The vortex spinning technology is one of the most promising new
inventions in the spinning market. This relatively new spinning system
was also developed by the Japanese firm Murata (Muratec). Murata’s No.
851 Vortex Spinner made its first appearance at OTEMAS’97 [34]. Vortex
spinning is a false twist process, and the twist insertion in this
system is achieved by means of air jets. The main attraction of vortex
spinning is that it is claimed to be capable of spinning 100% carded
cotton fibers at very high speeds (400m/min),
and the resulting yarn structure is more similar to ring yarn than to rotor yarn [4,9,13,15,53]. Figure 7 shows vortex yarn versus rotor and ring yarns. Other claimed advantages of vortex spinning are a low maintenance cost due to fewer moving parts, elimination of the roving frame stage, and improved fully automatic piecing system [48]. In addition to these, yarns produced by this method have low hairiness compared to normal ring yarns. This is claimed to be due to being “air-singed” and “air-combed,” which in turn results in reduced fabric pilling; and fabrics made from vortex yarns have outstanding abrasion resistance, moisture absorption, color-fastness and fast drying characteristics [4]. Murata suggests that MVS is best suited by far to the high volume production of medium cotton yarns from carded cotton. Thus, it seems that this spinning system presents more of a threat to rotor spinning.
One of the major setbacks of this spinning technology is the high speed drafting. In this system the drafting unit has to operate at a speed 10 times higher than in the case of ring spinning [28,65]. Other major problems are the fiber loss during spinning and the frequent contamination in the jet nozzles since fiber material may be fed to the spinning unit without being adequately cleaned (by combing for example)[9].
Principle of Vortex Spinning
In the MVS system a sliver is fed directly to a 4-line drafting unit. Figure 8 shows a MVS spinning unit. When the fibers leave the front roller of the drafting device, they are drawn into a fiber bundle passage by air suction created by the nozzle. The fiber bundle passage consists of a nozzle block and a needle holder. The needle holder has a substantially central, longitudinal axis and a guide surface that twists relative to the longitudinal axis (Figure 9.) A pin-like guide member associated with the needle holder protrudes toward the inlet of the spindle (Figure 10) [64].
Following the fiber passage, fibers are smoothly sucked into a hollow spindle. Twist insertion starts as the fiber bundle receives the force of the compressed air at the inlet of the spindle. The twisting motion tends to propagate from the spindle toward the front rollers. This propagation is prevented by the guide member which temporarily plays a role as the center fiber bundle. After fibers have left the guide member, the whirling force of the air jet separates fibers from the bundle. Since the leading ends of all fibers are moved forward around the guide member and drawn into the spindle by the preceding portion of fiber bundle being formed into a yarn, they present partial twist and are less affected by the air flow inside the spindle. On the other hand, when the trailing ends of the fibers which have left the front rollers move to a position where they receive the powerfully whirling force of the nozzle, they are separated from the fiber bundle, extend outwardly and twine over the spindle. Subsequently, these fibers are spirally wound
around the fiber core and formed into a vortex spun yarn as they are drawn into the spindle (Figure 11 and 12) [15,64].
Figure 9. (a) plan view, (b) front view, (c) side view, and (d) perspective view of the needle holder [64]
Figure 10. Needle holder with the guide member [64]
Figure 11. Principle of Vortex Spinning [64]
The finished yarn is wound on a package after its defects have been removed. During the yarn formation, as the twist propagation is prevented by the guide member, most of the fibers do not receive the false twist. Besides, the fiber separation from the bundle occurs everywhere in the entire outer periphery of the bundle. This results in a higher number of wrapper fibers in the yarn. That’s why vortex spun yarns present much more wrapper fibers than air jet spun yarns, and their yarn structure is similar to ring yarns [15,49,64]. Figure 13 represents an idealized structure of vortex spun yarn.
Figure 12. Yarn formation in vortex spinning [15]
Figure 13. Idealized structure of MVS yarn [15]
and the resulting yarn structure is more similar to ring yarn than to rotor yarn [4,9,13,15,53]. Figure 7 shows vortex yarn versus rotor and ring yarns. Other claimed advantages of vortex spinning are a low maintenance cost due to fewer moving parts, elimination of the roving frame stage, and improved fully automatic piecing system [48]. In addition to these, yarns produced by this method have low hairiness compared to normal ring yarns. This is claimed to be due to being “air-singed” and “air-combed,” which in turn results in reduced fabric pilling; and fabrics made from vortex yarns have outstanding abrasion resistance, moisture absorption, color-fastness and fast drying characteristics [4]. Murata suggests that MVS is best suited by far to the high volume production of medium cotton yarns from carded cotton. Thus, it seems that this spinning system presents more of a threat to rotor spinning.
One of the major setbacks of this spinning technology is the high speed drafting. In this system the drafting unit has to operate at a speed 10 times higher than in the case of ring spinning [28,65]. Other major problems are the fiber loss during spinning and the frequent contamination in the jet nozzles since fiber material may be fed to the spinning unit without being adequately cleaned (by combing for example)[9].
Principle of Vortex Spinning
In the MVS system a sliver is fed directly to a 4-line drafting unit. Figure 8 shows a MVS spinning unit. When the fibers leave the front roller of the drafting device, they are drawn into a fiber bundle passage by air suction created by the nozzle. The fiber bundle passage consists of a nozzle block and a needle holder. The needle holder has a substantially central, longitudinal axis and a guide surface that twists relative to the longitudinal axis (Figure 9.) A pin-like guide member associated with the needle holder protrudes toward the inlet of the spindle (Figure 10) [64].
Following the fiber passage, fibers are smoothly sucked into a hollow spindle. Twist insertion starts as the fiber bundle receives the force of the compressed air at the inlet of the spindle. The twisting motion tends to propagate from the spindle toward the front rollers. This propagation is prevented by the guide member which temporarily plays a role as the center fiber bundle. After fibers have left the guide member, the whirling force of the air jet separates fibers from the bundle. Since the leading ends of all fibers are moved forward around the guide member and drawn into the spindle by the preceding portion of fiber bundle being formed into a yarn, they present partial twist and are less affected by the air flow inside the spindle. On the other hand, when the trailing ends of the fibers which have left the front rollers move to a position where they receive the powerfully whirling force of the nozzle, they are separated from the fiber bundle, extend outwardly and twine over the spindle. Subsequently, these fibers are spirally wound
around the fiber core and formed into a vortex spun yarn as they are drawn into the spindle (Figure 11 and 12) [15,64].
Figure 9. (a) plan view, (b) front view, (c) side view, and (d) perspective view of the needle holder [64]
Figure 10. Needle holder with the guide member [64]
Figure 11. Principle of Vortex Spinning [64]
The finished yarn is wound on a package after its defects have been removed. During the yarn formation, as the twist propagation is prevented by the guide member, most of the fibers do not receive the false twist. Besides, the fiber separation from the bundle occurs everywhere in the entire outer periphery of the bundle. This results in a higher number of wrapper fibers in the yarn. That’s why vortex spun yarns present much more wrapper fibers than air jet spun yarns, and their yarn structure is similar to ring yarns [15,49,64]. Figure 13 represents an idealized structure of vortex spun yarn.
Figure 12. Yarn formation in vortex spinning [15]
Figure 13. Idealized structure of MVS yarn [15]