Crawler dryer scanning system

Horizon Testing Inc. is pleased to offer the ScanTech X1B Spider tank crawler. The Windows computer-controlled ultrasonic inspection crawler system is designed to continuously scan tank wall thicknesses as it moves up and/or around the tank wall.

General Theory

The operation principle of the system is based on the ultrasonic pulse-echo technique for measuring wall thicknesses commonly used in hand held thickness instruments. A transducer converts a pulse of electrical energy into ultrasonic sound vibration. The pulse is a longitudinal wave known as a straight beam that travels perpendicularly through the water to the tube wall. A small part of the energy is transmitted through the tube wall and is reflected off the back wall then back to the transducer.


The X1B Tank Crawler System uses a pulse echo single or dual transducer that transmits sound waves through the tank wall to determine the wall thickness. The transducer measures as it continuously scans and advances up on the tank wall. The thickness is recorded as the tank is scanned and generates a ‘B’ scan graph.

The software allows the technician to continually view the ‘A’ and ‘B’ scans during the acquisition process. A report feature allows the users to create a completely custom report of any length using a drag and drop interface.


  • Fastest method for inspecting remote access areas such as tank walls

  • Lightweight design

  • Moves over small obstacles

  • Continuous scanning of wall thickness

  • Can use single or dual element transducers

  • Reduces costs as no scaffolding is required


The ScanTech Tank crawler is capable of supporting the D2S Dryer Scanning System. The D2S is a Windows computer controlled ultrasonic inspection crawler system that is designed to continuously scan cast iron paper machine dryer rolls for thickness. The system scans and records velocity and time of flight information, assuring proper calibration at any point on the dryer roll. The D2S also provides the flexibility and reporting capabilities of the analyst software. 


  • Automated calibration

  • Fast inspection rate

  • Easily viewable ‘A’ scan display

  • Reliable trending

  • Automated reporting

  • View velocity data

For additional information please contact us.