BigPatents India

A device (24) for determining the conditions in a furnace is disclosed. The device comprises a gamma ray detector (28) within a shield (26) which blocks stray gamma rays. A tube (32) and a series of plates (34) form a path along which gamma rays emanating from a zone of the furnace at which the tube is pointed can pass to reach the detector (28). The output signal of the detector (28) is computer analysed to detect significant changes in the characteristics of the gamma rays reaching the detector (28). The device can be on mounting means permitting both horizontal and vertical motion thereby to permit interfaces between materials and also "banks" to be detected.