Flexible averaging resistance temperature detector
A temperature sensor. The sensor comprises a wire comprising a resistance temperature detector (RTD) sensing material wrapped around a flexible insulated metal core wire to form an assembly. A first end of the sensing wire is electrically connected to a first end of the core wire. The second end of the core wire provides a first lead, and an insulated lead wire is electrically connected to a second end of the sensing wire to provide a second lead. Shrink tubing encapsulates the assembly.
1. A temperature sensor comprising:
a wire comprising resistance temperature detector (RTD) sensing material wrapped in a plurality of adjacent windings around a flexible core wire to form distributed adjacent windings insulated from the core wire and including separation between adjacent windings to form a flexible assembly, the wire including a first end and a second end and the core wire including a first core end and a second core end, the first end electrically connected to the first core end, the second core end providing a first lead;
an insulated lead wire electrically connected to the second end of the wire to provide a second lead; and
shrink tubing adapted to cover at least the first end such that the sensor has a height of about one twentieth of an inch.
2. The temperature sensor of claim 1 , wherein the core wire includes braided strands of conductive metal.
3. The temperature sensor of claim 2 , wherein the core wire includes woven fiber glass insulation over the braided strands.
4. The temperature sensor of claim 3 , wherein the wire material comprising a sensing material includes one, or a combination of platinum, nickel, nickel-iron alloy and copper.
5. The temperature sensor of claim 4 , wherein the electrical connections to the wires are made using soldering or brazing.
6. The temperature sensor of claim 5 , wherein the sensor further comprises a strain relieving banding strip over the core wire and the second lead wire.
7. The temperature sensor of claim 6 , wherein the banding strap includes brass.
8. The temperature sensor of claim 6 , wherein the banding strap includes steel.
9. The temperature sensor of claim 6 , wherein the banding strip is crimped around the core wire and the insulated lead wire.
10. The temperature sensor of claim 9 , wherein the first and second lead wires exit the sensor at the same end.
11. The temperature sensor of claim 10 , wherein an insulated lead wire is electrically connected to the second core end to provide the first lead.
12. The temperature sensor of claim 11 , wherein a second banding strip is placed around the first and second lead wires.
13. The temperature sensor of claim 11 , wherein the insulated wire leads withstand a five-pound pull force without separating from the assembly.
14. A temperature sensor produced by the method comprising:
wrapping a plurality of adjacent windings of a first wire comprising a resistance temperature detector (RTD) sensing material around a flexible core wire to form distributed adjacent windings insulated from the core wire and including separation between adjacent windings, creating a flexible wire wrapped assembly, the first wire including a first end and a second end and the core wire including a first core end and a second core end;
electrically connecting the first end to the first core end;
providing leads for the temperature sensor by electrically connecting a first insulated lead to the second end and using the second core end as a second lead of the temperature sensor;
placing the wire wrapped assembly into a heat shrinkable polymer tubing material; and
covering at least the first end and the first core end of the temperature sensor by heating the polymer material.
15. The method of claim 14 , wherein providing leads includes electrically connecting a second insulated lead to the second core end.
16. The method of claim 15 , wherein the method further includes providing mechanical strain relief for the first and second leads.
17. The method of claim 14 , wherein electrically connecting to the sensing wire includes soldering or brazing.
18. A temperature sensor comprising:
a wire including resistance temperature detector sense material wrapped around a flexible core wire to form a flexible assembly;
a tip including a first end of the wire electrically connected to a first end of the core wire, the tip further covered by a heat shrinkable polymer material; and
an insulated second lead wire connected to a second end of the wire, wherein the flexible assembly has a height of about one twentieth of an inch.
19. The temperature sensor of claim 18 , wherein the heat shrinkable polymer material is polytetrafluoroethylene (PTFE).
20. A method of manufacturing a temperature sensor comprising steps of:
wrapping a plurality of windings of a first wire comprising resistance temperature detector sense material around a flexible core wire to form a flexible wire wrapped assembly, the first wire having a first and a second end and the core wire including a first core end and a second core end;
electrically connecting the first end of the wire to the first end of the core wire;
placing at least the electrically connected first end of the wire and first end of the core wire into a heat shrinkable polymer tubing material to form a tip; and
sealing the tip by heating the polymer material.
21. The method of claim 20 , wherein the heat shrinkable polymer material is polytetrafluoroethylene (PTFE).