Patent Application
20080155786
1. Field of Invention
The present invention represents a method and apparatus for producing yarn, and more particularly to a method and apparatus for producing a quality of yarn, wherein an iron-heating apparatus is installed on existing ring spinning machines to achieve the desired quality of yarn.
2. Description of Related Arts
Hairiness is one of important indexes to measure the quality of yarn. Hairiness can affect not only subsequent efficiency of yarn production, but also the quality and appearance of the final product. Reducing hairiness is very significant especially when shuttle-free machines are widely used today.
Generally speaking, hairiness is generated during the process of yarn production, wherein hairiness will be increased in spinning process and reduced in sizing process. With regard to ring spinning machines, fibers are twisted in a so-called twisting triangle area so that they can be effectively enwrapped into yarn during spinning, and yarn hairiness is consequently generated. It is mainly because the yarn twisted in the front roller in the twisting triangle area is under torques. Different magnitudes of torque are exerted on the outer and inner layers of the fiber. When the fiber is spun, if the torque is not large enough to overcome the rigidity of the fiber and made it bend to the center of the yarn, the fiber will become hairiness on the surface of the yarn. Moreover, hairiness can be formed at the very end of the fiber because the tension suddenly disappears at the exit of the twisting triangle area and the very end of the fiber can no longer be twisted into the fiber. It is generally believed that the physical property of the fiber is an important internal factor of hairiness in the process of yarn spinning. Hairiness can be reduced by longer or thinner fibers, enhancing the fineness of the fibers, increasing the number of twist of yarn or lowering the rigidity of the fiber.
Extensive researches regarding controlling hairiness have been conducted by domestic and international scholars. Two controlling methods are usually adopted: one is so-called ordinary methods and the other is the method of using hairiness-reducing equipment. Ordinary methods are through the process of optimization of certain industrial parameters or adopting some new techniques of yarn spinning to reduce hairiness, such as increasing the number of twist of yarn, lowering the speed of yarn spinning, appropriately increasing the tension of yarn spinning or decreasing the relaxation parameter in the area of spun yarn, or adopting the technology of compact yarn. Currently, the research is focused on adding some simple hairiness-reducing equipment on traditional ring spinning machines. An air-injection method is used so far in which the air-injection apparatus is installed between front roller and guide wire, so that the eddy of air flow can force the hairiness to stay close to the surface of yarn. This technique has been disclosed on “method and apparatus yarn treatment” patented on Apr. 10, 1974 (U.S. Pat. No. 4,14817,9), and “method and apparatus for modifying spun textile yarn” patented on Aug. 22, 1989 (U.S. Pat. No. 5,263,311). Major difference in above researches is that each air-injection apparatus generates different directions of air flow which has different hairiness-reducing effect. However, these apparatuses can only be installed after the twisting triangle area, meaning that the hairiness has already been formed and it can only be forced to stay close to the surface of yarn, but cannot be eliminated. Furthermore, specific air compressors and pipelines are necessary for these apparatuses. It can greatly affect the operative in a textile mill when such air-injection apparatus is also installed on the yarn equipment.
The present invention provides an effective method to reduce hairiness and enhance the quality of yarn. Specifically, this invention is to introduce an iron-heating apparatus especially to the fibers in the twisting triangle area.
In the present invention, the iron-heating apparatus is located in front of a front roller and a front leather roller on a ring spinning machine and the fiber is heated with high temperature at the exit of a front nip of the twisting triangle area. Specifically, the fiber directly enters the iron-heating apparatus from the exit of the front nip formed by the front leather roller and the front roller. The working temperature is between 60 and 300 centigrade. After being heated, the fiber goes through a guide wire, a traveler and a ring, and is then winded on a spun yarn tube. It is worth mentioning that the front roller and the front leather roller are provided to guide the fiber into the twisting triangle area.
The iron-heating apparatus comprises a base, a heating main body, a heat element, a temperature testing sensor and a thermal insulation layer. The heat element is positioned in the heating main body and the temperature testing sensor is either in the heating main body or on the surface thereof. The heating main body also includes an arc groove which is bell-mouthed and gradually shrunk toward the direction of yarn movement, wherein the fiber becomes more tightened and the diameter of the yarn decreases. More specifically, the modulus of the fiber is decreased after being heated and the fiber would more easily be collected and twisted together. The ratio of the width of the opening of the bell-mouthed groove k1 and the corresponding width of the fiber in the twisting triangle area is 1:1 to 1:1.5, while the ratio of the width of the groove k2 and the diameter of the yarn is 1:1.05 to 1:1.5. The shape of the bottom of the groove is semicircular and the depth of the groove h equals to k2. The heating main body is covered by the thermal insulation layer, and the heating main body is installed on the base.
The opening of the heating main body is close to the front nip from which the fiber comes, and then the fiber enters the heating main body and stays close to the groove of the heating main body along which the fiber moves forward. The heat element can be electronic heating wire (i.e. resistance) or heating mediums in the hollow tube. The bottom of the groove of the heating main body can be carved with features which are compatible with the twisting direction of the yarn. The heating main body in the iron-heating apparatus can be made from the materials which are abrasion-proof, thermal conductive and insulated, such as PTFE, ceramics and glass. The base and the heating main body in the iron-heating apparatus can be fabricated together as a whole.
According to the present invention, the fiber come from the front nip is directly heated by the iron-heating apparatus. The rigidity of the fiber, especially in the twisting triangle area, is reduced so that the fiber can subsequently be twisted more easily and hairiness can be avoided, especially long hairiness (longer than 3 mm) generated in subsequent processes. The friction of the groove can force hairiness to stay close to the surface of the fiber and significantly reduce the amount of hairiness. Meanwhile, the heating process is also a thermal setting process of the fiber and can significantly reduce the “kinking” phenomenon. The iron-heating apparatus in the present invention is an open structure, which has little interference to subsequent human operation, consumes less energy and is easy to install.
These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims.
The present invention is further illustrated along with the figures. As stated previously, it is generally believed that the physical property of the fiber is an important internal factor of hairiness in the process of yarn spinning. When the torque exerted on the fiber in the twisting triangle area is smaller than the rigidity of the fiber itself, hairiness is likely to form on the surface of the fiber. The present invention is based on the principle that the rigidity of the fiber is reduced with the increase of temperature. By placing an iron-heating apparatus 3 adjacent to an upper roller 1 and a lower roller 2, the fiber is heated with high temperature at the exit of a front nip and its rigidity is suddenly reduced so that the fiber can more easily be twisted. Meanwhile, to avoid hairiness (especially long hairiness) and improve the quality of yarn, the fiber in the twisting triangle area and movement of the surface fiber of yarn is controlled by the counter frictional force exerted on the fiber in the groove of the iron-heating apparatus 3. It is worth mentioning that the upper roller 1 and the lower roller 2 are provided to guide the fiber into the twisting triangle area. The principle of heating process is illustrated as follows. The upper roller 1 (front leather roller) and the lower roller 2 (front roller) are used to guide the yarn before the yarn is spun. The yarn is guided to pass through the upper and lower rollers 1, 2 at the front nip thereof within the twisting triangle area and to the groove of the heating main body 10 of the iron-heating apparatus 3 in which the fiber moves along and stays close to the wall of the groove. The heating main body 10 of the iron-heating apparatus 3 works with a heat element 11 to heat the fiber at certain working temperature and a temperature testing sensor 12 to ensure the yarn being heated within the working temperature. Also, the groove in the heating main body 10 of the iron-heating apparatus 3 provides a counter frictional force to the surface of the fiber. After heated by the iron-heating apparatus 3, the fiber goes through a guide wire 5, a traveler 6 and a ring 7, and then is enwrapped on a spun yarn tube 8.
The iron-heating apparatus 3 is installed in front of the upper roller 1 and the lower roller 2. The opening of the heating main body 10 of the iron-heating apparatus 3 is close to the front nip formed by the upper roller 1 and the lower roller 2. Surface A of the heating main body 10 facing towards the upper roller 1 is an arc surface having a curvature corresponding to the upper roller 1 or the lower roller 2. The fiber come from the from nip enters into and stays close to the groove 13 of the heating main body 10, and moves forward along the bottom of the groove.
The heat element 11 is located in the heating main body 10. The heat element 11, externally connected to a heat control system, can be electronic heating wire (i.e. resistance) or heating mediums in the hollow tube. The temperature testing sensor 12, wired to the switch of temperature control system, is located either in the heating main body 10 or on the surface thereof. The heat element 11 and the temperature testing sensor 12 work through the temperature control system to keep the heating main body 10 at working temperature between 60 and 300 centigrade. The exact working temperature depends on the materials of the fibers. For example, working temperature is 100 to 120 centigrade for polyester fiber while it is 180 to 280 centigrade for cotton.
The heating main body 10 in the iron-heating apparatus 3 can be made from the materials which are abrasion-proof, thermal conductive and insulated, such as PTFE, ceramics and glass. The base 9 in the iron-heating apparatus 3 has installation apertures which enable the base 9 and the heating main body 10 to be fabricated together as a whole. The heating main body 10 is covered by the thermal insulation layer which is used to prevent the loss of thermal energy, and then lower the consumption of energy. The thermal insulation layer can be some thermal insulation materials coated or pasted on the surface of the heating main body. An outer covering with the thermal insulation layer can be fabricated according to the shape of the heating main body.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200610166509.9 | Dec 2006 | CN | national |
