Abstract: Apparatus for indicating level of material comprises a cable vertically suspended so as to contact and be surrounded by the material. The cable is suspended from a cam follower mechanism that engages a cam coupled to a motor for selectively introducing slack in the cable, such that the upper portion of the cable unsupported by the material engages and is suspended from a load cell. Circuitry is responsive to cable weight measured by the load cell for indicating level of the material. The motor comprises a rotary electric motor having a horizontal axis of rotation perpendicular to the vertical cable. The cam comprises a cam plate coupled to the motor to rotate about the motor axis and having an asymmetric periphery surrounding the axis of rotation. The cam follower mechanism comprises an arm pivotally mounted in fixed position adjacent to the cam plate and supporting a roller that engages the cam plate periphery.

Abstract: A drop-weight material level indicator in which a spool is mounted above material whose level is to be sensed and is coupled to a motor for selectively unwinding and winding a drop line wound on the spool. The drop line is trained over an idler pulley carried at the end of a pivot arm, and over a second idler pulley to a drop weight. Level sensing electronics are coupled to the second idler pulley for measuring the amount of cable unwound as the drop weight descends toward the upper surface of the material. A magnet is carried on the pivot arm, and a reed switch is positioned adjacent thereto for sensing removal of tension from the drop line and consequent pivotal motion of the arm, and thereby indicating rupture of the drop line to an operator.

Abstract: A capacitance probe and method of probe manufacture for material level sensing systems and like applications. The probe includes a probe rod, a tubular guard coaxially surrounding the rod intermediate the rod ends, and insulation material formed as an integral piece in an injection molding operation surrounding the rod between the rod and guard and also surrounding and radially overlapping axially spaced ends of the tubular guard. One end of the rod and a portion of the guard intermediate its ends are exposed through the insulation material. The molded assembly is captured within a nipple or the like for mounting to a material vessel such that the exposed surfaces of the rod and guard are disposed internally of the vessel for capacitance coupling to material therewithin.

Abstract: Apparatus for indicating the level of flowable material in a storage bin comprising a motor mounted within a protective enclosure and coupled by a shaft to a paddle disposed within the bin to engage material contained therein. When the material reaches the level of the paddle, drag on the paddle causes the motor to rotate within the enclosure and thereby to activate switches disposed within the enclosure for indicating material level. A spring is mounted between the enclosure and the motor such that the spring urges the motor to both the switch-activating and the switch-deactivating positions in turn, and must be urged over center to permit motion of the motor in either direction between such positions.

Abstract: A capacitance probe and method of probe manufacture for material level sensing systems and like applications. The probe includes a probe rod, a tubular guard coaxially surrounding the rod intermediate the rod ends, and insulation material formed as an integral piece in an injection molding operation surrounding the rod between the rod and guard and also surrounding and radially overlapping axially spaced ends of the tubular guard. One end of the rod and a portion of the guard intermediate its ends are exposed through the insulation material. The molded assembly is captured within a nipple or the like for mounting to a material vessel such that the exposed surfaces of the rod and guard are disposed internally of the vessel for capacitance coupling to material therewithin.

Abstract: A capacitance probe and method of probe manufacture for material level sensing systems and like applications. The probe includes a probe rod, a tubular guard coaxially surrounding the rod intermediate the rod ends, and insulation material formed as an integral piece in an injection molding operation surrounding the rod between the rod and guard and also surrounding and radially overlapping axially spaced ends of the tubular guard. One end of the rod and a portion of the guard intermediate its ends are exposed through the insulation material. The molded assembly is captured within a nipple or the like for mounting to a material vessel such that the exposed surfaces of the rod and guard are disposed internally of the vessel for capacitance coupling to material therewithin.