the meter, and the Output Indicator light has been replaced with a Fine Adjust knob. (See Model PD Product Instructions for more)

•    The crystal in the Oscillator (PD-C) has been changed. There is a noticeable difference in the interrupt cycle rate from previous versions. The cycle is much faster now. This is an engineering change and not a problem with the instrument.

•    The Model PD Complete Holiday Detector kit comes with connector cables to use between operators when conducting a Pearson Method Holiday Detector survey. The length of cable between operators has been shortened from 30' to 20'.