Weft feeders are a popular choice for textile manufacturers. They are designed to accurately measure the length of thread released at every insertion. They usually include a variable-diameter drum and a swiveling arm. They also have a weft braking finger, which automatically stops the thread when it reaches a predetermined length. These machines are controlled by microprocessors.
There are different types of weft feeders, which offer various adjustments. These adjustments are based on the type of yarn and its count. They also differ in their insertion systems. Some models have independent motors, which can vary their speed to meet the needs of the process. They can also be connected to the weaving machine's driving unit.
Weft feeders use mechanical or photoelectric sensors to detect weft reserves. They can be pneumatic or electromechanical. In addition, they use a conical inlet. This allows the weft yarn to enter through the conical inlet 3. The air jet launches the weft yarn into the internal cavity of a winding arm 5. A magnet detects the overtaking of the weft yarn. The magnet then stops the winding arm in a predetermined angular position.
The weft feeder is also equipped with an electromagnetic unit. This unit is connected to the drum and movable stem. The stem can be moved to a first position for engaging the weft yarn, and it can be rotated to a second position for free unwinding. The electromagnetic unit has first and second adjacent coils that are electro magnetically energized. The stem moves toward the drum when the first coil is energized, and moves away from it when the other coil is energized.
Weft feeders also use a single electromagnetic unit for blocking the weft yarn. This design is commonly used because of its simplicity and economy. In addition, the stem is designed to prevent the weft yarn from unwinding when it is not energized. They also have a stop mechanism.
Another aspect of the weft feeder includes a second compressed air nozzle. It guides the weft yarn downstream of the first yarn guide eyelet, thereby preventing breakage. In addition, it also has yarn guide eyelets located downstream of the first yarn guide eyelet.
Weft feeders for air jet looms often include an anti-balloon device. This anti-balloon device is designed to reduce the thread's mechanical tension by reducing friction. It can also be adjustable, allowing operators to regulate the amount of friction they apply to the thread.
Another type of weft feeder is the fixed drum weft feeder. This type of weft feeder is suitable for air jet looms and water jet looms. This type is easy to use and maintains a large capacity of weft yarns.
