Inspecting flooded pipes in power plants requires skilled, high-precision handling, and robotic vehicles play an important role. In robotics, manipulators enable physical interaction with the robot’s surroundings. The seawater manipulator is capable of manoeuvring underwater in pipes, where it can be used to perform inspections with the help of high-performance cameras.
The German company Ibass develops, manufactures and distributes manipulators for various in-pipe applications; these include inspection, grinding, welding, retrieval and suction. The manipulators consist of a driving unit, work module and camera. They are operated electrically and pneumatically and therefore drag along lines behind them. These small robotic vehicles are used in power plants and refineries, as well as by pipe manufacturers and assembly fitters of pipeline systems. “For example, we make perfectly executed welding seams possible during assembly,” explains Michael Strasser, managing director of Ibass. RE motors by maxon motor are responsible for the dynamic drive of the robots.
The seawater manipulator developed by Ibass can manoeuvre and inspect pipes with inner diameters of 550 to 780 mm. This pipe diameter range accommodates the axial stroke of the pneumatic cylinder and the deflection of the scissor-type mechanism.
The scissor drive works with a total of 12 wheels, two each per scissor side and drive motor. Their variable contact force gives the vehicle a firm hold, even in coated pipes. For the drive a total of six powerful RE motors are used in combination with planetary gearheads – one per wheel pair. The DC motors are characterised by an efficiency of more than 90%, resulting in low energy consumption and a very high torque. These are important prerequisites for this type of application. The motors furthermore are equipped with ironless windings and neodymium magnets, which enable maximum performance packed into a minimum size.
High motor robustness is vital as the manipulator has to withstand the on-site conditions. It can handle a pressure of up to 2 bar, so can dive up to 20 metres deep. It provides a tractive force of about 2,5 kN and the robot can drive a distance of up to 200 metres into the pipe. The manipulators are equipped with lights at the front and back. At the front, there is a high-quality camera with pan-tilt head and a 10x zoom; at the rear a single-head camera is mounted. From grinding and testing to inspection and retrieval, the seawater manipulator can be fitted with all Ibass work modules and can overcome up to five pipe bends with ease.
The robustness and long service life of the maxon motors were decisive criteria when Ibass chose maxon motors. Motors and gearheads by maxon are not only used to drive the seawater manipulator. The Ibass work modules are also equipped with maxon RE motors, for example for rotation and axial adjustment of the dye penetration units. During the dye penetration test, the inner pipe surface is checked for cracks by means of a special technique.
Other applications of the seawater manipulator include visual inspection of power plant coolant pipes that cannot be emptied. They are also used for applying inner coatings to pipelines, as sealed wheel units are absolutely mandatory for this application. These in-pipe manipulators are important tools, and contribute to safety and reliability in installations such as nuclear power plants and offshore wind parks.
For more information contact Hans Burri, DNH Tradeserve, +27 (0)11 468 2722, [email protected], www.dnhtrade.co.za
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