Pyrometric temperature measuring instrument

• US 4,906,106 A
• Filed: 11/02/1988
• Issued: 03/06/1990
• Est. Priority Date: 11/03/1987
• Status: Expired due to Fees

• Current Assignee: BBC Brown Boveri AG Ch-5401 Baden Switzerland
• Original Assignee: Brown Boveri & CIE AG (ABB Limited)
• Inventors: Kaufmann, Meinolph, Schultheis, Lothar
• Primary Examiner(s): Yasich, Daniel M.
• Application Number:
  US07/265,956
• Time in Patent Office: 489 Days
• Field of Search: 374/161, 374/131, 374/162, 350/96.29
• US Class Current: 374/131
• CPC Class Codes: G01J 5/048 Protective parts
• CPC Class Codes: G01J 5/08 Optical arrangements
• CPC Class Codes: G01J 5/0818 Waveguides
• CPC Class Codes: G01J 5/0821 Optical fibres
• CPC Class Codes: G01J 5/0887 Integrating cavities mimicking black bodies, wherein the heat propagation between the black body and the measuring element does not occur within a solid; Use of bodies placed inside the fluid stream for measurement of the temperature of gases; Use of the reemission from a surface, e.g. reflective surface; Emissivity enhancement by multiple reflections
• CPC Class Codes: G01J 5/602 using selective, monochromatic or bandpass filtering

Abstract

A pyrometric temperature measuring instrument including at least one optical wave guide (1a) with a core (5) and a cladding (6), a light detector (3) and at least one pyrometric sensor (2a). The at least one optical wave guide (1a) has a large numerical aperture. The pyrometric sensor (2a) is located at one end of the at least one optical wave guide (1a) and covers at least a cross-section of the core (5) of an optical wave guide (1a). In a preferred embodiment, the light detector (3) is an InGaAs photodiode. The optical wave guide (1a) has a numerical aperture of 0.3 or more, a diameter of the core (5) of approximately 100 μm or more, and is surrounded by a light-tight cover (7).

Claims

1. Pyrometric temperature measuring instrument comprising:

at least one optical waveguide having a core and a cladding;

at least one pyrometric sensor provided at one end of said at least one optical waveguide; and

a liquid detector;

wherein;

said optical waveguide is a plastic clad silica (PCS) fiber, the core of which has a diameter of more than approximately 100 μ

m and wherein the optical waveguide has a numerical aperture of more than approximately 0.3;

said pyrometric sensor is a black layer covering at least a cross-section of the core at an end of the optical waveguide and possessing the properties of a black body at least in a wavelength region detectable by the liquid detector;

said light detector comprises a Indium, Galium, Arsenic (InGaAs) photodiode.

5. Pyrometric temperature measuring instrument according to one of claims 1, 2, or 3, wherein the black layer is a mixture of finely dispersed carbon and a silicon adhesive.

2. Pyrometric temperature measuring instrument comprising:

at least one optical waveguide having a core and a cladding;

at least one pyrometric sensor provided at one end of said at least one optical waveguide; and

a light detector;

wherein;

said optical waveguide is a plastic clad Silica (PCS) fiber surrounded by a light-tight cover, the core of which has a diameter of more the approximately 100 μ

m, and wherein the optical waveguide has a numerical aperture of more than approximately 0.3;

said pyrometric sensor is a black layer covering at least a cross-section of the core at an end of the optical waveguide and possessing the properties of a black body at least in a wavelength region detectable by the light detector;

said light detector is cooled and comprises an InGaAs photodiode and means for cooling said light detector are provided.

3. Pyrometric temperature measuring instrument comprising:

at least one optical waveguide having a core and a cladding;

at least one pyrometric sensor provided at one end of said at least one optical waveguide; and

a light detector;

wherein;

said optical waveguide is a plastic clad silica (PCS) fiber, the core of which has a diameter of more the approximately 100 μ

m, and wherein the optical waveguide has a numerical aperture of more than approximately 0.3;

said pyrometric sensor is a black layer covering at least a cross-section of the core at an end of the optical waveguide and possessing the properties of a black body at least in a wavelength region detectable by the light detector;

said light detector comprises at least two Indium, Galium, Arsenic (InGaAs) photodiodes, by which to determine a temperature light intensities are measured in the light detector in two different wavelength regions and a temperature is derived from a ratio of the two measured intensities.

4. Pyrometric temperature measuring instrument according to claim 3, comprising:

means for cooling the light detector.

6. Pyrometric temperature measuring instrument comprising:

at least one optical waveguide having a core and a cladding;

at least one pyrometric sensor provided at one end of said at least one optical waveguide; and

a light detector;

wherein;

said optical waveguide has a core of a diameter of more than approximately 100 μ

m and numerical aperture of more than approximately 0.3;

said optical waveguide and the pyrometric sensor are integrated into a glass fiber the pyrometric sensor being formed by a local doping of the core of the glass fiber by a material possessing the properties of a black body at least in a wavelength region detectable by the light detector;

said light detector comprises an Indium Galium, Arsenic (InGaAs) photodiode.

7. Pyrometric temperature measuring instrument comprising:

at least one optical waveguide having a core and a cladding;

several pyrometric sensors; and

a light detector;

wherein;

said optical waveguide has a core of a diameter of more than approximately 100 μ

m and numerical aperture of more than approximately 0.3;

said optical waveguide and the pyrometric sensors are integrated into a glass fiber the pyrometric sensors being formed by several local dopings of the core of the glass fiber by a material possessing the properties of a black body at least in a wavelength region detectable by the light detector;

said light detector comprises an Indium, Galium, Arsenic (InGaAs) photodiode.