US3726140A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid level indicating means
Assignee: Caterpillar Inc
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Filing: 1971-06-07
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Granted: 1973-04-10
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Expires: 1991-06-07
Abstract
Abstract A closed fuel tank comprises a liquid level indicating means having a transducer cell mounted adjacent the bottom thereof. The cell comprises a bottom wall having a centrally disposed opening formed therein to communicate fuel to an internal, air-filled chamber of the cell. A tube forms an extension of the opening and extends downwardly from the bottom wall to form a ''''bubble trap.'''' A perforated baffle member encapsulates the tube to retard ingress of fuel into the chamber to prevent pressure surges therein. The air pressure level in the cell, proportional to the head of fuel in the tank, is communicated to a calibrated fuel gage mounted externally of the tank.
Inventors
- 👤 G Barbee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:36
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/14
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
107 words
A liquid level indicating means adapted for use with a closed tank comprising a transducer cell having connected top, bottom, and side walls defining an air chamber of predetermined volume therein, means forming an opening through said bottom wall which is spaced a substantial distance from said Side walls and has an area substantially less than the area of said bottom wall, gage means operatively connected to said transducer cell for sensing and indicating variable air pressure levels in said air chamber and baffle means, comprising a perforated cap, attached exteriorly on said bottom wall to completely cover said opening to dampen pressure surges of liquid thereat.
Claim 2
Dependent Claim
107 words
A liquid level indicating means adapted for use with a closed tank comprising a transducer cell having connected top, bottom, and side walls defining an air chamber of predetermined volume therein, means forming an opening through said bottom wall which is spaced a substantial distance from said Side walls and has an area substantially less than the area of said bottom wall, gage means operatively connected to said transducer cell for sensing and indicating variable air pressure levels in said air chamber and baffle means, comprising a perforated cap, attached exteriorly on said bottom wall to completely cover said opening to dampen pressure surges of liquid thereat.
Claim 3
Dependent Claim
69 words
The invention of claim 1 further comprising a tank defining a liquid chamber therein having a volume substantially greater than said air chamber, said transducer cell mounted in said liquid chamber adjacent to a bottom of said tank and said gage means positioned externally of said tank whereby the variable air pressure indicated by said gage means is responsive to the head of liquid contained in said liquid chamber.
Claim 4
Dependent Claim
28 words
The invention of claim 2 further comprising means operatively connected to said gage means for visually indicating when the liquid in said tank falls below a predetermined level.
Claim 5
Dependent Claim
32 words
The invention of claim 3 wherein said means operatively connected to said gage means comprises an electrical circuit having a movable needle of said gage means forming a normally open switch thereof.
Claim 6
Dependent Claim
25 words
The invention of claim 1 further comprising a tube attached to and extending away from said bottom wall to form an extension of said opening.
Claim 7
Dependent Claim
76 words
The invention of claim 5 wherein said tube is cylindrical and is constructed in accordance with the formula amax Arc Tan (L/D) wherein: amax The maximum angle at which said bottom wall of said transducer cell can be tipped relative to a horizontally disposed plane without permitting a liquid in said tank from entering the air chamber of said transducer cell; L The vertical length of said tube; and D The inner diameter of said tube.
Claim 8
Dependent Claim
13 words
The invention of claim 6 wherein amax is no greater than approximately 45*.
Claim 9
Dependent Claim
31 words
The invention of claim 1 further comprising a tube attached to and extending away from said bottom wall to form an extension of said opening, said baffle means encapsulating said tube.
Claim 10
Dependent Claim
20 words
The invention of claim 1 wherein said opening has an area approximating one-tenth of the area of said bottom wall.
Claim 11
Dependent Claim
20 words
The invention of claim 1 wherein said opening is at least approximately located at the center of said bottom wall.
Claim 12
Dependent Claim
127 words
A liquid level indicating means adapted for use with a closed tank comprising a transducer cell having connected top, bottom, and side walls defining an air chamber of predetermined volume therein, means forming an opening through said bottom wall which is spaced a substantial distance from said side walls and has an area substantially less than the area of said bottom wall, gage means operatively connected to said transducer cell for sensing and indicating variable air pressure levels in said air chamber; baffle means attached exteriorly on said bottom wall to completely cover said opening to dampen pressure surges of liquid thereat and a tube attached to and extending away from said bottom wall to form an extension of said opening, said baffle means encapsulating said tube.
Claim 13
Dependent Claim
127 words
A liquid level indicating means adapted for use with a closed tank comprising a transducer cell having connected top, bottom, and side walls defining an air chamber of predetermined volume therein, means forming an opening through said bottom wall which is spaced a substantial distance from said side walls and has an area substantially less than the area of said bottom wall, gage means operatively connected to said transducer cell for sensing and indicating variable air pressure levels in said air chamber; baffle means attached exteriorly on said bottom wall to completely cover said opening to dampen pressure surges of liquid thereat and a tube attached to and extending away from said bottom wall to form an extension of said opening, said baffle means encapsulating said tube.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |