US4023412A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for detecting temperature variation utilizing the Curie point of a ferromagnetic material
Assignee: Shell USA Inc
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Filing: 1975-07-08
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Granted: 1977-05-17
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Expires: 1995-07-08
Abstract
Abstract A method and apparatus for detecting a temperature variation above or below a predetermined value by providing in the area where the temperature variation is to be detected an electrical circuit comprising at least two parallel conductors. The conductors are insulated from each other by a dielectric material and have positioned between them a quantity of a magnetically soft ferromagnetic material having a Curie point approximately equivalent to the predetermined temperature. By transmitting a pulse along said circuit and measuring the time interval before a reflection of the said pulse is detected, the location of a temperature variation can be detected.
Inventors
- 👤 Robert J. Luke
- 👤 Ronald C. Robson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:42
CPC Classifications
G; G01; G01M; G01M3/00; G01M3/02; G01M3/04; G01M3/16; G01M3/18; G01M3/186; F; F17; F17C; F17C13/00; F17C13/12; F17C13/126; G01K; G01K7/00; G01K7/36; G01K7/38; G01M3/002; G01R; G01R31/00; G01R31/08; G01R31/11; H; H01; H01B; H01B11/00; H01B11/18; H01B11/1834; H01B7/00; H01B7/08; H01B7/0807; F17C2203/00; F17C2203/03; F17C2223/00; F17C2223/01; F17C2223/0146; F17C2223/0153; F17C2223/0161; F17C2250/00; F17C2250/04; F17C2250/0404; F17C2250/0439; F17C2250/06; F17C2250/0605; F17C2250/0631; F17C2260/00; F17C2260/03; F17C2260/035; F17C2260/038; F17C2260/04; G01K3/00; G01K3/08; G01K3/14; G01K2003/145; G01K7/16; G01K2007/166; G01K2203/00
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
57 words
A method for detecting temperature variation above or below a predetermined value, comprising: a. transmitting an electrical signal of short duration along an electrical circuit in thermal contact with the area where the temperature variation is to be detected wherein the electrical circuit comprises: 1. at least two substantially parallel conductors insulated from each other; and 2.
Claim 2
Independent Claim
57 words
A method for detecting temperature variation above or below a predetermined value, comprising: a. transmitting an electrical signal of short duration along an electrical circuit in thermal contact with the area where the temperature variation is to be detected wherein the electrical circuit comprises: 1. at least two substantially parallel conductors insulated from each other; and 2.
Claim 3
Dependent Claim
36 words
ferromagnetic material having a Curie point about equal to the predetermined temperature positioned between said parallel conductors; b. detecting a reflection of the electrical signal; and c. measuring the time interval between transmitting the signal and
Claim 4
Dependent Claim
36 words
ferromagnetic material having a Curie point about equal to the predetermined temperature positioned between said parallel conductors; b. detecting a reflection of the electrical signal; and c. measuring the time interval between transmitting the signal and
Claim 5
Dependent Claim
41 words
detecting the reflection thereof. 2. The method of detecting temperature variation set forth in claim 1, further comprising: calculating from the time interval measurement the length of the electrical circuit along which the electrical signal travelled until a reflection thereof occurred.
Claim 6
Dependent Claim
71 words
The method of detecting temperature variation set forth in claim 2, further comprising: a. transmitting subsequently a second electrical signal from the other end of the electrical circuit; b. detecting a reflection of the second signal; c. measuring the time interval between transmitting the second signal and detecting the reflection thereof; and d. calculating the length of the electrical circuit along which the second signal travelled until a reflection thereof occurred.
Claim 7
Dependent Claim
23 words
The method for detecting temperature variation set forth in claim 3, wherein the electrical signal of short duration comprises: a pulse of voltage.
Claim 8
Dependent Claim
34 words
The method for detecting temperature variation set forth in claim 4, wherein: the substantially parallel conductors are insulated from each other by insulation material and the ferromagnetic material is dispersed in the insulation material.
Claim 9
Dependent Claim
18 words
The method of detecting temperature variation according to claim 5, wherein the electrical circuit comprises: a co-axial cable.
Claim 10
Dependent Claim
19 words
The method of detecting temperature variation set forth in claim 6, wherein the ferromagnetic material comprises: soft ferrite material.
Claim 11
Dependent Claim
19 words
The method of detecting temperature variation set forth in claim 7, wherein the soft ferrite material comprises: ferrite powder.
Claim 12
Dependent Claim
23 words
The method for detecting temperature variation set forth in claim 1, wherein the electrical signal of short duration comprises: a pulse of voltage.
Claim 13
Dependent Claim
34 words
The method of detecting temperature variation set forth in claim 1, wherein: the substantially parallel conductors are insulated from each other by insulation material and the ferromagnetic material is dispersed in the insulation material.
Claim 14
Dependent Claim
19 words
The method of detecting temperature variation set forth in claim 10, wherein the ferromagnetic material comprises: soft ferrite material.
Claim 15
Dependent Claim
19 words
The method of detecting temperature variation set forth in claim 11, wherein the soft ferrite material comprises: ferrite powder.
Claim 16
Dependent Claim
18 words
The method of detecting temperature variation according to claim 1, wherein the electrical circuit comprises: a co-axial cable.
Claim 17
Dependent Claim
32 words
The method for detecting temperature variation set forth in claim 1, further comprising: measuring the magnitude of the reflection to determine the extent of temperature variation above or below the predetermined value.
Claim 18
Dependent Claim
33 words
The method for detecting temperature variation set forth in claim 1, wherein: said parallel conductors are elongate and have said ferromagnetic material positioned along substantially the entire length of said parallel elongate conductors.
Claim 19
Dependent Claim
70 words
The method for detecting temperature variation set forth in claim 1, further comprising: locating the area of temperature variation along said electrical circuit by measuring the time interval between the detection of a first reflection of the electrical signal adjacent a first beginning boundary of the temperature variation area and the detection of a second reflection of the electrical signal adjacent a second end boundary of the temperature variation area.
Claim 20
Dependent Claim
41 words
The method for detecting temperature variation set forth in claim 16, further comprising: disposing said electrical circuit in a looped configuration with said electrical circuit having looped ends connecting substantially parallel portions for locating the boundaries of area of temperature variation.
Claim 21
Dependent Claim
95 words
Apparatus for detecting temperature variations above or below a predetermined value, comprising: a. an electrical circuit having at least two substantially parallel conductors, insulating material for insulating said conductors from each other, and a quantity of ferromagnetic material having a Curie point about equivalent to the predetermined temperature situated between said conductors; b. means for transmitting an electrical signal of short duration along said electrical circuit; c. means for detecting a reflection of the signal; and d. means for determining the time interval between the transmission of the signal and the detection of the reflection.
Claim 22
Dependent Claim
95 words
Apparatus for detecting temperature variations above or below a predetermined value, comprising: a. an electrical circuit having at least two substantially parallel conductors, insulating material for insulating said conductors from each other, and a quantity of ferromagnetic material having a Curie point about equivalent to the predetermined temperature situated between said conductors; b. means for transmitting an electrical signal of short duration along said electrical circuit; c. means for detecting a reflection of the signal; and d. means for determining the time interval between the transmission of the signal and the detection of the reflection.
Claim 23
Dependent Claim
22 words
The apparatus of claim 18, wherein: said substantially parallel conductors form a co-axial cable having a central conductor and an outer conductor.
Claim 24
Dependent Claim
18 words
The apparatus of claim 19, wherein: said central conductor is coated with a layer of said ferromagnetic material.
Claim 25
Dependent Claim
28 words
The apparatus of claim 20, wherein said insulation material is situated between the coated central conductor and said outer conductor and said insulation material comprises: a polyethene material.
Claim 26
Dependent Claim
14 words
The apparatus of claim 21, wherein said ferromagnetic material comprises: a soft ferrite material.
Claim 27
Dependent Claim
36 words
The apparatus of claim 22, further comprising: switching means for alternatively connecting said transmitting means, said detecting means, and said measuring means with one end of said electrical circuit and then with the other end thereof.
Claim 28
Dependent Claim
15 words
The apparatus of claim 18, wherein: said ferromagnetic material is dispersed in said insulating material.
Claim 29
Dependent Claim
14 words
The apparatus of claim 18, wherein said ferromagnetic material comprises: a soft ferrite material.
Claim 30
Dependent Claim
36 words
The apparatus of claim 18, further comprising: switching means for alternatively connecting said transmitting means, said detecting means, and said measuring means with one end of said electrical circuit and then with the other end thereof.
Claim 31
Dependent Claim
118 words
In a thermally insulated cryogenic storage system having a storage tank, cryogenic insulation and an apparatus for detecting failures, wherein the improvement comprises: a. an apparatus for detecting failures which detects temperature variations above or below a predetermined value comprising: 1. an electrical circuit having at least two substantially parallel conductors insulated from each other and a quantity of ferromagnetic material having a Curie point about equivalent to the predetermined temperature situated between said conductors; 2. means for transmitting an electrical signal of short duration along said electrical circuit; 3. means for detecting a reflection of the signal; and 4. means for determining the time interval between the transmission of the signal and the detection of the reflection.
Claim 32
Dependent Claim
118 words
In a thermally insulated cryogenic storage system having a storage tank, cryogenic insulation and an apparatus for detecting failures, wherein the improvement comprises: a. an apparatus for detecting failures which detects temperature variations above or below a predetermined value comprising: 1. an electrical circuit having at least two substantially parallel conductors insulated from each other and a quantity of ferromagnetic material having a Curie point about equivalent to the predetermined temperature situated between said conductors; 2. means for transmitting an electrical signal of short duration along said electrical circuit; 3. means for detecting a reflection of the signal; and 4. means for determining the time interval between the transmission of the signal and the detection of the reflection.
Claim 33
Dependent Claim
26 words
The system of claim 27, wherein: said substantially parallel conductors form a co-axial cable having a central conductor coated with a layer of said ferromagnetic material.
Claim 34
Dependent Claim
125 words
In a thermally insulated pipeline system designed for the transportation of gas having a pipeline and apparatus for detecting a failure or leak in the pipeline, wherein the improvement comprises: a. an apparatus for detecting failures which detects temperature variations above or below a predetermined value, comprising: 1. an electrical circuit having at least two substantially parallel conductors insulated from each other and a quantity of ferromagnetic material having a Curie point about equivalent to the predetermined temperature situated between said conductors; 2. means for transmitting an electrical signal of short duration along said electrical circuit; 3. means for detecting a reflection of the signal; and 4. means for determining the time interval between the transmission of the signal and the detection of the reflection.
Claim 35
Dependent Claim
125 words
In a thermally insulated pipeline system designed for the transportation of gas having a pipeline and apparatus for detecting a failure or leak in the pipeline, wherein the improvement comprises: a. an apparatus for detecting failures which detects temperature variations above or below a predetermined value, comprising: 1. an electrical circuit having at least two substantially parallel conductors insulated from each other and a quantity of ferromagnetic material having a Curie point about equivalent to the predetermined temperature situated between said conductors; 2. means for transmitting an electrical signal of short duration along said electrical circuit; 3. means for detecting a reflection of the signal; and 4. means for determining the time interval between the transmission of the signal and the detection of the reflection.
Claim 36
Dependent Claim
26 words
The system of claim 29, wherein: said substantially parallel conductors form a co-axial cable having a central conductor coated with a layer of said ferromagnetic material.
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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) | 1980-05-16 | 1980-11-15 | 1981-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-16 | 1984-11-15 | 1985-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-16 | 1988-11-15 | 1989-05-17 | $7700.00 | Window Closed / Lapsed |