US4956535A — Electrode systems for in situ vitrification

Claim 1

Independent Claim 210 words

An electrode for use in the process of in situ vitrification of soil by application of electric current to the soil via said electrode to raise the soil to a high temperature for melting said soil at levels along said electrode, said electrode comprising: a first electrically conductive electrode shaft member adapted for positioning at least partially below the soil surface and adapted for connection to a source of said current for the purpose of conducting said current to the soil while maintaining its integrity at high temperatures, and a second electrically conductive sleeve electrode member within which said first conductive electrode shaft member is internally positioned at least along a portion of the length of said first conductive electrode shaft member, said portion of the length of said first conductive electrode shaft member corresponding to a portion thereof as would be located substantially between the soil surface and a location along said first conductive electrode shaft member below the soil surface when said first conductive electrode shaft member is positioned at least partially below the soil surface, said second conductive sleeve electrode member being formed of a material and having a diameter for providing a higher degree of thermal conduction than exhibited by said first conductive electrode shaft member.

Claim 2

Dependent Claim 210 words

An electrode for use in the process of in situ vitrification of soil by application of electric current to the soil via said electrode to raise the soil to a high temperature for melting said soil at levels along said electrode, said electrode comprising: a first electrically conductive electrode shaft member adapted for positioning at least partially below the soil surface and adapted for connection to a source of said current for the purpose of conducting said current to the soil while maintaining its integrity at high temperatures, and a second electrically conductive sleeve electrode member within which said first conductive electrode shaft member is internally positioned at least along a portion of the length of said first conductive electrode shaft member, said portion of the length of said first conductive electrode shaft member corresponding to a portion thereof as would be located substantially between the soil surface and a location along said first conductive electrode shaft member below the soil surface when said first conductive electrode shaft member is positioned at least partially below the soil surface, said second conductive sleeve electrode member being formed of a material and having a diameter for providing a higher degree of thermal conduction than exhibited by said first conductive electrode shaft member.

Claim 3

Dependent Claim 33 words

The electrode according to claim 1 wherein said second conductive sleeve electrode member is formed of a material having non-wetting characteristics with molten glass providing a slip plane to promote cold cap subsidence.

Claim 4

Dependent Claim 27 words

The electrode according to claim 1 wherein said first electrode shaft member is formed of molybdenum and said second conductive sleeve electrode member is formed of graphite.

Claim 5

Dependent Claim 60 words

The electrode according to claim 3 wherein said shaft member at least above the level of said sleeve is coated with a material selected from the group consisting of MoSi 2 , ZrB 2 , HfB 2 , a mixture of MoSi 2 and ZrB 2 , a mixture of MoSi 2 and HfB 2 , stainless steel, and glass.

Claim 6

Dependent Claim 39 words

The electrode according to claim 1 further provided with a conductive material between said first conductive electrode shaft member and said second conductive sleeve electrode member for providing a conductive path between said shaft member and said sleeve member.

Claim 7

Dependent Claim 11 words

The electrode according to claim 5 wherein said material is comminuted.

Claim 8

Dependent Claim 28 words

The electrode according to claim 5 wherein said material comprises a ceramic for protecting said shaft member as said sleeve member is consumed proximate to the soil surface.

Claim 9

Dependent Claim 41 words

The electrode according to claim 7 wherein said material is selected from the group consisting of ZrB 2 , HfB 2 , a mixture of MoSi 2 and ZrB 2 , and a mixture of MoSi 2 and HfB 2 .

Claim 10

Dependent Claim 27 words

The electrode according to claim 7 wherein said material comprises a mixture including a major proportion of ZrB 2 and a minor proportion of MoSi 2 .

Claim 11

Dependent Claim 24 words

The electrode according to claim 9 wherein the proportion of ZrB 2 is approximately 88% and the proportion of MoSi 2 is approximately 12%.

Claim 12

Dependent Claim 13 words

The electrode according to claim 5 wherein said conductive material comprises a metal.

Claim 13

Dependent Claim 11 words

The electrode according to claim 11 wherein said metal comprises molybdenum.

Claim 14

Dependent Claim 36 words

The electrode according to claim 11 wherein said metal has a melting point rendering the same molten at operating temperatures of said process proximate levels where current is conducted to said soil and melts said soil.

Claim 15

Dependent Claim 11 words

The electrode according to claim 13 wherein said metal is copper.

Claim 16

Dependent Claim 32 words

The electrode according to claim 13 wherein said metal is initially comminuted, melts proximate levels where the soil is melted, and forms a solid plug below levels where said soil is melted.

Claim 17

Dependent Claim 74 words

The electrode according to claim 1 wherein said first electrode shaft member comprises a hollow cylinder formed from a first conductive metal adapted to maintain said electrode integrity at high temperatures, said first electrode shaft member having an interior bore provided with a second conductive metal having a melting point rendering the latter metal molten at operating temperatures of said process proximate levels where current is conducted to said soil and melts said soil.

Claim 18

Dependent Claim 22 words

The electrode according to claim 16 wherein said electrode shaft member is formed of molybdenum and said second conductive metal is copper.

Claim 19

Dependent Claim 23 words

The electrode according to claim 1 including means for connecting said electrode shaft member and said sleeve electrode member below the soil surface.

Claim 20

Dependent Claim 33 words

The electrode according to claim 18 wherein said connecting means comprises a threaded connection at the lower end of one of said electrode members engaging the remaining electrode member in substantially coaxial relation.

Claim 21

Dependent Claim 24 words

The electrode according to claim 18 wherein said electrode shaft member is formed of molybdenum and said conductive sleeve member is formed of graphite.

Claim 22

Dependent Claim 35 words

The electrode according to claim 20 wherein said connecting means comprises a graphite plug having a tapered threaded connection to said sleeve electrode member and having a tapered threaded connection with said electrode shaft member.

Claim 23

Dependent Claim 34 words

The electrode according to claim 20 wherein said connecting means comprises a graphite plug having a tapered threaded connection to said sleeve electrode member and having a threaded connection with said electrode shaft member.

Claim 24

Dependent Claim 27 words

The electrode according to claim 22 wherein said connection of said graphite plug with said electrode shaft member includes a diffusion barrier of copper plating or foil.

Claim 25

Dependent Claim 20 words

The electrode according to claim 18 further provided with comminuted glass material between said shaft member and said sleeve member.

Claim 26

Dependent Claim 144 words

An electrode for use in the process of in situ vitrification of soil by application of electric current to the soil via said electrode to raise the soil to a high temperature for melting said soil at levels along said electrode, said electrode comprising: an electrically conductive electrode shaft member adapted for positioning at least partially below the soil surface and adapted for connection to a source of said current for the purpose of conducting said current to the soil, said electrode shaft member being formed of a first conductive metal and having an interior cavity provided with a second conductive metal which has a lower melting point than the first metal and is molten at operating temperatures of said process at which the soil is molten, as where current is conducted to said soil by said electrode shaft member for melting said soil.

Claim 27

Dependent Claim 144 words

An electrode for use in the process of in situ vitrification of soil by application of electric current to the soil via said electrode to raise the soil to a high temperature for melting said soil at levels along said electrode, said electrode comprising: an electrically conductive electrode shaft member adapted for positioning at least partially below the soil surface and adapted for connection to a source of said current for the purpose of conducting said current to the soil, said electrode shaft member being formed of a first conductive metal and having an interior cavity provided with a second conductive metal which has a lower melting point than the first metal and is molten at operating temperatures of said process at which the soil is molten, as where current is conducted to said soil by said electrode shaft member for melting said soil.

Claim 28

Dependent Claim 21 words

The electrode according to claim 25 wherein said electrode shaft is formed of molybdenum and said second conductive metal comprises copper.

Claim 29

Dependent Claim 14 words

The electrode according to claim 25 wherein said second conductive metal is initially comminuted.

Claim 30

Dependent Claim 182 words

An electrode system for use in the process of in situ vitrification of soil by application of electric current to the soil to raise the soil to a high temperature for melting said soil, said electrode system comprising: a first electrode including an electrically conductive electrode shaft member positioned at least partially below the soil surface and adapted for connection to a source of said current for the purpose of conducting said current to the soil while maintaining its integrity at high temperatures at least below the surface of the soil, a second electrode for cooperating with said first electrode such that said current is applicable to the soil between said first and second electrodes, electrical connection means joined to said electrode shaft member of said first electrode at a position thereupon for location substantially below the surface of the soil, and conductor means joined to said connection means for coupling to said source of current and extending from said connection means along a path farther from the second electrode than the spacing between said electrode shaft member and said second electrode.

Claim 31

Dependent Claim 182 words

An electrode system for use in the process of in situ vitrification of soil by application of electric current to the soil to raise the soil to a high temperature for melting said soil, said electrode system comprising: a first electrode including an electrically conductive electrode shaft member positioned at least partially below the soil surface and adapted for connection to a source of said current for the purpose of conducting said current to the soil while maintaining its integrity at high temperatures at least below the surface of the soil, a second electrode for cooperating with said first electrode such that said current is applicable to the soil between said first and second electrodes, electrical connection means joined to said electrode shaft member of said first electrode at a position thereupon for location substantially below the surface of the soil, and conductor means joined to said connection means for coupling to said source of current and extending from said connection means along a path farther from the second electrode than the spacing between said electrode shaft member and said second electrode.

Claim 32

Dependent Claim 219 words

In an electrode system for use in the process of in situ vitrification of soil by application of electric current to the soil to raise the soil to a high temperature for melting said soil, a first electrode, wherein said first electrode is positioned at least partially below the soil surface and is adapted for connection to a source of said current for the purpose of conducting said current to the soil while substantially maintaining its integrity at high temperatures at least below the surface of the soil, a second electrode, wherein said second electrode is located at least partially below the soil surface in spaced relation to said first electrode, said second electrode also being adapted for connection to said source of current whereby current can be applied to the soil between said electrodes, sacrificial electrode means disposed generally between said first and second electrodes in more closely spaced relation to said second electrode than the spacing between said first electrode and said second electrode, electrical connection means joined to said first electrode, electrical connection means joined to said sacrificial electrode means, and means for switching current from said source between said electrical connection means joined to said sacrificial electrode means and said electrical connection means joined to said first electrode after initiation of melting of said soil.

Claim 33

Dependent Claim 219 words

In an electrode system for use in the process of in situ vitrification of soil by application of electric current to the soil to raise the soil to a high temperature for melting said soil, a first electrode, wherein said first electrode is positioned at least partially below the soil surface and is adapted for connection to a source of said current for the purpose of conducting said current to the soil while substantially maintaining its integrity at high temperatures at least below the surface of the soil, a second electrode, wherein said second electrode is located at least partially below the soil surface in spaced relation to said first electrode, said second electrode also being adapted for connection to said source of current whereby current can be applied to the soil between said electrodes, sacrificial electrode means disposed generally between said first and second electrodes in more closely spaced relation to said second electrode than the spacing between said first electrode and said second electrode, electrical connection means joined to said first electrode, electrical connection means joined to said sacrificial electrode means, and means for switching current from said source between said electrical connection means joined to said sacrificial electrode means and said electrical connection means joined to said first electrode after initiation of melting of said soil.

Claim 34

Dependent Claim 35 words

The system according to claim 29 wherein said sacrificial electrode means is placed in sufficient proximity to said first electrode so that soil substantially adjacent said first electrode is melted before current is switched thereto.

Claim 35

Dependent Claim 68 words

The electrode system according to claim 29 further including third and fourth electrodes completing a quadrilateral array with said first and second electrodes, and additional sacrificial electrode means located inwardly of said array generally in front of said second, third and fourth electrodes, and additional means for switching current between said sacrificial electrode means and the electrodes of the quadrilateral array after initiation of melting of said soil.

Claim 36

Dependent Claim 231 words

In an electrode system for use in the process of in situ vitrification of soil by application of electric current to the soil to raise the soil to a high temperature for melting said soil, a first electrode, wherein said first electrode is positioned at least partially below the soil surface and is adapted for connection to a source of said current for the purpose of conducting said current to the soil while substantially maintaining its integrity at high temperatures at least below the surface of the soil, a second electrode, wherein said second electrode is located at least partially below the soil surface in spaced relation to said first electrode, said second electrode also being adapted for connection to said source of current whereby current can be applied to the soil between said electrodes, outboard electrode means disposed farther from said second electrode than the spacing between said first electrode and said second electrode, being located generally on the opposite side of said first electrode from said second electrode, electrical connection means joined to said first electrode, electrical connection means joined to said outboard electrode means, conductor means for coupling to said source of current, and means for switching said conductor means from said electrical connection means joined to said first electrode to said electrical connection means joined to said outboard electrode means for extending the region of melted soil.

Claim 37

Dependent Claim 231 words

In an electrode system for use in the process of in situ vitrification of soil by application of electric current to the soil to raise the soil to a high temperature for melting said soil, a first electrode, wherein said first electrode is positioned at least partially below the soil surface and is adapted for connection to a source of said current for the purpose of conducting said current to the soil while substantially maintaining its integrity at high temperatures at least below the surface of the soil, a second electrode, wherein said second electrode is located at least partially below the soil surface in spaced relation to said first electrode, said second electrode also being adapted for connection to said source of current whereby current can be applied to the soil between said electrodes, outboard electrode means disposed farther from said second electrode than the spacing between said first electrode and said second electrode, being located generally on the opposite side of said first electrode from said second electrode, electrical connection means joined to said first electrode, electrical connection means joined to said outboard electrode means, conductor means for coupling to said source of current, and means for switching said conductor means from said electrical connection means joined to said first electrode to said electrical connection means joined to said outboard electrode means for extending the region of melted soil.

Claim 38

Dependent Claim 22 words

The electrode system according to claim 32 wherein said outboard electrode means extends less deeply into the ground than said first electrode.

Claim 39

Dependent Claim 59 words

The electrode system according to claim 32 further including third and fourth electrodes completing a quadrilateral array with said first and second electrodes, and additional outboard electrode means located outwardly of said array behind said second, third and fourth electrodes, and additional means for switching current to said outboard electrode means for squaring up a region of melted soil.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-09-10	1994-03-12	1994-09-11	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-09-10	1998-03-12	1998-09-11	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-09-10	2002-03-12	2002-09-11	$7700.00	Window Closed / Lapsed

Electrode systems for in situ vitrification

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