US 12,145,180 B2
Laser cleaning apparatus and method
John Redvers Clowes, New Milton (GB)
Assigned to Woodrow Scientific Limited, Southampton (GB)
Appl. No. 17/927,152
Filed by Woodrow Scientific Limited, Southampton (GB)
PCT Filed May 21, 2021, PCT No. PCT/EP2021/063651
§ 371(c)(1), (2) Date Nov. 22, 2022,
PCT Pub. No. WO2021/239617, PCT Pub. Date Dec. 2, 2021.
Claims priority of application No. 2007769 (GB), filed on May 25, 2020.
Prior Publication US 2023/0191462 A1, Jun. 22, 2023
Int. Cl. B08B 7/00 (2006.01); B08B 13/00 (2006.01); B23K 26/082 (2014.01); B23K 26/16 (2006.01); B63B 59/08 (2006.01); B63G 8/00 (2006.01); B64C 39/02 (2023.01); B64U 10/60 (2023.01); G08B 21/02 (2006.01); H01S 3/00 (2006.01); H01S 3/067 (2006.01); H01S 3/16 (2006.01)
CPC B08B 7/0042 (2013.01) [B08B 13/00 (2013.01); B23K 26/082 (2015.10); B23K 26/16 (2013.01); B63G 8/001 (2013.01); B64C 39/022 (2013.01); B64U 10/60 (2023.01); H01S 3/0007 (2013.01); H01S 3/0071 (2013.01); B63B 59/08 (2013.01); B63G 2008/005 (2013.01); B64U 2201/10 (2023.01); G08B 21/02 (2013.01); H01S 3/067 (2013.01); H01S 3/1618 (2013.01)] 18 Claims
OG exemplary drawing
 
1. Laser cleaning apparatus comprising:
a laser system configured to output laser light having a power, a wavelength, a temporal characteristic and a divergence;
a cleaning head;
proximity sensing apparatus;
a controller;
interlock apparatus; and
a delivery cable configured to deliver the laser light to the cleaning head;
wherein the cleaning head comprises:
an output aperture and output optics configured to focus the laser light to have a fluence at a focal plane of the output optics that is greater than an ablation threshold of a surface contaminant to be removed from a surface to be cleaned;
scanning apparatus configured to scan the laser light in at least one dimension across a scan region within the focal plane to cause the scanning laser light to have an effective divergence greater than the divergence of the laser light and to have a corresponding safe working distance from the output aperture determined by the effective divergence, the power, the wavelength and the temporal characteristic; and
scan monitoring apparatus configured to monitor the effective divergence of the scanning laser light and to determine an amount of change of the effective divergence of the scanning laser light and configured to generate an alarm signal in response to determining that the effective divergence has changed, wherein the generated alarm signal carries information indicative of the amount of change of the effective divergence;
wherein the proximity sensing apparatus is configured to generate a proximity alarm signal in response to determining the presence of an unauthorised person at a position closer to the output aperture than a permitted access distance, wherein the permitted access distance is greater than or equal to the safe working distance, and wherein the proximity sensing apparatus is configured to set the permitted access distance in response to receiving the alarm signal from the scan monitoring apparatus;
wherein the controller is configured to:
determine the permitted access distance dependent on the amount of change of the effective divergence; and
generate a control signal configured to cause the proximity sensing apparatus to operate using the determined permitted access distance; and
wherein the interlock apparatus is configured to cause the laser to shut down in response to receiving the proximity alarm signal.