Sensor line
A sensor line for detecting an external influence on a cable is described. The sensor line comprises: a capacitor, a first dielectric, which has a first compressibility and a first permittivity, and a second dielectric, which has a second compressibility and a second permittivity. The first compressibility is smaller than the second compressibility. The first permittivity differs from the second permittivity. The sensor line is configured so that at least the second dielectric is compressible or extensible in the event of a movement of the sensor line, so that a total permittivity, which is composed of the first permittivity and the second permittivity, is variable in the movement of the sensor line. Due to the change in total permittivity, a change in the capacitance of the capacitor can be produced, which is detectable, in order to detect the external influence on the cable.
1. A sensor line for detecting an external influence on a cable, wherein the sensor line comprises:
a capacitor,
a first dielectric, which has a first compressibility and a first permittivity, and a second dielectric, which has a second compressibility and a second permittivity,
wherein the first compressibility is smaller than the second compressibility,
wherein the first permittivity differs from the second permittivity,
wherein the sensor line is configured so that at least the second dielectric is compressible or extensible in the event of a movement of the sensor line, so that a total permittivity, which is composed of the first permittivity and the second permittivity, is variable in the movement of the sensor line, wherein due to the change in the total permittivity a change in the capacitance of the capacitor can be produced, which is detectable, in order to detect the external influence on the cable, wherein at least one of the dielectrics comprises a temperature-sensitive dielectric, wherein the sensor line is further configured to detect an external temperature influence on the sensor line by means of the temperature-sensitive dielectric, and wherein one of the first and second dielectrics has a positive temperature coefficient and the other of the first and second dielectrics has a negative temperature coefficient.
2. The sensor line according to claim 1 , wherein the first permittivity differs from the second permittivity by a factor of at least five.
3. The sensor line according to claim 1 , wherein the sensor line comprises a plurality of capacitors, and wherein the sensor line is configured so that a direction of a bend and/or a rotation direction of a torsion of the sensor line are detectable by a comparison of changes in the capacitances of the capacitors due to the movement of the sensor line.
4. The sensor line according to claim 1 , wherein the second dielectric comprises a gas or a gas mixture.
5. The sensor line according to claim 4 , wherein the sensor line is configured so that the total permittivity is variable due to a penetration of a medium into at least a part of a volume, which is taken up by the gas or the gas mixture.
6. The sensor line according to claim 1 , wherein the sensor line is further configured to detect an external temperature influence on the sensor line by means of an area extension of an electrode of the capacitor.
7. The sensor line according to claim 1 , wherein the second dielectric is wound around the first dielectric, in particular spirally.
8. The sensor line according to claim 1 , formed as a coaxial cable, wherein capacitor electrodes form an inner conductor and an outer conductor of the coaxial cable.
9. The sensor line according to claim 1 , wherein the first permittivity differs from the second permittivity by a factor of at least ten.
10. The sensor line according to claim 1 , wherein the first permittivity differs from the second permittivity by a factor of at least twenty.
11. The sensor line according to claim 1 , wherein the dielectrics are fitted alternating along a longitudinal direction of the sensor line in an interior of the sensor line.
12. A line, comprising:
a sensor line comprising:
a capacitor,
a first dielectric, which has a first compressibility and a first permittivity, and
a second dielectric, which has a second compressibility and a second permittivity,
wherein the first compressibility is smaller than the second compressibility,
wherein the first permittivity differs from the second permittivity,
wherein the sensor line is configured so that at least the second dielectric is compressible or extensible in the event of a movement of the sensor line, so that a total permittivity, which is composed of the first permittivity and the second permittivity, is variable in the movement of the sensor line, wherein due to the change in the total permittivity a change in the capacitance of the capacitor can be produced, which is detectable, in order to detect the external influence on the cable, and wherein the dielectrics are fitted alternating along a longitudinal direction of the sensor line in an interior of the sensor line;
a Bowden cable, which is fitted in the interior of the line and is fixed in a first region on a first side of the sensor line, and
a protective sheath, which is fixed in a second region on a second side of the sensor line,
wherein the line is configured so that the Bowden cable can be rotated or moved by torsion or bending of the line inside the protective sheath.
13. A system for detecting an external influence on a cable, wherein the system comprises:
a line comprising:
a sensor line comprising:
a capacitor,
a first dielectric, which has a first compressibility and a first permittivity, and
a second dielectric, which has a second compressibility and a second permittivity,
wherein the first compressibility is smaller than the second compressibility,
wherein the first permittivity differs from the second permittivity,
wherein the sensor line is configured so that at least the second dielectric is compressible or extensible in the event of a movement of the sensor line, so that a total permittivity, which is composed of the first permittivity and the second permittivity, is variable in the movement of the sensor line, wherein due to the change in the total permittivity a change in the capacitance of the capacitor can be produced, which is detectable, in order to detect the external influence on the cable, and wherein the dielectrics are fitted alternating along a longitudinal direction of the sensor line in an interior of the sensor line;
a Bowden cable, which is fitted in an interior of the line and is fixed in a first region on a first side of the sensor line, and
a protective sheath, which is fixed in a second region on a second side of the sensor line, wherein the line is configured so that the Bowden cable can be rotated or moved by torsion or bending of the line inside the protective sheath;
and
a filter system, which is configured to detect a type of external influence on the cable on the basis of a temporal change in the capacitance of the capacitor.
14. A method for detecting a mechanical influence or temperature influence on a cable or a medium intrusion into a cable, wherein the method comprises:
provision of one of:
(a) a sensor line comprising:
a capacitor,
a first dielectric, which has a first compressibility and a first permittivity, and
a second dielectric, which has a second compressibility and a second permittivity,
wherein the first compressibility is smaller than the second compressibility,
wherein the first permittivity differs from the second permittivity,
wherein the sensor line is configured so that at least the second dielectric is compressible or extensible in the event of a movement of the sensor line, so that a total permittivity, which is composed of the first permittivity and the second permittivity, is variable in the movement of the sensor line, wherein due to the change in the total permittivity a change in the capacitance of the capacitor can be produced, which is detectable, in order to detect the external influence on the cable, and wherein the dielectrics are fitted alternating along a longitudinal direction of the sensor line in an interior of the sensor line;
(b) a line comprising:
the sensor line,
a Bowden cable, which is fitted in an interior of the line and is fixed in a first region on a first side of the sensor line, and
a protective sheath, which is fixed in a second region on a second side of the sensor line, wherein the line is configured so that the Bowden cable can be rotated or moved by torsion or bending of the line inside the protective sheath;
(c) a system comprising the sensor line and a filter system which is configured to detect a type of external influence on the cable on the basis of a temporal change in the capacitance of the capacitor; or
(d) a system comprising the line and a filter system which is configured to detect a type of external influence on the cable on the basis of a temporal change in the capacitance of the capacitor; and
measurement of a change in a capacitance of a capacitor for detection of the mechanical influence or temperature influence on the cable or the medium intrusion into the cable.
15. The method according to claim 14 , wherein the sensor line comprises a plurality of capacitors, further comprising comparison of changes in the capacitances of the capacitors due to a movement of the cable, and determination of a direction of a bend and/or a rotation direction of a torsion of the cable on the basis of the comparison.