Abstract: Apparatus for determining location of at least a part of a first object, the apparatus comprising: a controller configured to: control an actuator to move an optical arrangement relative to the first object; control the optical arrangement to transmit an electromagnetic wave; receive a signal from the optical arrangement; and determine a location of an edge of the first object by determining whether a change in a parameter of the signal satisfies at least one criterion.

Abstract: Apparatus for determining location of at least a part of a first object, the apparatus comprising: a controller configured to: control an actuator to move an optical arrangement relative to the first object; control the optical arrangement to transmit an electromagnetic wave; receive a signal from the optical arrangement; and determine a location of an edge of the first object by determining whether a change in a parameter of the signal satisfies at least one criterion.

Abstract: Apparatus is provided for determining the clearance between a member and a casing surface over and relative to which the member moves, e.g. in a gas turbine engine. The apparatus includes a main waveguide and a reference element that is provided at a position intermediate the proximal and distal ends, or at the distal end, of the waveguide. The transmitter/receiver is arranged to transmit an electromagnetic signal through the main waveguide and receive (i) a first portion of the electromagnetic signal reflected from the reference element, (ii) a second portion of the electromagnetic signal reflected from the casing surface, and (iii) a third portion of the electromagnetic signal reflected from the member, allowing the relative positioning of the reference element, the casing surface and the member to be simultaneously determined.

Abstract: It is necessary to provide inspection arrangements in order to facilitate prototype design of assemblies such as gas turbine engines as well as insitu testing of such assemblies. Previously endoscope type arrangements have been utilized, but the flexible or rigid stems in such endoscopes can cause fouling and snagging in use. By providing an inspection arrangement in which the inspection element is combined with a positioning tool such that the inspection element can be detached from the positioning tool through a releasable element, it is possible to avoid such snagging problems. The inspection element will be relatively self-sufficient and incorporate possibly a camera or other sensor for temperature of otherwise. The inspection element will typically incorporate a wireless link arrangement, or possibly incorporate a storage device for data such that the inspection element can be retrieved later with that data.

Abstract: Apparatus is provided for determining the clearance between a member and a casing surface over and relative to which the member moves, e.g. in a gas turbine engine. The apparatus includes a main waveguide and a reference element that is provided at a position intermediate the proximal and distal ends, or at the distal end, of the waveguide. The transmitter/receiver is arranged to transmit an electromagnetic signal through the main waveguide and receive (i) a first portion of the electromagnetic signal reflected from the reference element, (ii) a second portion of the electromagnetic signal reflected from the casing surface, and (iii) a third portion of the electromagnetic signal reflected from the member, allowing the relative positioning of the reference element, the casing surface and the member to be simultaneously determined.

Abstract: By mounting a camera to rotate with a rotating component to be viewed it is possible to review the whole component illuminated by a light source. Generally the component will be specifically marked with target markings to highlight its profile to allow images produced by the camera to be compared for distortion and displacement. Such in situ monitoring arrangements also allow profiling of the surface, and by projection of a grid or matrix onto a component surface any distortion in that matrix is indicative of variations in the surface or through use of astigmatic techniques variations in the incident image pattern can be utilized in order to determine distance variations.

Abstract: It is necessary to provide inspection arrangements in order to facilitate prototype design of assemblies such as gas turbine engines as well as insitu testing of such assemblies. Previously endoscope type arrangements have been utilised, but the flexible or rigid stems in such endoscopes can cause fouling and snagging in use. By providing an inspection arrangement in which the inspection element is combined with a positioning tool such that the inspection element can be detached from the positioning tool through a releasable element, it is possible to avoid such snagging problems. The inspection element will be relatively self-sufficient and incorporate possibly a camera or other sensor for temperature of otherwise. The inspection element will typically incorporate a wireless link arrangement, or possibly incorporate a storage device for data such that the inspection element can be retrieved later with that data.

Abstract: In order to determine displacement, axial and radial in a rotating component, an optical displacement probe is used incident upon a target formed from surface features in a rotating component surface. The surface features create a target which is axially variable in terms of reflectivity, but substantially consistent for the same circumferential band incident position. In such circumstances, differences in responses can be determined by a controller deducting time period ?T differences between peaks 20, 21, 30, 31 in one axial position from the time period in a different axial position in order to provide an axial signal proportional to axial displacement. In terms of determining radial displacement, an angularly presented probe part in the form of an optical fiber 3 is used so that variation of the time period is proportional to radial as well as axial displacement.

Abstract: There are difficulties with regard to observing a rotating component in an obscuring environment such as typical of a gas turbine engine where there may be soot, flames, light signals and moisture. It will be understood that simply increasing the light intensity will increase scatter and therefore may “blind” a camera in terms of viewing distinctive features and targets within a rotating component. The present arrangement provides a mirror with an aperture such that an illuminating light source is directed towards a rotating component such that reflection is similarly incident upon the reflective mirror and light deflected to the camera. In such circumstances the camera is less susceptible to light scatter obscuration.

Abstract: Monitoring of clearance gaps between a rotating component and a surrounding cowling surface is difficult in view of the general packaging constraints. Furthermore, when such operation occurs at high temperature there may be distortion in view of natural expansion and contraction over thermal gradients of the monitoring arrangement. By provision of a diffractive optical element with light guided for reflection against an aperture end and a part of a rotating component, it is possible through shift in the reflective wavelength frequencies to monitor and determine clearance gaps between that aperture end and incident parts of the rotating component.

Abstract: A temperature measuring system, comprising an imaging device for focusing radiation towards a radiation detector, wherein the imaging device is a diffractive optical device.

Abstract: By mounting a camera to rotate with a rotating component to be viewed it is possible to review the whole component illuminated by a light source. Generally the component will be specifically marked with target markings to highlight its profile to allow images produced by the camera to be compared for distortion and displacement. Such in situ monitoring arrangements also allow profiling of the surface, and by projection of a grid or matrix onto a component surface any distortion in that matrix is indicative of variations in the surface or through use of astigmatic techniques variations in the incident image pattern can be utilised in order to determine distance variations.

Abstract: There are difficulties with regard to observing a rotating component in an obscuring environment such as typical of a gas turbine engine where there may be soot, flames, light signals and moisture. It will be understood that simply increasing the light intensity will increase scatter and therefore may “blind” a camera in terms of viewing distinctive features and targets within a rotating component. The present arrangement provides a mirror with an aperture such that an illuminating light source is directed towards a rotating component such that reflection is similarly incident upon the reflective mirror and light deflected to the camera. In such circumstances the camera is less susceptible to light scatter obscuration.

Abstract: In order to determine displacement, axial and radial in a rotating component, an optical displacement probe is used incident upon a target formed from surface features in a rotating component surface. The surface features create a target which is axially variable in terms of reflectivity, but substantially consistent for the same circumferential band incident position. In such circumstances, differences in responses can be determined by a controller deducting time period ?T differences between peaks 20, 21, 30, 31 in one axial position from the time period in a different axial position in order to provide an axial signal proportional to axial displacement. In terms of determining radial displacement, an angularly presented probe part in the form of an optical fibre 3 is used so that variation of the time period is proportional to radial as well as axial displacement.

Abstract: Monitoring of clearance gaps between a rotating component and a surrounding cowling surface is difficult in view of the general packaging constraints. Furthermore, when such operation occurs at high temperature there may be distortion in view of natural expansion and contraction over thermal gradients of the monitoring arrangement. By provision of a diffractive optical element with light guided for reflection against an aperture end and a part of a rotating component, it is possible through shift in the reflective wavelength frequencies to monitor and determine clearance gaps between that aperture end and incident parts of the rotating component.

Abstract: A temperature measuring system, comprising an imaging device for focusing radiation towards a radiation detector, wherein the imaging device is a diffractive optical device.

Abstract: A device and method for monitoring variations in the distance between an object and a datum, comprising: a light source, an astigmatic system for projecting an astigmatic image of the light source onto the object, the astigmatic system including the datum; and image shape detector means for detecting changes of shape of the astigmatic image on the object due to the variation in the distance between the object and the datum, and for producing a monitor signal whose value is dependant on the shape of the astigmatic image on the object: the astigmatic system being arranged such that light reflected from the astigmatic image on the object passes back through the astigmatic system and is thereby projected onto a light receiving surface of the image shape detection means as an astigmatic image of the astigmatic image on the object; wherein the astigmatic system comprises a zone plate.

Abstract: A device and method for monitoring variations in the distance between an object and a datum, comprising: a light source, an astigmatic system for projecting an astigmatic image of the light source onto the object, the astigmatic system including the datum; and image shape detector means for detecting changes of shape of the astigmatic image on the object due to the variation in the distance between the object and the datum, and for producing a monitor signal whose value is dependant on the shape of the astigmatic image on the object: the astigmatic system being arranged such that light reflected from the astigmatic image on the object passes back through the astigmatic system and is thereby projected onto a light receiving surface of the image shape detection means as an astigmatic image of the astigmatic image on the object; wherein the astigmatic system comprises a zone plate.