Method for judging whether there is a filament scattering defect in an fdy yarn

Abstract

The present application belongs to the field of textile technology, and relates to a method for judging whether FDY yarn has a yarn scattering defect, setting the suction force of a suction gun, and then peeling the yarn cake; after the peeling is completed, selecting a length of FDY yarn that is greater than or equal to 15 cm and that is not wound on the yarn cake; if the individual filaments in the FDY yarn are separated from each other, then the FDY yarn has a yarn scattering defect; if the individual filaments in the FDY yarn are combined with each other, then the FDY yarn does not have a yarn scattering defect; the selection method has two modes: one is to cut off both ends of the selected FDY yarn; and the other is to fix one end of the selected FDY yarn that is close to the yarn cake, and cut off the other end that is close to the suction gun. The present application can quickly and accurately judge whether the FDY yarn has a yarn scattering defect.

Description

Technical Field

[0001] This invention belongs to the field of textile technology and relates to a method for determining whether FDY yarn has loose yarn defects. Background Technology

[0002] During the production of polyester FDY yarn, abnormal yarns with loose filament defects may occur, meaning the fiber bundles are loose and not bundled. This is mainly due to insufficient oiling, resulting in oil-free yarns with an oil content of ≤0.1wt%, which reduces the cohesion of the yarn bundle and makes it impossible to form stable network points during subsequent web processing. Although network points cannot be formed stably, the compressed air injected by the compressed air device can still cause the yarn bundle to produce weak entanglement points.

[0003] These types of abnormal yarns are affected by winding tension and weak entanglement points, making it impossible to determine the presence of loose yarn defects from the appearance of the yarn cake. However, when these yarns are used as raw materials in subsequent processes, the fiber bundles will gradually unravel, forming loose yarns. The presence of loose yarns will seriously affect the normal operation of subsequent spinning processes (such as false twisting, twisting, and pre-weaving preparation), with the following specific impacts:

[0004] (1) Causing equipment failure and shutdown: FDY loose yarn is easy to get tangled on key components of the spinning equipment such as rollers, false twisters (friction discs / spindles), and guide wheels, causing equipment jamming and tangling shutdown. This not only interrupts the production process, but may also scratch the roller surface and wear out the false twisters, increasing equipment maintenance costs.

[0005] (2) Lowering the quality of finished products after spinning: FDY loose fibers will cause fuzz and breakage in the processed filaments. For example, when producing DTY with false twist, loose fibers will destroy the uniformity of twist, resulting in uneven elasticity and inconsistent bulkiness of the finished product. During warping before weaving, loose fibers will cause warp breaks, which will lead to holes and defects in the fabric and reduce the fabric grade.

[0006] Patent application CN118604099A discloses an online system for detecting polyester fibers with no or little oil. This system utilizes electrostatic identification, taking advantage of the fact that no oil-free fibers easily generate static electricity through friction. It employs an electrostatic identification device consisting of a U-shaped guide, a transparent glass tube, and a frequency sensor, in conjunction with an image recognition alarm system to detect no or little oil-free fibers. However, the necessary component, the U-shaped guide, is made of stainless steel. Stainless steel has relatively low hardness and does not meet the high wear resistance requirements for guiding synthetic fibers. This leads to rapid wear and scratches on the U-shaped guide by the yarn, resulting in a very short lifespan for the guide component and scratches the fiber surface, affecting the smoothness of the filaments and the quality of the finished product. This could potentially cause more serious quality problems than those caused by no oil-free fibers.

[0007] Patent CN221276001U discloses an online detection device for network points in a filament bundle. It utilizes an imaging module to acquire real-time images of the vibration frequency of the filament bundle ejected from the filament bundle, and then performs data analysis using an image analysis module. If no filament bundle vibration is detected, it may indicate a lack of network filaments, and an alarm signal can be issued promptly. However, the formation of weak entanglements can also cause the filament bundle to vibrate, and these weak entanglements are not true network points; therefore, the detection accuracy of this method is insufficient.

[0008] In addition, existing technologies include other methods for determining whether FDY yarn has loose fiber defects, such as periodic network status checks using a water bath method (which involves immersing the yarn bundle in water to observe for network points) or detecting the oil content of the yarn bundle. However, both of these methods require sampling and are complex, time-consuming, labor-intensive, and inefficient.

[0009] Therefore, it is of great significance to study a method for determining whether FDY yarn has loose yarn defects in order to achieve rapid detection and accurate identification. Summary of the Invention

[0010] The purpose of this invention is to solve the problems existing in the prior art and to provide a method for determining whether FDY yarn has loose yarn defects.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0012] A method for determining whether FDY yarn has a loose yarn defect involves setting the suction force of a suction gun and then stripping the yarn cake. After stripping, a section of FDY yarn with a length of ≥15cm that is not wrapped around the yarn cake is selected. If the individual filaments in the FDY yarn are separated from each other, there is a loose yarn defect. If the individual filaments in the FDY yarn are bound together, there is no loose yarn defect.

[0013] There are two selection methods: one is to cut off both ends of the selected FDY yarn; the other is to fix one end of the selected FDY yarn closer to the yarn cake and cut off the end closer to the suction gun.

[0014] During the production process, there is a switching process for the winding rollers, so the quality of the surface filaments in the filament cake differs from the quality of the other filaments. Therefore, it is necessary to strip the filament cake, which is a necessary process before the filament cake becomes a product.

[0015] The method for setting the range of suction power for the suction gun is as follows:

[0016] Oil-free filaments with an oil content of 0.1 wt% (containing loose filaments) were prepared and made into filament cake A. Filament cake A differed from the filament cake to be tested only in oil content. The suction force was set to 0.1 N, and filament cake A was stripped. After stripping, if it could not be determined whether loose filaments existed (i.e., there were single filaments in the filament cake that did not separate from each other), the suction force was increased by 0.1 N and stripping was continued until it could be determined that the oil-free filaments contained loose filaments. Finally, the suction force at which it could be determined that the oil-free filaments contained loose filaments was taken as the lower limit of the suction force of the suction gun, and the suction force of the suction gun must be greater than or equal to this lower limit.

[0017] Prepare FDY yarn of the same type as the yarn cake to be tested, but without the defect of loose yarn, and make it into yarn cake B. Set the suction force to 0.1N and strip the yarn cake B. After stripping, if it is not possible to determine whether there is a defect of loose yarn (i.e., there are single filaments in the yarn cake that do not separate from each other), increase the suction force by 0.1N and continue stripping until it can be determined that the FDY yarn has a defect of loose yarn (i.e., the single filaments in the yarn cake separate from each other). Finally, take the suction force that can determine that the FDY yarn has a defect of loose yarn as the upper limit of the suction force of the suction gun, and the suction force of the suction gun must be less than the upper limit.

[0018] In existing technologies, during the filament stripping process using a suction gun, the suction force of the gun causes the suspended FDY filaments to vibrate. The energy generated by this vibration can break the bonding force between the individual filaments in the suspended FDY filaments. If the bonding force between the individual filaments is less than the force generated by the vibration, the FDY filaments will scatter. This application's design of the suction force range ensures that during the stripping process, if the FDY filaments have fraying defects, the stripped FDY filaments will scatter; otherwise, they will not scatter.

[0019] In the production of FDY yarn using existing technology, the number of network points is required to be ≥7 per meter. Taking a product with exactly 7 network points per meter as an example, there is one network point every 14 centimeters on average. If the selected length is less than 15 centimeters, then this section of yarn may be a section without network points, which is easily misjudged as having a loose yarn defect.

[0020] As a preferred technical solution:

[0021] As described above, one method for determining whether FDY yarn has a loose yarn defect involves placing the yarn cake on the yarn cart and maintaining a distance of 2-3m between the suction gun and the yarn cake.

[0022] As described above, one method for determining whether FDY yarn has a loose yarn defect involves selecting FDY yarn that is not wrapped around the yarn cake with a length of 15-30cm. The selected length should not be too long, firstly because it is not convenient for observation, and secondly because as the cut length increases, the influence of gravity becomes more obvious, the repulsive force is limited, and the loose yarn defect is not easily revealed.

[0023] As described above, a method for determining whether FDY yarn has a loose yarn defect includes a suction gun comprising a compressor station I, a compressor pipe I, a venturi tube, a gun head housing, a waste yarn pipe, and a waste yarn storage box.

[0024] The Venturi tube consists of tube I and tube II;

[0025] Pipe I is a hollow tube with openings at both ends, and multiple through holes a are provided on the circumferential surface near one end of pipe I;

[0026] Pipe II is a composite pipe, consisting of connected pipe II x and pipe II y; the inner diameter of pipe II x and the inner diameter of pipe II y are the same, and the outer diameter of pipe II x is smaller than the outer diameter of pipe II y; the inner diameter of through hole a is smaller than the inner diameter of pipe II x;

[0027] The inner diameter of pipe I is greater than the inner diameter of pipe II x, and the outer diameter of pipe I is less than or equal to the outer diameter of pipe II y.

[0028] The gun head housing is a cube, and the gun head housing has a through hole b and a through hole c; the through hole b penetrates through the opposite side of the gun head housing; the central axis of the through hole c is perpendicular to the central axis of the through hole b, and the through hole c connects the inside of the through hole b and the outside.

[0029] One end of tube I, near through hole a, is inserted into the interior of through hole b and threadedly connected to through hole b; the other end of tube I, away from through hole a, is connected to one end of the waste wire pipe, and the other end of the waste wire pipe is connected to the interior of the waste wire storage box.

[0030] Tube II is inserted into the interior of through hole b from the other end of tube II, and tube II y of tube II is threadedly connected to through hole b; tube II x of tube II is located inside through hole b; the free end of tube II y is used to draw FDY filament.

[0031] One end of the compressed air pipeline I is inserted into the through hole c and threaded into the through hole c; the other end of the compressed air pipeline I is connected to the compressed air station I.

[0032] When pipe I, pipe II, and compressed air pipe I are connected through the nozzle housing, pipe II x is inserted into pipe I and the end of pipe I near the through hole a is in contact with pipe II y; when the end of pipe I near the through hole a is in contact with pipe II y, the through hole a is located between the two ends of pipe II.

[0033] When pipe I, pipe II and compressed air pipe I are connected through the nozzle housing, the end of compressed air pipe I inserted into through hole c is close to the circumferential surface of pipe I and is connected to all through holes a.

[0034] Compressed air station I is used to output compressed air to the Venturi tube, which can draw FDY filaments into the waste filament storage box through the Venturi tube effect. This is existing technology.

[0035] As described above, the method for determining whether FDY yarn has a loose yarn defect includes a suction gun that also includes valve I, a solenoid valve, and a time relay.

[0036] Valve I is a pneumatic pressure regulating valve with a pressure gauge; Valve I and the solenoid valve are installed on the compressed air pipeline I; Valve I is located between the compressed air station I and the solenoid valve. Valve I is used to conveniently and quickly adjust the air pressure input to the venturi tube, and the pressure gauge of the air itself can be used to determine whether there is a blockage; The time relay is connected to the solenoid valve by wires. The time relay is used to control the opening and closing of the solenoid valve to control the suction time.

[0037] As described above, one method for determining whether FDY yarn has a loose yarn defect involves multiple yarn cakes distributed in a matrix on a yarn rolling machine; a suction gun simultaneously strips the yarn from all the yarn cakes.

[0038] As described above, the method for determining whether FDY yarn has loose yarn defects employs a selection device.

[0039] The selection device includes compressed air pipeline II, valve island, finger cylinder, clamping block, cutter, fixing frame and control switch;

[0040] The fixing frame consists of rectangular plate I, rectangular plate II, connecting plate I, and connecting plate II;

[0041] Both rectangular plate I and rectangular plate II are horizontal plates, and they are placed parallel to each other.

[0042] Rectangular plate I and rectangular plate II are connected by connecting plate I; rectangular plate II is fixedly connected to connecting plate II, and connecting plate II is fixedly connected to the upper surface of pipe II y;

[0043] The number of finger cylinders is twice the number of silk cake rows. Half of the finger cylinders have their cylinder bases fixed to the lower surface of rectangular plate I, and the other half of the finger cylinders have their cylinder bases fixed to the lower surface of rectangular plate II.

[0044] Let the finger cylinder fixed on the lower surface of rectangular plate I be called finger cylinder I, and the finger cylinder fixed on the lower surface of rectangular plate II be called finger cylinder II.

[0045] The number of cutters and clamping blocks is the same as the number of finger cylinders; each of the two clamping claws of all finger cylinders I is fixedly connected to one clamping block; each of the two clamping claws of all finger cylinders II is fixedly connected to one cutter.

[0046] There are two valve islands, referred to as Valve Island I and Valve Island II; the valve islands are existing technology and each valve island comes with a built-in solenoid valve.

[0047] Valve island I is fixed on the upper surface of rectangular plate I, and valve island II is fixed on the upper surface of rectangular plate II; the input end of each finger cylinder I is connected to one output end of valve island I, and the input end of each finger cylinder II is connected to one output end of valve island II.

[0048] One end of the compressed air pipeline II is connected to the output end of the compressed air station II, and the other end is connected to both the input ends of valve island I and valve island II through a tee pipe.

[0049] Valve island I and valve island II are simultaneously electrically connected to a control switch, which is used to simultaneously control the opening and closing of the solenoid valves of valve island I and valve island II.

[0050] When the control switch opens the solenoid valves of valve island I and valve island II, so that all finger cylinders are in the air-ventilated state, the clamping blocks connected to the two grippers of finger cylinder I are in close contact with each other, and the blades of the cutters connected to the two grippers of finger cylinder II are in close contact with each other.

[0051] When the control switch closes the solenoid valves of valve island I and valve island II, causing all finger cylinders to be in a de-aired state, there is a gap I between the clamping blocks connected to the two grippers of finger cylinder I, and there is a gap II between the cutters connected to the two grippers of finger cylinder II.

[0052] The FDY filaments not wound on the filament cake pass through a gap I and a gap II in sequence;

[0053] The FDY yarn is selected by a selection device. One end of the selected yarn is clamped by two clamping blocks, and the other end is cut off by two cutters, so that the FDY yarn is suspended on the selection device. This makes it easier for people to observe whether there are loose yarn defects, and multiple yarn cakes can be operated at the same time. If both ends are cut off, multiple yarn cakes cannot be operated at the same time because the FDY yarn from different yarn cakes will be mixed together. If this method is operated manually, it will also increase additional influence and cause judgment errors.

[0054] As described above, one method for determining whether FDY yarn has a loose yarn defect involves 24 yarn cakes arranged in 4 rows and 6 columns on a yarn train, with the FDY yarns on each yarn cake passing through the same gap I and gap II.

[0055] As described above, in a method for determining whether FDY yarn has a loose yarn defect, the connecting plate II is rotatably fixed to the upper surface of tube IIy; the rotation direction is vertical. When the selection device is not needed, it can be rotated above tube IIy. For example, when the yarn is about to be stripped, the free end of the FDY yarn on the yarn cake needs to be manually moved to the free end of tube IIy of the suction gun. If the fixing frame of the selection device is still horizontally placed at this time, it will affect the operation.

[0056] The method for determining whether FDY yarn has a loose yarn defect as described above, the selection device also includes a filter, valve II, and a hose;

[0057] The filter and valve II are installed on the compressed air pipeline II, with the filter located between valve II and the compressed air station II.

[0058] The filter is used to filter the compressed air output from compressor station II to remove impurities;

[0059] Valve II is a pneumatic pressure regulating valve with a pressure gauge. Valve II is used to control the flow rate of compressed air output from compressor station II. Compressor station II itself can also adjust the output flow rate, but compressor station is usually not placed in the production workshop, so it is more convenient to set up valve II for adjustment.

[0060] One end of the hose is connected to the end of the compressed air pipeline II that is away from the compressed air station II, and the other end is connected to the input end of valve island I and valve island II through a tee pipe. The design of the hose can avoid affecting the rotation of the fixed frame.

[0061] The method described above for determining whether FDY yarn has loose yarn defects requires the use of a suction gun to peel the yarn cakes of various types. The method for setting the suction force range of the suction gun also includes the following:

[0062] Compare the lower limits of the suction force range corresponding to each variety of silk cake, and select the largest lower limit as the lower limit of the suction gun's suction force; compare the upper limits of the suction force range corresponding to each variety of silk cake, and select the smallest upper limit as the upper limit of the suction gun's suction force.

[0063] For different varieties of yarn cakes, when FDY yarn has loose yarn defects, since there are no network points, the bonding force between the filaments in different FDY yarns is very similar, and this bonding force will be much smaller than the bonding force between the filaments in all varieties of FDY yarn without loose yarn defects.

[0064] Beneficial effects:

[0065] (1) By setting the suction force range of the suction gun and combining it with the observation of the single filament bonding state of the FDY filament after stripping, the present invention avoids the problem of normal oily filaments being misjudged as oilless filaments and the high rejection rate caused by the electrostatic identification method in the prior art due to the influence of external factors. It also solves the problem of inaccurate detection caused by weak entanglement points in the network point detection device, and improves the accuracy of the judgment of loose filament defects.

[0066] (2) This invention does not require complex operations after sampling. It directly peels the filaments from the filament cake using a suction gun, and quickly selects and observes the FDY filaments using a selection device. The selection device can operate on multiple filament cakes at the same time without manual processing. Compared with existing technologies such as the water bath method, it greatly simplifies the operation process and improves the detection efficiency.

[0067] (3) The suction gun of the present invention is equipped with valve I to adjust the air pressure and judge whether it is blocked by pressure gauge. The time relay can control the suction time. The selection device can realize the synchronous operation of clamping block and cutting blade by controlling switch. The connecting plate II and tube II y can be rotatably connected to avoid affecting manual operation. The overall structural design makes the detection process more convenient and the operation more stable.

[0068] (4) This invention targets multiple varieties of silk cakes. By comparing the lower limit and upper limit of the suction force corresponding to each variety of silk cake, the maximum lower limit is selected as the unified lower limit and the minimum upper limit is selected as the unified upper limit. This determines the range of suction force values ​​suitable for multiple varieties of silk cakes. There is no need to adjust the detection parameters separately for different varieties of silk cakes, which improves the versatility of the method. Attached Figure Description

[0069] Figure 1 A schematic diagram showing the positional relationship between the suction gun, the selection device, the yarn cart, and the yarn cake;

[0070] Figure 2 and Figure 3 This is a schematic diagram of the structure of a Venturi tube; in which, Figure 2 For assembly diagram, Figure 3 This is an exploded view;

[0071] Figure 4 This is a schematic diagram of the gun head casing.

[0072] Figure 5 This is a schematic diagram showing the connection relationship between the Venturi tube, compressed air pipeline I, and nozzle housing;

[0073] Figure 6 This is a schematic diagram of the selected device;

[0074] Figure 7 This is a schematic diagram of the fixed frame structure;

[0075] Among them, 1-compressor station I, 13-valve I, 14-time relay, 16-solenoid valve, 17-gun head housing, 18-waste wire pipe, 19-waste wire storage box, 23-compressor pipe I, 24-pipe I, 25-pipe II x, 26-pipe II y, 27-through hole b, 28-through hole c;

[0076] 2-Filter, 3-Valve II, 4-Hose, 5-Tee, 7-Finger Cylinder, 8-Clamping Block, 9-Cutter, 10-Fixing Frame, 11-Compressed Air Pipe II, 12-Control Switch, 29-Rectangular Plate I, 30-Rectangular Plate II, 31-Connecting Plate I, 32-Connecting Plate II, 33-Compressed Air Station II;

[0077] 34-Silk cake, 35-Silk machine, 36-FDY silk. Detailed Implementation

[0078] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0079] A method for determining whether FDY yarn has a loose yarn defect involves setting the suction force of a suction gun and then stripping the yarn cake placed on a yarn cart (the distance between the suction gun and the yarn cake is 2-3m). After stripping, a section of FDY yarn with a length of 15-30cm that is not wrapped around the yarn cake is selected. If the individual filaments in the FDY yarn are separated from each other, a loose yarn defect exists. If the individual filaments in the FDY yarn are bound together, a loose yarn defect does not exist.

[0080] like Figure 1 As shown, the suction gun includes a compressed air station I 1, a compressed air pipe I 23, a venturi tube, a gun head housing 17, a waste wire pipe 18, a waste wire storage box 19, a valve I 13, a solenoid valve 16, and a time relay 14.

[0081] like Figure 2 and Figure 3 As shown, the Venturi tube includes tube I 24 and tube II; tube I 24 is a hollow tube open at both ends, and multiple through holes a are provided on the circumferential surface near one end of tube I 24; tube II is a composite tube, composed of connected tube II x 25 and tube II y 26; the inner diameter of tube II x 25 is the same as the inner diameter of tube II y 26, and the outer diameter of tube II x 25 is smaller than the outer diameter of tube II y 26; the inner diameter of through hole a is smaller than the inner diameter of tube II x 25; the inner diameter of tube I 24 is larger than the inner diameter of tube II x 25, and the outer diameter of tube I 24 is less than or equal to the outer diameter of tube II y 26;

[0082] like Figure 4 As shown, the gun head housing 17 is a cubic block, and has through holes b 27 and c 28. Through hole b 27 penetrates the opposite sides of the gun head housing 17; the central axis of through hole c 28 is perpendicular to the central axis of through hole b 27, and through hole c 28 connects the interior and exterior of through hole b 27. Figure 1 and Figure 5As shown, the end of tube I 24 near through hole a is inserted into the interior of through hole b 27 from one end of through hole b 27 and is threadedly connected to through hole b 27; the end of tube I 24 away from through hole a is connected to one end of waste wire pipe 18, and the other end of waste wire pipe 18 is connected to the interior of waste wire storage box 19; tube II is inserted into the interior of through hole b 27 from the other end of through hole b 27, and tube II y 26 is threadedly connected to through hole b 27; tube II x 25 is located inside through hole b 27; the free end of tube II y 26 is used to draw FDY wire 36;

[0083] One end of the compressed air pipe I 23 is inserted into the through hole c 28 and threadedly connected to the through hole c 28; the other end of the compressed air pipe I 23 is connected to the compressed air station I 1.

[0084] When pipe I 24, pipe II, and compressed air pipe I 23 are connected through nozzle housing 17, pipe II x 25 is inserted into pipe I 24 and the end of pipe I 24 near through hole a is in contact with pipe II y 26; when the end of pipe I 24 near through hole a is in contact with pipe II y 26, through hole a is located between the two ends of pipe II;

[0085] When pipe I 24, pipe II and compressed air pipe I 23 are connected through the gun head housing 17, the end of compressed air pipe I 23 inserted into through hole c 28 is close to the circumferential surface of pipe I 24 and is connected to all through holes a; compressed air station I 1 is used to output compressed air to the venturi tube, and to draw FDY filament into waste filament storage box 19 through the venturi tube effect;

[0086] Valve I 13 is a pressure regulating valve with a pressure gauge; Valve I 13 and solenoid valve 16 are installed on compressed air pipeline I 23; Valve I 13 is located between compressed air station I 1 and solenoid valve 16; Time relay 14 is connected to solenoid valve 16 by wire, and time relay 14 is used to control the opening and closing of solenoid valve 16 to control the suction time.

[0087] The working process of the suction gun is as follows: After setting the suction force of the suction gun, the compressed air pressure output by the air compressor station I1 is adjusted by valve I13. Then, the suction time is set by time relay 14, and the solenoid valve 16 is opened. The air compressor station I1 delivers compressed air to the venturi tube through the air compressor pipe I23. The suction force is generated by the venturi tube effect to strip the yarn cake 34. The waste yarn produced by stripping is sucked in through the free end of pipe II y 26 and enters the waste yarn storage box 19 in sequence through pipe II, pipe I 24 and waste yarn pipe 18. When the suction time set by time relay 14 is reached, the solenoid valve 16 is closed, the compressed air delivery stops, and the stripping work is completed.

[0088] There are two selection methods: one is to cut off both ends of the selected FDY yarn; the other is to fix one end of the selected FDY yarn closer to the yarn cake and cut off the end closer to the suction gun.

[0089] For the second selection method, a selection device is used, such as... Figure 1 and Figure 6 As shown, the selection device includes compressed air pipeline II 11, valve island, finger cylinder 7, clamping block 8, cutter 9, fixing frame 10, control switch 12, filter 2, valve II 3 and hose 4;

[0090] like Figure 1 , Figure 6 and Figure 7 As shown, the fixing frame 10 consists of rectangular plate I 29, rectangular plate II 30, connecting plate I 31, and connecting plate II 32; both rectangular plate I 29 and rectangular plate II 30 are horizontal plates and are placed parallel to each other; rectangular plate I 29 and rectangular plate II 30 are connected by connecting plate I 31; rectangular plate II 30 is fixedly connected to connecting plate II 32; connecting plate II 32 is rotatably fixed to the upper surface of pipe II y26, and the rotation direction is vertical rotation;

[0091] The number of finger cylinders 7 is twice the number of silk cake rows. Half of the finger cylinders 7 have their cylinder bases fixed to the lower surface of rectangular plate I 29, and the other half of the finger cylinders 7 have their cylinder bases fixed to the lower surface of rectangular plate II 30. The finger cylinders 7 fixed to the lower surface of rectangular plate I 29 are called finger cylinder I, and the finger cylinders 7 fixed to the lower surface of rectangular plate II 30 are called finger cylinder II.

[0092] The number of cutters 9 and clamping blocks 8 is the same as the number of finger cylinders 7; the two clamping claws of all finger cylinders I are each fixedly connected to one clamping block 8; the two clamping claws of all finger cylinders II are each fixedly connected to one cutter 9.

[0093] There are two valve islands, designated as Valve Island I and Valve Island II. Valve Island I is fixed to the upper surface of rectangular plate I 29, and Valve Island II is fixed to the upper surface of rectangular plate II 30. The input ends of all finger cylinders I are connected to one output end of Valve Island I, and the input ends of all finger cylinders II are connected to one output end of Valve Island II. One end of compressed air pipeline II 11 is connected to the output end of compressed air station II 33, and the other end is connected to both the input ends of Valve Island I and Valve Island II via a three-way pipe 5.

[0094] Valve island I and valve island II are simultaneously electrically connected to control switch 12, which is used to simultaneously control the opening and closing of valve island I and valve island II. When control switch 12 controls valve island I and valve island II to open, so that all finger cylinders 7 are in the air-ventilated state, the clamping blocks 8 connected to the two grippers of finger cylinder I are in close contact with each other, and the blades of the cutters 9 connected to the two grippers of finger cylinder II are in close contact with each other. When control switch 12 controls valve island I and valve island II to close, so that all finger cylinders 7 are in the air-deprived state, there is gap I between the clamping blocks 8 connected to the two grippers of finger cylinder I, and there is gap II between the cutters 9 connected to the two grippers of finger cylinder II. The FDY filament 36 not wound on the filament cake 34 passes through one gap I and one gap II in sequence.

[0095] Filter 2 and valve II 3 are installed on compressed air pipeline II 11. Filter 2 is located between valve II 3 and compressed air station II 33. Filter 2 is used to filter the compressed air output from compressed air station II 33. Valve II 3 is a pressure regulating valve with a pressure gauge. Valve II 3 is used to control the flow rate of compressed air output from compressed air station II 33. One end of hose 4 is connected to the end of compressed air pipeline II 11 away from compressed air station II 33, and the other end is connected to both valve island I and valve island II through a three-way pipe 5.

[0096] The working process of the selection device is as follows: Normally, the selection device is placed vertically at a 90° angle above the suction gun head via the connecting plate II 32. After stripping the wire, press down on the selection device to make the fixing frame 10 horizontal. Press the control switch 12, and the compressed air output from the compressed air station II 33 is delivered through the compressed air pipeline II 11. First, it passes through the filter 2 to filter impurities, then the flow rate is adjusted by the valve II 3, and then it is distributed to valve island I and valve island II through the hose 4 and the three-way pipe 5. Valve island I drives the clamping blocks 8 of the finger cylinder I to stick together tightly, clamping the FDY wire 36 (near the wire cake end) that is not wrapped on the wire cake 34. Valve island II synchronously drives the cutting blades 9 of the finger cylinder II to stick together tightly, cutting the FDY wire 36 (near the suction gun end), completing the cutting of a section of FDY wire 36. After the cutting is completed, the selection device is reset to a 90° vertical position.

[0097] There are 24 silk cakes 34, which are arranged in 4 rows and 6 columns on the silk spinning machine 35. The FDY silk 36 on each silk cake passes through the same gap I and gap II.

[0098] The method for setting the range of suction power for the suction gun is as follows:

[0099] (1) Prepare oil-free filaments with an oil content of 0.1wt% and make them into filament cake A. The only difference between filament cake A and the filament cake to be tested is the oil content. Set the suction force to 0.1N and strip the filament cake A. After stripping, if it is not possible to determine whether there is a loose filament defect, increase the suction force by 0.1N and continue stripping until it can be determined that there is a loose filament defect in the oil-free filament. Finally, take the suction force that can determine that there is a loose filament defect in the oil-free filament as the lower limit of the suction force of the suction gun, and the suction force of the suction gun must be greater than or equal to the lower limit.

[0100] (2) Prepare FDY yarn of the same type as the yarn cake to be tested but without loose yarn defects, and make it into yarn cake B. Set the suction force to 0.1N and strip the yarn cake B. After stripping, if it is not possible to determine whether there is loose yarn defect, increase the suction force by 0.1N and continue stripping until it can be determined that the FDY yarn has loose yarn defect. Finally, take the suction force that can determine that the FDY yarn has loose yarn defect as the upper limit of the suction force of the suction gun, and the suction force of the suction gun must be less than the upper limit.

[0101] It should be noted that if there are multiple varieties of silk cakes that need to be stripped by the suction gun, a uniform suction force range should be determined based on the suction force range corresponding to each variety of silk cakes: compare the lower limit of the suction force for each variety of silk cakes and select the maximum lower limit as the uniform lower limit; compare the upper limit of the suction force for each variety of silk cakes and select the minimum upper limit as the uniform upper limit.

[0102] To demonstrate that the method of this invention can accurately determine the loose fiber defects of different varieties of FDY yarn and has the advantage of efficiently covering the entire product inspection, this invention is verified through the following steps:

[0103] (1) Five different varieties of silk cakes were randomly selected for testing. The specifications and cross-sectional shapes of each variety are as follows:

[0104] Variety 1: 120dtex / 72f round;

[0105] Variety 2: 120dtex / 72f wavy straight line;

[0106] Variety 3: 290dtex / 96f round;

[0107] Variety 4: 88dtex / 48f trifoliate;

[0108] Variety 5: 106 dtex / 144 f round;

[0109] Each variety is individually configured with 24 silk cakes, and each variety contains two types of silk cakes: one type is oil-free / low-oil silk with an oil content of ≤0.1wt% confirmed by oil content testing, and the other type is silk with an oil content that meets the process standard (>0.1wt%).

[0110] (2) According to the method for determining the range of suction force of the present invention, the lower limit and upper limit of suction force corresponding to each variety of silk cake were measured respectively; wherein, the range of suction force for variety 1 is 0.5N~2.7N; for variety 2 it is 0.4N~2.5N; for variety 3 it is 0.4N~2.3N; for variety 4 it is 0.6N~2.8N; for variety 5 it is 0.6N~3.0N; the maximum lower limit of 0.6N for each variety was selected as the unified lower limit, and the minimum upper limit of 2.3N for each variety was selected as the unified upper limit. Finally, the unified suction force was set to 1.8N (within the range of 0.6N~2.3N).

[0111] (3) Control the distance between the suction gun and the silk cake to 2.5m, and test them in sequence according to the variety: peel the silk of 24 silk cakes of each variety in one go. After peeling, cut 20cm of unwound FDY silk corresponding to each silk cake through the selection device, observe the cohesion of each single filament, determine whether there is a loose silk defect and record the results.

[0112] (4) Verification using the water bath method: Under the conditions of room temperature of 20.5℃ and humidity of 67% in the physical testing room, take a 1m long sample and put it into fresh desalinated water without applying external force. After the fiber bundles disperse under the action of water surface tension (about 1s), observe the overall cohesion.

[0113] (5) Statistically verify the consistency between the detection results of the method of the present invention and the verification results of the water bath method.

[0114] Verification results show that all defective yarn cakes detected by the method of this invention were confirmed to have loose yarn defects by the traditional water bath method; yarn cakes judged to be normal also showed network points by the water bath method. The results of the two methods are completely consistent, proving that this method can accurately identify loose yarn defects. Furthermore, this invention can simultaneously detect 24 yarn cakes at a time, eliminating the need for long-distance sample transport, and the operation process is simple and efficient; while the traditional water bath method can only detect 1-4 samples at a time, and requires transfer from the production line to the material inspection laboratory, which is time-consuming and labor-intensive. In addition, this invention relies on the modification of the essential yarn stripping process of the product, and can cover all produced products; the traditional water bath method is limited by efficiency and can only perform periodic sampling inspections, which carries the risk of omission. This invention can avoid this problem and effectively reduce customer complaints about loose yarn in the downstream spinning process.

Claims

1. A method of determining whether an FDY yarn has a loose filament defect, characterized by, The suction gun suction force is set, and then the cake is peeled; after the peeling is finished, a length of ≥15 cm, the FDY yarn is not wound on the cake, if the single yarn in the FDY yarn is separated from each other, there is a silk defect, if the single yarn in the FDY yarn is combined with each other, there is no silk defect; The selected mode has two kinds: one is to cut off both ends of the selected FDY yarn; the second is to fix one end of the selected FDY yarn close to the cake, and cut off the end close to the suction gun; The setting method of the suction force value range of the suction gun is as follows: (1) prepare oil-free yarn with oil content of 0.1wt%, and make it into cake A, cake A and the cake to be tested only differ in oil content; the suction force value is set to 0.1N, and the cake A is peeled, when the peeling is finished, if it cannot be determined whether there is silk defect, the suction force is increased by 0.1N, and the peeling is continued, until it can be determined that the oil-free yarn has silk defect, finally the suction force which can determine that the oil-free yarn has silk defect is taken as the lower limit value of the suction force of the suction gun, and the suction force value of the suction gun should be greater than or equal to the lower limit value; (2) prepare FDY yarn with the same variety as the cake to be tested, but without silk defect, and make it into cake B, set the suction force value to 0.1N, and peel the cake B, when the peeling is finished, if it cannot be determined whether there is silk defect, the suction force is increased by 0.1N, and the peeling is continued, until it can be determined that the FDY yarn has silk defect, finally the suction force which can determine that the FDY yarn has silk defect is taken as the upper limit value of the suction force of the suction gun, and the suction force value of the suction gun should be less than the upper limit value.

2. The method of judging whether the FDY yarn has the scattered yarn defect according to claim 1, characterized in that, The cake is placed on the silk car, and the distance between the suction gun and the cake is 2-3m.

3. The method of claim 2, wherein the method is characterized by: The length of the selected FDY yarn not wound on the cake is 15-30cm.

4. The method of judging whether the FDY yarn has the scattered yarn defect according to claim 3, characterized in that, The suction gun includes a compressed air station I (1), a compressed air pipeline I (23), a Venturi tube, a gun head shell (17), a waste yarn pipeline (18) and a waste yarn storage box (19); The Venturi tube includes a pipe I and a pipe II; The pipe I is a hollow pipe with two open ends, and a plurality of through holes a are arranged on the peripheral surface close to one end of the pipe I; The pipe II is a composite pipe composed of a pipe II x and a pipe II y connected together; the inner diameter of the pipe II x and the inner diameter of the pipe II y are the same, and the outer diameter of the pipe II x is smaller than the outer diameter of the pipe II y; the inner diameter of the through hole a is smaller than the inner diameter of the pipe II x; The inner diameter of the pipe I is greater than the inner diameter of the pipe II x, and the outer diameter of the pipe I is smaller than or equal to the outer diameter of the pipe II y; The gun head shell (17) is a cubic block, and the gun head shell (17) is provided with a through hole b and a through hole c; the through hole b penetrates through the opposite sides of the gun head shell (17); the central axis of the through hole c is perpendicular to the central axis of the through hole b, and the through hole c communicates the inside of the through hole b with the outside; One end of the pipe I close to the through hole a is inserted into the inside of the through hole b from one end of the through hole b, and is threadedly connected with the through hole b; the other end of the pipe I is connected with one end of the waste yarn pipeline (18), and the other end of the waste yarn pipeline (18) is connected with the inside of the waste yarn storage box (19); Tube II is inserted into the inside of the through hole b from the other end of the through hole b, and is screwed with the through hole b; the tube II x is located in the inside of the through hole b; the free end of the tube II y is used for sucking the FDY yarn; One end of the compressed air pipeline I (23) is inserted into the through hole c and is screwed with the through hole c; the other end of the compressed air pipeline I (23) is connected with the compressed air station I (1); When the tube I, the tube II and the compressed air pipeline I (23) are connected through the gun head shell (17), the tube II x is inserted into the tube I and the end of the tube I close to the through hole a is attached to the tube II y; when the end of the tube I close to the through hole a is attached to the tube II y, the through hole a is located between the two ends of the tube II; When the tube I, the tube II and the compressed air pipeline I (23) are connected through the gun head shell (17), one end of the compressed air pipeline I (23) inserted into the through hole c is close to the peripheral surface of the tube I and communicates with all the through holes a.

5. The method of judging whether the FDY yarn has the scattered yarn defect according to claim 4, characterized in that, The suction gun further comprises a valve I (13), an electromagnetic valve (16) and a time relay (14); The valve I (13) is a pneumatic regulating valve with a pressure gauge; the valve I (13) and the electromagnetic valve (16) are installed on the compressed air pipeline I (23); the valve I (13) is located between the compressed air station I (1) and the electromagnetic valve (16); the time relay (14) is connected with the electromagnetic valve (16) through an electric wire, and is used for controlling the opening and closing of the electromagnetic valve (16) to control the suction time.

6. The method of judging whether or not a FDY yarn has a loose yarn defect according to claim 5, characterized in that, The number of the yarn cakes is multiple, and the multiple yarn cakes are distributed in a matrix form on the yarn car; the suction gun simultaneously peels the yarns of all the yarn cakes.

7. The method of judging whether or not a FDY yarn has a loose yarn defect according to claim 6, characterized in that, The selected yarn cake is selected by the selecting device; The selecting device comprises a compressed air pipeline II (11), a valve island, a finger air cylinder (7), a clamping block (8), a cutter (9), a fixing frame (10) and a control switch (12); The fixing frame (10) is composed of a rectangular plate I, a rectangular plate II, a connecting plate I and a connecting plate II; The rectangular plate I and the rectangular plate II are both horizontal plates and are placed in parallel; The rectangular plate I and the rectangular plate II are connected through the connecting plate I; the rectangular plate II is fixedly connected with the connecting plate II, and the connecting plate II is fixedly connected with the upper surface of the tube II y; The number of the finger air cylinders (7) is twice the number of the columns of the yarn cakes, half of which are fixedly connected with the bottom of the rectangular plate I, and the other half of which are fixedly connected with the bottom of the rectangular plate II; The finger air cylinders (7) fixedly connected with the bottom of the rectangular plate I are referred to as finger air cylinders I, and the finger air cylinders (7) fixedly connected with the bottom of the rectangular plate II are referred to as finger air cylinders II; The number of the cutters (9) and the clamping blocks (8) is the same as that of the finger air cylinders (7); the two clamping jaws of all the finger air cylinders I are respectively fixedly connected with a clamping block (8); the two clamping jaws of all the finger air cylinders II are respectively fixedly connected with a cutter (9); The number of the valve islands is two, which are respectively referred to as a valve island I and a valve island II; The valve island I is fixedly connected with the upper surface of the rectangular plate I, and the valve island II is fixedly connected with the upper surface of the rectangular plate II; the input ends of all the finger air cylinders I are respectively connected with an output end of the valve island I, and the input ends of all the finger air cylinders II are respectively connected with an output end of the valve island II; One end of the compressed air pipeline II (11) is connected with the output end of the compressed air station II, and the other end is connected with the input end of the valve island I and the valve island II through the three-way pipe (5); The valve island I and the valve island II are electrically connected with the control switch (12), and the control switch (12) is used for simultaneously controlling the opening and closing of the valve island I and the valve island II; When the control switch (12) controls the valve island I and the valve island II to be opened so that all the finger air cylinders (7) are in the air supply state, the clamping blocks (8) connected with the two clamping jaws of the finger air cylinder I are tightly attached to each other, and the cutting edges of the cutters (9) connected with the two clamping jaws of the finger air cylinder II are tightly attached to each other; When the control switch (12) controls the valve island I and the valve island II to be closed so that all the finger air cylinders (7) are in the air supply state, the clamping blocks (8) connected with the two clamping jaws of the finger air cylinder I have a gap I therebetween, and the cutters (9) connected with the two clamping jaws of the finger air cylinder II have a gap II therebetween; The FDY yarns not wound on the spool pass through a gap I and a gap II in sequence.

8. The method of judging whether or not a FDY yarn has a loose yarn defect according to claim 7, characterized in that, The number of the spools is 24, and the spools in each column pass through the same gap I and gap II.

9. The method of judging whether or not a FDY yarn has a loose yarn defect according to claim 8, characterized in that, The upper surface of the connecting plate II is rotatably fixedly connected with the pipe II y, and the rotation direction is vertical rotation.

10. The method of judging whether or not a FDY yarn has a loose yarn defect according to claim 9, characterized in that, The selecting device further comprises a filter (2), a valve II (3), and a hose (4); The filter (2) and the valve II (3) are arranged on the compressed air pipeline II (11), and the filter (2) is located between the valve II (3) and the compressed air station II; The filter (2) is used for filtering the compressed air output by the compressed air station II; The valve II (3) is a pressure regulating valve with a pressure gauge, and is used for controlling the flow of the compressed air output by the compressed air station II; One end of the hose (4) is connected with the end of the compressed air pipeline II (11) away from the compressed air station II, and the other end is connected with the input end of the valve island I and the valve island II through the three-way pipe (5).

11. The method of judging whether or not a FDY yarn has a loose yarn defect according to claim 9, characterized in that, There are multiple varieties of spools that need to be stripped by the suction gun; the setting method of the suction force value range of the suction gun includes the following contents: Compare the lower limit values of the suction force value ranges corresponding to the spools of each variety, and select the maximum lower limit value as the lower limit of the suction force of the suction gun; Compare the upper limit values of the suction force value ranges corresponding to the spools of each variety, and select the minimum upper limit value as the upper limit of the suction force of the suction gun.

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