Patent US5378889A successfully refreshed from Google Patents.
US5378889A
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Method and apparatus for detecting hydrocarbon fuels in a vapor state with an absorber-expander member
Assignee: CALIFORNIA LIGHTWAVE LABORATORIES
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Filing: 1993-09-23
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Granted: 1995-01-03
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Expires: 2013-09-23
Abstract
Abstract A method and apparatus for detecting the presence of hydrocarbon analyte in at least one of a liquid and vapor state. The apparatus (21) includes an optical fiber (22), an absorber-expander (31) mechanically coupled (32) to the optical fiber (22) to produce a change in transmission of light along the fiber (22) upon absorption of the hydrocarbon (33). The absorber-expander (31) is selected to absorb hydrocarbons, but not water, and to be capable of multiple reversible expansion and contraction cycles without significant structural degradation. Methyl terminated, silica and iron oxide filled, dimethyl polysiloxane provides a material which will experience substantial swelling in the presence of a hydrocarbon and yet is substantially reversible on desorption of the hydrocarbon from the absorber-expander (31). The method includes positioning an optical fiber (22) having such an absorber-expander (31) for absorption of hydrocarbons and detecting the decrease in light transmission produced by expansion of the absorber-expander (31), for example, by one of microbending and axial misalignment. The location of the absorber-expander (31) along strand (22) can be determined by optical time domain reflectometry or by digital sensing nodes (122), and multiple couplings (57) and biasing couplings (153) for mounting the absorber-expanders (152) to the optical fiber (151) can be used to enhance sensitivity.
Inventors
- 👤 William R. Lawrence
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:53
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/24; G01N33/241; H; H01; H01J; H01J5/00; H01J5/02; H01J5/16; G01M; G01M3/00; G01M3/02; G01M3/04; G01M3/042; G01M3/045; G01M3/047; G01N21/00; G01N21/75; G01N21/77; G01N21/7703; G01N33/18; G01N33/1826; G01N33/1833; G01N2021/7706; G01N2021/7723; G01N2021/7769; G01N2021/7783
Claims Analysis
Total Claims: 54
Claim 1
Independent Claim
105 words
A method for detecting the presence of a hydrocarbon analyte in at least one of a liquid and a vapor state comprising the steps of: positioning an optical fiber in a location for detection of said hydrocarbon with an absorber-expander member mechanically coupled to said fiber to produce a change in light transmission in said fiber upon absorption of said hydrocarbon analyte by, and expansion of, said absorber-expander member, said absorber-expander being hydrophobic and being selected to have multiple reversible expansion and contraction cycles upon absorption and evaporation of said hydrocarbon analyte by said absorber-expander; and detecting a change in light transmission in said fiber.
Claim 2
Independent Claim
105 words
A method for detecting the presence of a hydrocarbon analyte in at least one of a liquid and a vapor state comprising the steps of: positioning an optical fiber in a location for detection of said hydrocarbon with an absorber-expander member mechanically coupled to said fiber to produce a change in light transmission in said fiber upon absorption of said hydrocarbon analyte by, and expansion of, said absorber-expander member, said absorber-expander being hydrophobic and being selected to have multiple reversible expansion and contraction cycles upon absorption and evaporation of said hydrocarbon analyte by said absorber-expander; and detecting a change in light transmission in said fiber.
Claim 3
Dependent Claim
28 words
The method as defined in claim 1 and the additional step of: detecting the location along said fiber at which said absorber-expander causes a change in light transmission.
Claim 4
Dependent Claim
44 words
The method as defined in claim 1 and the additional step of: prior to said positioning step, coupling said absorber-expander member to said fiber to produce microbending of said fiber, and during said detecting step, detecting the location of a microbend in said fiber.
Claim 5
Dependent Claim
29 words
The method as defined in claim 1 wherein, said selecting step is accomplished by selecting as an absorber-expander a methyl terminated, silica and iron oxide filled, dimethyl polysiloxane polymer.
Claim 6
Dependent Claim
47 words
The method as defined in claim 1 wherein, prior to said positioning step, said absorber-expander is coupled to a first portion of said optical fiber to displace said first portion relative to a second portion of said optical fiber to produce axial misalignment in said optical fiber.
Claim 7
Independent Claim
119 words
A method of making a hydrocarbon detection apparatus comprising the steps of: selecting a silicone rubber member as an absorber-expander for a hydrocarbon in at least one of a liquid state and a vapor state, said silicone rubber member being selected to absorb and expand in the presence of said hydrocarbon and to recover and contract to a substantially undegradated condition in the absence of said hydrocarbon; mechanically coupling said silicone rubber member to a fiber optic strand in a manner producing one of microbending and axial misalignment of said strand upon expansion of said silicone rubber member; and optically coupling detection apparatus means to said strand for detection of the occurrence of decreased light transmission along said strand.
Claim 8
Independent Claim
119 words
A method of making a hydrocarbon detection apparatus comprising the steps of: selecting a silicone rubber member as an absorber-expander for a hydrocarbon in at least one of a liquid state and a vapor state, said silicone rubber member being selected to absorb and expand in the presence of said hydrocarbon and to recover and contract to a substantially undegradated condition in the absence of said hydrocarbon; mechanically coupling said silicone rubber member to a fiber optic strand in a manner producing one of microbending and axial misalignment of said strand upon expansion of said silicone rubber member; and optically coupling detection apparatus means to said strand for detection of the occurrence of decreased light transmission along said strand.
Claim 9
Dependent Claim
30 words
The method as defined in claim 6 wherein, said selecting step is accomplished by selecting as an absorber-expander a methyl terminated and iron oxide and silica filled silicone rubber member.
Claim 10
Dependent Claim
52 words
The method as defined in claim 7 wherein, said mechanically coupling step is accomplished by encircling said fiber optic strand with a rigid member and coupling said rigid member to said silicone rubber member for relative displacement of said rigid member and said fiber optic strand against each other to produce microbending.
Claim 11
Dependent Claim
40 words
The method as defined in claim 7 wherein, said mechanically coupling step is accomplished by encircling both said fiber optic strand and said silicone rubber member with a rigid member having a relatively short dimension along said fiber optic strand.
Claim 12
Dependent Claim
18 words
The method as defined in claim 9 wherein, said rigid member is provided by at least one ring.
Claim 13
Dependent Claim
25 words
The method as defined in claim 9 wherein, said rigid member is provided by a wire wound in a spiral around said silicone rubber member.
Claim 14
Dependent Claim
33 words
The method as defined in claim 6 wherein, said selecting step is accomplished by selecting a solid silicone rubber member which absorbs hydrocarbon fuels in both a liquid state and a vapor state.
Claim 15
Dependent Claim
46 words
The method as defined in claim 6 wherein, said selecting step is accomplished by selecting a silicone rubber member which expands upon absorption of hydrocarbons and contracts upon the emission of absorbed hydrocarbons by an amount proportional to the quantity hydrocarbon contacting said silicone rubber member.
Claim 16
Dependent Claim
28 words
The method as defined in claim 6 wherein, said mechanically coupling step is accomplished by encircling said strand and a portion of said rubber member by staple means.
Claim 17
Dependent Claim
43 words
The method as defined in claim 6 wherein, said mechanically coupling step is accomplished by coupling said rubber member to said strand in a manner producing a biasing microbend in said strand prior to any absorption of hydrocarbon by said silicone rubber member.
Claim 18
Dependent Claim
33 words
The method as defined in claim 6 wherein, said optically coupling step is accomplished by optically coupling detection means to said strand suitable for detecting the location of a microbend along said strand.
Claim 19
Dependent Claim
78 words
The method as defined in claim 6 wherein, said mechanically coupling step is accomplished by coupling a plurality of silicone rubber members to a plurality of fiber optic strands at discrete locations producing a digital detection array; and said optical coupling step is accomplished by coupling a detection means to said plurality of strands forming said digital detection array suitable for determining the location of microbending based upon sensing of the presence of microbending on combinations of strands.
Claim 20
Dependent Claim
104 words
The method as defined in claim 6 and the step of: mechanically coupling a temperature control member to a second fiber optic strand, said temperature control member expanding and contracting in proportion to temperature changes by an amount substantially known relative to the expansion and contraction of said silicone rubber member and said temperature control member maintaining its dimensional stability when in contact with said hydrocarbon rubber member for the same temperature changes; optically coupling said second fiber optic strand to said detection means; and positioning said second fiber optic strand so that said temperature control member is closely proximal said silicone rubber member.
Claim 21
Dependent Claim
50 words
The method as defined in claim 6 wherein, said mechanically coupling step is accomplished by mechanically coupling a plurality of absorber-expander members to a single fiber optic strand along a length thereof to provide a series detection array, said absorber-expanders having differing expansion rates upon absorption of a given hydrocarbon.
Claim 22
Dependent Claim
47 words
The method as defined in claim 6 wherein, said mechanically coupling step is accomplished by mechanically coupling a plurality of discrete absorber-expanders to a plurality of fiber optic strands to produce a parallel detection array, said absorber-expanders having differing expansion rates upon absorption of a given hydrocarbon.
Claim 23
Dependent Claim
50 words
The method as defined in claim 6 wherein, said mechanically coupling step is accomplished by mechanically coupling said silicone rubber member to said fiber optic strand to produce microbending of said strand with coupling means multiplying the amount of microbending of said strand upon expansion of said silicone rubber member.
Claim 24
Dependent Claim
28 words
The method as defined in claim 21 wherein, said mechanically coupling step is accomplished by mounting a plurality of side-by-side strand-encircling rigid members on said fiber optic strand.
Claim 25
Dependent Claim
78 words
The method as defined in claim 6 wherein, said fiber optic strand is provided by two strand portions axially aligned for transmission of a signal from one strand portion to the other; and said mechanically coupling step is accomplished by coupling said silicone rubber member to one of said strand portions of said fiber optic strand for displacement of said one of said strand portions transversely relative to the other of said strand portions to produce axial misalignment.
Claim 26
Dependent Claim
64 words
The method as defined in claim 6 wherein, said optic fiber strand is provided by two strand portions axially aligned for transmission of a signal from one strand portion to the other; and said mechanically coupling step is accomplished by coupling said silicone rubber member to both of said strand portions for displacement of said strand portions in opposite directions relative to each other.
Claim 27
Dependent Claim
98 words
A detection apparatus for detecting the presence of at least one of a liquid hydrocarbon and a hydrocarbon vapor comprising: an optical fiber; an absorber-expander member mechanically coupled to said optical fiber to produce a change in transmission of light along said optical fiber upon absorption of said hydrocarbon, said absorber-expander being formed of a hydrophobic hydrocarbon-absorbing rubber material selected to expand upon absorption of said hydrocarbon and selected to retain sufficient structural integrity to permit repetitive use; and detection apparatus optically coupled to said optical fiber for detection of a change in light transmission along said fiber.
Claim 28
Dependent Claim
98 words
A detection apparatus for detecting the presence of at least one of a liquid hydrocarbon and a hydrocarbon vapor comprising: an optical fiber; an absorber-expander member mechanically coupled to said optical fiber to produce a change in transmission of light along said optical fiber upon absorption of said hydrocarbon, said absorber-expander being formed of a hydrophobic hydrocarbon-absorbing rubber material selected to expand upon absorption of said hydrocarbon and selected to retain sufficient structural integrity to permit repetitive use; and detection apparatus optically coupled to said optical fiber for detection of a change in light transmission along said fiber.
Claim 29
Dependent Claim
25 words
The apparatus as defined in claim 25 wherein, said rubber material is selected from the group consisting of silicone rubber, latex rubber and Norprene rubber.
Claim 30
Dependent Claim
21 words
The apparatus as defined in claim 26 wherein, said rubber material is dimethyl polysiloxane having silica and iron oxide fillers therein.
Claim 31
Dependent Claim
34 words
The apparatus as defined in claim 25 wherein, said absorber-expander member is mechanically coupled by a rigid member extending from said absorber-expander member to said optical fiber to produce microbending of said optical fiber.
Claim 32
Dependent Claim
18 words
The apparatus as defined in claim 28, and adhesive means coupling said rigid member to said absorber-expander member.
Claim 33
Dependent Claim
15 words
The apparatus as defined in claim 28 wherein, said rigid member encircles said optical fiber.
Claim 34
Dependent Claim
20 words
The apparatus as defined in claim 30 wherein, said rigid member encircles both said optical fiber and said absorber-expander member.
Claim 35
Dependent Claim
27 words
The apparatus as defined in claim 28 wherein, said rigid member is provided by a ring encircling said optical fiber and a portion of said absorber-expander member.
Claim 36
Dependent Claim
44 words
The apparatus as defined in claim 32 wherein, said optical fiber and said absorber-expander are both cylindrical and oriented with central longitudinal axes substantially parallel and said ring is substantially circular and has a width dimension along said optical fiber which is relatively thin.
Claim 37
Dependent Claim
27 words
The apparatus as defined in claim 33, and a plurality of spaced apart, side-by-side relatively rigid rings each encircling both said optical fiber and said absorber-expander member.
Claim 38
Dependent Claim
21 words
The apparatus as defined in claim 28 wherein, said absorber-expander member is mechanically coupled to said optical fiber by a staple.
Claim 39
Dependent Claim
31 words
The apparatus as defined in claim 28 wherein, said absorber-expander member is mechanically coupled to said optical fiber by a strand wound around both said optical fiber and said absorber-expander member.
Claim 40
Dependent Claim
14 words
The apparatus as defined in claim 36 wherein, said strand is a metallic wire.
Claim 41
Dependent Claim
56 words
The apparatus as defined in claim 25, and a plurality of absorber-expander members each formed as defined for the first-named absorber-expander, said absorber-expanders each being mechanically coupled to said optical fiber at spaced apart positions along the length of said optical fiber in a manner producing microbending of said optical fiber upon absorption of said hydrocarbon.
Claim 42
Dependent Claim
19 words
The apparatus as defined in claim 25 wherein, said absorber-expander member will absorb gasoline, Jet-A fuel and diesel fuel.
Claim 43
Dependent Claim
21 words
The apparatus as defined in claim 39 wherein, said absorber-expander member will absorb said hydrocarbon in both liquid and vapor states.
Claim 44
Dependent Claim
98 words
The apparatus as defined in claim 25 wherein, said optical fiber is provided with a first fiber portion having a first end and a second fiber portion having a second end spaced apart from and optically aligned with said first end for transmission of light from said first fiber portion to said second fiber portion; and said absorber-expander being mechanically coupled to one of said first fiber portion and said second fiber portion to produce displacement of said one laterally relative to the other of the fiber portions by an amount affecting light transmission along said fiber portions.
Claim 45
Dependent Claim
40 words
The apparatus as defined in claim 41 wherein, said absorber-expander is coupled to both said first fiber portion and said second fiber portion and supported for displacement of said first fiber portion and said second fiber portion in opposite directions.
Claim 46
Dependent Claim
41 words
The apparatus as defined in claim 25 wherein, said absorber-expander member is mechanically coupled to said optical fiber by a coupling assembly producing displacement of said optical fiber by an amount greater than the amount of expansion of said absorber-expander member.
Claim 47
Dependent Claim
33 words
The apparatus as defined in claim 25 wherein, said absorber-expander member is mechanically coupled to said optical fiber in a manner biasing said optical fiber with a pre-established microbend at said absorber-expander member.
Claim 48
Dependent Claim
24 words
The apparatus as defined in claim 44, and mounting apparatus mechanically coupling said absorber-expander to said optical fiber, said mounting apparatus producing said microbend.
Claim 49
Dependent Claim
68 words
The apparatus as defined in claim 45 wherein, said mounting apparatus is provided by a ring-like member having a central portion extending around said optical fiber and having a pair of spaced apart leg portions engaging said absorbent-expander member, said leg portions being movable between selected fixed relative positions to pull said central portion toward said optical fiber and establish the amount of microbending biasing said optical fiber.
Claim 50
Dependent Claim
171 words
The apparatus as defined in claim 25 wherein, said absorber-expander member is formed of a rubber material having a known rate of expansion for each of two differing hydrocarbon fuels; and further comprising: an additional optic fiber having an additional absorber-expander member formed of a hydrocarbon-absorbing rubber member mechanically coupled thereto in a manner producing a change in light transmission upon expansion of said additional hydrocarbon-absorbing rubber member, said additional absorber-expander member having a known rate of expansion for each of said two differing hydrocarbon fuels, which rates of expansion differ from the rates of expansion of the first named absorber-expander member; said additional absorber-expander member being positioned proximate said first named absorber-expander member; and said detection apparatus being optically coupled to said additional optical fiber and being formed to quantify the amount of change of light transmission produced upon expansion of the absorber-expanders and including computational apparatus for comparison of the quantity of change of transmission of light from the two optical fibers to determine the hydrocarbon fuel being detected.
Claim 51
Dependent Claim
139 words
The apparatus as defined in claim 25, and an additional optical fiber having an additional rubber member mechanically coupled thereto in a manner substantially identical to coupling of said absorber-expander member to the first-named optical fiber; said additional rubber member having a thermal coefficient of expansion having a known relationship to a thermal coefficient of expansion of said absorber-expander member, and said additional rubber member being substantially incapable of absorbing hydrocarbons absorbed by said absorber-expander member; said additional rubber member being positioned proximate said absorber-expander member; and said detection apparatus being optically coupled to said additional optical fiber and being formed to quantify the amount of change in light transmission produced by expansion of said absorber-expander member and said additional rubber member, and including comparison and computational apparatus for comparing said amount of change and subtracting temperature induced change.
Claim 52
Dependent Claim
139 words
The apparatus as defined in claim 25, said optical fiber has a plurality of substantially similar absorber-expander members mechanically coupled to said optical fiber along a length thereof; a plurality of additional optical fibers positioned proximate the first-named optical fiber; a plurality of additional absorber-expander members substantially similar to the first-named absorber-expander member and mechanically coupled to each of said additional optical fibers; said first-named absorber-expander members and said additional absorber-expander members being coupled along their respective optical fibers in a digital detection array with a different combination of absorber-expanders at each of a plurality of detection sites; said detection apparatus being coupled to each of said additional optical fibers; and computer means coupled to said detection apparatus and formed to be responsive to combinations of signals from said detection apparatus to determine the location of a detected hydrocarbon.
Claim 53
Dependent Claim
70 words
A hydrocarbon detection apparatus comprising: an optical fiber; a methyl terminated, silica and iron oxide filled dimethyl polysiloxane rubber member mechanically coupled to said optical fiber to produce microbending of said fiber upon absorption of at least one of a liquid hydrocarbon and a hydrocarbon vapor by said red silicone rubber; and microbend detection apparatus optically coupled to said fiber to detect the presence of a microbend in said fiber.
Claim 54
Dependent Claim
70 words
A hydrocarbon detection apparatus comprising: an optical fiber; a methyl terminated, silica and iron oxide filled dimethyl polysiloxane rubber member mechanically coupled to said optical fiber to produce microbending of said fiber upon absorption of at least one of a liquid hydrocarbon and a hydrocarbon vapor by said red silicone rubber; and microbend detection apparatus optically coupled to said fiber to detect the presence of a microbend in said fiber.
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