GB2622441A

GB2622441A - A laser tool

Info

Publication number: GB2622441A
Application number: GB2213653.5A
Authority: GB
Inventors: Kirk Simon; Keogh Keelan; Dieudonne Yannik
Original assignee: UK Atomic Energy Authority
Current assignee: UK Atomic Energy Authority
Priority date: 2022-09-16
Filing date: 2022-09-16
Publication date: 2024-03-20
Also published as: GB202213653D0; WO2024056828A1

Abstract

A laser tool, e.g. a pig for cleaning insides of pipes, can have a first gas flow which can blow away removed debris, and a second gas flow for rotating and translating laser beam optics (e.g. mirror 316) relative to the tool housing. The pneumatic drive may include aerodynamic aerofoils 344, which can rotate in the second gas flow, like turbine blades, e.g. to rotate angled laser mirror 316. Housing for lenses 314 may have threads. Dried or filtered air at one variable pressure (second gas) may spin rotary airfoils 344, while an inert gas knife (first gas) stream flows at a different pressure. First and second gases may be the same or different. The laser tool may be connected to a pig crawler, for driving the pig through a pipeline. Without electrical components, the pig, having a pneumatic motor for scanning the laser beam, may be suitable for ionising radiation environments.

Description

A Laser Tool

Technical Field

The present disclosure relates to a laser tool and is particularly, although not exclusively, concerned with a laser ablation tool suitable for incorporation into a pig to be driven through a pipe, in order to laser ablate an interior surface of the pipe.

Background

Tools incorporating laser light emitters that are configured to focus a beam of laser light onto a surface away from the tool are useful for a number of applications. For example, laser tools can be used for etching, welding, cutting, heat treating and for ablating coatings or unwanted deposits from surfaces.

It is often desirable to perform a laser ablation process on the inside surfaces of pipes, in order to remove deposits from the inside of the pipes for maintenance or decommissioning purposes.

Typically, in order to perform a laser ablation process on a section of piping, a laser tool mounted on a mechanical arm is used. The mechanical arm can be articulated to extend into the pipe in order to position and direct the focused laser beam onto the surface to be processed. If the mechanical arm is unable to reach a particular section of the pipe that is to be worked on, the pipe may be cut, to remove or provide access to the particular section. However, in some situations, it may be undesirable for the pipe to be cut in order to provide access. For example, cutting the pipe breaches the natural containment of material within the pipe.

Furthermore, if the mechanical arm is electrically actuated or controlled. it may be unsuitable for use in environments with high levels of radiation.

Statements of Invention

According to an aspect of the present disclosure, there is provided a laser tool, the tool comprising: a tool body for receiving an optical input and one or more gas inputs; an optical assembly comprising: one or more optical components for forming a focused laser beam, e.g. from the optical input, and directing the focused laser beam away from the tool, e.g. towards a surface external to the tool; an optical assembly moving device for moving the optical assembly relative to the tool body, so as to scan the focused laser beam over the surface; and a housing for supporting the one or more optical components, wherein the housing at least partially defines one or more first channels for one or more first flows of gas from the gas inputs to pass through the optical assembly around the one or more optical components, and an exit channel for the gases to flow out of the housing, e.g. over the surface, wherein the optical assembly at least partially defines one or more second channels for a second flow of gas from the gas inputs to flow to the optical assembly moving device, in order to cause the optical assembly moving device to move the optical assembly relative to the tool body.

The laser tool may further comprise an outer casing. The optical assembly, and optionally the tool body, may be at least partially received within the outer casing. The tool body may be fixedly coupled to the outer case. The optical assembly may be movably coupled to the tool body and may be movably coupled to the outer casing.

The second channels may be at least partially formed by a space between, e.g. radially between, the outer casing and the optical assembly.

The laser tool may be integrated into a pig to be received within a pipe. The outer casing may be configured, e.g. shaped and sized, to be received within the interior of the pipe. The one or more optical components may be configured to direct the focused laser beam onto an interior surface of the pipe. The optical assembly moving device may be for moving the optical assembly relative to the tool body, so as to scan the focused laser beam around the internal surface of the pipe. The laser tool may further comprise a connecting part, such as a universal joint, for connecting the laser tool to a locomotion apparatus, such as a pig crawler, for driving the pig through a pipe.

The optical assembly moving device may be configured to drive the optical assembly to rotate about an axis of the laser tool in a continuous direction. The optical assembly moving device may comprise one or more aerodynamic surfaces over and/or against which the second flow of gas flows. The optical assembling moving device may be configured to drive movement of the optical assembly by virtue of the second flow of gas over and/or against the one or more aerodynamic surfaces. For example, the one or more aerodynamic surfaces may form one or more baffles, serpentine channels aerofoils or blades, e.g. fan blades. The aerodynamic surfaces may be configured as a turbine, e.g. a rotating stage of the turbine, or a pneumatic motor. The optical assembly moving device may comprise a bladed disc formed from a body part of the optical assembly and a plurality of projections, comprising the aerodynamic surfaces, projecting radially from the body part.

The optical assembly moving device may comprise one or more movement transfer features, such as castellations, and the housing may comprise a corresponding number of complementary movement transfer features. The movement transfer features and the complementary movement transfer features may be configured to engage one another such that the housing moves together with the optical assembly moving device. Engagement between the one or more movement transfer features and the complementary movement transfer features may act to maintain optical alignment of the optical components during motion of the optical assembly.

The housing and the optical assembly moving device may be substantially cylindrical.

The optical assembly moving device may be sleeved outside the housing. The housing may be tubular. The housing may comprise one or more apertures formed in a tube wall of the housing. The one of more first channels may extend through the one or more openings. The one or more first channels may be at least partially formed by one or more spaces between, e.g. radially between, the housing and the optical assembly moving device. The apertures may be at least partially aligned with one or more of the optical components supported within the housing, and optionally with one or more portions of the housing at which the optical components can be connected to the housing, such as threaded portions. Two or more of the apertures may be spaced along a longitudinal axis of the housing and/or two or more of the apertures may be spaced circumferentially about a longitudinal axis of the housing.

The optical components may comprise one or more lenses, such as a collimating lens and a focussing lens. The optical components may further comprise one or more beam directing components, such as a mirror, prism and/or axi-conal lens. The optical components may be arranged such that an optical path of the laser light between two, more than two or each of the optical components is aligned with a direction in which the optical assembly moves and/or an axis about which the optical assembly rotates.

The exit channel may be configured to direct the gas leaving the housing towards a focal point of the focused laser beam and/or over an optical window provided on the housing, through which window the focused laser beam leaves the housing.

According to another aspect of the present disclosure, there is provided a method for the above-mentioned laser tool, wherein the method comprises: positioning the laser tool relative to a surface to be processed; providing an optical input to the laser tool; providing one or more gas inputs to the laser tool.

The method may comprise providing first and second gas inputs to the laser tool. A composition, flow rate and/or pressure of the first gas input may be different from the second gas input.

The method may comprise modulating a pressure and/or flow rate of gas supplied to one or more of the gas inputs in order to control a speed at which the optical assembly moves relative to the tool body.

Additionally or alternatively, the composition, flow rate and/or pressure of the first gas input and/or the second gas input may be controlled in order to create an inert environment at the focal point of the focused laser beam, e.g. at the surface.

Additionally or alternatively again, the composition, flow rate and/or pressure of the first gas input and/or the second gas input may be controlled, in order to create a flow, e.g. a cross flow, of the first and/or second gases over the surface, e.g. at the focal point.

According to another aspect of the present disclosure, there is provided a pig to be received within a pipe and comprising a laser tool for forming a focused laser beam directed onto an interior surface of a pipe in which the pig is received, wherein the pig comprises: a tool body, wherein the tool body comprises an optical input and one or more gas inputs an optical assembly, wherein the optical assembly comprises: one or more optical components for forming and directing the focussed laser beam; and an optical assembly moving device for moving the optical assembly relative to the tool body, so as to scan the focused laser beam over the interior surface of the pipe, wherein the optical assembly moving device is configured to receive a flow of gas from the one or more gas inputs to drive the movement of the optical assembly relative to the tool body.

To avoid unnecessary duplication of effort and repetition of text in the specification, certain features are described in relation to only one or several aspects or embodiments of the invention. However, it is to be understood that, where it is technically possible, features described in relation to any aspect or embodiment of the invention may also be used with any other aspect or embodiment of the invention. For example, features described in relation to the first mentioned aspect may be combined with the features of the second mentioned aspect.

Brief Description of the Drawings

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a perspective view of a laser tool, according to arrangements of the present disclosure; Figure 2 is a perspective exploded view of the laser tool shown in Figure 1; Figure 3 is a cross-sectional view of the laser tool shown in Figures 1 and 2; Figure 4 is top view of an optical assembly for the laser tool shown in Figures 1 and 2; Figure 5 is a cross-sectional view of the optical assembly along the line A-A depicted in Figure 4; Figure 6 is a perspective exploded view of the optical assembly shown in Figures 3 and 4; Figure 7 is a top cross-sectional view of the laser tool shown in Figures 1 and 2, illustrating flow paths of gas through the laser tool; and Figure 8 is a side cross-sectional view of the laser tool shown in Figures 1 and 2, illustrating flow paths of gas through the laser tool; and Figure 9 is a flow chart illustrating a method for a laser tool, according to arrangements

of the present disclosure.

Detailed Description

With reference to Figures 1, 2 and 3, a laser tool 2, according to arrangements of the present disclosure, comprises a tool body 100, for receiving an optical input 102, e.g. providing a source of laser light, and one or more gas inputs 104, 106.

As shown in Figures 2 and 3, the optical input 102 may comprise a laser emitter 50, which may be coupled to a source of laser light away from the laser tool 2. The tool body 100 may comprise a cavity 112 for receiving a laser emitter 50. The laser emitter 50 may be couplable to the laser source via an optical cable 60. The gas inputs 104, 106 may comprise one or more, e.g. respective, gas connectors 105 for connecting to respective ducts or tubes (not shown) configured to carry gas to the laser tool 2 from one or more gas sources (not shown) separate from the laser tool.

The laser tool 2 further comprises an optical assembly 300, as described in more detail below with reference to Figures 4 to 6, the optical assembly 300 is movably mounted on the laser tool 2, e.g. for movement relative to the tool body 100.

The laser tool 2 may further comprise an outer casing 200. The optical assembly 300 may be movably coupled to the outer casing 200. At least part of the optical assembly 300 may be received inside of the outer casing 200. Additionally or alternatively, at least part of the tool body 100, may be received within the outer casing 200. The tool body 100 may be fixedly coupled to the outer casing 200. As depicted, a distal end 300a of the optical assembly may protrude from the outer casing 200 at an opposite end of the outer casing 200 from an end from which the tool body 100 extends.

The outer casing 200 may be tubular, for example, the outer casing 200 may be a substantially cylindrical tube having substantially cylindrical inside and outside surfaces. The cylindrical shape of the outer casing 200 may define a central axis Ac of the laser tool 2. Alternatively, at least a part of the inside and/or outside surfaces may be any other shape. For example, the inside surface may be cylindrical and at least part of the outside may be square, e.g. square in cross-section in a plane normal to the central axis A. At least part of the tool body 100 and/or the optical assembly 300 may be received within a hollow interior of the outer casing 200.

In one or more arrangements, the laser tool 2 may be incorporated into a pig to be received within a pipe. More particularly, the outer casing 200 may be configured to be received within the interior of a pipe. In some arrangements, the laser tool 2 may be configured to be received within a 2 inch (0.05m) diameter pipe. The laser tool 2 may further comprise a plurality of transfer units 210, such as ball transfer units, for engaging the internal walls of a pipe to support the movement of the laser tool 2 through the pipe. As depicted, the transfer units 210 may be coupled to the outer casing 200. Additionally or alternatively, one or more transfer units 210 may be coupled to the tool body 100.

As shown in Figures 2 and 3, the tool body 100 may comprise a head part 110 coupled to the optical assembly 300, and an extension part 120 coupled to the head part 110.

The extension part 120 may be arranged outside, or at least partially outside, of the outer casing 200. The laser tool 2 may further comprise a connecting part 130 for connecting the laser tool 2 to a pig crawler 70 for driving the laser tool 2 through a pipe. As depicted, the connecting part 130 may comprise a universal joint. Alternatively, the connecting part may comprise any other suitable connector. The connecting part 130 may be coupled to an opposite end of the extension part 120 from the head part 110.

As shown, the optical cable 60 may extend from the laser emitter 50 received in the cavity 112 in the head part 110 along a length of the extension part 120. The extension part 120 may be configured to guide the optical cable 60 along a pipe in which the laser tool 2 is received over a length of the extension part 120. A length of the extension part 120, e.g. along the central axis A° of the laser tool, may be configured to ensure that a bend radius of the optical cable 60 is greater than a minimum permitted bend radius when the laser tool 2 is being driven through a pipe. As described above, the optical assembly 300 may be movably coupled to the tool body 100. In particular, the optical assembly may be movably coupled to the head part 110. This may allow the optical assembly 300 to move, e.g. rotate, as described below without affecting the optical input 10, e.g. by twisting the optical cable.

As illustrated, the head part 110 may be substantially cylindrical. The head part 110 may be shaped to fit inside the hollow interior of the outer casing 200, such that central axes of the outer casing 200 and the head part 110 are substantially aligned. The head part 110 may be fixedly coupled to the outer casing 200. The head part 110 may further comprise a coupling part 114 for coupling, e.g. movably coupling, the head part 110 to the optical assembly 300. For example, the coupling part 114 may comprise a cylindrical portion of the head part 110 having a reduced diameter (relative to a maximum diameter of the head part 110) to be received within a cylindrical space in the optical assembly 300, as described below.

With reference to Figures 4, 5 and 6, the optical assembly 300 comprises one or more optical components 310 and a housing 320 for supporting the one or more optical components in the optical assembly 300. The optical assembly 300 further comprises an optical assembly moving device 340 for moving the optical assembly 300 relative to other components of the laser tool 2, such as the tool body 100, and optionally the outer casing 200.

The optical assembly 300 may be supported on the laser tool 2 for rotational movement about an axis of rotation AR. When the optical assembly 300 is received within the outer casing 200, the axis of rotation AR may be aligned with the central axis A° of the outer casing. Additionally or alternatively, the optical assembly 300 may be supported for translational movement. For example, the optical assembly 300 may be configured to rotate and/or translate relative to the tool body 100 and/or the outer casing 200.

The laser tool 2 may comprise one or more bearings 212, such as plain bearings, ball bearings and/or roller bearings, e.g. needle bearings, for supporting movement, e.g. rotation, of the optical assembly relative to the outer casing 200. As depicted, at least one of the bearings 212 may be coupled to, e.g. disposed about the housing 320.

The optical components 310 are for forming a focused laser beam, e.g. from the optical input, directed away from the laser tool 2, e.g. towards a surface external to the tool. The optical components 310 may be configured to form the focused laser beam and project the focussed laser beam away from the laser tool 2 in a predetermined direction and focused at one or more pre-determined distances away from the optical assembly 300. For example, when the laser tool 2 is integrated into a pig, the optical components 310 may be configured to form a laser beam focused on an interior surface of the pipe in which the laser tool 2 is received.

The optical components 310 may comprise one or more lenses 312, 314. In the arrangement depicted in Figures 5 and 6, the optical components 310 comprise a collimating lens 312 arranged to receive the laser light from the optical input 102, e.g. from the laser emitter 50, and form a collimated beam of laser light within the optical assembly, e.g. inside the housing 320. In other arrangements, the optical input 102 may be configured to provide a collimated beam of laser light to the laser tool.

Accordingly, in some arrangements, the collimating lens 312 may be omitted. The optical components 310 further comprise a focusing lens 314 arranged to receive the collimated beam of laser light and produce a focused beam of laser light.

The optical components 310, e.g. the lenses 312, 314, may be threadedly connected to the housing 320. The housing 320 may comprise one or more threaded portions 323 extending a length along the housing. The threaded portions 3232 may extend along an internal surface of the housing. For example, the one or more threaded portions 323 may extend along the housing in a direction with a component aligned with the axis of rotation AR. Distances between the optical input 102 and the optical components 310 may thereby be adjusted, e.g. in order to adjust a focal length of the laser tool, by adjusting the positions of the optical components, e.g. the one or more of the lenses 312, 314, using the threaded connections. As depicted, lens nuts 313 may be provided on either side of the lenses 312, 314, e.g. along the threads, for securing the positions of the lenses within the housing 320.

The optical components 310 may further comprise one or more beam directing components 316. The beam directing components 316 may be arranged to receive the focused beam of laser light from the one or more lenses 312, 314 and direct the laser beam in a desired direction away from the laser tool, e.g. towards a surface to be processed. In the arrangement shown, the beam directing components 316 comprise a mirror angled relative to the one or more lenses 312, 314. In other arrangements, the beam directing components may additionally or alternatively comprise a prism or conical lens, such as an axi-conal lens.

The optical components 310 may be arranged such that light propagates between two, more than two or each of the optical components along the axis of rotation AR of the optical assembly. For example, centre points of the optical components 310, e.g. the lenses 312, 314 and one or more of the beam directing components, may be aligned with the axis of rotation AR of the optical assembly.

The laser tool 2 may further comprise an optical window 318 through which the focused and directed laser beam is passed to leave the housing 320. The optical window 318 may be configured to restrict ingress of dust, debris and other contaminants into the interior of the housing 320, without restricting, e.g. attenuating, the laser light passing out of the housing. The optical window 318 may be provided at a distal end 300a of the optical assembly, e.g. on a part of the optical assembly that projects out of the outer casing 200 of the laser tool 2.

As shown in Figures 4, 5 and 6, the housing 320 may comprise a first part 322, in which the one or more lenses 312, 314 are housed, and a second part 324, in which the beam directing components 316 and the optical window 318 are housed. The first part 322 may be substantially tubular. For example, the first part 322 may be a substantially cylindrical tube having an inner surface 322a and an outer surface 322b and defining a longitudinal axis AL aligned with the axis of rotation AR. An interior of the first part 322 may form an optical cavity 326 within which laser light from the optical input 102 may propagate between the optical components 310 of the optical assembly.

When the tool body 100 is coupled to the optical assembly 300, the coupling part 114 of the tool body may be received within the optical cavity 326. The optical assembly 300 may further comprise a bearing 328, such as a plain bearing, ball bearing or roller bearing, arranged within the optical cavity 326 so as to be provided between the coupling part 114 of the tool body 100 and the optical assembly 300, e.g. the inner surface 322a of the housing. The bearing 328 may thereby be arranged to support movement, e.g. rotation, of the optical assembly 300 relative to the tool body 100. In alternative arrangements, a part of the housing 320 may be received within an opening formed in the tool body 100 for movably coupling the housing to the tool body and/or the bearing may be provided on the tool body.

The first and second parts 322, 324 of the housing may be configured to couple together such that the first and second parts 322, 324 of the housing move together, e.g. rotate together about the axis of rotation AR of the optical assembly. In particular, the first part 322 may comprise one or more engaging portions 325, such as castellations, and the second part 324 may comprise a corresponding number of complementary engaging portions 327 to engage the engaging portions 325 to transfer rotational motion of the first part 322 to the second part 324. Proving the housing as two separate parts may improve the ease with which the optical assembly can be manufactured and assembled, and may improve the ease with which the optical components provided in the optical assembly can be adjusted, maintained, e.g. cleaned, and/or replaced.

As described in greater detail below, the components of the laser tool 2, e.g. the tool body 100, the outer casing 200 and the housing 320, form one or more first channels for one or more first flows of gas from the gas inputs to pass through the optical assembly 300, e.g. through the optical cavity 326, around one or more of the optical components 310. As depicted in Figure 5, the housing 320, e.g. the second part 324 of the housing, may define an exit channel 332 for gases flowing through the first channels to flow out of the housing 320 over the surface being processed. The exit channel 332 may be arranged to direct the flow of gas leaving the housing 320 over, or towards, an area of the surface at which the focused laser beam from the laser tool 2 is directed. In this way, dust and debris at the surface being processed by the laser tool may be blown away from the laser tool 2. In particular, the flow of gas leaving the housing 320 may produce a flow, e.g. cross flow, of gases at the focal point of the laser, which may act to clear away dust/debris created in use of the laser tool 2.

Additionally or alternatively, the exit channel 332 may be configured to direct the flow of gas leaving the housing 320 over the optical window 318.

The optical assembly moving device 340 may be for moving the optical assembly 300 so as to scan the focussed laser beam produced by the optical assembly 300 over a surface to be processed. In the arrangement shown, the optical assembly moving device 340 is configured to rotate the optical assembly 300 about the rotation axis AR in a continuous direction. However, in other arrangements, the optical assembly moving device 340 may be configured to move the optical assembly 300 in an oscillating or reciprocating manner, and may be configured to move, e.g. translate, the optical assembly device through a linear or arcuate path or through a path comprising a combination of linear and arcuate portions. Translations of the optical assembly 300 may be in addition, or as an alternative to rotational movement of the optical assembly 300.

As described below, the optical assembly moving device 340 may comprise a pneumatic motor. Moving the optical assembly 300 using a pneumatically powered moving device enables the laser tool to be hardened against interference from radiation, e.g. such that the operation of the tool is unaffected, e.g. substantially or completely unaffected, by radiation, e.g. ionising radiation. This is due to the absence of electronic components on the laser tool 2 for controlling and/or operating the laser tool 2.

The laser tool, e.g. the tool body 100, the housing 320 and the outer casing 200 may form one or more second gas flow channels. The second gas flow channels may be separate from, e.g. fluidically isolated from, the first gas flow channels. The second gas flow channels may be arranged to receive a flow of gas from one or more of the gas inputs 104, 106. The second gas flow channels may be arranged to receive a flow of gas from different ones of the gas inputs from the first gas flow channels. Alternatively, the first and second gas flow channels may be arranged to receive a flow of gas from one or more same ones of the gas inputs 104 to each other.

The second gas flow channels are configured to carry second flows of gas from one or more of the gas inputs 104, 106 to the optical assembly moving device 340. The optical assembly moving device 340 is configured to cause the optical assembly 300 to move by virtue of the second gas flows being delivered to the optical assembly moving device 340. In other words, providing the second gas flows to the optical assembly moving device 340 may cause the optical assembly moving device 340 to move the optical assembly 300.

The optical assembly moving device 340 may comprise a body part 342. The body part 342 may be a substantially cylindrical tube having an inner surface 342a and an outer surface 342b. The body part 342 of the optical assembly moving device may be sleeved outside the housing 320, e.g. the first part 322 of the housing. The body part 342 may comprise one or more movement transfer features 343, such as castellafions, for engaging complementary movement transfer features 329 formed on the housing 320 for transferring movement of the optical assembly moving device 340 to the housing.

The optical assembly moving device 340 may comprise one or more projections 344, which project radially outward relative to body part 342. The projections 344 may project in to the second gas flow channels. The projections comprise aerodynamic surfaces 346 disposed within the second gas flow channels. The aerodynamic surfaces may extend radially between the body part 342, e.g. the outer surface 342h of the body part, and the radial extents of the projections 344. The aerodynamic surfaces 346 are arranged such that the second flow of gases within the second gas flow channels flows over and/or against the aerodynamic surfaces 346 and urges the optical assembly moving device 340 to move. For example, the projections 344 may be shaped as aerofoils. The aerodynamic surfaces on opposing, e.g. circumferentially opposing, sides of each projection 344 may be configured together to generate a reduced pressure on one side, e.g. circumferential side, of the projection 344 compared to the other side of the projection, in order to cause the optical assembly moving device 340 to move, e.g. rotate.

The number and configuration, e.g. shape, of the projections 344 may be selected based on properties of the second gas flow, e.g. pressure and/or flow rate of the gas supplied to the second gas flow channels, the direction of the flow of gases through the second flow channels relative to the projections and a desired movement, e.g. rotational speed, of the optical assembly 300.

In some arrangements, the configuration, e.g. shape and/or orientation, of the projections 344 may be selectively adjustable in order to adjust the movement of the optical assembly moving device driven by the second flow of gases. In other arrangements, the second gas flow, e.g. the pressure and/or flow rate of the second flow of gases may be adjusted in order to adjust the movement of the optical assembly moving device. For example, the operation of a gas source (not shown) connected to one or more of the gas inputs may be adjusted in order to modulate the pressure and/or flow rate of the second flow of gases. In this way, the rate at which the focused laser beam is scanned over the surface may be controlled.

The first and second gas flow channels are illustrated in greater detail in Figures 7 and 8. In the arrangement depicted, two gas connectors 105a, 105b are depicted, which form two gas inputs 104, 106 to provide flows of gas to the first and second gas flow channels respectively. In some arrangements, the first and second gas inputs may receive gases from separate gas sources, not shown. The separate gas sources may, for example, be configured to supply gases at different pressures and/or may be configured to supply different compositions of gases. For example, the first gas input may be supplied with dry, filtered air from a first gas source at a first pressure, and the second gas input may be supplied with air which is not dried or filtered at a second pressure different from the first pressure. In other arrangements, the first and/or second gas sources may be a source of an inert gas, such as argon gas. In some arrangements, the gas sources may be configured to vary the pressure and/or flow rate of gases supplied to the first and/or second gas inputs 104, 106. Alternatively, the laser tool 2 may be configured to selectively vary the pressure and/or flow rate of gases entering the first and/or second gas flow channels from the gas inputs 104, 106.

As depicted, the tool body 100, e.g. the head part 110, may comprise a first tool body passage 116. A first end 116a of the first tool body passage is fluidically connected to the first gas connector 105a and a second end 116b of the first tool body passage is fluidically connected to the optical cavity 326 inside the housing 320.

The housing 320 of the optical assembly comprises a plurality of apertures 331 formed in a tube wall of the housing 320. As depicted, two or more of the apertures 331 may be spaced circumferentially about the housing. Additionally or alternatively, two or more of the apertures 331 may be spaced apart from one another along the longitudinal axis of the housing 320. The apertures 331 extend between the optical cavity 326 formed within the housing and an outside of the housing. As shown in Figure 8, the housing 320 and the optical assembly moving device 340, e.g. the body part 342 of the optical assembly moving device, may be configured to form a plurality of spaces 348 between, e.g. radially between, the outside of the housing 320 and an inside of the body part 342 of the optical assembly moving device. The plurality of spaces 348 may extend circumferentially about the longitudinal axis AL of the housing. For example, the plurality of spaces may extend completely (360°) around the longitudinal axis of the housing. The plurality of spaces 348 may be at least partially aligned with respective ones of the apertures 331 in the housing 320. In this way, parts of the first gas channels may be formed between e.g. radially between, the housing 320 and the body part 342 of the optical assembly moving device. Further, as depicted in Figure 8, the apertures 331 and the spaces 348 may be at least partially aligned with respective ones of the optical components 310. The apertures 331 and the spaces 348 may be substantially aligned with the threaded portions 323 in the housing for supporting the optical components 310. In some arrangements, a length of the apertures 331 and the spaces 348 in an axial direction of the housing may be greater than or equal to respective lengths of the threaded portions 323, with which they are aligned. In this way, the first gas channels may be formed to enable gases to flow around the optical components 310 supported by the housing.

The exit channel 332 formed in the second part 324 of the housing may be in fluidic communication with the optical cavity 326 inside the housing, and the first gas flow channels may extend through the exit channel 332 to allow the first flow of gas to leave the laser tool 2 and be directed over the surface being processed.

In this way, the first gas flow channels may be established to allow the first flow of gas to flow through the optical cavity 326, and around and between the optical components 310. The first flow of gas may thereby be used to cool the optical components 310. Additionally or alternatively, the first flow of gas passing through the first gas flow passage may act to remove any dust and/or debris that has entered the optical cavity 326.

As depicted in Figure 7, the tool body 100, e.g. the head part 110, may further comprise a second tool body passage 118. A first end 118a of the second tool body passage 118 is fluidically connected to the second gas connector 105b and a second end 118b of the second tool body passage is fluidically connected to a further space 349 formed between, e.g. radially between, the body part 342 of the optical assembly moving device, e.g. the radially outer surface 342b of the body part, and an inner surface of the outer casing 200. The further space 349 may thereby form at least part of the second gas flow channels. The further space 349 may extend circumferentially about the longitudinal axis AL of the housing. For example, the further space 349 may extend completely (360°) around the longitudinal axis AL. As described above, the projections 344 comprising the aerodynamic surfaces 346 may projected radially outwardly relative to the body part 342 of the optical assembly moving device 340 and therefore extend into the further space 349. The second gas flow channels are thereby formed such that the optical assembly moving device, e.g. the aerodynamic surfaces 346, are within the second gas flow channels. The second flow of gases may thereby cause movement of the optical assembly movement device. A second flow channel opening 350 may be formed at a distal end of the laser tool 2, e.g. in the outer casing 200, for the gases flowing within the second gas flow channels to flow out of the laser tool.

With reference to Figure 9, a method 900 for a laser tool, such as the laser tool 2 described above, comprises a first step 902, at which the laser tool is positioned relative to a surface to be processed. The method 900 further comprises a second step 904 at which an optical input and one or more gas inputs are provided to the laser tool. The one or more gas inputs may comprise two or more different gases. For example, a first gas input may comprise dried filtered air, or an inert gas, such as argon, and a second gas input may comprise air, e.g. that has not been dried or filtered.

As described above, providing the optical input and the gas inputs to the laser tool causes the tool to provide a focussed laser beam onto a surface away from the laser tool and to scan the focussed laser beam over the surface, e.g. due to movement (rotation) of the optical assembly 300 of the laser tool. In particular, when the laser tool 2 is incorporated into a pig to be driven through a pipe, movement of the optical assembly 300 may rotate the optical assembly so as to scan the focussed laser beam circumferentially around the inside surface of the pipe.

The method 900 may comprise an optional third step 906, in which the tool is advanced over the surface, e.g. by driving a pig incorporating the laser tool through a pipe using a pig driver coupled to the laser tool.

The method 900 may comprise an optional fourth step 908, in which a pressure and/or flow rate of gas supplied to one or more of the gas inputs is modulated in order to control a speed, e.g. rate of rotation, at which the optical assembly 300 moves, e.g. rotates, relative to the tool body 100.

Additionally or alternatively, the composition, flow rate and/or pressure of the first gas input and/or the second gas input maybe controlled in order to create an inert environment at the focal point of the focused laser beam, e.g. at the surface. Additionally or alternatively again, the composition, flow rate and/or pressure of the first gas input and/or the second gas input may be controlled, in order to create a flow, e.g. a cross flow, of the first and/or second gases over the surface, e.g. at the focal point.

It will be appreciated by those skilled in the art that although the invention has been described by way of example, with reference to one or more exemplary examples, it is not limited to the disclosed examples and that alternative examples could be constructed without departing from the scope of the invention as defined by the appended claims.

Claims

Claims 1. A laser tool, the tool comprising: a tool body for receiving an optical input and one or more gas inputs; an optical assembly comprising: one or more optical components for forming a focused laser beam and directing the focused laser beam away from the tool; an optical assembly moving device for moving the optical assembly relative to the tool body, so as to scan the focused laser beam; and a housing for supporting the one or more optical components, wherein the housing at least partially defines one or more first channels for one or more first flows of gas from the gas inputs to pass through the optical assembly around the one or more optical components, and an exit channel for the first flows of gas to leave the housing, wherein the optical assembly at least partially defines one or more second channels for a second flow of gas from the gas inputs to flow to the optical assembly moving device, in order to cause the optical assembly moving device to move the optical assembly relative to the tool body.
2. The laser tool of claim 1, wherein the laser tool further comprises an outer casing, wherein the optical assembly, and optionally the tool body, are at least partially received within the outer casing.
3. The laser tool of claim 2, wherein the tool body is fixedly coupled to the outer case and wherein the optical assembly is movably coupled to the outer casing.
4. The laser tool of claim 2 or 3, wherein the second channels are at least partially formed by a space between the outer casing and the optical assembly.
5. The laser tool of any of claims 2 to 4, wherein the laser tool is integrated into a pig to be received inside a pipe, wherein the outer casing is configured to be received within the interior of the pipe.
6. The laser tool of claim 5, wherein the laser tool further comprises a connecting part, such as a universal joint, for connecting the laser tool to a pig crawler for driving the pig through a pipe.
7. The laser tool of any of the preceding claims, wherein the optical assembly moving device is configured to drive the optical assembly to rotate about an axis of the laser tool in a continuous direction.
8. The laser tool of claim 7, wherein the optical assembly moving device comprises one or more aerodynamic surfaces over and/or against which the second flow of gas flows, wherein the optical assembling moving device is configured to drive movement of the optical assembly by virtue of the second flow of gas over and/or against the one or more aerodynamic surfaces.
9. The laser tool of any of the preceding claims, wherein the optical assembly moving device comprises one or more movement transfer features and the housing comprises a corresponding number of complementary movement transfer features features, wherein the movement transfer features and the complementary movement transfer features are configured to engage one another such that the housing moves together with the optical assembly moving device.
10. The laser tool of any of the preceding claims, wherein the housing and the optical assembly moving device are substantially cylindrical, and wherein the optical assembly moving device is sleeved outside the housing.
11. The laser tool of claim 10, wherein the housing is tubular, wherein the housing comprises one or more apertures formed in a tube wall of the housing and wherein the one of more first channels extend through the one or more openings.
12. The laser tool of claim 11, wherein the one or more first channels are at least partially formed by one or more spaces between the housing and the optical assembly moving device.
13. The laser tool of claim 11 or 12, wherein the apertures are at least partially aligned with one or more of the optical components supported within the housing.
14. The laser tool of any of claims 11 to 13, wherein two or more of the apertures are spaced along a longitudinal axis of the housing and/or wherein two or more of the apertures are spaced circumferentially about a longitudinal axis of the housing.
15. The laser tool of any of the preceding claims, wherein the optical components comprise one or more lenses, such as a collimating lens and a focussing lens, and one or more beam directing components, such as a mirror, prism and/or axi-conal lens.
16. The laser tool of any of the preceding claims, wherein the optical components are arranged such that an optical path of the laser light between two, more than two or each of the optical components is aligned with a direction in which the optical assembly moves and/or an axis about which the optical assembly rotates.
17. The laser tool of any of the preceding claims, wherein the exit channel is configured to direct the gas leaving the housing towards a focal point of the focused laser beam and/or over an optical window provided on the housing, through which the focused laser beam leaves the housing.
18. A method for the laser tool of any of the preceding claims, wherein the method comprises: positioning the laser tool relative to a surface to be processed; providing an optical input to the laser tool; providing one or more gas inputs to the laser tool.
19. The method of claim 18, wherein the method comprises providing first and second gas inputs to the laser tool, wherein a composition, flow rate and/or pressure of the first gas input is different from the second gas input.
20. The method of claim 18 or 19, wherein the method further comprises: controlling the composition, flow rate and/or pressure of the first gas input and/or the second gas input, in order to create an inert environment at the focal point of the focused laser beam.
21. The method of any of claims 18 to 20, wherein the method further comprises: controlling the composition, flow rate and/or pressure of the first gas input and/or the second gas input, in order to create a flow of the first and/or second gases over the surface.
22. The method of any of claims18 to 21, wherein the method comprises modulating a pressure and/or flow rate of gas supplied to one or more of the gas inputs in order to control a speed at which the optical assembly moves relative to the tool body.
23. A pig to be received within a pipe and comprising a laser tool for forming a focused laser beam directed onto an interior surface of a pipe in which the pig is received, wherein the pig comprises: a tool body, wherein the tool body comprises an optical input and one or more gas inputs an optical assembly, wherein the optical assembly comprises: one or more optical components for forming and directing the focussed laser 15 beam; and an optical assembling moving device for moving the optical assembly relative to the tool body, so as to scan the focused laser beam over the interior surface of the pipe, wherein the optical assembly moving device is configured to receive a flow of gas from the one or more gas inputs to drive the movement of the optical assembly relative to the tool body.