MARK IV-B Magnetic Crawler Inspection System
and the MARK I Lightweight Vehicle

Send inquiries to: info@ndtint.com

NDT International, Inc. developed the MARK IV-B magnetic wheeled crawler inspection system as a portable, AC or DC powered, inspection vehicle usable for ultrasonic thickness measurement of steel storage tanks, piping and other steel structures.  It has been adapted for other similar applications where inspection is not easily accessible by normal methods.  The steerable crawler vehicle is powered by two 12 VDC high torque gear motors and carries a center mounted spring-loaded ultrasonic transducer and water line.

The operator can make a nearly continuous scan from top to bottom of a tank from the ground.  Information gathered in this manner can be used to determine the probability of corrosion and pitting in an entire vessel.  Our system is comprised of the MARK IV-B crawler vehicle, the spring-loaded dual element crawler transducer with integral water line, 100 ft. long cable assembly and our Crawler Control Module that accepts both AC and DC input power..

• System Includes:
  MARK IV-B Crawler Vehicle with two 12 VDC high torque gearmotors, high strength magnetic wheels and connector panel for transducer lines, power line and water line.  Overall physical dimensions of the vehicle are 12" L x 6" W x 6" H.; Vehicle Weight is 8 lbs.
  
  Vehicle speed range is from 1 to 30 feet per minute when on AC power.  Speed will vary when using an external DC power source.  Scanning results are best when the vehicle moves at slower speed.  Vehicle holding force is up to 50 lbs. per wheel depending on surface conditions and paint coating thickness that will greatly impact the holding force of the vehicle.
  
  Crawler Transducer is a 1/2" diameter x 5 MHz high Gain spring-loaded dual transducer with an integral water tube for couplant application.  It is compatible with nearly any ultrasonic flaw detector and many high-end thickness gauges.
  
  Cable Assembly standard length is 100 feet and includes Power line, Dual Transducer line and a 1/8" ID PVC Couplant/Water line in a braided plastic sheath to prevent tangles.
  
  Power/Control Unit 110 VAC or 12 VDC Power Input. Has Left/Right, Forward/Reverse and Power Level Motor Controls.
  
  Spare Parts Kit (for minimum of two year operation): Includes (2) gear motors, (1) transducer, (1) complete wheel assembly with axles & gears, (2) stainless steel drive chains, all misc. tubing fittings and electrical connectors
  
  The system does not include an ultrasonic testing instrument.  This would be quoted as a separate, optional item.
  
  It has no location encoding capability.
  
  OPTIONAL Single large Fiberglass Transport Case or pair of smaller cases - black composite ABS, hinged cover, four handles, two latches, with foam lined compartments.
  
  Warranty:  One year from date of shipment parts & labor on primary components
  Thirty days on motors, transducers, cables and batteries
  
  Lead Time:  Currently 8 to 12 weeks, F.O.B. West Chester, PA - All shipping charges are extra.
  
  Terms of Payment: 50% within 10 days of order. Work will not commence until prepayment is received.  Net Balance due prior to shipment.
  
  Frequently Asked Questions:

• Minimum and Maximum Range of Measurement?
  Absolute minimum range using the 5.0 MHz transducer is about 0.060" (1.5mm) to maximum of 6.000" (150.0mm).

• Prerequisites required for the thickness measurement?
  Operator should be well trained in ultrasonic theory and applications.
  Vessel being inspected should be clean with no flaking paint or rust.

• Accuracy of the results?
  Typical accuracy depends upon thickness.
  Under 1.00" Thick +/- 0.003" Over 1.00" Thick +/- 1% of wall.

• Spares availability?
  Kit price includes spares for 2 years operation.

• Life of the magnetic wheels?
  Typical life of steel/neodymium/steel "sandwich" wheels is a minimum of 5 years.

• Crawler vehicle weight is approx. 8 lbs.
  Approximate shipping weight for the complete system with transit case is 200 lbs

• Equipment guarantee?
  One year warranty on instrumentation parts & labor.
  Thirty days on motors, transducer, cables & batteries.

• If a system is ordered, how will you deliver it to our location?
  Foreign shipment via TNT Global Express (Air) or your specified carrier.
  Domestic shipment by UPS Ground Service.
  
  MARK I Lightweight Crawler Vehicle
  
  If you need something easy to use and inexpensive consider our MARK I Crawler vehicle.  This is a 3-wheeled vehicle that has been designed to be manipulated (raised and lowered) by hand using an extension pole with pulley system (not supplied by NDT) or just a rope with a top-side assistant.  The same High Gain 1/2" diameter, 5 MHz spring-loaded dual transducer as the motor driven MARK IV-B is included.  It can be attached to many different ultrasonic testing instrument as long as they can drive a signal through the 50 foot long cable.
  
                                           

The Mark I Crawler Vehicle measures only 8 1/2" L x 6" W x 4 1/2" H.  It includes a plastic Shim Set for adjusting the clearance of the magnets attached to the underside of the nylon chassis.  These magnets provide a holding force of 8 lbs. @ 1/8" clearance from the steel surface.  Also included is a 50 foot long Transducer and Couplant Line Cable Assembly and a hand pumped, 2 gallon capacity Couplant Supply Tank.  Weight of the Crawler is 2 1/2 lbs. with transducer.

Updated September 12, 2011