Production method of low-cost pure cotton yarn

Abstract

The invention discloses a low-cost pure cotton yarn production method, which adopts fine staple cotton and long stapled cotton fibers as raw materials, realizes the production of high-quality pure cotton yarn under the condition of reducing the use amount of the long stapled cotton fibers by controlling the distribution of the two fibers in a yarn body in spinning, and then provides the low-cost pure cotton yarn production method. Long stapled cotton / fine staple cotton core-spun roving with long stapled cotton serving as outer wrapping fibers and fine staple cotton serving as the center is prepared through a core-spun technology in the roving process, a four-roller three-area drafting structure is adopted in the spinning process, and long stapled cotton / fine staple cotton fiber strands with long stapled cotton fibers mainly located on the outer portion and long stapled cotton and fine staple cotton mixed fibers serving as the center are prepared through drafting. Then pure cotton spun yarn with the outer portion mainly made of long stapled cotton fibers and the center made of long stapled cotton and fine staple cotton mixed fibers is produced through twisting, distribution control over the two kinds of fibers in the yarn body is achieved, and therefore low-cost production of the pure cotton yarn with the excellent appearance effect and the yarn forming quality is achieved.

Description

Technical Field

[0001] The invention relates to the field of novel yarns, in particular to a method for producing low-cost pure cotton yarn. Background Art

[0002] With the development of social economy, people's living standards are constantly improving. For textiles used in clothing, in addition to the pursuit of wearing comfort, people are paying more and more attention to their fashion and functionality, pursuing unique styles and various functions, such as antibacterial and antistatic functions. In order to meet this demand of consumers, it has become an important task for the textile industry to continuously develop new yarns and fabrics. With the development of science and technology, the competition in the textile market is becoming more and more fierce. In order to maximize profits, various manufacturers are constantly developing in the direction of high-end, high-grade, good technical content and high added value.

[0003] Pure cotton yarn is the most common type of yarn and the most mature spinning method at present. Natural cotton fiber is used as raw material in the production of pure cotton yarn. Cotton fiber generally includes fine-staple cotton fiber and long-staple cotton fiber. The average length of fine-staple cotton fiber is generally within 30mm, and the length dispersion is large. Long-staple cotton has excellent quality. Its fiber is soft and long, generally 33-39 mm, and the longest can reach 64 mm. The fineness is 7000-8500 m / g, the width is 15-16 microns, the strength is high, 4-5 gf / root, the breaking length is 33-40 km, and there are more twists, 80-120 / cm, so it is generally suitable for the production of high-quality pure cotton yarn. However, the price of long-staple cotton fiber is high, which increases the production cost of the corresponding yarn. Summary of the invention

[0004] The purpose of the present invention is to provide a method for producing low-cost pure cotton yarn, which adopts fine-staple cotton fiber and long-staple cotton fiber as raw materials to achieve low-cost production of pure cotton yarn with excellent appearance effect and yarn quality.

[0005] The present invention provides a method for producing low-cost pure cotton yarn, comprising the following steps:

[0006] Step 1: Cotton matching. Fine-staple cotton is selected from Shandong Jinxiang cotton with an average length of 28.3mm and an average Micronaire value of 4.3, Hebei Dongguang cotton with an average length of 28.7mm and an average Micronaire value of 5.1, and Anhui Wuwei cotton with an average length of 27.2mm and an average Micronaire value of 4.9. Each plate uses 6 bales of Shandong Jinxiang cotton, 6 bales of Hebei Dongguang cotton, and 1 bale of Anhui Wuwei cotton. The arrangement order of the three cotton bales in each round plate is as follows:

[0007] The center circumference of the disc is equipped with 2 Shandong Jinxiang cotton bales and 2 Hebei Dongguang cotton bales, and the two cotton bales are arranged alternately. Along the outer circumference of the center of the disc, there is 1 Anhui Wuwei cotton bale, and the outer circumference of the disc is equipped with 4 Shandong Jinxiang cotton bales and 4 Hebei Dongguang cotton bales, and the two cotton bales are arranged alternately. The long-staple cotton uses 100% Xinjiang long-staple cotton fiber;

[0008] Step 2: Blowing and combing: the selected fine-staple cotton is blown and combed to obtain fine-staple cotton slivers, and the long-staple cotton is blown and combed to obtain long-staple cotton slivers;

[0009] The third step: combing the long-staple cotton, the long-staple cotton strips obtained in the second step are sequentially wound into strips and rolled into small combed rolls with excellent uniformity, and the small combed rolls are combed into long-staple cotton combed strips;

[0010] Step 4: drawing, the fine-staple cotton sliver obtained in the second step is drawn three times to obtain fine-staple cotton sliver, and the long-staple cotton combed sliver obtained in the third step is drawn two times to obtain long-staple cotton sliver;

[0011] Step 5: fine-staple cotton roving, the fine-staple cotton sliver obtained in the fourth step is drawn, thinned, twisted and wound by a roving machine to obtain fine-staple cotton roving;

[0012] Step 6: long-staple cotton / fine-staple cotton mixed roving, the long-staple cotton sliver obtained in the fourth step and the fine-staple cotton roving obtained in the fifth step are passed through a roving machine to obtain a long-staple cotton / fine-staple cotton core-spun roving with the long-staple cotton roving as the outer roving and the fine-staple cotton roving as the core yarn; a core-spun roving feeding device is arranged on the upper part of the drafting system of the roving machine, and the core-spun roving feeding device includes a pressing roller and a tension adjusting device, wherein the long-staple cotton sliver is fed into the drafting system of the roving machine by the rear roller of the roving machine After the drafting action of the drafting system, long-staple cotton slivers are obtained and pressed and output by the front roller. The fine-staple cotton roving wound on the roving tube is first pressed by the pressing roller after being wound out of the roving tube, and is actively unwound from the roving tube under the drive of the pressing roller. The unwound fine-staple cotton roving then enters the tension regulating device, and is then output by the tension regulating device and pressed and output by the front roller of the roving frame, and the pressing and output point of the fine-staple cotton roving at the front roller is located in the middle of the long-staple cotton slivers;

[0013] The seventh step: spinning, the long-staple cotton / fine-staple cotton core-spun roving obtained in the sixth step is drawn, thinned, twisted and wound by a spinning machine to obtain a long-staple cotton / fine-staple cotton mixed spinning with long-staple cotton fibers on the outside and long-staple cotton and fine-staple cotton mixed fibers in the center; the long-staple cotton / fine-staple cotton core-spun roving is fed into the four-roller three-zone of the spinning machine through the rear roller and the drafting structure of the fixed double short aprons and the elastic long and short aprons are respectively adopted. Under the synergistic effect of the drafting roller and the apron structure, the fine-staple cotton roving located in the center of the long-staple cotton / fine-staple cotton core-spun roving and the long-staple cotton roving located on the outside are simultaneously During the stretching, the long-staple cotton and fine-staple cotton fibers are mixed as the twist in the two rovings is removed during the stretching process. In the mixing process, the long-staple cotton fibers located on the outside with long fiber length and good consistency hinder the fine-staple cotton fibers, so that the long-staple cotton fibers in the long-staple cotton / fine-staple cotton slivers obtained after drawing are mainly located on the outside of the slivers, and the center is a mixed fiber of long-staple cotton and fine-staple cotton. Finally, under the action of twisting, a long-staple cotton / fine-staple cotton mixed yarn is obtained, which is mainly long-staple cotton fibers on the outside and a mixed fiber of long-staple cotton and fine-staple cotton in the center.

[0014] A low-cost pure cotton yarn production method as described above, wherein preferably, the carding step of the fine-staple cotton is: the selected fine-staple cotton fibers are sequentially grabbed by a disc-type cotton grabber according to the mixing ratio, and the fine-staple cotton fibers are initially opened and mixed during the grabbing process; the fine-staple cotton fibers grabbed according to the mixing ratio are opened and mixed by an automatic cotton mixer, and impurities are separated and removed during the opening process; various fine-staple cotton fibers are fully mixed by a multi-bin cotton mixer, and the fine-staple cotton fibers are opened and removed during the mixing process; the fine-staple cotton fibers are further opened, carded and removed by a porcupine cotton opener; the opened cotton fibers are uniformly fed by a cotton feeder; the fine-staple cotton flow uniformly fed by the single-beater roll forming machine is made into a uniform fine-staple cotton roll; the fine-staple cotton roll is finely opened, carded, removed and slivered by a cotton carding machine to obtain a fine-staple cotton strip.

[0015] A low-cost pure cotton yarn production method as described above, wherein preferably, the long-staple cotton is subjected to the following steps of cleaning and combing: the selected long-staple cotton is grabbed according to the mixing ratio by a reciprocating cotton grabber, the grabbed long-staple cotton fibers are transported and condensed by airflow driven by a cotton condenser + a double-axial flow cotton opener, the long-staple cotton fibers are opened, removed from impurities and mixed by a double-axial flow cotton opener, the long-staple cotton fibers are further opened, combed and removed from impurities by a three-licker-in cotton opener, the cotton layers are opened and evenly arranged by a cotton box and then transported to a carding machine, and the transported long-staple cotton layer is subjected to more detailed opening, combing, removal of impurities and stripping in the carding machine to obtain long-staple cotton strips.

[0016] A method for producing low-cost pure cotton yarn as described above, wherein, preferably, in the seventh step, the spinning frame uses a four-roller super-large drafting spinning frame, and the drafting system of the spinning frame adopts a three-zone drafting structure.

[0017] A method for producing low-cost pure cotton yarn as described above, wherein preferably, in the seventh step, the rear drafting zone between the rear roller and the middle rear roller is a drafting finishing zone of a light roller rubber roller structure, and the drafting multiple of the rear drafting zone is set between 1.05 and 1.35. The long-staple cotton roving located on the outside of the fed long-staple cotton / fine-staple cotton core-spun roving is stretched and thinned as a whole under the small drafting action of the rear drafting zone, and the interaction force between the long-staple cotton fibers is weakened during the stretching and thinning. At the same time, the fine-staple cotton roving located in the center is stretched and thinned as a whole under the small drafting action, and the interaction force between the fine-staple cotton fibers is weakened during the stretching and thinning. However, since the drafting multiple of the rear drafting zone is small, the long-staple cotton fibers and the fine-staple cotton fibers at this time still have a distinct internal and external layered structure, thereby obtaining the first long-staple cotton / fine-staple cotton sliver with the long-staple cotton fibers located on the outside and the fine-staple cotton fibers located in the center.

[0018] A low-cost pure cotton yarn production method as described above, wherein preferably, the first long-staple cotton / fine-staple cotton sliver enters the middle drafting zone between the middle rear roller and the middle front roller, and a middle rear lower short leather ring is installed on the middle rear roller through a fixed lower pin, and a middle rear upper short leather ring is installed on the middle rear rubber roller through a fixed upper pin, and a fixed leather ring control mechanism composed of the middle rear lower short leather ring and the middle rear upper short leather ring extends into the middle drafting zone, and the middle drafting zone is a transitional drafting zone, and the drafting multiple of the middle drafting zone is set between 1.35 and 1.75. At this time, the long-staple cotton sliver located on the outside of the first long-staple cotton / fine-staple cotton sliver is stretched and thinned under the synergistic action of the drafting roller and the leather ring structure, and at the same time, the interaction force between the long-staple cotton fibers in the stretching and thinning is further weakened, and the fibers located inside The fine-staple cotton slivers are stretched and thinned under the action of drawing, and the interaction force between the fine-staple cotton fibers is further weakened during the stretching and thinning. Due to the reduction of the interaction force between the external long-staple cotton and the internal fine-staple cotton fibers, when the number of fibers is large, the internal fine-staple cotton fibers gradually penetrate into the long-staple cotton fibers under the control of the fixed leather ring structure, thereby achieving mutual mixing between the long-staple cotton fibers and the fine-staple cotton fibers. During the mixing process, the long-staple cotton fibers located on the outside with good consistency hinder the fine-staple cotton fibers, so that the mixing between the two occurs only in the middle part of the sliver, thereby obtaining a second long-staple cotton / fine-staple cotton sliver with the long-staple cotton fibers located on the outside and the fine-staple cotton fibers and a small amount of long-staple cotton fibers located in the center.

[0019] A low-cost pure cotton yarn production method as described above, wherein preferably, the second long-staple cotton / fine-staple cotton sliver enters the front drafting zone between the middle front roller and the front roller, and a middle front lower long leather ring is provided on the middle front roller through a fixed lower pin and an elastic tension frame, and a middle front upper short leather ring is provided on the middle front rubber roller through an elastic upper pin, the middle front lower leather ring and the middle front upper leather ring are pressed against each other to form an elastic middle front leather ring control zone, the middle front leather ring control zone extends into the front drafting zone, the front drafting zone is the main drafting zone, and the drafting multiple of the front drafting zone is set between 15 and 70. At this time, the long-staple cotton sliver located outside in the second long-staple cotton / fine-staple cotton sliver undergoes a large stretching and thinning under the action of a large stretching, and at the same time, the long-staple cotton fibers in the stretching and thinning process are greatly stretched and thinned. The interaction force between the fibers is further weakened, and the fine-staple cotton and a small amount of long-staple cotton mixed whiskers located inside are greatly stretched and thinned under the action of drawing. At the same time, the interaction force between the fibers is further weakened during the stretching and thinning. Due to the reduction of the interaction force between the fibers, the fine-staple cotton fibers and the long-staple cotton fibers are further infiltrated and mixed under the control of the elastic leather ring structure when the number of fibers is small. In the mixing process, the long-staple cotton fibers located outside with long fiber length and good consistency hinder the fine-staple cotton fibers, so that the fine-staple cotton fibers never reach the edge of the whiskers, thereby obtaining long-staple cotton / fine-staple cotton whiskers with the long-staple cotton fibers located at the outermost edge and the fine-staple cotton fibers and long-staple cotton fibers located in the middle.

[0020] A method for producing low-cost pure cotton yarn as described above, wherein preferably, after the long-staple cotton / fine-staple cotton slivers obtained by the drafting system are output, long-staple cotton / fine-staple cotton mixed spun yarn is obtained under the action of twisting twist. During the twisting process, since the long-staple cotton fibers located at the outermost edge of the sliver are long in length and have good consistency in length distribution, the long-staple cotton fibers are directly bent under the action of twisting, and during the bending process, the long-staple cotton fibers are mutually entangled to form a web to form a long-staple cotton outer wrapped spun yarn. The fine-staple cotton fibers and the long-staple cotton fibers located in the middle of the sliver are mutually transferred under the action of twisting twist, thereby obtaining a long-staple cotton / fine-staple cotton core yarn with a certain strength, thereby obtaining a pure cotton spun yarn with long-staple cotton fibers on the outside and a mixed fiber of long-staple cotton and fine-staple cotton in the center.

[0021] A method for producing low-cost pure cotton yarn as described above, wherein preferably, the strip roll adopts a strip roll machine, 16-24 long-staple cotton strips obtained in the second step are guided by guide rollers and guide rollers, rotated 90 degrees on a V-shaped platform, arranged in parallel and combined, and the combined long-staple cotton strips enter a 3 / 3 drafting device under the guidance of the guide roller, the drafting multiple of the drafting device is between 1.1 and 1.4, the combined long-staple cotton strips are stretched to obtain a long-staple cotton layer, the long-staple cotton layer is pressed by a pressing roller to prevent sticking, and then the long-staple cotton layer is driven by the cotton roll roller to make a long-staple cotton roll.

[0022] A method for producing low-cost pure cotton yarn as described above, wherein preferably, the winding is performed using a winding machine, and 6 long-staple cotton rolls are respectively fed into respective drafting devices, and the drafting multiples of the drafting devices are between 5.2 and 7.5. After the long-staple cotton rolls are drafted, the long-staple cotton web is turned 90 degrees by a smooth curved guide plate and then stacked and combined in 6 layers on a cotton conveying platform, and then enters a pressing roller and is rolled into a long-staple cotton combed small roll by a roll roller.

[0023] Compared with the prior art, the present invention adopts a core-skinning process in the roving process to prepare long-staple cotton / fine-staple cotton core-skinned roving with long-staple cotton as the outer fiber and fine-staple cotton as the center, and adopts a four-roller three-zone drafting structure in the spun yarn process to prepare long-staple cotton / fine-staple cotton whiskers with long-staple cotton fibers mainly located on the outside and long-staple cotton and fine-staple cotton mixed fibers in the center through drafting, and then prepares the production of pure cotton spun yarn with mainly long-staple cotton fibers on the outside and long-staple cotton and fine-staple cotton mixed fibers in the center through twisting, and then realizes the distribution control of the two fibers in the yarn body, and realizes the production of high-quality pure cotton yarn while reducing the amount of long-staple cotton fibers, thereby realizing the low-cost production of pure cotton yarn with excellent appearance effect and yarn quality. DETAILED DESCRIPTION

[0024] The embodiments described below by reference are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0025] The invention provides a method for producing low-cost pure cotton yarn, wherein Xinjiang long-staple cotton fibers are sequentially subjected to cleaning and carding, combing and drawing to obtain long-staple cotton combed slivers, fine-staple cotton fibers are sequentially subjected to opening and cleaning, combing, drawing and roving to obtain fine-staple cotton rovings, and then the long-staple cotton slivers and the fine-staple cotton rovings are subjected to a roving process to obtain long-staple cotton / fine-staple cotton core-spun rovings, and a core-spun production process is adopted in the roving process, wherein the long-staple cotton slivers are fed through the rear roller of a roving machine, and a drafting system is output at the front roller to obtain long-staple cotton whiskers, the fine-staple cotton rovings are fed through the front roller of the roving machine, and are output through the front roller together with the long-staple cotton whiskers obtained by drafting, and then the long-staple cotton / fine-staple cotton core-spun rovings are obtained under the action of twisting twist, and the long-staple cotton / fine-staple cotton core-spun rovings are subjected to the rear roller together to obtain long-staple cotton whiskers. The yarn is fed into a spinning frame with a four-roller three-zone drafting structure. Under the drafting action, the fine cotton roving located in the center and the long-staple cotton roving located outside of the long-staple cotton / fine-staple cotton core-spun roving are stretched at the same time. At this time, as the twist in the two rovings is removed during the stretching process, the long-staple cotton and fine-staple cotton fibers are mixed. In the mixing process, the long-staple cotton fibers located outside with long fiber length and good consistency hinder the fine-staple cotton fibers, so that the long-staple cotton fibers in the long-staple cotton / fine-staple cotton sliver obtained after the drafting are mainly located outside the sliver, and the center is a mixed fiber of long-staple cotton and fine-staple cotton. Finally, under the action of twisting twist, a pure cotton yarn with mainly long-staple cotton fibers on the outside and a mixed fiber of long-staple cotton and fine-staple cotton in the center is obtained, which includes the following steps:

[0026] The first step: cotton matching. The fine-staple cotton is made of Shandong Jinxiang cotton with an average length of 28.3mm and an average micronaire value of 4.3, Hebei Dongguang cotton with an average length of 28.7mm and an average micronaire value of 5.1, and Anhui Wuwei cotton with an average length of 27.2mm and an average micronaire value of 4.9. Each plate uses 6 bales of Shandong Jinxiang cotton, 6 bales of Hebei Dongguang cotton and 1 bale of Anhui Wuwei cotton. The arrangement order of the three types of cotton bales in each disc is as follows: 2 Shandong Jinxiang cotton bales and 2 Hebei Dongguang cotton bales are configured on the central circumference of the disc, and the two types of cotton bales are arranged at intervals, 1 Anhui Wuwei cotton bale is configured along the outer circumference of the center of the disc, and 4 Shandong Jinxiang cotton bales and 4 Hebei Dongguang cotton bales are configured on the outer circumference of the disc, and the two types of cotton bales are arranged at intervals; long-staple cotton uses 100% Xinjiang long-staple cotton fiber.

[0027] The second step: cleaning and combing, the selected fine cotton is opened and combed to obtain fine cotton strips. In the opening and cleaning of fine cotton, the selected fine cotton fibers are sequentially grabbed by the disc-type cotton grabber according to the mixing ratio, and the fine cotton fibers are initially opened and mixed during the grabbing process. The fine cotton fibers grabbed according to the mixing ratio are opened and mixed by the automatic cotton mixer, and the impurities are separated and removed during the opening process. The various fine cotton fibers are fully mixed by the multi-bin cotton mixer, and the fine cotton fibers are opened and removed during the mixing process. The fine cotton fibers are finally opened by the porcupine cotton opener. The fine cotton fibers are further opened, combed and impurity-removed. The cotton fibers after opening are uniformly fed by the cotton feeder. The fine cotton flow uniformly fed by the single-beater roll forming machine is made into uniform fine cotton rolls. The opening and cleaning process adopts "reasonable cotton distribution, multiple bales, frequent grabbing and less grabbing, enhanced mixing, short process, low speed, fine cotton grabbing, full mixing, gradual opening, reduced tumbling, more combing, more loosening and less beating, thin feeding, light quantitative, large spacing, more mixing, early falling and less broken, no fiber damage, combing instead of beating, less tumbling, anti-adhesion, gradual opening, a small amount of The process principle is "grabbing, fully mixing, low speed, thin feeding"; in the process of plucking cotton, according to the principle of fine plucking cotton, ensure that the plucking amount of each tooth of the plucking beater blade of the disc plucking machine is small; in the automatic cotton mixing process, the airflow generated by the condenser fan feeds the raw materials grabbed by the automatic plucking machine to mix, highly loosen, and remove some impurities; in the multi-bin mixing process, after the raw materials are fed, they are evenly blown into multiple cotton bins under the action of airflow to form a raw material mixture, and the fiber layers of each bin are transported through a 90° turn, and the distance difference is used to obtain mixing, and the excess The fibers are thrown into the mixing chamber to achieve further fine mixing; in the porcupine opening process, the mechanical parts between the beater and the dust bar are used to complete the opening and impurity removal; in the vibration feeding process, the fibers delivered by the cotton feeder are further loosened and mixed, and are evenly fed into the lap forming machine to form cotton rolls; in the single beater lap forming process, the mechanical parts between the beater and the dust bar are used to complete the opening and impurity removal, and form uniform fine-pile cotton rolls; in the fine-pile cotton carding, the fine-pile cotton rolls are subjected to the fine opening, combing, impurity removal and slitting of the carding machine to produce fine-pile cotton strips.

[0028] Long-staple cotton is produced into long-staple cotton slivers through the cleaning and carding process. In this process, the selected long-staple cotton is grabbed by the reciprocating cotton plucking machine according to the mixing ratio, and the airflow-driven transportation and condensation of the grabbed long-staple cotton fibers are realized through the cotton condenser + double-axial flow cotton opener, and the long-staple cotton fibers are opened, removed from impurities and mixed through the double-axial flow cotton opener, and further opened, combed and removed from impurities through the three-licker-in cotton opener, and the cotton fibers are opened and the cotton layer is evenly arranged through the cotton box and then transported to the carding machine, and the long-staple cotton slivers are obtained after the transported long-staple cotton layer is more carefully opened, combed, removed from impurities and formed into strips in the carding machine.

[0029] The third step: combing long-staple cotton. The long-staple cotton strips obtained in the second step are combed to obtain long-staple cotton combed strips through a combing process. The combing process includes combing preparation and combing. The combing preparation includes strip lap and lap. The strip lap adopts a strip lap machine. 16-24 long-staple cotton strips obtained in the second step are guided by the guide roller and the guide roller. The V-shaped platform rotates 90 degrees to arrange them in parallel and merge them. The merged long-staple cotton strips enter the 3 / 3 drafting device under the guidance of the guide roller. The drafting multiple of the drafting device is between 1.1 and 1.4. The merged long-staple cotton strips are drawn to obtain a long-staple cotton layer. The long-staple cotton layer is pressed by a pressing roller to prevent sticking. Then the long-staple cotton layer is driven by the cotton roll roller to form a long-staple cotton roll; the lap is rolled using a lap machine. 6 long-staple cotton rolls are respectively entered into their respective drafting devices, and the drafting multiple of the drafting device is between 5.2 and 7.5, after each long-staple cotton roll is drafted, the long-staple cotton web is turned 90 degrees by a smooth curved guide plate and then stacked and combined on the cotton conveying platform in 6 layers, and then enters the compacting roller and is rolled into a long-staple cotton combed small roll by the roll forming roller; combing adopts a combing machine, and the prepared long-staple cotton combed small roll is passed through the combing machine to obtain a long-staple cotton combed strip, and the combing machine includes a nipper feeding part, a cylinder combing part, a separation and combination part, and a strip forming and coiling part from front to back along the moving direction of the long-staple cotton fiber in the combing machine. The nipper feeding part includes a cotton feeding roller and upper and lower nippers, and a nipper feeding part is arranged at the rear of the nipper feeding part There is a tension roller. The long-staple cotton combed small roll is pressed by the cotton feeding roller after passing through the tension roller. At this time, the tension of the long-staple cotton combed small roll is adjusted by the tension roller, so that the long-staple cotton combed small roll can enter the nipper feeding part uniformly under constant tension control. The long-staple cotton combed small roll output by the cotton feeding roller is then held by the upper and lower nippers. The upper and lower nippers in the nipper feeding part swing back and forth periodically, and the long-staple cotton combed small roll is fed periodically by swinging back and forth; the cylinder combing part includes a lower cylinder and an upper top comb. The upper and lower nippers swing periodically to feed the long-staple cotton Under the effective clamping of the nipper, the lower cylinder combs the front and middle parts of the long-staple cotton combed roll fiber bundle extending out of the panel, thereby removing short fibers and part of the dust in the combing process and making the fibers straight and parallel. The upper top comb combs the rear end of the fiber bundle and prevents the short fibers and dust caught in the whiskers from re-entering the cotton web. The separation and combination part includes the upper separation roller and the lower separation roller. In each working cycle, the cotton web of the previous working cycle is poured in first, and the front end of the whiskers sent by the nipper is grasped in time and superimposed on the poured cotton web to achieve combination. The speed of the jaws is greater than the speed of the top comb feeding the beard clump. The fibers held by the separation jaws are drawn out from the feeding beard clump, and their tail ends are combed by the top comb. The sliver coiling part includes a pressing roller and a coiler. The long-staple cotton web output by the separation and combination part is gathered through the bell mouth, thereby changing the long-staple cotton web from a net structure to a strip structure. During the gathering process, the long-staple cotton web produces a longitudinal mixing effect due to the different time of reaching the bell mouth. The long-staple cotton fibers that are reassembled into strips are then pressed and fixed by the pressing roller and continuously wound in the sliver cylinder through the coiler, thereby obtaining a long-staple cotton combed sliver.

[0030] The fourth step: drawing. The fine-staple cotton strips obtained in the second step are drawn through three passes to obtain fine-staple cotton strips, and the long-staple cotton combed strips obtained in the third step are drawn through two passes to obtain long-staple cotton strips. Six fine-staple cotton strips are fed into the first drawing of the fine-staple cotton strips, and the first fine-staple cotton strips are drawn and thinned by the drawing system of the drawing frame and then re-combined. The drawing multiple of the drawing system is between 6.05 and 6.5. The fibers in the fine-staple cotton strips are straightened and arranged by drawing, and the random combination of thick and thin sections of the fine-staple cotton strips is achieved by combining. , thereby improving the uniformity of the strips. In the second drawing, 6 first fine cotton strips are fed, and after being stretched and thinned by the drafting system of the drawing frame, they are re-combined to obtain the second fine cotton strips. The drafting multiple of the drafting system is between 6.15 and 6.35. The fibers in the fine cotton strips are straightened and arranged by drafting, and the random combination of thick and thin sections of the fine cotton strips is achieved by combining, thereby improving the uniformity of the strips. In the third drawing, 6 second fine cotton strips are fed, and after being stretched and thinned by the drafting system of the drawing frame, they are re-combined. The newly combined fine-staple cotton sliver is made, and the drafting multiple of the drafting system is between 6.2 and 6.4. The fibers in the fine-staple cotton sliver are straightened and arranged by drafting, and the random combination of thick and thin sections of the fine-staple cotton sliver is achieved by combining, thereby improving the uniformity of the sliver. In the first drawing of long-staple cotton, 6 long-staple cotton combed slivers are fed, and after being stretched and thinned by the drafting system of the drawing frame, they are combined again to make semi-cooked long-staple cotton slivers. The drafting multiple of the drafting system is between 6.45 and 6.55, and the long-staple cotton combed sliver is achieved by drawing. The inner fibers are straightened and arranged, and random combination of thick and thin sections of the combed long-staple cotton strips is achieved through merging, thereby improving the uniformity of the strips. In the second drawing, 6 semi-ripe strips of long-staple cotton are fed, and after being stretched and thinned by the drawing system of the drawing frame, they are re-combined to obtain cooked long-staple cotton strips. The drafting multiple of the drafting system is between 6.15 and 6.35. The inner fibers of the semi-ripe long-staple cotton strips are straightened and arranged through drawing, and random combination of thick and thin sections of the semi-ripe long-staple cotton strips is achieved through merging, thereby improving the uniformity of the strips.

[0031] Step 5: Fine-staple cotton roving: The fine-staple cotton sliver obtained in the fourth step is drawn, thinned, twisted and wound by the roving machine to obtain fine-staple cotton roving. The roving machine should not only continue to improve the straightness of the fiber, but also perform twisting and gathering to create conditions for the large drafting of the roving machine. The roving process design is mainly aimed at improving the quality of the roving to achieve stable elongation, small weight difference, uniform sliver, compact structure and good forming. The roving machine should improve the quality of mechanical flat repair, the drafting gear meshing is normal, the roller bending and the rubber roller eccentricity must meet the requirements, there is no oil shortage, and the cotton collector is open. The proper installation position, flexible rotation of the rubber roller, correct starting position of the iron cannon, stable elongation, smooth spindle shell, normal operation and free of hanging flowers in the channel, etc., can improve the roving evenness, reduce weight unevenness and reduce yarn defects; the finishing area is between the front roller and the second roller, and the holding distance can be slightly greater than or equal to the quality length of the fiber, designed to be 35mm; the main drafting area is between the second roller and the third roller, and the holding distance is equal to the length of the rubber ring frame plus the length of the free zone, designed to be 47mm; the simple roller drafting is between the third roller and the fourth roller, and the holding distance is designed to be 45mm.

[0032] Step 6: long-staple cotton / fine-staple cotton mixed roving: the long-staple cotton sliver obtained in the fourth step and the fine-staple cotton roving obtained in the fifth step are passed through a roving machine together to obtain long-staple cotton / fine-staple cotton core-spun roving, wherein the long-staple cotton sliver is fed into the drafting system of the roving machine by the rear roller of the roving machine, and the fed long-staple cotton sliver is stretched by the drafting action of the drafting system to obtain long-staple cotton sliver, and the obtained long-staple cotton sliver is pressed and driven to be output by the front roller of the roving machine, and a core-spun roving feeding device is arranged on the upper part of the drafting system of the roving machine, and the core-spun roving feeding device includes a pressing roller and a tension adjusting device, and the fine-staple cotton roving wound on the roving tube is first pressed by the pressing roller after being wound out of the roving tube, and is first unwound from the roving tube driven by the pressing roller, The unwound fine-staple cotton roving then enters the tension adjusting device, and is then output by the tension adjusting device and pressed and output by the front roller of the roving frame, thereby realizing the tension adjustment of the fine-staple cotton roving entering the front roller through the tension adjusting device, and the pressing and output point of the fine-staple cotton roving at the front roller is located in the middle part of the long-staple cotton whiskers, thereby making the fine-staple cotton roving and the long-staple cotton whiskers be pressed and output together by the front roller of the roving frame, and the output fine-staple cotton roving and the long-staple cotton whiskers are twisted into long-staple cotton roving under the action of twisting twist, and the fine-staple cotton roving is wrapped in the center during the twisting process, thereby obtaining a long-staple cotton / fine-staple cotton core-spun roving with the long-staple cotton roving as the outer roving and the fine-staple cotton roving as the core yarn.

[0033] Step 7: Spinning: The long-staple cotton / fine-staple cotton core-spun roving obtained in the sixth step is stretched, thinned, twisted and wound by a spinning machine to obtain a long-staple cotton / fine-staple cotton mixed spun yarn. The spinning machine uses a four-roller three-zone super-large drafting spinning machine. The drafting system of the spinning machine adopts a four-roller three-zone drafting structure. The fed long-staple cotton / fine-staple cotton core-spun roving first enters the rear drafting zone between the rear roller and the middle rear roller. The rear drafting zone is a drafting and finishing zone of a light roller rubber roller structure. The drafting multiple of the rear drafting zone is set between 1.05 and 1.35. The long-staple cotton roving located on the outside undergoes overall stretching and thinning under the action of small drafting. During the stretching and thinning, the interaction force between the long-staple cotton fibers is weakened. At the same time, the fine-staple cotton roving located in the center undergoes overall stretching and thinning under the action of small drafting. The interaction force between the fine-staple cotton fibers during the stretching and thinning is weakened, but because the drafting multiple in the rear drafting zone is small, the long-staple cotton fibers and the fine-staple cotton fibers at this time still present a distinct internal and external layered structure, thereby obtaining the first long-staple cotton / fine-staple cotton whiskers with the long-staple cotton fibers located on the outside and the fine-staple cotton fibers located in the center, and then the first long-staple cotton / fine-staple cotton whiskers enter the middle drafting zone between the middle rear roller and the middle front roller, and a middle rear lower short leather ring is installed on the middle rear roller through a fixed lower pin, and a middle rear upper short leather ring is installed on the middle rear rubber roller through a fixed upper pin, and a fixed leather ring control mechanism composed of the middle rear lower short leather ring and the middle rear upper short leather ring extends into the middle drafting zone. The middle drafting zone is a transitional drafting zone, and the drafting multiple in the middle drafting zone is set between 1.35 and 1.75. At this time, The long-staple cotton slivers located outside of the first long-staple cotton / fine-staple cotton slivers are stretched and thinned under the synergistic action of the drafting roller and the leather ring structure, and the interaction force between the long-staple cotton fibers is further weakened during the stretching and thinning. The fine-staple cotton slivers located inside are stretched and thinned under the drafting action, and the interaction force between the fine-staple cotton fibers is further weakened during the stretching and thinning. Due to the reduction of the interaction force between the external long-staple cotton and the internal fine-staple cotton fibers, the internal fine-staple cotton fibers gradually penetrate into the long-staple cotton fibers under the control of the fixed leather ring structure when the number of fibers is large, thereby achieving mutual mixing between the long-staple cotton fibers and the fine-staple cotton fibers. In the mixing process, the long-staple cotton fibers located outside with long fiber length and good consistency are The fine-staple cotton fiber acts as an obstacle, so that the mixing between the two occurs only in the middle part of the whisker, thereby obtaining a second long-staple cotton / fine-staple cotton whisker with long-staple cotton fibers located on the outside and fine-staple cotton fibers and a small amount of long-staple cotton fibers located in the center, and then the second long-staple cotton / fine-staple cotton whisker enters the front drafting zone between the middle front roller and the front roller, and a middle front lower apron is arranged on the middle front roller, and a middle front lower long apron is arranged on the middle front roller through a fixed lower pin and an elastic tension frame, and a middle front upper short apron is arranged on the middle front rubber roller through an elastic upper pin, the middle front lower apron and the middle front upper apron press each other to form an elastic middle front apron control zone, and the middle front apron control zone extends into the front drafting zone, the front drafting zone is the main drafting zone, and the drafting multiple of the front drafting zone is set between 15 and 70.At this time, the long-staple cotton strands located outside of the second long-staple cotton / fine-staple cotton strands are greatly stretched and thinned under the action of large stretching, and the interaction force between the long-staple cotton fibers is further weakened during the stretching and thinning. The fine-staple cotton and a small amount of long-staple cotton mixed strands located inside are greatly stretched and thinned under the action of large stretching, and the interaction force between the fibers is further weakened during the stretching and thinning. Due to the reduction in the interaction force between the fibers, the fine-staple cotton fibers and the long-staple cotton fibers are further infiltrated and mixed under the control of the elastic leather ring structure when the number of fibers is small. During the mixing process, the long-staple cotton fibers located outside with long fiber length and good consistency hinder the fine-staple cotton fibers, so that the fine-staple cotton fibers never reach the edge of the strands, that is, the long-staple cotton fibers always cover the fine-staple cotton fibers in the middle. Thus, long-staple cotton / fine-staple cotton whiskers are obtained, wherein the long-staple cotton fibers are located at the outermost edge, and the fine-staple cotton fibers and long-staple cotton fibers are located in the middle. After the long-staple cotton / fine-staple cotton whiskers obtained by the drafting system are output, long-staple cotton / fine-staple cotton mixed spun yarn is obtained under the action of twisting twist. During the twisting process, since the long-staple cotton fibers located at the outermost edge of the whiskers are long in length and have good consistency in length distribution, the long-staple cotton fibers are directly bent under the action of twisting, and during the bending process, the long-staple cotton fibers are mutually entangled to form a web to form a long-staple cotton outer-wrapped spun yarn. The fine-staple cotton fibers and long-staple cotton fibers located in the middle of the whiskers are mutually transferred under the action of twisting twist, thereby obtaining a long-staple cotton / fine-staple cotton core yarn with a certain strength, thereby obtaining a pure cotton spun yarn with long-staple cotton fibers on the outside and long-staple cotton and fine-staple cotton mixed fibers in the center. Taking the preparation of pure cotton weaving yarn with a linear density of 60S as an example, the corresponding process parameters are as follows: (1) Raw material selection,

[0034] Long-staple cotton blending and performance indicators of each cotton bale

[0035]

[0036] Fine cotton with cotton

[0037]

[0038] (2) Design of key process parameters

[0039] Fine-staple cotton opening and cleaning:

[0040] A002D disc type cotton plucking machine

[0041] Process parameters Parameter design Trolley rotation speed (r / min) 1.8 Beater speed (rpm) 740 Distance of blade extending out from rib (mm) 2.75 Interval drop distance of the beater (mm / time) 3.25

[0042] FA017 Automatic Cotton Mixing Machine

[0043] Process parameters Parameter design Feeding roller speed (r / min) 2.59 Cotton stripping beater speed (r / min) 429 Cotton beating machine speed (r / min) 272 Angle nail curtain line speed (m / min) 80 Cotton cord linearity (m / min) 2.17 Cotton cord linearity (m / min) 1.54 Distance between corner nail curtain and cotton stripping beater (mm) 1 The distance between the corner nail curtain and the cotton beater (mm) 45

[0044] FA029 Multi-bin Cotton Mixing Machine

[0045] Process parameters Parameter design Cotton roller speed (r / min) 726 Cotton stripping roller speed (r / min) 543 Angle nail cord speed (m / min) 110 Horizontal cord speed (m / min) 0.7

[0046] FA106A porcupine type cotton opener

[0047] Process parameters Parameter design Beater speed (r / min) 540 Feed roller speed (r / min) 46 The distance between the beater and the feeding roller (mm) 6.5 Distance between beater and dust stick (mm) Import gauge 12, export gauge 16.5 Distance between dust sticks (mm) One group of imports: 13, two groups in the middle: 8, one group of export: 5.5 The distance between the beater and the stripping knife (mm) 1.6

[0048] FA161 Vibrating Cotton Feeder

[0049] Process parameters Parameter design Corner nail curtain speed (m / min) 35 Flat curtain speed (m / min) 7.5 Cotton roller speed (r / min) 230 Cotton stripping roller speed (r / min) 400 Feeding roller speed (r / min) 4.9 Distance from stripping roller to inclined curtain (mm) 16

[0050] FA141A Single Beater Rolling Machine

[0051]

[0052]

[0053] Overall process of cotton opening and cleaning

[0054]

[0055] Fine-staple cotton carding:

[0056]

[0057] Long-staple cotton combing preparation:

[0058]

[0059] Long-staple combed cotton:

[0060]

[0061]

[0062] Fine-staple cotton drawing:

[0063]

[0064] Fine-staple cotton yarn:

[0065]

[0066] Fine yarn:

[0067]

[0068] (4) Quality testing:

[0069] At the same time, the selected long-staple cotton was used to process the pure cotton combed weaving yarn of full long-staple cotton 60S, and the quality was compared with the pure cotton yarn processed by this patent. The test results are as follows:

[0070] Yarn evenness test

[0071]

[0072] Yarn strength test

[0073]

[0074]

[0075] It is easy to see from the test results that the pure cotton yarn processed by fine-staple cotton and long-staple cotton in this patent has comparable indicators to the pure cotton combed yarn processed by full long-staple cotton, especially the strong CV and yarn hairiness. This is because this patent uses core-spun composite for fine-staple cotton and long-staple cotton, and effectively controls the distribution of the two fibers in the yarn body during the drafting process of the spinning process.

[0076] The structure, features and effects of the present invention are described in detail above based on the embodiments shown. The above is only a preferred embodiment of the present invention, but the present invention is not limited to the scope of implementation shown. Any changes made according to the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the specification, should be within the protection scope of the present invention.

Claims

1. A method for producing low-cost pure cotton yarn, characterized in that: The following steps are involved: Step 1: Cotton matching. Fine-staple cotton is selected from Shandong Jinxiang cotton with an average length of 28.3mm and an average Micronaire value of 4.3, Hebei Dongguang cotton with an average length of 28.7mm and an average Micronaire value of 5.1, and Anhui Wuwei cotton with an average length of 27.2mm and an average Micronaire value of 4.

9. Each plate uses 6 bales of Shandong Jinxiang cotton, 6 bales of Hebei Dongguang cotton, and 1 bale of Anhui Wuwei cotton. The arrangement order of the three cotton bales in each round plate is as follows: The center circumference of the disc is equipped with 2 Shandong Jinxiang cotton bales and 2 Hebei Dongguang cotton bales, and the two cotton bales are arranged alternately. Along the outer circumference of the center of the disc, there is 1 Anhui Wuwei cotton bale, and the outer circumference of the disc is equipped with 4 Shandong Jinxiang cotton bales and 4 Hebei Dongguang cotton bales, and the two cotton bales are arranged alternately. The long-staple cotton uses 100% Xinjiang long-staple cotton fiber; Step 2: Blowing and combing: the selected fine-staple cotton is blown and combed to obtain fine-staple cotton slivers, and the long-staple cotton is blown and combed to obtain long-staple cotton slivers; The third step: combing the long-staple cotton, the long-staple cotton strips obtained in the second step are sequentially wound into strips and rolled into small combed rolls with excellent uniformity, and the small combed rolls are combed into long-staple cotton combed strips; Step 4: drawing, the fine-staple cotton sliver obtained in the second step is drawn three times to obtain fine-staple cotton sliver, and the long-staple cotton combed sliver obtained in the third step is drawn two times to obtain long-staple cotton sliver; Step 5: fine-staple cotton roving, the fine-staple cotton sliver obtained in the fourth step is drawn, thinned, twisted and wound by a roving machine to obtain fine-staple cotton roving; Step 6: long-staple cotton / fine-staple cotton mixed roving, the long-staple cotton sliver obtained in the fourth step and the fine-staple cotton roving obtained in the fifth step are passed through a roving machine to obtain a long-staple cotton / fine-staple cotton core-spun roving with the long-staple cotton roving as the outer roving and the fine-staple cotton roving as the core yarn; a core-spun roving feeding device is arranged on the upper part of the drafting system of the roving machine, and the core-spun roving feeding device includes a pressing roller and a tension adjusting device, wherein the long-staple cotton sliver is fed into the drafting system of the roving machine by the rear roller of the roving machine After the drafting action of the drafting system, long-staple cotton slivers are obtained and pressed and output by the front roller. The fine-staple cotton roving wound on the roving tube is first pressed by the pressing roller after being wound out of the roving tube, and is actively unwound from the roving tube under the drive of the pressing roller. The unwound fine-staple cotton roving then enters the tension regulating device, and is then output by the tension regulating device and pressed and output by the front roller of the roving frame, and the pressing and output point of the fine-staple cotton roving at the front roller is located in the middle of the long-staple cotton slivers; The seventh step: spinning, the long-staple cotton / fine-staple cotton core-spun roving obtained in the sixth step is drawn, thinned, twisted and wound by a spinning machine to obtain a long-staple cotton / fine-staple cotton mixed spinning with long-staple cotton fibers on the outside and long-staple cotton and fine-staple cotton mixed fibers in the center; the long-staple cotton / fine-staple cotton core-spun roving is fed into the four-roller three-zone of the spinning machine through the rear roller and the drafting structure of the fixed double short aprons and the elastic long and short aprons are respectively adopted. Under the synergistic effect of the drafting roller and the apron structure, the fine-staple cotton roving located in the center of the long-staple cotton / fine-staple cotton core-spun roving and the long-staple cotton roving located on the outside are simultaneously During the stretching, the long-staple cotton and fine-staple cotton fibers are mixed as the twist in the two rovings is removed during the stretching process. In the mixing process, the long-staple cotton fibers located on the outside with long fiber length and good consistency hinder the fine-staple cotton fibers, so that the long-staple cotton fibers in the long-staple cotton / fine-staple cotton slivers obtained after drawing are mainly located on the outside of the slivers, and the center is a mixed fiber of long-staple cotton and fine-staple cotton. Finally, under the action of twisting, a long-staple cotton / fine-staple cotton mixed yarn is obtained, which is mainly long-staple cotton fibers on the outside and a mixed fiber of long-staple cotton and fine-staple cotton in the center.

2. The method for producing low-cost pure cotton yarn according to claim 1, characterized in that: The cleaning and combing steps of fine cotton are as follows: the selected fine cotton fibers are sequentially grabbed by a disc-type cotton grabber according to the mixing ratio, and the fine cotton fibers are initially opened and mixed during the grabbing process; the fine cotton fibers grabbed according to the mixing ratio are opened and mixed by an automatic cotton mixer, and impurities are separated and removed during the opening process; various fine cotton fibers are fully mixed by a multi-bin cotton mixer, and the fine cotton fibers are opened and removed from impurities during the mixing process; the fine cotton fibers are further opened, combed and removed from impurities by a porcupine cotton opener, and the opened cotton fibers are uniformly fed by a cotton feeder; the fine cotton flow uniformly fed from the cotton feeder is made into a uniform fine cotton roll by a single-beater roll forming machine, and the fine cotton roll is made into fine cotton strips after the fine opening, combing, impurity removal and stripping of the cotton carding machine.

3. The method for producing low-cost pure cotton yarn according to claim 1, characterized in that: The cleaning and carding steps of long-staple cotton are as follows: the selected long-staple cotton is grabbed by a reciprocating cotton plucking machine according to the mixing ratio, the grabbed long-staple cotton fibers are transported and condensed by airflow driven by a cotton condenser + a double-axial flow cotton opener, and the long-staple cotton fibers are opened, removed from impurities and mixed by a double-axial flow cotton opener, and further opened, combed and removed from impurities by a three-licker-in cotton opener, and the cotton layers are opened and evenly arranged by a cotton box and then transported to a carding machine, and the long-staple cotton layer is more finely opened, combed, removed from impurities and formed into strips in the carding machine to obtain long-staple cotton strips.

4. The method for producing low-cost pure cotton yarn according to claim 1, characterized in that: In the seventh step, the spinning frame adopts a four-roller super-large drafting spinning frame, and the drafting system of the spinning frame adopts a three-zone drafting structure.

5. The method for producing low-cost pure cotton yarn according to claim 1, characterized in that: In the seventh step, the rear drafting zone between the rear roller and the middle rear roller is a drafting finishing zone of the light roller rubber roller structure, and the drafting multiple of the rear drafting zone is set between 1.05 and 1.

35. The long-staple cotton roving located on the outside of the fed long-staple cotton / fine-staple cotton core-spun roving undergoes overall stretching and thinning under the small stretching action of the rear drafting zone, and the interaction force between the long-staple cotton fibers is weakened during the stretching and thinning. At the same time, the fine-staple cotton roving located in the center undergoes overall stretching and thinning under the small stretching action, and the interaction force between the fine-staple cotton fibers is weakened during the stretching and thinning. However, since the drafting multiple of the rear drafting zone is small, the long-staple cotton fibers and the fine-staple cotton fibers at this time still have a distinct internal and external layered structure, thereby obtaining the first long-staple cotton / fine-staple cotton sliver with the long-staple cotton fibers located on the outside and the fine-staple cotton fibers located in the center.

6. The method for producing low-cost pure cotton yarn according to claim 5, characterized in that: The first long-staple cotton / fine-staple cotton sliver enters the middle drafting zone between the middle rear roller and the middle front roller, and a middle rear lower short leather ring is installed on the middle rear roller through a fixed lower pin, and a middle rear upper short leather ring is installed on the middle rear rubber roller through a fixed upper pin. The fixed leather ring control mechanism composed of the middle rear lower short leather ring and the middle rear upper short leather ring extends into the middle drafting zone. The middle drafting zone is a transitional drafting zone, and the drafting multiple of the middle drafting zone is set between 1.35 and 1.

75. At this time, the long-staple cotton sliver located outside of the first long-staple cotton / fine-staple cotton sliver is stretched and thinned under the synergistic action of the drafting roller and the leather ring structure. At the same time, the interaction force between the long-staple cotton fibers in the stretching and thinning is further weakened, and the fine-staple cotton sliver located inside is stretched under the drafting action. The fibers are stretched and thinned, and the interaction force between the fine-staple cotton fibers is further weakened during the stretching and thinning process. Due to the reduction of the interaction force between the external long-staple cotton and the internal fine-staple cotton fibers, the internal fine-staple cotton fibers gradually penetrate into the long-staple cotton fibers under the control of the fixed leather ring structure when the number of fibers is large, thereby achieving mutual mixing between the long-staple cotton fibers and the fine-staple cotton fibers. During the mixing process, the long-staple cotton fibers located on the outside with good fiber length and consistency hinder the fine-staple cotton fibers, so that the mixing between the two occurs only in the middle part of the whisker, thereby obtaining a second long-staple cotton / fine-staple cotton whisker with the long-staple cotton fibers located on the outside and the fine-staple cotton fibers and a small amount of long-staple cotton fibers located in the center.

7. The method for producing low-cost pure cotton yarn according to claim 6, characterized in that: The second long-staple cotton / fine-staple cotton sliver enters the front drafting zone between the middle front roller and the front roller, and a middle front lower long apron is provided on the middle front roller through a fixed lower pin and an elastic tension frame, and a middle front upper short apron is provided on the middle front rubber roller through an elastic upper pin. The middle front lower apron and the middle front upper apron press each other to form an elastic middle front apron control zone, and the middle front apron control zone extends into the front drafting zone. The front drafting zone is the main drafting zone, and the drafting multiple of the front drafting zone is set between 15 and 70. At this time, the long-staple cotton sliver located outside in the second long-staple cotton / fine-staple cotton sliver undergoes a large stretching and thinning under the action of a large stretching, and at the same time, the interaction force between the long-staple cotton fibers in the stretching and thinning is further reduced. The fine-staple cotton and a small amount of long-staple cotton mixed strands located inside are greatly stretched and thinned under the action of drawing, and the interaction force between the fibers is further weakened during the stretching and thinning. Due to the reduction of the interaction force between the fibers, the fine-staple cotton fibers and the long-staple cotton fibers are further infiltrated and mixed under the control of the elastic leather ring structure when the number of fibers is small. In the mixing process, the long-staple cotton fibers located outside with long fiber length and good consistency hinder the fine-staple cotton fibers, so that the fine-staple cotton fibers never reach the edge of the strands, thereby obtaining long-staple cotton / fine-staple cotton strands with the long-staple cotton fibers located at the outermost edge and the fine-staple cotton fibers and long-staple cotton fibers located in the middle.

8. The method for producing low-cost pure cotton yarn according to claim 7, characterized in that: The long-staple cotton / fine-staple cotton slivers obtained by the drafting system are output and then subjected to the action of twisting to obtain a long-staple cotton / fine-staple cotton mixed spun yarn. During the twisting process, since the long-staple cotton fibers located at the outermost edge of the sliver are long in length and have good consistency in length distribution, the long-staple cotton fibers are directly bent under the action of twisting, and during the bending process, the long-staple cotton fibers are entangled with each other to form a web to form a long-staple cotton outer wrapped spun yarn. The fine-staple cotton fibers and the long-staple cotton fibers located in the middle of the sliver are transferred to each other under the action of twisting, thereby obtaining a long-staple cotton / fine-staple cotton core yarn with a certain strength, thereby obtaining a pure cotton spun yarn with long-staple cotton fibers on the outside and long-staple cotton and fine-staple cotton mixed fibers in the center.

9. The method for producing low-cost pure cotton yarn according to claim 1, characterized in that: The strip roll adopts a strip roll machine, and 16-24 long-staple cotton strips obtained in the second step are guided by guide rollers and guide rollers, rotated 90 degrees on a V-shaped platform, and arranged in parallel and combined. The combined long-staple cotton strips enter the 3 / 3 drafting device under the guidance of the guide roller. The drafting multiple of the drafting device is between 1.1 and 1.

4. The combined long-staple cotton strips are stretched to obtain a long-staple cotton layer. The long-staple cotton layer is pressed by a pressing roller to prevent sticking, and then the long-staple cotton layer is driven by the cotton roll roller to make a long-staple cotton roll.

10. The method for producing low-cost pure cotton yarn according to claim 1, characterized in that: The winding is done by a winding machine, with 6 long-staple cotton rolls entering their respective drafting devices, and the drafting multiple of the drafting device is between 5.2 and 7.

5. After the long-staple cotton rolls are drafted, the long-staple cotton web is turned 90 degrees through a smooth curved guide plate and then stacked and combined in 6 layers on the cotton conveying platform. After being combined, it enters the pressing roller and is then rolled into small long-staple cotton combed rolls by the rolling roller.

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