AN ULTRA-LOW PRECIOUS METAL THERMOCOUPLE TEMPERATURE SENSOR
Disclosed is a temperature sensing device including a thermocouple having a pair of wires, a temperature measuring junction between the wires, and an insulator covering the wires and a. protective sheath. The protective sheath includes a sapphire tertiary sheath surrounding the wires, the temperature measuring junction, and the insulator of the thermocouple, a secondary sheath surrounding the tertiary sheath, and a primary sheath surrounding the secondary sheath.
1 . A temperature sensing device comprising:
a thermocouple having a pair of wires, a temperature measuring junction between the wires, and an insulator covering the wires; and
a protective sheath comprising:
a tertiary sheath surrounding the wires, the temperature measuring junction, and the insulator of the thermocouple,
a secondary sheath surrounding the tertiary sheath, and
a primary sheath surrounding the secondary sheath;
wherein the tertiary sheath contains sapphire.
2 . The temperature sensing device of claim 1 , wherein the primary sheath contains at least one of sapphire, alumina, zirconium, mullite or a combination thereof.
3 . The temperature sensing device of claim 1 , wherein the secondary sheath contains at least one of alumina, zirconium, mullite or a combination thereof.
4 . The temperature sensing device of claim 1 , wherein the primary sheath or the secondary sheath comprise multiple layers.
5 . The temperature sensing device of claim 1 , further comprising a fin extending along a length of the protective sheath.
6 . The temperature sensing device of claim 5 , wherein the fin extends along a length of the thermocouple device configured to contact a molten material.
7 . The temperature sensing device of claim 5 , wherein the fin defines an angled surface.
8 . The temperature sensing device of claim 1 , wherein the primary sheath contains high purity alumina and the secondary sheath contains high purity alumina.
9 . The temperature sensing device of claim 1 , wherein the protective sheath is free of precious metal.
10 . A temperature sensing device comprising:
a temperature sensor for measuring a temperature of an environment; and
a protection means for protecting the temperature sensor comprising:
a tertiary protection means surrounding the temperature sensor,
a secondary protection means surrounding the tertiary protection means, and
a primary protection means surrounding the secondary protection means;
wherein the tertiary protection means contains sapphire.
11 . The temperature sensing device of claim 10 , wherein the primary protection means contains at least one of sapphire, alumina, zirconium, mullite or a combination thereof.
12 . The temperature sensing device of claim 10 , wherein the secondary protection means contains at least one of alumina, zirconium, mullite or a combination thereof.
13 . The temperature sensing device of claim 10 , wherein the primary protection means or the secondary protection means comprise multiple layers.
14 . The temperature sensing device of claim 10 , further comprising a fin extending along a length of the protection means.
15 . The temperature sensing device of claim 14 , wherein the fin extends along a length of the temperature sensor configured to contact a molten material.
16 . The temperature sensing device of claim 14 , wherein the fin defines an angled surface.
17 . The temperature sensing device of claim 10 , wherein the protection means is free of precious metal.