US4231231A — Cryogenic ceramic and apparatus

Claim 1

Independent Claim 128 words

Ceramic material: (a) characterized by (1) being a dielectric insulator and (2) having values of specific heat at selected temperatures below 15° K. that are greater than or at least equal to the values of specific heat of pure Pb at those same temperatures, and (b) consisting essentially of a crystalline phase with a composition defined by the molar formula AB 2 O 4 wherein A is one or more of Group 2b metal ions plus other divalent metal ion or ions where at least about 90 mole % of A is Group 2b metal ion or ions, and B is either Cr ion or Cr ion plus one or more of other trivalent metal ions where at least about 90 mole % of B is Cr ion.

Claim 2

Dependent Claim 128 words

Ceramic material: (a) characterized by (1) being a dielectric insulator and (2) having values of specific heat at selected temperatures below 15° K. that are greater than or at least equal to the values of specific heat of pure Pb at those same temperatures, and (b) consisting essentially of a crystalline phase with a composition defined by the molar formula AB 2 O 4 wherein A is one or more of Group 2b metal ions plus other divalent metal ion or ions where at least about 90 mole % of A is Group 2b metal ion or ions, and B is either Cr ion or Cr ion plus one or more of other trivalent metal ions where at least about 90 mole % of B is Cr ion.

Claim 3

Dependent Claim 118 words

Ceramic material: (a) Characterized by (1) being a dielectric insulator and (2) having values of specific heat at selected temperatures below 15° K. that are greater than or at least equal to the values of specific heat of pure Pb at those same temperatures, and (b) consisting essentially of a crystalline phase with a composition defined by the molar formula AB 2 O 4 wherein A is Cd ion alone or in combination with one or more of other divalent metal ions where at least about 90 mole % of A is Cd ion, and B is Cr ion plus other trivalent metal ion or ions where at least about 90 mole % of B is Cr ion.

Claim 4

Dependent Claim 118 words

Ceramic material: (a) Characterized by (1) being a dielectric insulator and (2) having values of specific heat at selected temperatures below 15° K. that are greater than or at least equal to the values of specific heat of pure Pb at those same temperatures, and (b) consisting essentially of a crystalline phase with a composition defined by the molar formula AB 2 O 4 wherein A is Cd ion alone or in combination with one or more of other divalent metal ions where at least about 90 mole % of A is Cd ion, and B is Cr ion plus other trivalent metal ion or ions where at least about 90 mole % of B is Cr ion.

Claim 5

Dependent Claim 12 words

Material of claim 2 wherein the other trivalent metal ion is Fe.

Claim 6

Dependent Claim 9 words

Material of claim 3 wherein A is Cd ion.

Claim 7

Dependent Claim 149 words

Ceramic material: (a) characterized by (1) being a dielectric insulator and (2) having values of specific heat at selected temperatures below 15° K. that are greater than or at least equal to the values of specific heat of pure Pb at those same temperatures, and (b) consisting essentially of (1) a crystalline phase with a composition defined by the molar formula AB 2 O 4 where A is selected from one or more of Group 2b metal ions alone or in combination with one or more of other divalent metal ions where at least about 90 mole % of A is Group 2b metal ion or ions, and B is either Cr ion or Cr ion plus one or more of other trivalent metal ions where at least about 90 mole % of B is Cr ion, and (2) a mineralizer crystalline phase that is of the niobite type.

Claim 8

Dependent Claim 149 words

Ceramic material: (a) characterized by (1) being a dielectric insulator and (2) having values of specific heat at selected temperatures below 15° K. that are greater than or at least equal to the values of specific heat of pure Pb at those same temperatures, and (b) consisting essentially of (1) a crystalline phase with a composition defined by the molar formula AB 2 O 4 where A is selected from one or more of Group 2b metal ions alone or in combination with one or more of other divalent metal ions where at least about 90 mole % of A is Group 2b metal ion or ions, and B is either Cr ion or Cr ion plus one or more of other trivalent metal ions where at least about 90 mole % of B is Cr ion, and (2) a mineralizer crystalline phase that is of the niobite type.

Claim 9

Dependent Claim 48 words

Material of claim 5 wherein the niobite type phase has a composition defined by the molar formula AC 2 O 6 where A is the same as in the AB 2 O 4 spinel phase and C is selected from one or both of Nb and Ta ions.

Claim 10

Dependent Claim 9 words

Material of claim 6 wherein C is Nb ion.

Claim 11

Dependent Claim 192 words

In cryogenic refrigeration apparatus comprising a load to be refrigerated, a refrigerant adapted to refrigerate the load at temperatures below 15° K., thermal energy absorbing elements associated with the refrigerant and adapted to function at temperatures below 15° K., wherein the improvement comprises at least one of the thermal energy absorbing elements being composed of ceramic material: (a) characterized by (1) being a dielectric insulator and (2) having values of specific heat at selected temperatures below 15° K. that are greater than or at least equal to the values of specific heat of pure Pb at those sampe temperatures, and p2 (b) consisting essentially of a crystalline phase with a composition defined by the molar formula AB 2 O 4 where A is selected from one or more of Group 2b metal ions alone or in combination with one or more of other divalent metal ions where at least about 90 mole % of A is Group 2b metal ion or ions, and B is either Cr ion or Cr ion plus one or more of other trivalent metal ions where at least about 90 mole % of B is Cr ion.

Claim 12

Dependent Claim 192 words

In cryogenic refrigeration apparatus comprising a load to be refrigerated, a refrigerant adapted to refrigerate the load at temperatures below 15° K., thermal energy absorbing elements associated with the refrigerant and adapted to function at temperatures below 15° K., wherein the improvement comprises at least one of the thermal energy absorbing elements being composed of ceramic material: (a) characterized by (1) being a dielectric insulator and (2) having values of specific heat at selected temperatures below 15° K. that are greater than or at least equal to the values of specific heat of pure Pb at those sampe temperatures, and p2 (b) consisting essentially of a crystalline phase with a composition defined by the molar formula AB 2 O 4 where A is selected from one or more of Group 2b metal ions alone or in combination with one or more of other divalent metal ions where at least about 90 mole % of A is Group 2b metal ion or ions, and B is either Cr ion or Cr ion plus one or more of other trivalent metal ions where at least about 90 mole % of B is Cr ion.

Claim 13

Dependent Claim 38 words

The apparatus of claim 8 wherein the refrigerant is fluid refrigerant, and the at least one of the elements is regenerator packing adapted to alternately take up thermal energy from and give up thermal energy to the refrigerant.

Claim 14

Dependent Claim 29 words

The apparatus of claim 8 wherein said at least one of the elements is a thermal damper connected to the load and interposed between the load and the refrigerant.

Claim 15

Dependent Claim 44 words

The apparatus of claim 8 wherein the load includes at least one superconducting component and the at least one of the elements is dielectric insulation associated with the at least one component to electrically insulate the component from other conductive parts of the apparatus.

Claim 16

Dependent Claim 9 words

Apparatus of claim 8 wherein B is Cr ion.

Claim 17

Dependent Claim 9 words

Apparatus of claim 12 wherein A is Zn ion.

Claim 18

Dependent Claim 9 words

Apparatus of claim 12 wherein A is Cd ion.

Claim 19

Dependent Claim 16 words

Apparatus of claim 8 wherein B is Cr ion plus other trivalent metal ion or ions.

Claim 20

Dependent Claim 12 words

Apparatus of claim 15 wherein the other trivalent metal ion is Fe.

Claim 21

Dependent Claim 9 words

Apparatus of claim 16 wherein A is Cd ion.

Claim 22

Dependent Claim 22 words

Apparatus of claim 8 wherein A is one or more of Group 2b metal ions plus other divalent metal ion or ions.

Claim 23

Dependent Claim 21 words

Apparatus of claims 8, 12, 13, 14, 15, 16, 17 or 18 wherein the ceramic material includes a mineralizer crystalline phase.

Claim 24

Dependent Claim 14 words

Apparatus of claim 19 wherein the mineralizer crystalline phase is of the noibite type.

Claim 25

Dependent Claim 48 words

Apparatus of claim 20 wherein the niobite type phase has a composition defined by the molar formula AC 2 O 6 where A is the same as in the AB 2 O 4 spinel phase and C is selected from one or both of Nb and Ta ions.

Claim 26

Dependent Claim 9 words

Apparatus of claim 21 wherein C is Nb ion.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1983-11-04	1984-05-05	1984-11-04	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1987-11-04	1988-05-05	1988-11-04	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1991-11-04	1992-05-05	1992-11-04	$7700.00	Window Closed / Lapsed

Cryogenic ceramic and apparatus

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