Abstract: A vibration detector (1) comprising at least one fibre optic sensor (2) mechanically coupled to a flexible support member (3). The vibration detector (1) is mounted on the outside of the pipeline and a signal from the fibre optic sensor is measured. This signal is indicative of whether the vibration detector is experiencing vibrations due to collisions of contaminant particles with each other and/or with the walls of the pipeline. A method for detecting particulate contaminants in a fluid flowing in a pipeline is also provided.

Abstract: A method of monitoring strain on a wind turbine blade that has several structural components comprises locating at least three strain sensors (2a, 2b, 2c) on one of the structural components of the turbine blade, the positions of the strain sensors defining a plane transverse to the longitudinal direction of the turbine blade and resolving strain signals from the three strain sensors into strain measurements in two orthogonal directions.

Abstract: An optical fibre strain sensor array comprises several sensor support panels spaced in its longitudinal direction and at least one connecting member extending in the longitudinal direction, which mechanically interconnects the sensor support panels. An optical fibre is supported by the sensor support panels and the connecting member. The optical fibre extends with the connecting member between the sensor support panels and forms a curve on the sensor support panel, the curve including at least one portion of the optical fibre that extends in the transverse direction. The width of the connecting member is substantially less than the width of the sensor support panels, such that the connecting member is capable of flexure in the transverse direction. This has the advantage that the connecting member can be flexed to take up any slack during installation of the optical fibre strain sensor array in a wind turbine blade and can be fitted to the turbine blade even if the blade has a conical shape.

Abstract: A wind turbine blade (1) incorporating an optical fibre (4) configured for structural monitoring of the turbine blade. The optical fibre comprises at least one strain sensor (5). One end of the optical fibre (4) is an output point, which is connected to a data processing device (3) configured to process signals from the strain sensor (5). The other end of the optical fibre is an alternative output point, which is also connectable to the data processing device, such that in the event of a breakage in the optical fibre, signals from the strain sensor are available from at least one of the output points.

Abstract: A load monitoring system for wind turbine blades utilizes optical fibre strain sensors (5) moulded into the turbine blades. A sensor monitoring instrument is located in the hub (3) of the turbine. Various arrangements of cabling are disclosed to maximize fault tolerance. Various arrangements of a temperature compensation device for the strain sensors is also disclosed. The strain sensors (5) and optical fibre (7) may be provided on a pre-cured patch (9) for incorporation in the structure of the turbine blade. Furthermore, it is disclosed that each blade comprises an optical fibre strain sensor and a cable to connect the sensors to processing equipment, wherein each such cable includes a connector at each end whereby each blade can be replaced independently. Also, it is shown to provide an output connector for connecting the sensor to processing equipment in a cavity that is filled with a material for inhibiting free movement of the output connector.

Abstract: The present invention provides a buoy supported antenna for underwater radio communications. The antenna of the present invention comprises an elongate section submerged in water and a feed point for feeding electrical signals to the antenna located on the elongate section, the elongate section is attached to an underwater object at a first end thereof, and during deployment is suspended by a buoy at a second end thereof so that the elongate section is substantially self supporting and vertical in orientation. At least a first portion of the elongate section comprises a flexible wire having an electrically conductive core, which is electrically insulated on an outer surface thereof. During operation the flexible wire radiates electromagnetic signals through the water.

Abstract: The present invention provides an antenna for underwater radio communications. The antenna of the present invention comprises an elongate section submerged in water and a feed point for feeding electrical signals to the antenna located on the elongate section, the elongate section is attached to an underwater object at a first end thereof, and during deployment hangs downwards there from so that said elongate section is substantially vertical in orientation. A first portion of the elongate section comprises a flexible wire having an electrically conductive core, which is electrically insulated on an outer surface thereof. During operation the flexible wire radiates electromagnetic signals through the water.

Abstract: A system for the structural monitoring of blades 1 on a wind turbine. Each blade 1 has respective optical fibre bragg grating sensors 5. The system has a number of input connectors, which connect to the strain sensors 5 of respective blades 1. A single output connector connects to a data processing device 3 which processes signals from the strain sensors 5. The input connectors each have a signal path to the output connector that is different in length to the signal path from the other input connectors, such that signals from a given blade 1 can be identified at the data processing device 3 by the time of arrival of the signals. The system has the advantage that the each of the blades 1, including the sensors attached to it or embedded within it can be identical and therefore interchangeable.

Abstract: A curvature sensing device 10 comprising, a first fibre Bragg grating (FBG) strain sensor 12, a second FBG strain sensor 14, a flexible piece comprising two end pieces 16, 18 joined by a tubular mid-section 20. The device 10 further comprises 16 contact rollers 22 provided on the internal surfaces of the end pieces 16, 18, which maintain the end pieces 16, 18 tangential to a pipe around which the device 10 is located. The FBG strain sensors 12, 14 are embedded within the mid-section 20 and are arranged in two generally orthogonal planes, so that the curvature is measured in two dimensions. This enables the device 10 to detect both the magnitude and direction of bending/curvature within a pipe. Bending in a pipe is transferred through the end pieces 16, 18 to the mid-section 20. The FBG sensors 12, 14 measure bending of the mid-section 20 from which bending of the pipe can be inferred.

Abstract: Apparatus for interrogating an optical fibre comprising a plurality of fibre Bragg gratings each having a resonant wavelength in a different discrete wavelength band. The apparatus comprises a delay arrangement interposed in use in an optical path for light supplied to and/or reflected from the fibre Bragg gratings. The delay arrangement is configured to apply a different time delay to light in each of the discrete wavelength bands, whereby the light reflected from each of the fibre Bragg gratings is received at an interrogator port of the apparatus in a different discrete time interval.

Abstract: A method of monitoring strain on a helicopter rotor blade that has several structural components comprises locating at least three strain sensors 2a, 2b, 2c on one of the structural components of the rotor blade, the positions of the strain sensors defining a plane transverse to the longitudinal direction of the rotor blade and resolving strain signals from the three strain sensors into strain measurements in two orthogonal directions.

Abstract: A method of monitoring the performance of a wind turbine (1) uses bending moment data from strain sensors (4) in the turbine blades (2) to calculate rotational speed of the turbine (1), angular position of the turbine blades (2), drive torque and resultant load on the rotor (3). The method has the advantage that the inputs to the drive train of the wind turbine can be (5) measure directly.

Abstract: A method of monitoring mechanical characteristics of helicopter rotor blades 1 comprises mounting at least one strain sensor 2 to at least one rotor blade 1 and measuring the mechanical load on the rotor blade as indicated by the strain sensor 2.

Abstract: A method of detecting the formation of ice on the blades of a wind turbine 1. The wind turbine has at least one turbine blade 2 mounted to a rotor and provided with at least a first strain sensor 4 for measuring mechanical strain of the turbine blade. The method comprises detecting changes in an output signal of the strain sensor 4 due to changes in the mass of the turbine blade 2 caused by the formation of ice on the turbine blade.

Abstract: An integrated optical device includes a substrate, at least a face of the substrate providing a first cladding layer, the first cladding layer including a mesa formation; a waveguide core formed on the first cladding layer so that the waveguide core substantially covers the mesa formation; and a second cladding layer formed over the waveguide core and the first cladding layer.

Abstract: An integrated optical device includes a substrate, at least a face of the substrate providing a first cladding layer, the first cladding layer including a mesa formation; a waveguide core formed on the first cladding layer so that the waveguide core substantially covers the mesa formation; and a second cladding layer formed over the waveguide core and the first cladding layer.