Downhole transmission system comprising a coaxial capacitor
A transmission system in a downhole component comprises a plurality of data transmission elements. A coaxial cable having an inner conductor and an outer conductor is disposed within a passage in the downhole component such that at least one capacitor is disposed in the passage and having a first terminal coupled to the inner conductor and a second terminal coupled to the outer conductor. Preferably the transmission element comprises an electrically conducting coil. Preferably, within the passage a connector is adapted to electrically connect the inner conductor of the coaxial cable and the lead wire. The coaxial capacitor may be disposed between and in electrically communication with the connector and the passage. In another embodiment a connector is adapted to electrical connect a first and a second portion of the inner conductor of the coaxial cable and a coaxial capacitor is in electrical communication with the connector and the passage.
1 . A transmission system in a downhole component, comprising:
a plurality of data transmission elements connected by a coaxial cable;
the coaxial cable having an inner conductor and an outer conductor disposed within a passage in the downhole component;
at least one capacitor disposed in the passage and having a first terminal coupled to the inner conductor and a second terminal coupled to the outer conductor.
2 . The transmission system of claim 1 wherein the transmission elements comprises a lead wire extending from a coil.
3 . The transmission system of claim 2 wherein the system further comprises a connector adapted to electrically connect the inner conductor of the coaxial cable and the lead wire.
4 . The transmission system of claim 1 wherein the system further comprises a connector adapted to electrically connect the first and second portions of the inner conductor.
5 . The transmission system of claim 1 wherein the capacitor displaces a portion of dielectric material within the coaxial cable.
6 . A transmission system in a downhole component, comprising:
a plurality of data transmission elements wherein each data transmission element comprises an electrically conducting coil,
a lead wire on at least one coil;
a coaxial cable disposed within a passage in the downhole component; and
a connector adapted to electrically connect an inner conductor of the coaxial cable and the lead wire; and
a coaxial capacitor disposed between and in electrical communication with the connector and the passage.
7 . The transmission system according to claim 6 , wherein the transmission element comprises an anti-rotation device coaxially mounted on the lead wire for preventing the electrically conducting coil to rotate about the axis of the lead wire.
8 . The transmission system according to claim 6 , wherein the data transmission element comprises electrical contacts adapted to be in electrical communication with an adjacent transmission element in an adjacent downhole component.
9 . The transmission system according to claim 6 , wherein the data transmission element comprises an inductive coupler adapted to be in magnetic communication with an adjacent transmission element in an adjacent downhole component.
10 . The transmission system according to claim 9 , wherein the inductive coupler houses the electrically conducting coil in MCEI material.
11 . The transmission system according to claim 10 , wherein the MCE material is ferrite.
12 . The transmission system according to claim 6 , wherein the passage is formed in the downhole component.
13 . The transmission system according to claim 6 , wherein the passage is a metal tube.
14 . The transmission system according to claim 6 , wherein the passage is an outer conductor of the coaxial cable.
15 . The transmission system according to claim 6 , wherein the connector is comprised of a signal section.
16 . The transmission system according to claim 6 , wherein the connector is comprised of at least two sections.
17 . The transmission system according to claim 16 , wherein the at least two sections are separated by a spacer.
18 . The transmission system according to claim 6 , wherein the connector is at least partially electrically insulated.
19 . The transmission system according to claim 6 , wherein the capacitor comprises at least one electrically conducting spacer in electrical communication with the passage.
20 . The transmission system according to claim 6 , wherein the transmission system comprises a sealing assembly.
21 . The transmission system according to claim 20 , wherein the sealing assembly is axial mounted around the lead wire.
22 . A transmission system in a downhole component, comprising:
a plurality of data transmission elements;
a coaxial cable, disposed within a passage in the downhole component, comprising a first and a second portion of an inner conductor;
a connector adapted to electrically connect the first and second portions of the inner conductor wherein a coaxial capacitor is disposed between and in electrical communication with the connector and the passage;
wherein the first portion is in electrical communication with a first data transmission element, and the second portion is in electrical communication with a second transmission element.
23 . The transmission system according to claim 22 , wherein the transmission system comprises at least one inductor located on either side of the coaxial capacitor.
24 . The transmission system according to claim 22 , wherein the transmission element comprises an anti-rotation device coaxially mounted on the lead wire for preventing an electrically conducting coil to rotate about the axis of the lead wire.
25 . The transmission system according to claim 22 , wherein the data transmission element comprises a direct electrical coupler.
26 . The transmission system according to claim 22 , wherein the data transmission element comprises an inductive coupler.
27 . The transmission system according to claim 26 , wherein the inductive coupler houses an electrically conducting coil in MCEI material.
28 . The transmission system according to claim 27 , wherein the MCEI material is ferrite.
29 . The transmission system according to claim 22 , wherein the transmission system further comprises a sealing assembly mounted axial around the lead wire.
30 . The transmission system according to claim 22 , wherein the passage is formed in the downhole component.
31 . The transmission system according to claim 22 , wherein the passage is a metal tube.
32 . The transmission system according to claim 22 , wherein the passage is an outer conductor of the coaxial cable.
33 . The transmission system according to claim 22 , wherein the connector is comprised of a signal section.
34 . The transmission system according to claim 22 , wherein the connector is comprised of at least two sections.
35 . The transmission system according to claim 34 , wherein the at least two sections are separated by a spacer.
36 . The transmission system according to claim 22 , wherein the connector is at least partially electrically insulated.
37 . The transmission system according to claim 22 , wherein the coaxial capacitor is axially mounted to the connector.
38 . The transmission system according to claim 22 , wherein the capacitor comprises at least one electrically conducting spacer in electrical communication with the passage.