Distributed temperature sensor with optical-fiber sensing element

Patent 4830513 Issued on May 16, 1989. Estimated Expiration Date:

November 18, 2007. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

3622243

Monitoring arrangement utilizing fiber optics
Patent #: 4151747
Issued on: 05/01/1979
Inventor: Gottlieb , et al.

Optical attenuation monitor system and method
Patent #: 4365896
Issued on: 12/28/1982
Inventor: Mihalow

Temperature-sensitive optrode
Patent #: 4542987
Issued on: 09/24/1985
Inventor: Hirschfeld

Method and apparatus for measuring temperature profile with a single optical fiber
Patent #: 4576485
Issued on: 03/18/1986
Inventor: Lambert

Temperature sensor for cables
Patent #: 4610552
Issued on: 09/09/1986
Inventor: Kobayashi , et al.

Method and apparatus for making a contact-free measurement of the actual position and of the profile of a coarse surface
Patent #: 4652131
Issued on: 03/24/1987
Inventor: Fercher , et al.

Position detection apparatus Patent #: 4710026
Issued on: 12/01/1987
Inventor: Magome , et al.

Inventor

Grego, Giorgio

Application

No. 07/122057 filed on 11/18/1987

US Classes:

374/131, With radiation conducting element250/227.14, Condition responsive light guide (e.g., light guide is physically affected by parameter sensed which results in light conveyed to the photocell)356/43, OPTICAL PYROMETERS356/477, Using fiber or waveguide interferometer356/484, Having light beams of different frequencies (e.g., heterodyning)356/519Having partially reflecting plates in series (e.g., Fabry-Perot type)

Examiners

Primary: Yasich, Daniel M.

Attorney, Agent or Firm

Dubno; Herbert

International Classes

G01K 11/32 (20060101)
G01K 11/00 (20060101)

Foreign Application Priority Data

1986-11-24 IT

Abstract

The distributed temperature sensor employs an optical fiber as sensing element located in an ambient or near a body of which the temperature is to be monitored or measured. A source of light pulses sends into the fiber, pulses of predetermined duration. The backscattered radiation is collected for each pulse and the frequency spectrum variations in the backscattered radiation with respect to the incident radiation are analyzed. A computer obtains the temperature from said variations. The source and the spectrum variation analyzer are part of an optical time domain reflectometer which allows the temperature information to be associated with the information on the position of the backscattering point along the fiber.