Roller breakage detector for roller hearth kilns

摘要

Light projectors (8) are located outside of a kiln inlet (2) and at positions below the axis of a roller array (5) for generating optical signals in the lengthwise direction. Light receptors (10) are located outside of a kiln outlet (3) and at positions below the axis of the roller array for independently receiving the optical signals from the projectors. When the rollers (5) rotate normally, the light generated from the projectors enter intermediately the receptors. When there is roller breakage, the broken roller falls due to gravity and tilts down. Then, a part of the light generated from the projectors is cut off by the broken roller piece. Hence, no ray reaches the receptor corresponding to the shielded ray. This ensures that roller breakage is detected.