US4471223A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Level and interface detection
Assignee: Imperial Chemical Industries Ltd
•
Filing: 1982-03-09
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Granted: 1984-09-11
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Expires: 2002-03-09
Abstract
Abstract Method and apparatus to determine the position of a liquid/liquid or liquid/vapor interface in a remote inaccessible location, for example in undersea oil storage tanks, by exposing the liquids or liquid and vapor to gamma-radiation from a source adjacent to or within the vessel containing the liquid(s) and monitoring the gamma-radiation issuing from the liquids or liquid and vapor, and using long lengths of optical fibre to convey the signals received to a measuring instrument. The invention employs optical fibres which may be up to several hundred meters long and among its advantages is the need for no moving parts, electrical supply or electronics at the remote location.
Inventors
- 👤 James A. Hurst
- 👤 David M. Gilhen
- 👤 Peter Jackson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:11
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/28; G01F23/284; G01F23/288
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
122 words
Apparatus for determining the position of a liquid-liquid or liquid-vapour interface of a body of liquids or liquid and vapour having such an interface, comprising: at least one stationarily located source of gamma-rays constructed and adapted to be arranged, when in use, for emitting gamma-rays into the liquids or liquid and vapour; a detector system comprising at least one stationarily located gamma-ray scintillator constructed and adapted to be arranged, when in use, as a detector for detecting gamma-rays issuing from the liquids or liquid and vapour; and for each such detector, an optical fibre which is operatively linked to that detector and which is at least 20 meters long for conveying the signals from each respective said detector to a measuring instrument.
Claim 2
Dependent Claim
122 words
Apparatus for determining the position of a liquid-liquid or liquid-vapour interface of a body of liquids or liquid and vapour having such an interface, comprising: at least one stationarily located source of gamma-rays constructed and adapted to be arranged, when in use, for emitting gamma-rays into the liquids or liquid and vapour; a detector system comprising at least one stationarily located gamma-ray scintillator constructed and adapted to be arranged, when in use, as a detector for detecting gamma-rays issuing from the liquids or liquid and vapour; and for each such detector, an optical fibre which is operatively linked to that detector and which is at least 20 meters long for conveying the signals from each respective said detector to a measuring instrument.
Claim 3
Dependent Claim
16 words
Apparatus as claimed in claim 1 in which the source of gamma-rays is cesium-137 of cobalt-60.
Claim 4
Dependent Claim
58 words
Apparatus as claimed in claim 1 in which the detector system comprises an array of a plurality of stationarily located gamma-ray scintillators similar to and including said at least one gamma-ray scintillator and adapted to be arranged, when in use, along the length of the vessel containing the liquid or liquids whose level or interface is being detected.
Claim 5
Dependent Claim
28 words
Apparatus as claimed in claim 1 in which the at least one gamma-ray scintillator is selected from crystals of cesium iodide, crystals of sodium iodide and plastic scintillators.
Claim 6
Dependent Claim
29 words
Apparatus as claimed in claim 1 in which the detector system includes at least one photo-multiplier tube linked by the optical fibre to the at least one gamma-ray scintillator.
Claim 7
Dependent Claim
24 words
Apparatus as claimed in claim 3 in which the optical fibres linked to a plurality of scintillators are coupled into a single measuring instrument.
Claim 8
Dependent Claim
55 words
Apparatus as claimed in claim 6, wherein: the diameter of the optical fibre for each said detector is in the range of 400 to 600 μm; and said apparatus further includes an underwater oil storage tank constructed and arranged, when in use, to contain said body of liquids or liquid and vapor having said interface.
Claim 9
Dependent Claim
26 words
Apparatus as claimed in claim 1 in which the length of optical fibre linking the detector system to a measuring instrument is at least 50 meters.
Claim 10
Dependent Claim
26 words
Apparatus as claimed in claim 1 in which the diameter of the optical fibre for each said detector is in the range 400 to 600 μm.
Claim 11
Independent Claim
89 words
A method for determining the position of the interface between two liquids or a liquid and a vapour in a vessel located in a remote position which comprises exposing the liquids or the liquid and vapour to gamma-radiation emitted from a fixed source adjacent to or within the vessel, monitoring the gamma-radiation issuing from the liquids or the liquid and vapour using a stationarily located gamma-ray scintillator and transmitting the signal from said scintillator along a length of at least 20 meters of optical fibre to a measuring instrument.
Claim 12
Independent Claim
89 words
A method for determining the position of the interface between two liquids or a liquid and a vapour in a vessel located in a remote position which comprises exposing the liquids or the liquid and vapour to gamma-radiation emitted from a fixed source adjacent to or within the vessel, monitoring the gamma-radiation issuing from the liquids or the liquid and vapour using a stationarily located gamma-ray scintillator and transmitting the signal from said scintillator along a length of at least 20 meters of optical fibre to a measuring instrument.
Claim 13
Dependent Claim
27 words
A method as claimed in claim 10 in which the signal from the scintillator is tramsmitted along a length of at least 50 meters of optical fibre.
References Cited (Backward Citations)
US3138709A
Cited
US3668392A
Cited
US3794428A
Cited
GB1586641A
Cited
US4155013A
Cited
US4267819A
Cited
US4292628A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-09-11 | 1988-03-12 | 1988-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-11 | 1992-03-12 | 1992-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-11 | 1996-03-12 | 1996-09-11 | $7700.00 | Window Closed / Lapsed |