The Microtex sensors developed up till now for textile applications are mainly devoted to weft detection in air-jet looms.
A basic distinction must be done about the physical detection principle:
Microtex sensors are based on transmitted light, and not on reflected light.
With transmitted light sensors, the yarn detection signal is due to the quantity of light subtracted by the yarn from a fixed uniform optical field, produced by the sensor in the reed channel.
Two main features come down from this principle:
For the above reasons the transmitted light principle must also be adopted in the devices dedicated to the control and the measurement of the yarn titre.
In general, two main criteria are adopted in the weaving technique for the weft detection for what concerns the position of the sensor along the reed:
Microtex produces sensors for each and for both these applications, as described in detail in the following.
In particular, as the sensors based on transmitted light, for the above application 1), are, in general, mechanically invasive of the space between two adjacent reed dents, causing possible draw-backs in the weaving process, Microtex recently developed a sensor - MTX-NT01 - which is not invasive and, thanks to a return optical weft control, adds a four-times incremental sensitivity to the high reliability of the sensors based on transmitted light.