Abstract: The invention provides a method and a system for monitoring of yarn drawn axially from a bobbin (24a). It is desired to monitor one or both of remaining capacity of an active bobbin and transfer from one active bobbin 24a to the next. A free portion (30) of the yarn moves circumferentially about the bobbin as the yarn is drawn from it. The invention involves a sensor responsive to electromagnetic radiation arranged to sense the free portion (30) of the yarn and to provide an output which varies with a period P corresponding to the period of the circumferential movement of the free portion of the yarn about the bobbin (24a). The period P can be interpreted to provide the desired information.

Abstract: A method of and apparatus for monitoring the processing of a multifilament yarn to indicate a number of protrusions in the yarn is provided. In this method, a multifilament yarn is passed through a light beam directed from a light emitting device to a light receiving device, and the amount of light received by the light receiving device is measured at predetermined time intervals. From the measured amounts of light over a predetermined time period a measuring and computing device produces a frequency distribution, and a threshold level representative of an ideal yarn is calculated from the frequency distribution. The number of measurements that fall outside that threshold level is recorded and is indicative of the number of filament breaks and loops in the yarn.

Abstract: A method of and apparatus for monitoring the processing of a multifilament yarn to indicate a number of protrusions in the yarn is provided. In this method, a multifilament yarn is passed through a light beam directed from a light emitting device to a light receiving device, and the amount of light received by the light receiving device is measured at predetermined time intervals. From the measured amounts of light over a predetermined time period a measuring and computing device produces a frequency distribution, and a threshold level representative of an ideal yarn is calculated from the frequency distribution. The number of measurements that fall outside that threshold level is recorded and is indicative of the number of filament breaks and loops in the yarn.

Abstract: Cleaning of a textile machine or part of such a machine is effected by directing a laser beam at the part to be cleaned for an appropriate length of time. This may be done with the part in situ in its normal operating position in the machine, and the machine may be run in its normal operating condition, possibly with the yarn running to avoid machine down time. Alternatively, the operation may include moving the yarn to a substitute part whilst the original part is cleaned, or moving a substitute part into the normal operating position whilst the part to be cleaned is moved to a cleaning position. A lens system may direct a parallel beam to the part to be cleaned from a remote location, or a fiber optic cable may extend near to that part to guide the laser beam to it.