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Crawler for inner tube testing

The crawler is used for semi-automatic mechanized testing of internal and external pipe surfaces in pipelines, depending on material and wall thickness. It ensures safety through early detection of pipeline defects such as defects at welding seams and adjacent heat-affected zones as well as imperfections in the base material (corrosion, erosion, cracks and deposits). Due to its compact method of construction driving through and inspection of pipelines with a maximum of 4 bends is possible. In the straight sections, the maximum range is 70 meters.

The manipulator (crawler) will be inserted into the test object trough existing openings and tightened with 6 axes in the pipe interior via compressed air. Each axis has its own drive, which allows the crawler to move around the pipe in the axial direction.


  1. Available range of diameters: DN80-DN450
  2. for austenitic and ferritic pipe materials
    insertion on valves or fittings can be precisely positioned by means of encoders
  3. can be moved over branches
  4. allows the installation and operation of different tools and test equipment:
    – grinding tools
    – cleaning and vacuuming
    – internal visual inspection/Videoscopy
    – eddy current testing

Characteristics of an eddy current testing system

  1. the sensor socket is designed modular and is easy to install and therefore all-purpose applicable in crawler systems
  2. automatic retracting movements of the (test-) tools at power
  3. ovalities of the tube inside surface may be covered by an automatic tracking system
  4. defects from a depth of 1 mm can be detected regardless of its
  5. very good signal separation of surface effects (noise) and defect signals
  6. test coverage = 100% of the tube inside surface
  7. exact positioning and repeatability by precise encoder