Internal Tube Inspection with the IHR-Rotor

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Inspection of tubes at the manufacturer

Internal tube inspection
Rohmann manufactures special internal rotors that are inserted manually or with a device deep into the tube or the drill hole to check the integrity of tubes and deep drill holes. This procedure is used to inspect heat exchangers or pressure pipes, axial bores on rotor disks and heavy artillery such as gun barrels.

The internal rotors are manufactured as standard IHR rotor in various graduations for diameters greater than 13 mm. The diameters of the contactless rotating probes, the protective caps and the centering devices are selected based on the actual diameter of the tube that is to be inspected. Depending on the voltage that is supplied by the test instrument the rotating speed of the contactless probe ranges from 1,200 to 1,600 rpm. The test speed depends on the rotor speed, the active area of the probe and the speed with which the device is pulled.

Sensors that touch the surface are available for tubes with larger diameters. These are often inspected on mechanical benches and/or with mechanical feed devices that feature computers to record and display the data of the inspection. Sensors that touch the surface are moved at lower speeds to reduce wear and avoid damage that may be caused by excessive friction. The wear protection may be replaced.

Test systems and accessories:

ELOTEST PL500
Designed as 2-channel unit in a 19?/4HU-rack; 375 mm deep
• Test frequency: 10 Hz to 12 MHz
• Front panel featuring 9?-color display 800 x 480 pixel 16 : 9-display for the simultaneous depiction of up to 8 signals with a display rate of 250,000 signal dots/channel

EloLine software:
Standard software to visualize and document test results during the eddy current inspection of long products. Simple circumferential coil systems and complex multi-channel rotor or multiplex applications are supported. Up to 8 test channels are processed and combined into a collective result that may be evaluated in a location-dependent manner.

HR-rotors
Available standard sizes:

IRSA and IRSD sensors:
The standard rotating probes for the IHR-rotors are interchanged based on the diameter of the tube. One sensor is required per tube diameter. The probes work contactless and may additionally be protected against touching the tube. Standard IRSA absolute probes come with a KA-3 probe element whilst the IRSD differential probes come with a KD-7 probe element. The dimensions range from 17.5 mm to 50.0 mm in 0.5 mm-graduations.

RSVF rotating probes:
RSVF-probes are available in various dimensions and regulating ranges starting at a diameter of 60 mm. The epoxy probe carrier may be equipped with various probe types (absolute, differential, multi-differential). An epoxy platelet that 0.3 mm thick is used as wear protection. Depending on the rotor the probe carriers may be equipped with 1, 2 or 3 channels and distance compensation. The spring-loaded holder presses the probes slightly against the inner wall of the tube thus compensating for minor ovalities.