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A valve assembly, such as a tap for a liquefied gas cylinder, includes an overfill protection device and a liquid level gauge having an electrode assembly comprising a pair of lamellar electrodes mounted closely adjacent a housing member of the overfill protection device and deflectable into close p

A valve assembly, such as a tap for a liquefied gas cylinder, includes an overfill protection device and a liquid level gauge having an electrode assembly comprising a pair of lamellar electrodes mounted closely adjacent a housing member of the overfill protection device and deflectable into close proximity with a float of the overfill protection device for insertion into the gas cylinder. A circuit board is provided, preferably mounted on the electrode assembly, and has an electronic converter circuit for measuring the electrical capacitance between the electrodes and producing in response to the measured capacitance an output signal representative of the liquid level in the container. A display means is mounted on a body of the valve assembly or remote therefrom, to indicate the liquid level in the container in response to the output signal from the electronic converter circuit.

대표청구항 ▼

The invention claimed is: 1. A valve assembly for a fluid container comprising: a valve body having a longitudinal axis and a base end adapted to secure the valve body in an opening of the container; a capacitive liquid level gauge for detecting the liquid level in the container, said level gauge b

The invention claimed is: 1. A valve assembly for a fluid container comprising: a valve body having a longitudinal axis and a base end adapted to secure the valve body in an opening of the container; a capacitive liquid level gauge for detecting the liquid level in the container, said level gauge being secured to said valve body base end and extending downwardly therefrom in the direction of the longitudinal axis, said level gauge comprising two elongate, relatively thin lamellar, conductive electrodes, said electrodes having a length and normally remaining in straight parallel condition spaced apart from one another in the direction of the length thereof; and a circuit board having an electronic converter circuit for measuring the electrical capacitance between the two electrodes and producing in response to said measured capacitance an outlet signal representative of the liquid level in the container; said electronic converter circuit being adapted to modify the power consumed from a power supply in response to the liquid level detected in the fluid container, the modification of the power consumed being in response to a modulation in the electric current consumed by a load means controlled by said electronic converter circuit. 2. The valve assembly of claim 1, in which said electronic converter circuit comprises microprocessor means adapted to calculate the liquid level from the detected capacitance. 3. The valve assembly of claim 1, in which said electronic converter circuit comprises a reference capacitor means for calculating the liquid level from the detected capacitance. 4. The valve assembly of claim 1, in which said electronic converter circuit further comprises a timer means, and the capacitance between the electrodes is detected from the time elapsed for a predetermined number of oscillation cycles of said timer means. 5. The valve assembly of claim 1, wherein each electrode has opposite side surfaces, and the electrodes are arranged in overlying relationship, with one of the side surfaces of one electrode facing a side surface of the other electrode. 6. The valve assembly of claim 1, wherein both of the electrodes are trough-shaped in cross-section; said electrodes being oriented with a concave side thereof facing in the same direction. 7. The valve assembly of claim 1, wherein both of the electrodes are curved in cross-section; said electrodes being oriented with a concave side thereof facing in the same direction. 8. The valve assembly of claim 1, wherein said at least one electrode is trough-shaped in transverse cross-section with a concave side and an oppositely facing convex side. 9. The valve assembly of claim 1, wherein both of said electrodes are comprised of flexible spring band material. 10. The valve assembly of claim 1, wherein both electrodes are generally identical in cross-sectional shape. 11. The valve assembly of claim 1, wherein a first electrode of the two electrodes is secured to said valve body base end and a second electrode of the two electrodes is electrically non-conductively secured at least adjacent a proximal and a distal end thereof to said first electrode, and said valve body base end is electrically conductive. 12. The valve assembly of claim 1, wherein the circuit board is mounted on the level gauge. 13. The valve assembly of claim 1, comprising a single wire connection to said circuit board, the electrical return being through said valve body, said valve body being comprised of electrically conductive material. 14. The valve assembly of claim 1, having a display means mounted on said valve body, said display means receiving said outlet signal and indicating said liquid level in said container responsive to said output signal. 15. The valve assembly of claim 1, wherein the valve body has an electrical outlet and a remote display means is connected to said outlet, said display means receiving said output signal and indicating said liquid level in the container in response to said outlet signal. 16. A capacitive liquid level gauge for sensing the liquid level in a pressurized liquefied gas cylinder; the level gauge comprising: a gauge head; an electrode assembly secured to said gauge head and depending downwardly therefrom, said electrode assembly comprising a pair of elongate, relatively thin, lamellar conductive electrodes, said electrodes each having a length and being formed to normally remain straight spaced apart from one another and parallel to one another in the direction of the length thereof; and a circuit board having an electronic converter circuit for measuring the electrical capacitance between the two electrodes and producing in response to said measured capacitance an outlet signal representative of the liquid level; said electronic converter circuit being adapted to modify the power consumed from a power supply in response to the liquid level detected in a fluid container in which the gauge is placed, the modification of the power consumed being in response to a modulation in the electric current consumed by a load means controlled by said electronic converter circuit. 17. The level gauge of claim 16, in which said electronic converter circuit comprises microprocessor means adapted to calculate the liquid level from the detected capacitance. 18. The level gauge of claim 16, in which said electronic converter circuit comprises a reference capacitor means for calculating the liquid level from the detected capacitance. 19. The level gauge of claim 16, in which said electronic converter circuit further comprises a timer means, and the capacitance between the electrodes is detected from the time elapsed for a predetermined number of oscillation cycles of said timer means. 20. The level gauge of claim 16, wherein each of said electrodes has opposite side surfaces, and the electrodes are arranged in overlying relationship, with one of the side surfaces of one electrode facing a side surface of the other electrode. 21. The level gauge of claim 16, wherein both of the electrodes are trough-shaped in cross-section; said electrodes being oriented with a concave side thereof facing in the same direction. 22. The level gauge of claim 16, wherein both of the electrodes are curved in cross-section; said electrodes being oriented with a concave side thereof facing in the same direction. 23. The level gauge of claim 16, wherein said at least one electrode is trough-shaped in transverse cross-section with a concave side and an oppositely facing convex side. 24. The level gauge of claim 16, wherein both electrodes are comprised of flexible spring band material. 25. The level gauge of claim 16, wherein both electrodes are generally identical in cross-sectional shape. 26. The level gauge of claim 16, wherein said gauge head is electrically non-conductive, a first electrode of said two electrodes being secured to said gauge head end and a second electrode of the two electrodes being electrically non-conductively secured at least adjacent a proximal and a distal end thereof to said first electrode. 27. The level gauge of claim 16, wherein the circuit board is mounted on said electrode assembly. 28. The level gauge of claim 16, comprising a single wire connection to said circuit board, the electrical return being through said gauge head, said gauge head being comprised of electrically conductive material. 29. The level gauge of claim 16, having a display means mounted on said gauge head, said display means receiving said outlet signal and indicating said liquid level in a container in which the gauge is placed in response to said output signal. 30. The level gauge of claim 16, wherein said gauge head has an electrical outlet and a remote display means is connected to said outlet, said display means receiving said output signal and indicating said liquid level in a container in which the gauge is placed in response to said outlet signal. 31. The level gauge of claim 16 wherein the gauge head is a valve body.