Patent EP0347095A1 successfully refreshed from Google Patents.
EP0347095A1
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EP
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Optical liquid-level sensing means
Assignee: IMO Industries Inc
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Filing: 1989-06-07
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Granted: —
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Expires: 2009-06-07
Abstract
Abstract An optical sensor element provides cantilevered support of a bent length of glass-rod core (45) of first refractive index having a cladding (46) of second refractive index that is less than the refractive index of the core, and wherein the outer radius of the bend (which may be a single bend, or a plurality of spaced bends) is at least the diameter of the cladded core. Provision is made at the respective ends of the cladded core for completing a light circuit via the length of the cladded core, and flexible leads, as of multi-mode optical fiber, enable completion of the optical circuit to a remotely located control unit having an electrically powered light source and a photodetector, at the respective ends of the circuit. Provision of threshold-operated circuitry at the control unit enables automatic electronic evaluation (and further-remote output delivery) of signals which reflect (a) one or more detected liquid levels, (b) interface level between two mingled liquids having different specific gravity, and (c) the monitored integrity of the optical circuit as a whole.
Inventors
- 👤 Joseph D. Rando
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 11:40
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/28; G01F23/284; G01F23/292; G01F23/2921; G01F23/2922; G01F23/2925; G01F23/2927; G02; G02B; G02B13/00; G02B13/0095; Y; Y10; Y10S; Y10S250/00; Y10S250/90; Y10S250/904
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
88 words
As an article of manufacture for use in optical measurement of liquid level, a sensor element comprising an elongate length of glass core of first refractive index with a cladding of second refractive index that is less than said first refractive index, said length having at least one bend intermediate the ends of said length, wherein the outer radius of said bend is at least the diameter of the cladded core, and means at the respective ends of said length for completing a light circuit through said length.
Claim 2
Dependent Claim
88 words
As an article of manufacture for use in optical measurement of liquid level, a sensor element comprising an elongate length of glass core of first refractive index with a cladding of second refractive index that is less than said first refractive index, said length having at least one bend intermediate the ends of said length, wherein the outer radius of said bend is at least the diameter of the cladded core, and means at the respective ends of said length for completing a light circuit through said length.
Claim 3
Dependent Claim
28 words
The article of claim 1, in which the outer radius of said bend is in the range of one to ten times the diameter of the cladded core.
Claim 4
Dependent Claim
59 words
The article of claim 1, in which the outer radius of said bend is in the range of two to three times the diameter of the cladded core; whereby, with said bend in air, a light circuit can be completed through said length but will be substantially incomplete via said length when said bend is immersed in a liquid.
Claim 5
Dependent Claim
75 words
The article of claim 1 in which the outer radius of said bend is in the range of three to ten times the diameter of the cladded core; whereby, with said bend in air, a light circuit can be completed through said length and, with said bend immersed in a liquid, light transmission via said length will be reduced sufficiently to identify both the fact of liquid immersion and the integrity of the light circuit.
Claim 6
Dependent Claim
110 words
The article of claim 1, in which the outer radius of said bend is in the range of five to ten times the diameter of the cladded core; whereby, with said bend in air, a light circuit can be completed through said length and, with said bend immersed in a pool of two liquids of different specific gravity wherein the liquids define a separation interface, light transmission via said length will be sufficiently and differently reduced when immersed in either of the liquids to enable identification of the particular liquid in which it is currently immersed, thereby enabling identification of the instantaneous level of the interface between the two liquids.
Claim 7
Dependent Claim
38 words
The article of claim 2, in which the glass core is of diameter in the range 50 microns to 12.5 mm, and in which the numerical aperture of the cladded core is in the range 0.2 to 0.8.
Claim 8
Dependent Claim
25 words
The article of claim 6, in which the glass core is of approximately 0.025-inch diameter, and in which the numerical aperture is approximately two thirds.
Claim 9
Dependent Claim
29 words
The article of claim 1, in which said bend is one of two such bends, said bends being spaced from each other by a straight portion of said length.
Claim 10
Dependent Claim
32 words
The article of claim 8, in which said bends are each to the extent of substantially π/2 radians and in which the ends of said length are in spaced substantially parallel relation.
Claim 11
Dependent Claim
46 words
The article of claim 1, in which one of the ends of said length is terminated by a reflector, and in which beam-splitting means is coupled to the other end of said length, whereby light entering said core may be segregated from light exiting said core.
Claim 12
Dependent Claim
33 words
The article of claim 1, and including base structure mounting the cladded core via at least one of the ends of said length, said bend being at cantilevered offset from said base structure.
Claim 13
Dependent Claim
31 words
The article of claim 8, and including base structure mounting the cladded core via both of the ends of said length, said bends being at cantilevered offset from said base structure.
Claim 14
Dependent Claim
29 words
The article of claim 10, and including base structure mounting said other end of said length, said bend and said reflector being at cantilevered offset from said base structure.
Claim 15
Dependent Claim
17 words
The article of claim 13, in which said beam-splitting means is additionally mounted by said base structure.
Claim 16
Dependent Claim
30 words
The article of any one of claims 11 to 14, in which said base structure includes floodable relatively rigid means spaced from and surrounding the cantilevered portion of said length.
Claim 17
Dependent Claim
36 words
The article of any one of claims 11 to 14, in which flexible means including two light-conducting elements for separate light-transmission to and light-transmission from said article are coupled at one end to the cladded core.
Claim 18
Dependent Claim
62 words
A liquid-level measuring system comprising the article of claim 1 and a remote control unit therefor, said control unit including a light source and a light detector, and flexible means including two light-conducting elements which are respectively coupled at one end to said light source and to said detector, and which are respectively coupled at the other end to said cladded core.
Claim 19
Dependent Claim
25 words
The system of claim 17, in which said remote control unit includes threshold-responsive means operative to produce an output signal upon detector response below threshold.
Claim 20
Dependent Claim
32 words
The system of claim 18, in which said threshold responsive device is one of a plurality each of which produces an output signal for a different level of detector response below threshold.
Claim 21
Dependent Claim
54 words
The system of claim 18, in which said article of claim 1 is one of two such articles each of which is mounted for bend exposure to a different liquid level, and in which said threshold-responsive means and said flexible means are each coupled to serve a different one of the said two articles.
Claim 22
Dependent Claim
24 words
The system of claim 17, in which the couplings of said light-conducting elements to said light source and to said detector are selectively detachable.
Claim 23
Dependent Claim
31 words
The article of claim 8, in which an elastomeric O-ring is in stressed circumferentially continuous engagement with the cladded core at substantially the mid-point of the straight portion between said bends.
Claim 24
Dependent Claim
17 words
The system of claim 17, in achieved of said flexible light-conducting elements is a multi-mode optical fiber.
References Cited (Backward Citations)
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