Granite Roll Radar Sample Images

 

A granite roll is measured at forty to fifty stations depending on the size of the roll. The following are some examples of typical images:

 

Cracks: An internal crack generates a parabolic reflection on the radar profile. The suspected roll area is scanned at every two inches (50 mm) to measure the length and direction of the crack.
Structures: Granite is not homogeneous. The radar measurements are used to lay out the structural direction of the granite which possibly indicates the weakest direction.

 

Mineral Enclaves: The radar measurement detects large deviating targets in the shell, such as quartz, feldspar, and biotite enclaves (agglomerations). These reflections are different from those formed by cracks. The enclaves do not compromise safety, however, they may cause the roll surface to crumble locally affecting paper quality and roll life.

 

Rust: Strong radar reflections caused by rust penetrations are often found between the end flange and the granite body. They are wide near the surface and weaken toward the roll center, contrary to the reflections by cracks.

 

Filling: Variations in urethane or concrete filling in the center hole are detected by the radar. Dampers, centering supports, filler pipes may also be located.