US 6,672,725 B1Granted

Transpiration purged optical probe

AssigneeThe United States of America as represented by the United States Department of Energy

InventorsJohn VanOsdol, Steven Woodruff

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Abstract

An optical apparatus for clearly viewing the interior of a containment vessel by applying a transpiration fluid to a volume directly in front of the external surface of the optical element of the optical apparatus. The fluid is provided by an external source and transported by means of an annular tube to a capped end region where the inner tube is perforated. The perforation allows the fluid to stream axially towards the center of the inner tube and then axially away from an optical element which is positioned in the inner tube just prior to the porous sleeve. This arrangement draws any contaminants away from the optical element keeping it free of contaminants. In one of several embodiments, the optical element can be a lens, a viewing port or a laser, and the external source can provide a transpiration fluid having either steady properties or time varying properties.

An optical probe for improved viewing of the interior of a containment chamber comprising:

an inner cylindrical tube having an inner tube diameter, an inner tube length and an inner tube end face;
an outer cylindrical tube having a specified outer tube diameter and an outer tube length where said outer tube diameter is greater than said inner tube diameter, where said outer tube encloses said inner tube to form a cylindrical annulus between an outer surface of said inner tube and an inner surface of said outer tube;
an end tube coupling system where a coupling face of said end tube system joins with said inner tube end face to create a coupling face and where a cylindrical length of said end tube system is scaled such that a combined length of said inner tube and said end tube system approximately equals said length of said outer tube and where a porous cylindrical length of tube which is part of said end tube coupling system and which is positioned in opposition to said coupling face and extends from an outer end of said tube system towards said coupling face and is symmetrically perforated to allow a fluid to pass from said annulus to a cylindrical volume formed by cylindrical inner face of said end tube system where said fluid initially experiences a generally radial flow which turns axial as a central axis of said cylindrical volume is approached;
a capping device which seals said annulus at a position approximating an outer tube end face of said outer tube and an end face of said tube system;
an optical means for providing an optical access to the interior of the containment vessel where said optical means is positioned interior to said inner tube and at a position within said end tube coupling system in a region exclusive of perforation and acts to direct the axial motion of the fluid along said central axis in a direction opposed to said optical means;
a fluid coupling system which couples said annulus to an external fluid source which provides a transpiration fluid to said annulus.

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Abstract

Claims12