Temperature compensated wire-conducting tube and method of manufacture

Abstract

A method and apparatus for manufacturing a continuous metal tube having a plurality of electrical conductors disposed therein, by using a spring member to depress the electrical conductors while a flat metal strip is formed into a tubular member and welded to enclose the electrical conductors. The spring member functions to protect the electrical conductors from heat damage. The welding occurs completely downstream of the spring member in order to avoid excessive heat buildup in the spring member.

What is claimed is: 
     
       1. A method for manufacturing a continuous metal tube having electrical conductors disposed within the tube, said method comprising: feeding a continuous strip of flat metal into a tube-forming station;   feeding continuous multiple electrical conductors into said tube-forming station, at least some of the conductors being twisted upon themselves to form unitary twisted bundles and the remainder of the conductors being left in an untwisted condition;   forming said strip of first metal into a tubular member with the edges of said strip being aligned and substantially in contact;   depressing said electrical conductors to the side of the formed tubular member opposite the aligned edges to protect said conductors from heat damage; and   continuously welding the aligned edges together to provide a continuous tubular member.   
     
     
       2. The method of claim 1 including utilizing a corrosion resistant alloy steel as said metal. 
     
     
       3. The method of claim 1 including surrounding at least the portion of the tubular member being welded with an inert gas. 
     
     
       4. The method of claim 1 including using carbon steel as the metal. 
     
     
       5. The method of claim 1 including providing a sufficient length of each twisted bundle of wires so that at least a portion of each bundle of wires contacts another twisted bundle or the interior wall of the tube. .Iadd. 
     
     
       6.  A wire-conducting tube formed of an improved combination of a tubular conduit and electrical conductor wire for transmission of electricity to a remote location, comprising: a) an elongated tubular conduit formed of metal having an inner surface and an inner diameter;   b) at least one insulated conductor wire having an outer surface and extending through the conduit, the wire having a permanent helical shape such that the outer surface of the insulated conductor wire is in substantially continuous contact with the inner surface of the conduit, the insulated conductor wire having an outside diameter, wherein said conduit inner diameter is greater than said conductor wire outside diameter such that an annular space is formed between the insulated conductor wire and said conduit inner surface, said annular space being devoid of a solid material where said helical shape of the insulated conductor wire can expand and contract in response to temperature changes;   c) the conduit for storing on a drum and having enough flexibility to be stored on said drum and unwound for positioning the conduit in a downhole application for transmitting electricity through the conduit wire, with the wire maintaining itself in position in the conduit when the conduit is in a substantially vertical downhole position; and   d) wherein the conduit is formed of a continuous strip of metal, the metal being formed in a tubular shape with juxtaposed edges welded so as to provide a fluid tight conduit..Iaddend..Iadd.7. A wire-conducting tube formed of an improved combination of a tubular conduit and electrical conductor wire for transmission of electricity to a remote location, comprising:   a) an elongated tubular conduit formed of metal having an inner surface and an inner diameter;   b) at least one insulated conductor wire having an outer surface and extending through the conduit, the wire having a permanent helical shape such that the outer surface of the insulated conductor wire is in substantially continuous contact with the inner surface of the conduit, the insulated conductor wire having an outside diameter, wherein said conduit inner diameter is greater than said conductor wire outside diameter such that an annular space is formed between the insulated conductor wire and said conduit inner surface, said annular space being devoid of a solid material where said helical shape of the insulated conductor wire can expand and contract in response to temperature changes;   c) the conduit for storing on a drum and having enough flexibility to be stored on said drum and unwound for positioning the conduit in a downhole application for transmitting electricity through the conduit wire, with the wire maintaining itself in position in the conduit when the conduit is in a substantially vertical downhole position; and   d) wherein the conduit is formed of a corrosion-resistant metal having relatively high strength at temperatures greater than 400° F..Iaddend..Iadd.8. The wire-conducting tube of claim 7, wherein the   
     
     
        corrosion-resistant metal includes stainless steel..Iaddend..Iadd.9.  A wire-conducting tube formed of an improved combination of a tubular conduit and electrical conductor wire for transmission of electricity to a remote location, comprising: a) an elongated tubular conduit formed of metal having an inner surface and an inner diameter;   b) at least one insulated conductor wire having an outer surface and extending through the conduit, the wire having a permanent helical shape such that the outer surface of the insulated conductor wire is in substantially continuous contact with the inner surface of the conduit, the insulated conductor wire having an outside diameter, wherein said conduit inner diameter is greater than said conductor wire outside diameter such that an annular space is formed between the insulated conductor wire and said conduit inner surface, said annular space being devoid of a solid material where said helical shape of the insulated conductor wire can expand and contract in response to temperature changes;   c) the conduit for storing on a drum and having enough flexibility to be stored on said drum and unwound for positioning the conduit in a downhole application for transmitting electricity through the conduit wire, with the wire maintaining itself in position in the conduit when the conduit is in a substantially vertical downhole position;   d) amd further including a plurality of insulated conductor wires extending through the conduit, said plurality of wires being in substantially continuous contact with the inner surface of the conduit; and   e) wherein the plurality of wires includes eleven 22-gauge wires positioned in two twisted groups containing three wires each and five wires remaining free..Iaddend..Iadd.10. A wire-conducting tube formed of an improved combination of a tubular conduit and electrical conductor wire for transmission of electricity to a remote location, comprising:   a) an elongated tubular conduit formed of metal having an inner surface and an inner diameter;   b) at least one insulated conductor wire having an outer surface and extending through the conduit, the wire having a permanent helical shape such that the outer surface of the insulated conductor wire is in substantially continuous contact with the inner surface of the conduit, the insulated conductor wire having an outside diameter, wherein said conduit inner diameter is greater than said conductor wire outside diameter such that an annular space is formed between the insulated conductor wire and said conduit inner surface, said annular space being devoid of a solid material where said helical shape of the insulated conductor wire can expand and contract in response to temperature changes;   c) the conduit for storing on a drum and having enough flexibility to be stored on said drum and unwound for positioning the conduit in a downhole application for transmitting electricity through the conduit wire, with the wire maintaining itself in position in the conduit when the conduit is in a substantially vertical downhole position; and   d) wherein the conduit has a 0.375 inch O.D. and a wall thickness of 0.049 inch..Iaddend..Iadd.11. A wire-conducting tube formed of an improved combination of a tubular conduit and electrical conductor wire for transmission of electricity to a remote location, comprising:   a) an elongated tubular conduit formed of metal having an inner surface and an inner diameter;   b) at least one insulated conductor wire having an outer surface and extending through the conduit, the wire having a permanent helical shape such that the outer surface of the insulated conductor wire is in substantially continuous contact with the inner surface of the conduit, the insulated conductor wire having an outside diameter, wherein said conduit inner diameter is greater than said conductor wire outside diameter such that an annular space is formed between the insulated conductor wire and said conduit inner surface, said annular space being devoid of a solid material where said helical shape of the insulated conductor wire can expand and contract in response to temperature changes;   c) the conduit for storing on a drum and having enough flexibility to be stored on said drum and unwound for positioning the conduit in a downhole application for transmitting electricity through the conduit wire, with the wire maintaining itself in position in the conduit when the conduit is in a substantially vertical downhole position; and   d) wherein friction between the outer surface of the insulated conductor wire and the inner surface of the conduit maintains the insulated conductor wire in position in the conduit when the conduit is in a substantially vertical downhole position..Iaddend..Iadd.12. A wire-conducting tube formed of an improved combination of a tubular conduit and electrical conductor wire for transmission of electricity to a remote location, comprising:   a) an elongated tubular conduit formed of metal having an inner surface and an inner diameter;   b) at least one insulated conductor wire having an outer surface and extending through the conduit, the wire having a permanent helical shape such that the outer surface of the insulated conductor wire is in substantially continuous contact with the inner surface of the conduit, the insulated conductor wire having an outside diameter, wherein said conduit inner diameter is greater than said conductor wire outside diameter such that an annular space is formed between the insulated conductor wire and said conduit inner surface, said annular space being devoid of a solid material where said helical shape of the insulated conductor wire can expand and contract in response to temperature changes;   c) the conduit for storing on a drum and having enough flexibility to be stored on said drum and unwound for positioning the conduit in a downhole application for transmitting electricity through the conduit wire, with the wire maintaining itself in position in the conduit when the conduit is in a substantially vertical downhole position; and   d) wherein the annular space is filled with a purge gas..Iaddend..Iadd.13. A wire-conducting tube formed of an improved combination of a tubular conduit and electrical conductor wire for transmission of electricity to a remote location, comprising:   a) an elongated tubular conduit formed of metal having an inner surface and an inner diameter;   b) at least one insulated conductor wire having an outer surface and extending through the conduit, the wire having a permanent helical shape such that the outer surface of the insulated conductor wire is in substantially continuous contact with the inner surface of the conduit, the insulated conductor wire having an outside diameter, wherein said conduit inner diameter is greater than said conductor wire outside diameter such that an annular space is formed between the insulated conductor wire and said conduit inner surface, said annular space being devoid of a solid material where said helical shape of the insulated conductor wire can expand and contract in response to temperature changes;   c) the conduit for storing on a drum and having enough flexibility to be stored on said drum and unwound for positioning the conduit in a downhole application for transmitting electricity through the conduit wire, with the wire maintaining itself in position in the conduit when the conduit is in a substantially vertical downhole position; and   d) wherein the conduit is formed of a first material and the insulated conductor wire is formed of a second material, and wherein said second material expands at a faster rate than said first material with rising temperature..Iaddend..Iadd.14. The wire-conducting tube of claim 13, wherein said first material includes stainless steel and said second material is copper..Iaddend..Iadd.15. A wire-conducting tube formed of an improved combination of a tubular conduit and electrical conductor wire for transmission of electricity to a remote location, comprising:   a) an elongated tubular conduit formed of metal having an inner surface and an inner diameter;   b) at least one insulated conductor wire having an outer surface and extending through the conduit, the wire having a permanent helical shape such that the outer surface of the insulated conductor wire is in substantially continuous contact with the inner surface of the conduit, the insulated conductor wire having an outside diameter, wherein said conduit inner diameter is greater than said conductor wire outside diameter such that an annular space is formed between the insulated conductor wire and said conduit inner surface, said annular space being devoid of a solid material where said helical shape of the insulated conductor wire can expand and contract in response to temperature changes;   c) the conduit for storing on a drum and having enough flexibility to be stored on said drum and unwound for positioning the conduit in a downhole application for transmitting electricity through the conduit wire, with the wire maintaining itself in position in the conduit when the conduit is in a substantially vertical downhole position; and   d) wherein said tubular conduit has a length of at least 1,000 feet..Iaddend.