EP0225023A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Temperature measurement
Assignee: National Power PLC
•
Filing: 1986-10-15
•
Granted: —
•
Expires: 2006-10-15
Abstract
Abstract A method of measuring temperature comprises the steps of consecutively launching (1, 2) input pulses of light at two different wavelengths into a temperature sensing element in the form o' an elongate optical fibre (3); passing Raman scattered light from said element and deriving from said input pulses to intensity detectors (7, 8); obtaining from the detectors (7, 8) output signals indicative of the intensity of the Raman scattered light; and processing said output signals to provide a temperature measurement. A known position (10) along the optical fibre (3) is maintained at a known temperature to provide a reference for deriving temperature measurements at other positions along the optical fibre.
Inventors
- 👤 Geoffrey Walton Bibby
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 11:37
CPC Classifications
G; G01; G01K; G01K11/00; G01K11/32
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
152 words
A method of measuring temperature, characterised by the steps of consecutively launching (1, 2) input pulses of light at two different wavelengths, λ 1 and λ 2 , into a temperature sensing element (3); passing Raman scattered light from said element and deriving from said input pulses, at wavelengths λ 2 and λ 1 respectively, to an intensity detector or detectors (7, 8); obtaining from said detector or detectors (7, 8) output signals indicative of the intensity of the Raman scattered light at the wavelengths λ 2 and λ 1 deriving from said input pulses at wavelengths λ 1 and λ 2 respectively; and processing (9) said output signals to provide a temperature measurement; the wavelengths λ 1 and λ 2 being chosen such that where v is the Stokes shift in wavenumber units of the Raman scattered light at wavelength λ 2 arising from input light at wavelength λ 1 .
Claim 2
Independent Claim
152 words
A method of measuring temperature, characterised by the steps of consecutively launching (1, 2) input pulses of light at two different wavelengths, λ 1 and λ 2 , into a temperature sensing element (3); passing Raman scattered light from said element and deriving from said input pulses, at wavelengths λ 2 and λ 1 respectively, to an intensity detector or detectors (7, 8); obtaining from said detector or detectors (7, 8) output signals indicative of the intensity of the Raman scattered light at the wavelengths λ 2 and λ 1 deriving from said input pulses at wavelengths λ 1 and λ 2 respectively; and processing (9) said output signals to provide a temperature measurement; the wavelengths λ 1 and λ 2 being chosen such that where v is the Stokes shift in wavenumber units of the Raman scattered light at wavelength λ 2 arising from input light at wavelength λ 1 .
Claim 3
Dependent Claim
31 words
A method as claimed in Claim 1, characterised in that an elongate optical fibre (3) is used as the temperature sensing element, said input pulses being launched into one end thereof.
Claim 4
Dependent Claim
45 words
A method as claimed in Claim 2, characterised in that a known position (10) along the optical fibre (3) from said one end is maintained at a known temperature to provide a reference for deriving temperature measurements at other positions along the optical fibre (3).
Claim 5
Dependent Claim
117 words
Apparatus for use in carrying out a method as claimed in any preceding claim, comprising a temperature sensing element (3); means (1, 2) to launch said input pulses consecutively into said element (3); means (4) arranged to pass scattered light from said element to wavelength selection means (5, 6) arranged to pass only scattered light at wavelength X 2 and derived from input pulses at wavelength λ 1 , and only scattered light at wavelength λ 1 and derived from input pulses at wavelength λ 2 to intensity detector means (7, 8) operative to provide said output signals; and processing means (9) to which said output signals are supplied and operative to provide a temperature measurement therefrom.
Claim 6
Dependent Claim
19 words
Apparatus as claimed in Claim 4, characterised in that said temperature sensing element (3) is an elongate optical fibre.
Claim 7
Dependent Claim
30 words
Apparatus as claimed in Claim 4 or Claim 5, characterised in that said launching means comprises two separate sources (1, 2) of light for pulses of said two wavelengths respectively.
Claim 8
Dependent Claim
23 words
Apparatus as claimed in Claim 4 or Claim 5, characterised in that said launching means comprises a single tunable source of monochromatic light.
Claim 9
Dependent Claim
37 words
Apparatus according to any one of Claims 4 to 7, characterised in that said wavelength selection means includes a tunable filter by way of which said scattered light is passed to said intensity detector means (7, 8).
Claim 10
Dependent Claim
38 words
Apparatus as claimed in any one of Claims 4 to 7, characterised in that said wavelength selection means includes two separate filters (5, 6) passing light of said two wavelengths respectively to said intensity detector means (7, 8).
Claim 11
Dependent Claim
57 words
Apparatus as claimed in Claim 5, or in any one of Claims 6 to 9 as dependent on Claim 5, characterised in that a known position (10) along the optical fibre (3) from said one end is maintained at a known temperature to provide a reference for deriving temperature measurements at other positions along the optical fibre.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.