Abstract: A sensing head for sludge detectors for use in effecting accurate sludge level detection in settling tanks, clarifiers, digesters, and the like, wherein the head that serves as the device probe comprises a cylindrical housing centered on its longitudinally extending axis and defining a reentrant indentation at one side of the head which extends toward the head other side beyond the longitudinal axis and defines a pair of opposed upper and lower housing walls and a gap therebetween, with such walls respectively having a light source and a light sensitive device, both separately lens covered and field replacable free of tool use, and in electrically connected relation with the detector cable of, for instance, portable detectors, to which cable the head is separately connected, for make-break light principal operation when the head is submerged in use; the head housing has upper and lower end caps sealingly secured thereto, an elastomeric bumper mounted on the lower end cap to protect the head lower end and side
Abstract: A sensing head for sludge detectors for use in effecting accurate sludge level detection in settling tanks, clarifiers, digesters, and the like, wherein the head that serves as the device probe comprises a cylindrical housing centered in its longitudinally extending axis and defining a reentrant indentation at one side of the head which extends toward the head other side beyond the longitudinal axis and defines a pair of opposed upper and lower housing walls and a gap therebetween, with such walls respectively having a light source and a light sensitive device, both separately lens covered, in electrically connected relation with the detector cable of, for instance, portable detectors, to which cable the head is separately connected, for make-break light principal operation when the head is submerged in use; the head housing has upper and lower end caps sealingly secured thereto, an elastomeric bumper mounted on the lower end cap to protect the head lower end and sides from damage, a lens guard mounted in the