Leak detector

1. A leak-detecting sensor device for a hose section, the device comprising:

a sensor comprising an optical fibre, the sensor adapted to react to the presence of a fluid;

a protective sleeve housing the sensor, the protective sleeve adapted for expansion and contraction when the hose section expands and contracts, respectively; and

tension means connecting a first end of the sensor to the protective sleeve, the tension means adapted to tension the sensor in the protective sleeve.

2. A hose section, having an inner carcass and an outer carcass, comprising a device according to claim 1 , the device being fixed relative to a first end of the hose section, wherein the or each sensor is arranged between the inner hose carcass and the outer hose carcass of the hose section.

3. A hose section according to claim 2 , further comprising a second sensor device fixed relative to a second end of the hose section, wherein the or each sensor of the second device is arranged between the inner hose carcass and the outer hose carcass.

4. A leak-detecting sensor device for a hose section, the device comprising:

a sensor comprising an optical fibre and arranged to react to the presence of a fluid;

a protective sleeve housing the sensor, arranged for expansion and contraction when the hose section expands and contracts, respectively, wherein the protective sleeve comprises a coiled elongate member; and

tension means connecting a first end of the sensor to the protective sleeve, arranged to tension the sensor in the protective sleeve, wherein the tension means comprises biasing means connected to the coiled elongate member at the first end of the protective sleeve and to the first end of the sensor.

5. A device according to claim 4 , wherein the biasing means is positioned within the protective sleeve between the first end of the protective sleeve and the first end of the sensor and is arranged to bias the respective first ends towards each other.

6. A leak-detecting sensor device for a hose section, the device comprising:

a sensor comprising an optical fibre and arranged to react to the presence of a fluid;

a protective sleeve housing the sensor, wherein the protective sleeve comprises a coiled elongate member arranged for expansion and contraction when the hose section expands and contracts, respectively; and

tension means connecting a first end of the sensor to the protective sleeve, arranged to tension the sensor in the protective sleeve, wherein the tension means comprises biasing means connected to the coiled elongate member at a first end of the protective sleeve and to the first end of the sensor, a thread connecting the first end of the sensor to the biasing means, and a collar arranged to secure the thread to the first end of the sensor.

7. A device according to claim 6 , wherein the collar is arranged to contract on exposure to heat thereby securing the thread to the first end of the sensor.

8. A leak-detecting sensor device for a hose section, the device comprising:

a sensor comprising an optical fibre and arranged to react to the presence of a fluid, wherein the optical fibre comprises at a first end a mirrored surface arranged to reflect back along the optical fibre light that is emitted into the optical fibre;

a protective sleeve housing the sensor, arranged for expansion and contraction when the hose section expands and contracts, respectively; and

tension means connecting a first end of the sensor to the protective sleeve, arranged to tension the sensor in the protective sleeve.

9. A leak-detecting sensor device for a hose section, the device comprising:

a sensor comprising an optical fibre and arranged to react to the presence of a fluid;

a protective sleeve housing the sensor, arranged for expansion and contraction when the hose section expands and contracts, respectively;

tension means connecting a first end of the sensor to the protective sleeve, arranged to tension the sensor in the protective sleeve;

optical means arranged to emit light into the optical fibre and detect light from the optical fibre; and

processing means operatively connected to the optical means and arranged to process data relating to the detected light.

10. A device according to claim 9 , further comprising a transmitter operatively connected to the processing means and arranged to transmit a signal carrying the processed data.

11. A device according to claim 9 , further comprising a second sensor, wherein the first sensor is arranged to react to the presence of a first fluid and the second sensor is arranged to react to the presence of a second fluid, different from the first fluid.

12. A leak detection system comprising:

a sensor comprising an optical fibre and arranged to react to the presence of a fluid;

a protective sleeve housing the sensor, arranged for expansion and contraction when the hose section expands and contracts, respectively;

tension means connecting a first end of the sensor to the protective sleeve, arranged to tension the sensor in the protective sleeve;

optical means arranged to emit light into the optical fibre and detect light from the optical fibre;

processing means operatively connected to the optical means and arranged to process data relating to the detected light;

a transmitter operatively connected to the processing means; and

monitoring means comprising a detector arranged to receive a signal from the transmitter and means to process the received signal.