US3796098A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid level gauge
Assignee: Individual
•
Filing: 1972-04-19
•
Granted: 1974-03-12
•
Expires: 1992-04-19
Abstract
Abstract A combination visual liquid level warning gauge and filler plug for liquid filled tanks such as medium voltage switchgear and distribution equipment, having a cylindrical body of transparent material forming the plug which passes through the wall of the tank. The inner end of the cylinder is bevelled into two internally reflecting facets, which reflect a legend from both sides of a generally planar symbol-bearing area which bisects the angle between the facets within the transparent body. The refractive index of the transparent plug is selected to be close enough to that of the liquid in the tank that contact of the liquid with the facets will eliminate the internal reflection from the facets and render the legend invisible from the outer end of the plug. A socket is provided in the wall of the tank to receive the plug, and an expanded head on the plug seats against a collar on the socket to limit the plug movement into the tank. Mating apertures through the plug and collar permit insertion of a retaining pin, which then may be sealed against tampering by a lead seal.
Inventors
- 👤 F Trayer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:36
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/28; G01F23/284; G01F23/292; G01F23/2921; G01F23/2922; Y; Y10; Y10S; Y10S116/00; Y10S116/05
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
238 words
A liquid-level gauge for tanks and the like, comprising a body of transparent material disposable through a wall of the tank, and a receiving socket for said body, retainingly mountable in a wall of the tank and dimensioned to permit a portion of said body to extend into a region occupied by the liquid contents of the tank when the tank is filled to the desired level, and to permit a portion of said body to be seen from outside the tank, said body having an axis generally corresponding to the normal line of sight from the exterior to the interior of the tank through said socket, a tip portion of said body within the tank having two facets symetrically arranged at an angle of approximately 45* to said axis, an opaque legend bearing area vertically mounted in said tip portion with opposite sides of the legend area each bearing separate and distinct letters or symbols oriented differently thereon, said letters or symbols of a color contrasting that of said legend area, said legend area being visible from the outer end of said body by reflection from said facets to said legend area of light rays passing generally parallel to said axis when said facets are free from contact with liquid within said tank, whereby said legend area will be rendered invisible when said facets are contacted by liquid contents of said tank to impede light reflection therefrom.
Claim 2
Dependent Claim
238 words
A liquid-level gauge for tanks and the like, comprising a body of transparent material disposable through a wall of the tank, and a receiving socket for said body, retainingly mountable in a wall of the tank and dimensioned to permit a portion of said body to extend into a region occupied by the liquid contents of the tank when the tank is filled to the desired level, and to permit a portion of said body to be seen from outside the tank, said body having an axis generally corresponding to the normal line of sight from the exterior to the interior of the tank through said socket, a tip portion of said body within the tank having two facets symetrically arranged at an angle of approximately 45* to said axis, an opaque legend bearing area vertically mounted in said tip portion with opposite sides of the legend area each bearing separate and distinct letters or symbols oriented differently thereon, said letters or symbols of a color contrasting that of said legend area, said legend area being visible from the outer end of said body by reflection from said facets to said legend area of light rays passing generally parallel to said axis when said facets are free from contact with liquid within said tank, whereby said legend area will be rendered invisible when said facets are contacted by liquid contents of said tank to impede light reflection therefrom.
Claim 3
Dependent Claim
20 words
A liquid level gauge as described in claim 1, and wherein said two facets are approximately perpendicular to each other.
Claim 4
Dependent Claim
78 words
A liquid level gauge as described in claim 2, and wherein said legend area is borne on two sides of said opaque body of material located adjacent the inner end of said transparent body and between said two facets, whereby said legend will be readable in normal orientation along said axis after reflection of one side of said opaque body by each of said facets when said facets are free of contact with liquid contents of the tank.
Claim 5
Dependent Claim
48 words
A liquid level gauge as described in claim 1, and wherein said gauge further comprises a retaining pin insertable through mating apertures in said body and said socket to retain said body in said socket without obstructing the view of said legend from the exterior of the tank.
Claim 6
Dependent Claim
154 words
A liquid level gauge as described in claim 1, and wherein said gauge further comprises at least one O-ring seal between said trAnsparent body and said socket, and a retaining pin, said socket being formed as a cylindrical tube passing through the wall of the tank, said transparent body being formed as a cylindrical body fitting within said cylindrical tube and sealed therebetween by said O-ring seal, said transparent body having an enlarged head portion adapted to seat against the outer end of said socket to limit inward motion of said transparent body in said socket, said outer end of said socket having two transverse apertures therethrough along a chord of said cylindrical socket, said transparent body having a chordal aperture therethrough mating with said apertures in said socket, said apertures being dimensioned to permit passage of said retaining pin therethrough without obstructing the view of said legend from the exterior of the tank.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-11 | 1977-09-10 | 1978-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-11 | 1981-09-10 | 1982-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-11 | 1985-09-10 | 1986-03-12 | $7700.00 | Window Closed / Lapsed |