Abstract: A storage installation capable of storing a variety of materials includes a shielded level sensing device disposed entirely externally of the container. The sensing device includes an elongated strip of metal which is associated with shielding circuitry for electrostatic protection of the strip. The sensing metal strip serves as a capacitor component in an oscillator circuit which is arranged so that the electrostatic field emanating from the sensing strip will change oscillator amplitude in proportion to the level to be sensed of material in the container. Detected changes in amplitude of the oscillator circuit produce a DC level proportional to the level of the oscillator amplitude, which in turn may be processed to indicate the level of material within the storage container.

Abstract: A storage installation which is capable of storing a variety of materials, both conductive and non-conductive, includes a level sensing device disposed entirely externally of the container for the material such as to the exterior of the walls thereof. The sensing device includes an elongated strip of metal preferably copper or brass cut to the length of the container when arranged in a vertical direction therefor and applied to the exterior of the container by suitable adhesive material. The sensing element serves as a capacitor component in an oscillator circuit which is arranged whereby the electrostatic field emanating from the sensing strip will change the oscillator amplitude proportional to the level of the material in the container. The detected changes in amplitude in the oscillator circuit will produce a DC level proportional to the level of the oscillator amplitude. The DC level in turn will be processed by a remote indicator circuit to drive a readout meter, bar graph or digital unit.

Abstract: A storage installation which is capable of storing a variety of free-flowing materials, both conductive and non-conductive, includes a level sensing device which may be disposed either exteriorly or interiorly thereof. The device has either one or a plurality of level sensor and sensor circuit pairs which are preferably disposed vertically within a non-electrically conducting tube which may be hermetically sealed from contact with the stored material. The level sensors comprise respective sensing capacitors, each having effectively a single plate construction. Grounded electrical contacts, if relatively adjacent, may comprise the other side of the effective sensing capacitor. Electrostatic force lines flow outward from the sensing capacitor(s), and are differentially interfered with by the presence or absence of materials or objects to be sensed. Such interference affects the dielectric constant of the respective sensing capacitor, which can in turn be detected to drive a level indicator display.

Abstract: A storage installation which is capable of storing a variety of free-flowing materials, both conductive and non-conductive, includes a level sensing device disposed preferably vertically therein. The device has a plurality of level sensor and sensor circuit pairs disposed vertically within a non-electrically conducting tube which is hermetically sealed from contact with the stored material. The level sensors comprise plural sensing capacitors, each having cylindrical upper plates and grounded lower plates. Electrostatic force lines from the sensing capacitors penetrate walls of the sealed tube, and are differentially interfered with by the presence or absence of material to be sensed. Such interference affects the dielectric constant of the respective sensing capacitor, which can in turn be detected by a relatively small corresponding circuit housed directly in the tube. DC signals from the respective circuits are brought out of the tube to drive a level indicator display.

Abstract: A collapsible foldable boat comprises a plurality of waterproof structural plates arranged in spaced relation to each other in the form of a boat hull, and a plurality of waterproof, flexible connecting pieces sealed to the plates and hinging them to each other. The plates are arranged in spaced longitudinal and transverse rows to enable folding both longitudinally and transversely. Interlocking end bulkheads, keelboard, and side rails maintain the boat disassembleably in a rigid, stable, assembled condition.