Kitchener, ON

Innovation Polymers was recently tasked with designing a conformable wedge that could be used with a phased-array probe to inspect the intrados of runner blades in Francis hydraulic turbines. These turbines consist of a set of curved blades arranged radially around an axis of rotation. The blades are welded in position at a crown plate on the top and a shroud ring at the bottom. The contact between the blade and the plate is manually blended to form a smooth radius; however, that radius varies along the length of the contact. Inspection of the welds is carried out using phased-array ultrasonic testing.

In order to accommodate the change in radius without having a large collection of curved wedges, Innovation Polymers designed a conformable wedge that allowed inspection of the length of the blade with a single wedge that could also allow for small irregularities in the blending quality.