US5793705A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ultrasonic liquid level gauge for tanks subject to movement and vibration
Assignee: International Business Machines Corp
•
Filing: 1996-09-18
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Granted: 1998-08-11
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Expires: 2016-09-18
Abstract
Abstract One or more high-frequency ultrasonic transducers are used to measure the liquid level of tanks containing any type of fluid, but fuel in particular. The invention relates specifically to tanks that are subject to movement and vibration which generally makes the use of ultrasonic echoes unreliable for obtaining accurate level measurements. A special algorithm is used to obtain the temporal center of the distribution of echo arrival times over a preset time interval. From this temporal center of an echo distribution, the liquid level is readily obtained through the acoustic velocity, time and distance relationship. An annular piezoelectric plate, independently driven at low ultrasonic frequencies (kHz range), mounted on the tank bottom surrounds the high frequency ultrasonic transducer. The function of the piezoelectric plate is to send out propagating ultrasonic waves (essentially longitudinal) to maintain the tank area in the immediate region of the high-frequency transducer free from debris and sediment deposits at the bottom of the tank thereby avoiding the uncertainty in the measurement that is introduced by debris on the tank bottom.
Inventors
- 👤 Denos Constantinos Gazis
- 👤 William Francis Kane
- 👤 Robert Jacob von Gutfeld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:43
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/28; G01F23/296; G01F23/2962; G01S; G01S15/00; G01S15/02; G01S15/06; G01S15/08; G01S15/10; G01S15/101; G01S15/86; G10; G10K; G10K11/00; G10K11/004; G01S15/88
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
132 words
An ultrasonic echo system for measuring and determining a height of a liquid in a storage vessel, said system comprising: an ultrasonic transducer mounted on the bottom of the vessel; an ultrasonic pulse unit for causing said transducer to emit ultrasonic pulses and for receiving echoes of said ultrasonic pulses; means for processing said received echoes to determine a center of a distribution of the received echoes as a function of time; and means for determining a liquid level height based on a velocity of the ultrasonic pulses in said liquid and a time of said center of said distribution wherein said means for determining performs an averaging of two of echo arrival times within a predetermined time interval to determine said liquid level height, independent of an amplitude of said echoes.
Claim 2
Dependent Claim
132 words
An ultrasonic echo system for measuring and determining a height of a liquid in a storage vessel, said system comprising: an ultrasonic transducer mounted on the bottom of the vessel; an ultrasonic pulse unit for causing said transducer to emit ultrasonic pulses and for receiving echoes of said ultrasonic pulses; means for processing said received echoes to determine a center of a distribution of the received echoes as a function of time; and means for determining a liquid level height based on a velocity of the ultrasonic pulses in said liquid and a time of said center of said distribution wherein said means for determining performs an averaging of two of echo arrival times within a predetermined time interval to determine said liquid level height, independent of an amplitude of said echoes.
Claim 3
Dependent Claim
126 words
An ultrasonic echo system for measuring and determining a height of a liquid in a storage vessel, said system comprising: an ultrasonic transducer mounted on the bottom of the vessel; an ultrasonic pulse unit for causing said transducer to emit ultrasonic pulses and for receiving echoes of said ultrasonic pulses; means for processing said received echoes to determine a center of a distribution of the received echoes as a function of time; means for determining a liquid level height based on a velocity of the ultrasonic pulses in said liquid and a time of said center of said distribution; and a second low frequency transducer mounted circumferentially about said ultrasonic transducer, said low frequency transducer emitting low frequency acoustic waves to maintain a clean tank surface.
Claim 4
Dependent Claim
126 words
An ultrasonic echo system for measuring and determining a height of a liquid in a storage vessel, said system comprising: an ultrasonic transducer mounted on the bottom of the vessel; an ultrasonic pulse unit for causing said transducer to emit ultrasonic pulses and for receiving echoes of said ultrasonic pulses; means for processing said received echoes to determine a center of a distribution of the received echoes as a function of time; means for determining a liquid level height based on a velocity of the ultrasonic pulses in said liquid and a time of said center of said distribution; and a second low frequency transducer mounted circumferentially about said ultrasonic transducer, said low frequency transducer emitting low frequency acoustic waves to maintain a clean tank surface.
Claim 5
Dependent Claim
35 words
The system of claim 1 further including means for adjusting a time at which said processing is to occur thereby suppressing spurious and unwanted pulse echoes that occur before a preset time interval of interest.
Claim 6
Dependent Claim
15 words
The system of claim 1 wherein said ultrasonic transducer operates in the megahertz frequency range.
Claim 7
Dependent Claim
22 words
The system of claim 4 wherein said transducer operates in the frequency range of from about 0.5 MHZ to about 10 MHZ.
Claim 8
Dependent Claim
15 words
The system of claim 4 wherein said low frequency transducer operates in the kilohertz range.
Claim 9
Dependent Claim
24 words
The system of claim 6 wherein said low frequency transducer operates in the frequency range of from about 10 kHz to about 50 kHz.
Claim 10
Dependent Claim
106 words
An ultrasonic echo system for measuring and determining a height of a liquid in a storage vessel, said system comprising: an ultrasonic transducer mounted on the bottom of the vessel; an ultrasonic pulse unit for causing said transducer to emit ultrasonic pulses and for receiving echoes of said ultrasonic pulses; a second independently driven, low frequency transducer mounted circumferentially about said ultrasonic transducer, said low frequency transducer emitting low frequency acoustic waves to maintain a clean tank surface; and means for determining a liquid level height based on a velocity of the ultrasonic pulses in said liquid and a time of a center of a distribution.
Claim 11
Dependent Claim
106 words
An ultrasonic echo system for measuring and determining a height of a liquid in a storage vessel, said system comprising: an ultrasonic transducer mounted on the bottom of the vessel; an ultrasonic pulse unit for causing said transducer to emit ultrasonic pulses and for receiving echoes of said ultrasonic pulses; a second independently driven, low frequency transducer mounted circumferentially about said ultrasonic transducer, said low frequency transducer emitting low frequency acoustic waves to maintain a clean tank surface; and means for determining a liquid level height based on a velocity of the ultrasonic pulses in said liquid and a time of a center of a distribution.
Claim 12
Dependent Claim
35 words
The system of claim 8 further including means for adjusting a time at which said processing is to occur thereby suppressing spurious and unwanted pulse echoes that occur before a preset time interval of interest.
Claim 13
Dependent Claim
15 words
The system of claim 9 wherein said ultrasonic transducer operates in the megahertz frequency range.
Claim 14
Dependent Claim
22 words
The system of claim 10 wherein said transducer operates in the frequency range of from about 0.5 MHZ to about 10 MHZ.
Claim 15
Dependent Claim
15 words
The system of claim 8 wherein said low frequency transducer operates in the kilohertz range.
Claim 16
Dependent Claim
24 words
The system of claim 12 wherein said low frequency transducer operates in the frequency range of from about 10 kHz to about 50 kHz.
Claim 17
Dependent Claim
134 words
An ultrasonic echo system for measuring and determining a height of a liquid in a storage vessel, said system comprising: a plurality of ultrasonic transducers mounted on the bottom of the vessel; an ultrasonic pulse unit for causing said transducer to emit ultrasonic pulses and for receiving echoes of said ultrasonic pulses means for processing said received echoes to determine a center of a distribution of the received echoes as a function of time; and means for determining a liquid level height based on a velocity of the ultrasonic pulses in said liquid and a time of said center of said distributions, wherein said means for determining performs an averaging of two of echo arrival times within a predetermined time interval to determine said liquid level height, independent of an amplitude of said echoes.
Claim 18
Dependent Claim
134 words
An ultrasonic echo system for measuring and determining a height of a liquid in a storage vessel, said system comprising: a plurality of ultrasonic transducers mounted on the bottom of the vessel; an ultrasonic pulse unit for causing said transducer to emit ultrasonic pulses and for receiving echoes of said ultrasonic pulses means for processing said received echoes to determine a center of a distribution of the received echoes as a function of time; and means for determining a liquid level height based on a velocity of the ultrasonic pulses in said liquid and a time of said center of said distributions, wherein said means for determining performs an averaging of two of echo arrival times within a predetermined time interval to determine said liquid level height, independent of an amplitude of said echoes.
Claim 19
Dependent Claim
130 words
An ultrasonic echo system for measuring and determining a height of a liquid in a storage vessel, said system comprising: a plurality of ultrasonic transducers mounted on the bottom of the vessel; an ultrasonic pulse unit for causing said transducer to emit ultrasonic pulses and for receiving echoes of said ultrasonic pulses; means for processing said received echoes to determine a center of a distribution of the received echoes as a function of time; means for determining a liquid level height based on a velocity of the ultrasonic pulses in said liquid and a time of said center of said distribution; and a plurality of second low frequency transducers mounted circumferentially about said ultrasonic transducers, said low frequency transducers emitting low frequency acoustic waves to maintain a clean tank surface.
Claim 20
Dependent Claim
130 words
An ultrasonic echo system for measuring and determining a height of a liquid in a storage vessel, said system comprising: a plurality of ultrasonic transducers mounted on the bottom of the vessel; an ultrasonic pulse unit for causing said transducer to emit ultrasonic pulses and for receiving echoes of said ultrasonic pulses; means for processing said received echoes to determine a center of a distribution of the received echoes as a function of time; means for determining a liquid level height based on a velocity of the ultrasonic pulses in said liquid and a time of said center of said distribution; and a plurality of second low frequency transducers mounted circumferentially about said ultrasonic transducers, said low frequency transducers emitting low frequency acoustic waves to maintain a clean tank surface.
Claim 21
Dependent Claim
35 words
The system of claim 14 further including means for adjusting a time at which said processing is to occur thereby suppressing spurious and unwanted pulse echoes that occur before a preset time interval of interest.
Claim 22
Dependent Claim
17 words
The system of claim 14 wherein said plurality of ultrasonic transducers operate in the megahertz frequency range.
Claim 23
Dependent Claim
23 words
The system of claim 17 wherein said plurality of transducers operate in the frequency range of from about 0.5M to about 10 MHZ.
Claim 24
Dependent Claim
17 words
The system of claim 15, wherein said plurality of low frequency transducers operate in the kilohertz range.
Claim 25
Dependent Claim
26 words
The system of claim 19 wherein said plurality of low frequency transducers operate in the frequency range of from about 10 kHz to about 50 kHz.
Claim 26
Dependent Claim
20 words
The system of claim 14 wherein centers of distributions of the received echoes from said ultrasonic transducers are averaged together.
Claim 27
Dependent Claim
21 words
The system of claim 15 wherein said plurality of low frequency transducers is one less than said plurality of ultrasonic transducers.
Claim 28
Dependent Claim
21 words
The system of claim 22 wherein said one less than is achieved by the physical absence of a low frequency transducer.
Claim 29
Dependent Claim
19 words
The system of claim 22 wherein said one less than is achieved by not operating said low frequency transducer.
Claim 30
Dependent Claim
25 words
The system of claim 15 further including means for calculating a build-up of debris over the ultrasonic transducer not having an associated low frequency transducer.
Claim 31
Dependent Claim
54 words
The system of claim 14 wherein said means for processing includes means for calculating t av , where t av is the center of said distribution, in accordance with t.sub.av =t.sub.1 + (t.sub.f -t.sub.1)/2! where t 1 is a first echo to be counted and t f is a last echo to be counted.
Claim 32
Dependent Claim
28 words
The system of claim 26 wherein said means for determining includes means for determining an ultrasonic velocity of said pulses in said liquid as a function of temperature.
Claim 33
Dependent Claim
76 words
The system of claim 27 wherein said means for determining further includes means for calculating said liquid level height in accordance with ##EQU6## where v(T) is the ultrasonic velocity in said liquid as a function of temperature and Δt is a round trip travel time of said pulses in the vessel wall where Δt=2D/v.sub.C and D is a thickness of the vessel wall and VD is the velocity of the ultrasonic pulses in the vessel wall.
Claim 34
Dependent Claim
129 words
An ultrasonic echo system for measuring and determining a height of a liquid in a storage vessel, said system comprising: an ultrasonic transducer mounted on the top of the vessel; an ultrasonic pulse unit for causing said transducer to emit ultrasonic pulses and for receiving echoes of said ultrasonic pulses; means for processing said received echoes to determine a center of a distribution of the received echoes as a function of time; and means for determining a liquid level height based on a velocity of the ultrasonic pulses and a time of said center of said distribution, wherein said means for determining performs an averaging of two of echo arrival times within a predetermined time interval to determine said liquid level height, independent of an amplitude of said echoes.
Claim 35
Dependent Claim
129 words
An ultrasonic echo system for measuring and determining a height of a liquid in a storage vessel, said system comprising: an ultrasonic transducer mounted on the top of the vessel; an ultrasonic pulse unit for causing said transducer to emit ultrasonic pulses and for receiving echoes of said ultrasonic pulses; means for processing said received echoes to determine a center of a distribution of the received echoes as a function of time; and means for determining a liquid level height based on a velocity of the ultrasonic pulses and a time of said center of said distribution, wherein said means for determining performs an averaging of two of echo arrival times within a predetermined time interval to determine said liquid level height, independent of an amplitude of said echoes.
Claim 36
Dependent Claim
125 words
An ultrasonic echo system for measuring and determining a height of a liquid in a storage vessel, said system comprising: an ultrasonic transducer mounted on the top of the vessel; an ultrasonic pulse unit for causing said transducer to emit ultrasonic pulses and for receiving echoes of said ultrasonic pulses; means for processing said received echoes to determine a center of a distribution of the received echoes as a function of time; and means for determining a liquid level height based on a velocity of the ultrasonic pulses and a time of said center of said distribution; and a second low frequency transducer mounted circumferentially about said ultrasonic transducer, said low frequency transducer emitting low frequency acoustic waves to maintain a clean top tank surface.
Claim 37
Dependent Claim
125 words
An ultrasonic echo system for measuring and determining a height of a liquid in a storage vessel, said system comprising: an ultrasonic transducer mounted on the top of the vessel; an ultrasonic pulse unit for causing said transducer to emit ultrasonic pulses and for receiving echoes of said ultrasonic pulses; means for processing said received echoes to determine a center of a distribution of the received echoes as a function of time; and means for determining a liquid level height based on a velocity of the ultrasonic pulses and a time of said center of said distribution; and a second low frequency transducer mounted circumferentially about said ultrasonic transducer, said low frequency transducer emitting low frequency acoustic waves to maintain a clean top tank surface.
Claim 38
Dependent Claim
35 words
The system of claim 29 further including means for adjusting a time at which said processing is to occur thereby suppressing spurious and unwanted pulse echoes that occur before a preset time interval of interest.
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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) | 2001-08-10 | 2002-02-09 | 2002-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-10 | 2006-02-09 | 2006-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-10 | 2010-02-09 | 2010-08-11 | $7700.00 | Window Closed / Lapsed |