US3729997A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid level sensor
Assignee: Individual
•
Filing: 1971-12-27
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Granted: 1973-05-01
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Expires: 1991-12-27
Abstract
Abstract A device of the gas-bubbling type for determining the level of a body of liuqid comprises a dual-diaphragm, multiplying lever arrangement whereby the pressure necessary to effect bubbling is multiplied or amplified to a higher pressure which can be read directly as hydrostatic head and/or used to operate a control switch. The sensor comprises two chambers, one at a low and the other at a high pressure. Each chamber has like diaphragms exposed to ambient pressure and connected by a lever mechanism whereby the movement of the low pressure diaphragm causes an opposite and greater movement of the high pressure diaphragm. The low pressure chamber receives the pressure necessary to effect bubbling through a conduit placed in the body of the liquid, the level of which is to be measured. The high pressure chamber receives instrument air (or other control gas) through a regulating valve operated by the high pressure diaphragm, and a small amount of air is continuously passed from the high pressure chamber through a throttling or needle valve into the low pressure chamber, and thence to the bubbler conduit in the liquid. Because the control pressure is taken from the high pressure side of the sensor, a regular commercially available pressureoperated switch can be used with good results. Springs are not required to load the diaphgram. Instead, the sensor operates by mechanically balancing two pressures without the aid of springs, making it very sensitive and accurate, and the diaphragms can withstand over pressures without rupturing.
Inventors
- 👤 O Luke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:18
CPC Classifications
G; G01; G01L; G01L5/00; G01L5/18; G01F; G01F23/00; G01F23/14; G01F23/16; G01F23/165; G01F23/167; G01L13/00; G01L13/02; G01L13/025; G01L15/00; Y; Y10; Y10T; Y10T137/00; Y10T137/2278; Y10T137/2409; Y10T137/7287
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
231 words
A liquid level sensing device comprising, in combination: a. an inlet chamber adapted to contain a gas having a pressure P1 therein, one wall of which has an inlet diaphragm exposed to a pressure PA, b. an outlet chamber adapted to contain a gas having a pressure P2 therein, one wall of which has an outlet diaphragm exposed to said pressure PA, c. a conduit connecting said inlet and outlet chambers and having gas flow throttling means therein, d. outlet conduit means adapted to connect said outlet chamber with the body of a reservoir of liquid, the level of which is to be sensed, e. inlet conduit means adapted to admit a gas at an inlet pressure of PI greater than said pressure P1 to said inlet chamber and including therein a control valve operatively connected to said inlet diaphragm and adapted to tend to open with a decrease in said pressure P1 and to tend to close with an increase in said pressure P1, f. an inlet pivot point operating connected to said said inlet diaphragm on the PA pressure side thereof, and an outlet pivot point operatively connected to said outlet diaphragm on the PA pressure side thereof, and g. a lever mechanism operating on said inlet and outlet pivot points and adapted to amplify and transmit the force of one proportionally into a reverse force on the other.
Claim 2
Dependent Claim
231 words
A liquid level sensing device comprising, in combination: a. an inlet chamber adapted to contain a gas having a pressure P1 therein, one wall of which has an inlet diaphragm exposed to a pressure PA, b. an outlet chamber adapted to contain a gas having a pressure P2 therein, one wall of which has an outlet diaphragm exposed to said pressure PA, c. a conduit connecting said inlet and outlet chambers and having gas flow throttling means therein, d. outlet conduit means adapted to connect said outlet chamber with the body of a reservoir of liquid, the level of which is to be sensed, e. inlet conduit means adapted to admit a gas at an inlet pressure of PI greater than said pressure P1 to said inlet chamber and including therein a control valve operatively connected to said inlet diaphragm and adapted to tend to open with a decrease in said pressure P1 and to tend to close with an increase in said pressure P1, f. an inlet pivot point operating connected to said said inlet diaphragm on the PA pressure side thereof, and an outlet pivot point operatively connected to said outlet diaphragm on the PA pressure side thereof, and g. a lever mechanism operating on said inlet and outlet pivot points and adapted to amplify and transmit the force of one proportionally into a reverse force on the other.
Claim 3
Dependent Claim
54 words
The device of claim 1 wherein said gas flow throttling means and the proportioning given by said lever mechanism are adjustable and adapted to permit the ratio of P1/P2 to be set at a predetermined value, and to limit the amount of gas flowing through said outlet conduit means to a predetermined low level.
Claim 4
Dependent Claim
24 words
The device of claim 2 wherein said inlet and outlet diaphragms and pivot points face one another and said lever mechanism is mounted therebetween.
Claim 5
Dependent Claim
127 words
The device of claim 3 wherein said lever mechanism comprises: h. an inlet lever arm one end of which is mounted for rotation and the mid-section of which rests on said inlet pivot point, i. an outlet lever arm the end of which opposite the end of said inlet lever arm so mounted is mounted for rotation, and the mid-section of which rests on said outlet pivot point, j. a pivot block intermediate and operatively connecting said inlet and outlet lever arms, one end of which is adapted to serve as an intermediate pivot point, said intermediate pivot point being spaced from the line of said inlet and outlet pivot points in the plane given by the three pivot points along the line of said lever arms.
Claim 6
Dependent Claim
45 words
The device of claim 4 wherein the spacing of said intermediate pivot point from the line of said inlet and outlet points is adjustable by moving said pivot block along said lever arms whereby said ratio of P1/P2 can be set at said predetermined value.
Claim 7
Dependent Claim
32 words
The device of claim 1 including means connecting to said inlet chamber for observing said pressure P1 and for translating the same into the level of said liquid above a datum level.
Claim 8
Dependent Claim
20 words
The device of claim 1 including control means connected to said inlet chamber and operated by the pressure P1 thereon.
Claim 9
Dependent Claim
149 words
In the determination of the level of a body of a liquid wherein a small amount of a gas is bubbled into said body, and the pressure P0 of said gas necessary to effect such bubbling is observed, the improvement comprising: a. passing said gas at an initial inlet pressure PI through a regulating valve into an inlet chamber maintained at a pressure P1, then through a throttling valve set to give a predetermined pressure drop into an outlet chamber maintained at a pressure P2, which is substantially the same as said pressure P0, and thence into said body, while maintaining the ratio of P1/P2 at a predetermined value by increasing the flow of said gas into said inlet chamber by operation of said regulating valve if said ratio should tend to decrease, and vice-versa, and b. observing said pressure P1 as a predetermined multiple of said pressure P0.
Claim 10
Dependent Claim
149 words
In the determination of the level of a body of a liquid wherein a small amount of a gas is bubbled into said body, and the pressure P0 of said gas necessary to effect such bubbling is observed, the improvement comprising: a. passing said gas at an initial inlet pressure PI through a regulating valve into an inlet chamber maintained at a pressure P1, then through a throttling valve set to give a predetermined pressure drop into an outlet chamber maintained at a pressure P2, which is substantially the same as said pressure P0, and thence into said body, while maintaining the ratio of P1/P2 at a predetermined value by increasing the flow of said gas into said inlet chamber by operation of said regulating valve if said ratio should tend to decrease, and vice-versa, and b. observing said pressure P1 as a predetermined multiple of said pressure P0.
Claim 11
Dependent Claim
24 words
The determination of claim 8 wherein the observing of said pressure P1 is translated into the level of said liquid above a datum level.
Claim 12
Dependent Claim
22 words
The determination of claim 8 wherein said observing of said pressure P1 is translated into a control action to control said level.
Claim 13
Dependent Claim
59 words
The determination of claim 8 wherein said ratio of P1/P2 is maintained by two diaphragms, one of which is responsive to pressure P1 and the other to pressure P2, with the two diaphragms being interconnected by an adjustable proportioning lever mechanism, and the P1 diaphragm is operatively connected to and serves to dictate the movement of said regulating valve.
References Cited (Backward Citations)
US2736199A
Cited
US3491599A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-30 | 1976-10-30 | 1977-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-30 | 1980-10-30 | 1981-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-30 | 1984-10-30 | 1985-05-01 | $7700.00 | Window Closed / Lapsed |