Wide angle optical viewer

An improved vessel viewer of the type containing a biconvex or double convex lens positioned to permit a viewer to view into a heated interior of a vessel, the improvement comprising:

• two substantially identical plano-convex lenses, axially aligned with said bi-convex optical lens and positioned with convex surfaces facing each other, said bi-convex optical lens having a diameter which is larger than the diameter of said plano-convex lenses, and said bi-convex lens and said plano-convex lenses comprising an axially aligned three-lens system;
• two planar, heet resistant lenses, axially aligned with and encasing said three-lens system between the two planar lenses, a cylindrical lens housing means having an interior bore for holding the lenses in a spaced apart series, wherein said lenses are inserted into said interior bore of the housing, and said housing means maintains the lenses in a desired axial alignment, and said lenses are mounted at a desired distance from one another to provide the optimum image clarity and angle of view, and a tube of sufficient length to reach to the interior of a furnace or burner, having one end affixed to a viewing end of the housing, whereby said viewer looks into an end of the tube to view the interior of the furnace, while the end of said tube affixed to said wide angle lens apparatus is inserted into the interior of a furnace or burner, and further, said appartus affords the viewer a wide angle view regardless of the viewer's distance from the viewing device.

A vessel and wide angle viewer combination comprising:

• a vessel having a wall and interior space wherein said wall has at least one viewport having an opening into said interior space,
• a lens housing for mounting lenses, penetrating the opening of said viewport and extending into the burner interior;
• two substantially identical plano-convex lenses, positioned with convex surfaces facing each other, axially aligned with a bi-convex lens having a diameter which is larger than the diameter of the preceding two lenses to form a three-lens system, encased by two planar, heat-resistant lenses axially aligned with said three-lens system;
• a lens retainer means for retaining the lens in the desired alignment, and a pipe or tube of sufficient length to extend the wide angle viewer further into the interior of the vessel, affixed to the lens housing, whereby an observer looks into a viewing end of the pipe or tube to view the interior, while the other end of said pipe or tube affixed to said wide angle lens apparatus is inserted into the interior of said vessel, and further, said combination affords the observer a wide angle view of the interior of the burner regardless of the observer's distance from said viewport.