Combustion apparatus for analytical instruments

Claim 2

A COMBUSTION FURNACE FOR ANALYTICAL APPARATUS COMPRISING AN INDUCTION COIL WITH A VERTICALLY EXTENDING AXIS, A COMBUSTION TUBE MOUNTED WITHIN SAID COIL, AN UPPER CLOSURE MEMBER FOR SEALABLY COUPLING TO AN UPPER END OF SAID COMBUSTION TUBE, SAID UPPER CLOSURE MEMBER INCLUDING AN EXHAUST GAS PASSAGE THERETHROUGH, AND A SEPARATE APERTURE EXTENDING THROUGH SAID UPPER CLOSURE MEMBER ALONG THE VERTICAL AXIS THEREOF, A LOWER CLOSURE MEMBER FOR SEALABLY ENGAGING THE LOWER END OF SAID COMBUSTION TUBE, SAID LOWER CLOSURE MEMBER INCLUDING A PASSAGEWAY EXTENDING THERETHROUGHT TO DEFINE A CARRIER GAS INLET COMMUNICATING WITH THE INTERIOR OF SAID COM-

Claim 3

The combination as claimed in claim 1 wherein said exhaust gas passage of said upper closure member extends verticallY through a bottom surface of said upper closure member to communicate with the interior of said combustion tube and includes a radially extending portion extending through a side of said upper closure member for providing an exhaust port for removal of combustion gases from said combustion tube.

Claim 4

The combination as claimed in claim 2 wherein said upper closure member includes a sealing member extending around the exterior of the lower periphery thereof to engage an inner surface of said combustion tube for sealing said upper closure member to said combustion tube.

Claim 5

The combination as claimed in claim 3 wherein said combustion tube is a cylindrical sleeve having a circumferential constriction formed at its upper end and immediately below said sealing member and extending inwardly sufficiently to shield said sealing member from combustion by-products.

Claim 6

A combustion furnace for analytical apparatus comprising an induction coil with a vertical axis, a vertical combustion tube within said coil, a base closure member mounted against the bottom end of said tube and having passage defining means for delivering gas into said tube, a vertically reciprocable elevator movable between a position of sealing against said base member and supporting a crucible within the field of said coil and a position downwardly displaced therefrom, a top fitting closing the top end of said combustion tube, means defining a second gas passage therethrough, and an oxygen lance mounted in said top fitting for delivering combustion gas into said crucible.

Claim 7

A combustion furnace for analytical apparatus comprising an induction coil with a vertical axis, a vertical combustion tube within said coil, a base closure member mounted against the bottom end of said tube and having passage defining means for delivering gas into said tube, a vertically reciprocable elevator movable between a position of sealing against said base member and supporting a crucible within the field of said coil and a position downwardly displaced therefrom, a top fitting closing the top end of said combustion tube, means defining a second gas passage therethrough, and an oxygen lance mounted in said top fitting for delivering combustion gas into said crucible.

Claim 8

The combination as claimed in claim 5 wherein said oxygen lance is adjustably mounted in said top fitting for adjustment toward and away from said crucible.

Claim 9

The combination as claimed in claim 5 wherein said lance is a high silica tube and said top fitting telescopes within the top end of said combustion tube, said top fitting having a sealing ring thereabout in the telescoped portion thereof to seal against the interior surface of said combustion tube, said tube having a circumferential constriction extending inwardly immediately below said top fitting a distance sufficient for shielding said sealing ring from combustion by-products.

Claim 10

For use in a furnace for heating specimens to their combustion temperature wherein the specimens are placed in a crucible positioned in a combustion tube with sealed end closures, and means extending through the end closures to provide a flow of gas through the combustion tube to carry combustion gases from the combustion tube, an improved combustion tube comprising: a continuously extending cylindrical body having a first open end the interior wall surface of which defines an interior cylindrical sealing surface immediately adjacent said first open end and a circumferential restriction formed inwardly in said cylindrical body and spaced from said first end to shield said sealing surface from combustion by-products, said combustion tube including an enlarged open opposite end defining a cylindrical wall extending substantially parallel with said cylindrical body and defining a cylindrical interior sealing surface having a diameter greater than the diameter of said cylindrical body.

Claim 11

For use in a furnace for heating specimens to their combustion temperature wherein the specimens are placed in a crucible positioned in a combustion tube with sealed end closures, and means extending through the end closures to provide a flow of gas through the combustion tube to carry combustion gases from the combustion tube, an improved combustion tube comprising: a continuously extending cylindrical body having a first open end the interior wall surface of which defines an interior cylindrical sealing surface immediately adjacent said first open end and a circumferential restriction formed inwardly in said cylindrical body and spaced from said first end to shield said sealing surface from combustion by-products, said combustion tube including an enlarged open opposite end defining a cylindrical wall extending substantially parallel with said cylindrical body and defining a cylindrical interior sealing surface having a diameter greater than the diameter of said cylindrical body.

Claim 12

The combustion tube as defined in claim 8 wherein said combustion tube is made of high silica glass.

Claim 13

An induction furnace comprising: a vertically extending induction coil; a cylindrical combustion tube positioned within said induction coil and including an open upper end, an enlarged cylindrical lower open end and a circumferential restriction spaced from said open upper end; an upper closure member for sealably fitting into said upper end of said combustion tube and including an axial opening through an end thereof for receiving an oxygen lance tube therethrough and further including a relatively large opening formed axially upwardly through a bottom surface of said upper closure member and communicating with a radially extending port for exhausting combustion And carrier gases from said combustion tube, said upper closure member including a peripheral sealing member positioned adjacent said restriction of said combustion tube; and a lower closure member including means for supporting a crucible within the induction field of said induction coil when said lower closure member is sealably fitted in the enlarged lower end of said combustion tube, said lower closure member including an axially extending aperture opening at the top surface of said lower closure member and means for introducing a carrier gas to said last named aperture to provide a flow of gas upwardly through said combustion tube.

Claim 14

An induction furnace comprising: a vertically extending induction coil; a cylindrical combustion tube positioned within said induction coil and including an open upper end, an enlarged cylindrical lower open end and a circumferential restriction spaced from said open upper end; an upper closure member for sealably fitting into said upper end of said combustion tube and including an axial opening through an end thereof for receiving an oxygen lance tube therethrough and further including a relatively large opening formed axially upwardly through a bottom surface of said upper closure member and communicating with a radially extending port for exhausting combustion And carrier gases from said combustion tube, said upper closure member including a peripheral sealing member positioned adjacent said restriction of said combustion tube; and a lower closure member including means for supporting a crucible within the induction field of said induction coil when said lower closure member is sealably fitted in the enlarged lower end of said combustion tube, said lower closure member including an axially extending aperture opening at the top surface of said lower closure member and means for introducing a carrier gas to said last named aperture to provide a flow of gas upwardly through said combustion tube.