1.FUNCTIONS

Pearson Type HolidayDetector:
The Tinker & Rasor Pearsontype detector was designed to locate discontinuities, flaws or breaks in thecoating of buried pipelines.  This method makes possible the exact locationof coating breaks in buried lines without access to the surface of the coatedpipe.  Locating electrical discontinuities aids in evaluating theapplication of a coating and also these discontinuities can be repaired toeliminate corrosion and to reduce the amount of current required for cathodicprotection.
 

Short Location:
The apparatus isalso effective in locating shorts or undesirable electrical contacts toa buried coated pipe. Such electrical contact should be removed prior toplacing a pipeline under cathodic protection as these contacts would draina large amount of protective potential from the coated pipe. 
 

Pipe Locator:
The apparatus canbe used very effectively as a pipe locator on coated pipelines which areelectrically connected by a screw or welded joints. This application isparticularly effective where it is desired to locate and follow one pipelinealong a right-or-way where there are number of buried lines. 
 
 

2.OPERATING METHOD

Pearson SurveyMethod:
The method usedto locate discontinuities is that of applying audio frequency A.C. energybetween the coated pipe and ground. A traverse along the pipeline is madein with the difference in potential is indicated across approximately twentyto thirty feet of soil above the line. This potential difference is notedin the Receiver. When an area is reached where the difference in potentialis considerably greater than the average potential over the pipe, a discontinuityis assumed to lie under this area. 
 

Method of LocatingShorts:
The method of locatingshorts or contacts on a coated pipe is that of applying a relatively largeamount (five to fifteen watts) of audio frequency A.C. between the pipeand a remote ground connection. A traverse is made along the pipeline witha Receiver equipped with a search coil. A short or contact is observedalong the traverse where the average A.C. signal picked up over the linesuddenly drops to a very low level. This is assumed to be a point directlyabove the contact. 
 

Method of LocatingPipe:
An audio frequencyA.C. signal is placed between the coated pipe and a good ground connection.The Receiver, containing a search coil, is passed over the area where thepipe is assumed to be located. As the Receiver is moved back and forthin a horizontal plane over the pipe, a sharp null will occur in the receivedsignal. The pipe to be located is assumed to be directly under this null.A well coated pipeline can be followed for a very great distance by thismethod when audio power of from five to fifteen watts is applied to thecoated pipe. 
 
 

3.APPARATUS

The complete apparatusfurnished with the Pearson-type detector comprises the following:

• Solid state Oscillator 
• Solid state Receiverwith filter
• Lightweight headphonesw/plug and cushions 
• Shoe cleats 
• Connecting cables 
• Carrying Case

The Oscillatorprovided with the set has been designed to use the latest developmentsin this type of instrumentation. A signal of 750 C.P.S. is generated byusing a power transistor switching circuit. This arrangement eliminatestroublesome vibrators, buzzers or other
moving part elements.The Oscillator converts low voltage (12 volts) D.C. to stable audio frequencyA.C. directly; hence, by a highly efficient method, the input current tothe Oscillator is only 1.7 amperes for a full output of 15 watts, a conversionefficiency of better
than 80%. A maximumof energy can be transferred from the Oscillator to the pipe, the outputof the Oscillator is provided with taps so that voltages of 2.5, 5, 7.5,15, 50 and 100 volts are available to match the load. 

An interrupter isprovided to make the signal more easily recognized. The interrupter isactuated by a switch on the panel of the Oscillator. The Oscillator willproduce 15 watts of 750 cycle signal into a 500 ohm load with the outputselector set at the 100 volt position. 

NOTE: Model PD-C (Rev. B) uses anew crystal that produces an interrupt frequency at a faster rate than previousmodels. Users familiar with this instrument may notice the difference.

The Receiver employsa high gain amplifier and a sharply tuned 750 cycle filter. Modern circuitdesign insures maximum circuit stability even when operated at ambienttemperature extremes. The filter attenuates A.C. power line and other interference,permitting operation in the vicinity of high tension lines. 

A loudspeaker isbuilt into the Receiver, eliminating the need for earphones except in noisyareas. Plugging the earphones into the jack marked PHONES disables theloudspeaker. A search coil is contained within the receiver and is normallyconnected to the Receiver input. 

Plugging the cablefrom the cleat terminal board into the jack marked CLEATS automaticallydisconnects the search coil and connects the cleats to the amplifier. Themeter gives a visual indications of signal intensity and also serves tocheck battery conditions. 

To test the battery,turn the Receiver on and push the button marked BATTERY TEST. Replace batteryif necessary. 

The Shoe Cleats providedwith the detector have been designed for maximum foot comfort and for themost effective ground contact. All necessary connecting cables are furnished.Terminal boards with belt loops are furnished to provide a convenient meansof making the necessary connections between shoe cleats and the Receiver. 
 
 

4.UNPACKING & INSPECTION

Note the placementof the various components as received and repack into the same manner whennot in use. If damage has occurred in shipment, file a claim with the carrierimmediately. If it is necessary to contact your supplier or manufacturerconcerning damaged or missing items, be sure to include all the informationsuch as serial number, purchase order number and invoice number. This willassure you of obtaining proper and expeditious service. 
 
 

5.OPERATING INSTRUCTIONS 

Pearson Survey:(Alsosee condensed Operating Instructions)
The following componentsare required for a Pearson Survey of a buried pipeline

• Oscillator with connectingcables 
• Twelve volt storagebattery (not furnished) 
• Receiver 
• Two sets of shoe cleats
• Cleat connecting cables 
• Terminal Boards 

Connect a 12-volt storagebattery to the battery terminals, observing correct polarity (red is positive or+, black is negative or -).  Set the output voltage switch to 2.5, theinterrupter switch to “OFF”, and the battery switch to “ON”.  TheFine Adjust knob should be advanced all the way to the Right (MAX).  Next,advance the output voltage control until the LED lights on the Oscillator showRed. Then move the Fine Adjust knob to the Left (MIN) until the LED lights showGreen.

NOTE: Model PD-C (Rev. B) uses a new crystal that produces an interrupt frequency at a faster rate than previous models. Users familiar with this instrument may notice the difference.

Ifoverloaded, circuit breaker will trip.  To reactivate, reduce drivingvoltage and reset circuit breaker.

 Turnthe interrupter switch “ON”, if desired, and the Oscillator is ready foruse.

           For the most recent Oscillator, PD-C (Rev. B), the instructions are:

1.Connect 12 volt battery, observing polarity.

2.Connect to pipe and ground. Output Voltage to 2.5, Fine Adjust all the way tothe Right (MAX).

3.Interrupter to OFF. Battery to ON.

4.Advance Output Voltage until Red LEDs light. Move Fine Adjust towards MIN untilGreen LED lights.

5.Interrupter to ON. Instrument is now ready for use.

            NOTE: Model PD-C (Rev. B) uses a new crystal that produces an interrupt frequency at a faster rate than previous models. Users familiar with this instrument may notice the difference.

The terminal boards should be attached to the belts of the operators.(The board with the cord and plug is used by the operator who carries theReceiver). 

Both operators fastencleats on their shoes, then attach cleat cable to each cleat, running thecables inside their pant legs. The key operator connects with wires fromboth of his cleats to the lower terminal on his terminal board. The secondaryoperator connects the wires from both of his cleats to the lower terminalon his terminal board. The secondary operator connects the wires from bothof his cleats and on the end of the long connecting cable to his terminalboard. The other end of the connecting cable goes to the upper terminalof the key man's terminal board. The plug coming from the key man's terminalboard is plugged into the jack marked CLEATS, the Receive is turned "ON",and the apparatus is ready for use. 

The traverse alongthe pipeline is made by walking over the pipe at a slow pace. Beginningadjacent to the Oscillator, set the Receiver volume so that the signalfrom the Oscillator can be heard at a very low level. As progress awayfrom the Oscillator is made, the signal may drop and the level can be raisedagain by increasing the volume. A discontinuity is indicated by an increasein average signal level, followed by a relatively sharp decrease, thenanother increase and then back to normal level as progress is made overthe discontinuity. 

The exact point ofdiscontinuity lies under the point of decreased signal or null.. This,then, is the point halfway between the two operators. If a series of discontinuitiesexist in close proximity to each other, the null effect may not be heard,or very difficult to observe. In this case, one man walks along the lineand the other walks at right angles to the line and a discontinuity isnoted by an increase in signal directly over the fault. 
 

Locating Shortsor Contacts:
The following componentsare required for locating line shorts: 

• Oscillator and 12 voltauto battery 
• Oscillator to pipe cable 
• Remote ground connection 
• Receiver

    Using this null method, it is possible to trace the path of the pipelineas long as there is a 
    relatively large amount of audio current flowing in it. If the coated pipeis in contact with a 
    foreign systems, the audio current will leave the coated pipe at this pointand audio current
    will flow in the foreign system. The same null effect will then be presenton the foreign
    system as on the coated pipe from audio Oscillator to point of contact. 
 

Locating Pipelines:
The apparatus andmethod required for locating welded or screwed pipe is the same as forlocating shorts or contacts. After connecting the Oscillator, hold theReceiver level over the ground and note the intensity of the received signal.As the Receiver is brought near the pipe, the signal will gradually increaseand then will null sharply as the Receiver passes directly over the pipe.It is also possible to determine the depth of a pipe. First mark its exactcenter, using the method described above. 

Once the centeringof the pipe has been accomplished, it is relatively easy to measure thedepth by triangulation. In order to determine the depths of pipes, it isnecessary to position the Receiver in a 45 degree angle to the ground surface.This is accomplished by holding the Receiver so that its longest axis isperpendicular to the path of the pipe and then tilting it back until theair bubble in the depth angle gauge lies between the outer edge of thecenter ring and the black border. 

Starting at the pointdirectly above the pipe center line, and keeping the Receiver as closeto the surface as possible without scratching it on the ground, move slowlyaway from the pipe at a right angle, maintaining the Receiver at 45 degree.When a new null or minimum signal is obtained, the depth of the pipe belowthe surface is the same as the distance between the center line of thepipe and the leading edge of the Receiver.
 
 

6.SHIPPING INSTRUCTIONS 

All instruments being returned for repair should be sent PREPAID to either address below: 

Ship Via Courrier (UPS, FedEx, DHL, etc)

Tinker & Rasor
ATTN: Repairs
791 S. Waterman Ave.
San Bernardino, CA 92408

Ship Via US Postal Mail

Tinker & Rasor
ATTN: Repairs
PO BOX 6890
San Bernardino, CA 92412-6890

Include with shipment information the nature of the problem, purchase order, serial number
and return delivery address, phone and fax numbers. Immediate service is guaranteed!

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