US 12,461,025 B2
Method and device for detecting defects of a strand-like product
Harald Sikora, Bremen (DE); Armin Holle, Achim (DE); and Kolja Tobias Schuh, Bremen (DE)
Assigned to SIKORA AG, Bremen (DE)
Appl. No. 18/270,648
Filed by Sikora AG, Bremen (DE)
PCT Filed Dec. 20, 2021, PCT No. PCT/EP2021/086789
§ 371(c)(1), (2) Date Jun. 30, 2023,
PCT Pub. No. WO2022/148642, PCT Pub. Date Jul. 14, 2022.
Claims priority of application No. 10 2021 100 051.3 (DE), filed on Jan. 5, 2021.
Prior Publication US 2024/0068939 A1, Feb. 29, 2024
Int. Cl. G01N 21/35 (2014.01); G01N 21/3581 (2014.01); G01N 21/89 (2006.01); G01N 21/892 (2006.01); G01N 21/954 (2006.01)
CPC G01N 21/3581 (2013.01) [G01N 21/8914 (2013.01); G01N 21/892 (2013.01); G01N 21/954 (2013.01); G01N 2021/8918 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for detecting a defect of a strand-like product conveyed in a conveying direction at a conveying speed of more than 50 m/min, the method comprising:
determining a frequency of a lateral movement of the strand-like product, wherein the lateral movement occurs on a direction that is transverse to the conveying direction;
emitting terahertz radiation at a wavelength by at least one transmitter onto the strand-like product conveyed in the conveying direction;
reflecting the terahertz radiation by the strand-like product;
receiving the reflected terahertz radiation by at least one receiver;
detecting a temporary change in the terahertz (THz) radiation received by the at least one receiver; and
inferring a defect in the strand-like product when a frequency of the temporary change in the terahertz radiation received by the at least one receiver is higher than the frequency of the lateral movement of the strand-like product.