Browse Prior Art Database

Optical Temperature Profiling of Belt Ovens

IP.com Disclosure Number: IPCOM000108094D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 85K

Publishing Venue

IBM

Related People

Decain, DM: AUTHOR [+2]

Abstract

Disclosed is a means of measuring the temperature along the full length of zone belt ovens without interrupting the flow of product parts. A temperature-sensitive optical sensor (OS) is used in conjunction with an interrogating light beam which originates at (L), passes through OS at all points along the entire length of the belt oven, and is detected at (D), as shown in the insert in Fig. 2. OS changes its optical density as a function of temperature. Some desirable features of OS are as follows: (1) its internal transmission should be a strong, but not abrupt, function of temperature, (2) OS should be usable up to 500 degrees C, and (3) the temperature dependence of its optical density should be reproducible over a large number of temperature cycles.

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Optical Temperature Profiling of Belt Ovens

       Disclosed is a means of measuring the temperature along
the full length of zone belt ovens without interrupting the flow of
product parts.  A temperature-sensitive optical sensor (OS) is used
in conjunction with an interrogating light beam which originates at
(L), passes through OS at all points along the entire length of the
belt oven, and is detected at (D), as shown in the insert in Fig. 2.
OS changes its optical density as a function of temperature.  Some
desirable features of OS are as follows: (1) its internal
transmission should be a strong, but not abrupt, function of
temperature, (2) OS should be usable up to 500 degrees C, and (3) the
temperature dependence of its optical density should be reproducible
over a large number of temperature cycles.

      Although not originally designed for this purpose, optical
materials having just these favorable properties are readily
available from Schott Glass Technologies and the Hoya Corporation.
When using a red probe wavelength, such as 6328 angstrom, red to
orange colored glass filters are suitable.  More precisely, these are
sharp cut, long (wavelength) pass optical filters composed of a base
glass which derives its designed optical properties, namely, the
spectral location and sharpness of the onset of its optical
absorption edge, to a colloidal suspension of precipitated
"semiconductor" particles (*).

      An example of suitable OS characteristics is s...