JPH04245941A - Yarn heating device - Google Patents

Abstract

PURPOSE: To provide a yarn heating arrangement where the overall length of a heating zone can be less than that of a conventional plate heater and also inconvenience attaching to a well-known arrangement due to the decrease in the heating zone can be removed or reduced. CONSTITUTION: This yarn heating arrangement disposed in a straight yarn path crimping zone of a yarn texturing machine 30 comprises the first heater 32 which is maintained at a temperature in excess of the preferred crimp setting temperature for a yarn 13 and may be above the melting temperature of the yarn 13 and heats the yarn 13 rapidly by radiation to a temperature of 85-98% of its crimp setting temperature, and a smoothing heater 31 contacted by the yarn and maintained at the crimp setting temperature in order to heat the yarn 13 to that temperature. The overall length of the two heaters 31, 32 is less than that of a conventional contact heater, but they provide equivalent yarn temperature control which is greater than that provided by a high temperature non-contact heater alone. The heaters 31, 32 are located between a twist- stop 23 and a false-twisting device 17 of the texturing machine 30.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a yarn heating device, and more particularly to a device for heating processed yarn during processing.

Conventionally, in processing continuous filament yarn, yarn is pulled out from a yarn package,
The yarn is heated and cooled while being crimped, and the processed yarn is wound into another package. If a set yarn is desired rather than a stretch yarn, a second heating step may be provided between the crimping and winding steps. Such a crimping process is carried out by imparting a false twist to the yarn while it is heated and cooled, followed by untwisting.

0003

[Problem to be Solved by the Invention] If such false twisting is attempted at the starting position of the heating region, changes in the yarn direction, particularly around the guide, will impede the passage of the twist. Desirably, the thread path between the device and the upstream end of the heater is substantially straight. The faster yarn take-up speeds in modern processing machines allow the yarn temperature to be raised sufficiently while it is being twisted, and to maintain a temperature high enough to withstand the mechanical action of the false twisting equipment. In order to lower the yarn, it is necessary to provide extensive heating and cooling zones, and at the same time to ensure that when the yarn is untwisted, the memory of the applied twist is retained. Such long heating and cooling zones, if taken together to form a substantially straight yarn path, would make the processing machines very large and would require operator access to all parts of these machines. This is difficult to do without the use of ladders, trolleys, and/or "remote control" equipment.

0004

BACKGROUND OF THE INVENTION It is therefore desirable to reduce the length of heating and cooling regions, and various arrangements have been proposed in the prior art that can reduce one or both of these regions. For example, in GB 1 136 746 a heated feed roller is placed upstream of the plate heater. In this case, the purpose of installing a heated feed roller is to make the yarn crimp occur, and to preheat the yarn before entering the crimp area, In this case, the yarn is heated by a plate heater. This arrangement reduces the time required to fix the temperature of the yarn and the crimp imparted to it, and thus the length of the heater plate. A twisting device is installed between the heated feed roller and the plate heater, which defines the exact length of the crimp area, i.e. the twisting area, and carefully controls the processing characteristics of the yarn. be done. The preheated feed roller is kept at a temperature between 56% and 77% of the plate heater, i.e. it is insufficient to recrystallize the yarn molecules to fix the twist imparted to the yarn. , if the twist stop was removed, the twist would reach the heated feed roller.

[0005] In GB 1350588 the heating means are divided into two parts. The first part of the heating device (which can be of any of various types, e.g. plates, rollers or pins) has a sufficient temperature to draw the yarn, even though it is in the crimped region. It is only intended to raise the temperature. Only in the second part of the heating device (i.e. the plate heater) is the temperature of the yarn raised to a level sufficient for twist fixation. In this case, the first
The heating means is maintained at a temperature between 45% and 76%, preferably 60%, of the temperature of the second heating means.

[0006] In the above-mentioned two conventional techniques, the length of the plate heater for more crimping may be shorter than that in the case where no preheating is performed, but the overall length of the preheating and main heating areas is The length of is not significantly reduced compared to a single plate heater.

GB 2026560 discloses that upstream of the twisting device (ie outside the crimping area)
An apparatus is described in which the yarn is heated by a heating device provided with heating rollers disposed on the yarn, and the yarn is heated to a temperature sufficient to fix the subsequently applied twist. Furthermore, heating downstream of the twist setting device and in the crimping region is only required after the yarn has cooled below the required twist setting temperature. However, in the absence of a heater present in the crimping or twisting region, precise control of the temperature in that region, and thus the final properties of the textured yarn, is not possible, and its winding without contact with such a heater is not possible. The fact that the yarn is unsupported over a long distance in the shrinkage region makes the process unstable. Furthermore, heating to such a temperature before heating causes the yarn molecules to crystallize in an untwisted state. This is then retained as a yarn memory during subsequent cooling. The "twist memory" of the yarn is thus damaged and the yarn is not processed in the desired state. Crimping, such as twisting, and optionally applying drawing tension, must be carried out before the yarn reaches the desired twist setting temperature, so that the retained "
"memory" is only in the crimped state and, if desired, in the stretched state. This may be the case when a twisting device or other anti-crimping means is placed upstream of any means for bringing the yarn to a temperature above the twist fixing temperature, but this is not the case in the device of GB 2026560. It won't happen.

European Patent Application Publication No. 0087124
The patent application discloses a preheating plate and a main heating plate as well as a twisting device provided between them. However, since the preheating plate is located far upstream of the crimping area where the twisting device and the main heater are located, the yarn cools down before reaching the main heater. It is therefore stated that the length of the main heater is not reduced by providing a preheating device and that the preheating effect achieved by other conventional devices is not achieved with this device.

As a variation of the use of contact heaters in which the yarn reaches a temperature substantially equal to that of the heater, it has been proposed to use a non-contact heater, which It can be much higher than the melting temperature. Such a heater makes it possible to heat the yarn very rapidly and therefore requires a relatively short yarn path in the heating region compared to other conventional contact heaters. However, since the yarn temperature increases very rapidly through the heating zone while traveling along the yarn path, even a small change in the length of the heating zone or the heat transfer ratio causes a large change in the output temperature. It is very difficult to accurately control the actual temperature that the thread reaches and not to vary significantly above or below the desired twist set temperature. Therefore, it is difficult to accurately control the final properties of processed yarn using such a heating device. Furthermore, when a non-contact heater is used, the process tends to become unstable because there is nothing to support the yarn in the crimped region.

0010

OBJECTS OF THE INVENTION It is an object of the present invention to be able to reduce the length of the heating area compared to the length when using only conventional plate heaters, and to avoid the use of conventionally known arrangements for reducing the heating area. It is an object of the present invention to provide a heating device that can eliminate or reduce the inconveniences associated with.

[0011]

[Means for Solving the Problems] The present invention provides a first method that is maintained at a temperature exceeding a predetermined twist fixing temperature of the yarn and capable of heating the yarn to a temperature below the predetermined twist fixing temperature. A smoothing heater provided downstream of the heating means and the first heating means, maintained substantially at the predetermined twist fixing temperature, and capable of heating the yarn substantially to the predetermined twist fixing temperature. This is achieved by a yarn heating device provided in the twisting area. Preferably, the first heating means is maintained above the melting temperature of the yarn, and the first heating means may be a non-contact means capable of heating the yarn by radiation. Preferably, furthermore, the smoothing heater is a contact heater, which contact heater may be a plate providing a substantially straight thread path. The first heating means may be capable of heating the yarn to a temperature between 85% and 98% of the twist fixing temperature. Temperature sensing means may be arranged in the vicinity of the outlet of the first heating means, and control means may be provided to control the temperature of the first heating means when the yarn temperature is outside the desired range.
The temperature of the heating means may be controlled in response to a signal received from the temperature sensing means so that the temperature remains within the above range as the yarn travels from the first heating means into contact with the smoothing heater. good. The first heating means may be an infrared heater. The contact smoothing heater is
Heating may be accomplished in any manner known in the art, for example by electrical heating elements disposed longitudinally of the heating element or by a gas phase fluid in good thermal contact with the heater plate.

[0012] The temperature of the first heating means is at least 350°C.
For example, the temperature may be set at 650°C, and the smoothing heater may be set at a temperature in the range of 180°C to 280°C, for example, 225°C. The length of the first heating means is substantially 0.75 m
and the length of the smoothing heater is substantially 0.
．． It may be 25m.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic front view of a conventional false twisting machine equipped with a relatively long plate type heater, and FIG. 2 is a non-contact type heater that replaces the plate heater of the apparatus shown in FIG. FIG. 2 is a schematic front view of a device that has been replaced by an embodiment of the present invention.

Referring to FIG. 1, a conventional false twisting machine 10 is shown in FIG. first feeding device 14, long plate heater 1
5, a cooling plate 16, a false twisting device 17, a second feeding (and stretching) device 18, and a winding means 19. The first feeding device 14 transports the yarn 13 into the package 12.
The yarn 13 is supplied to the heater 15 by pulling it out from the heater 15. The heater 15 and the cooling plate 16 are aligned with each other to form a substantially straight, but relatively long, yarn path in the heating and cooling zone in which the yarn 13 passes through the false twisting device. 17 and the heating and cooling areas extend beyond the worker passageway 20. Therefore, the inlet end of the heater is located at a point directly above the top of the creel 11. In order to guide the yarn 13 from the first feed device 14 to the inlet of the heater 15, a sled 21 is provided on the track 22, and a detent guide 23 is provided on the sled 21. The sled 21 is movable to the bottom of the track 22 in the vicinity of the first feeding device 14 for threading and is then moved to an operating position at the top of the track 22 to transfer the yarn 13 to the heater 1.
5 and the surface of the cooling plate 16. The second feeding device 18 takes the yarn 13 from the false twisting device 17 to the winding means 1.
9, and when rotating at a higher feed speed than the first yarn feeding device 14, the yarn 1
3 is stretched between two feed devices 14,18.

The temperature of the heating plate 15 is substantially controlled to a temperature at which false twist can be fixed in the yarn 13, and the length of the heating plate 15 is typically 1.5 m to 2.5 m.
This makes it possible for the yarn 13 to reach the above temperature within the time that it is in contact with it. The length of the cooling plate 16 is 1 thread.
3 is sufficiently coolable to withstand the mechanical effects of the false twisting device 17 and even retains its twist memory when untwisted between the false twisting device 17 and the second feeding device 18. ing. Due to these required lengths and the preference to provide a substantially straight yarn path in the heating and cooling regions so that the twist is traced back to the twist stop guide 23, the inlet end of the heater 15 The section is above the height of a worker standing in the worker walkway 20 and an upper maintenance platform 24 is therefore provided. This increases the price of the processing machine 10, and
The overall height of the is increased.

Referring to FIG. 2, there is shown a false twisting machine that is generally the same as machine 10 described above, so that corresponding parts of the two machines 13, 30 correspond. Indicated by quotation marks. However, in the processing machine 30, the long plate heater 15 of the processing machine 10 is replaced with a short plate-shaped smoothing heater 31 and a non-contact first heater 32. two heaters 31, 32
The combined length of the processing machine 10 is approximately 1/2 of the length of a single heater 15 of the conventional processing machine 10, and therefore the overall size, especially the height, of the processing machine 30 according to the present invention is significantly smaller than that of the processing machine 10. It is smaller than that of . This reduction in heater length can be expressed as follows. A typical single contact heater 15 with a length L of 2.25 m and a temperature Th of 225°C has a P. of 167 f34. E. It is assumed that a (polyester) yarn is running at a speed S of 800 m/min (13.3 m/sec) in an ambient temperature of 20° C. (=the yarn temperature at the inlet of the heater is Ti). The following relationship, namely Loge[(Th-Ti)/(Th-Ty)]
=703L/(Cp×D×S) where Loge is the natural logarithm, Ty is the yarn temperature at the heater outlet, D is the yarn fineness (decitex), and Cp is P. E. By using the specific heat (=0.45 cai/g°C) of (polyester), the yarn temperature Ty is 182.8°C.

Now, in the same ambient environment as described above, the yarn is running at the same speed and is continuously heated by two contact heaters, the first heater is 0.75 m long and has a temperature of 400 m. It is assumed that the second smoothing heater has a length of 0.25 m and a temperature of 225°C. By sequentially using the above relationship for the two heaters, the yarn temperature Ty1 at the outlet of the first heater =
The temperature Ti2 at the inlet of the second heater is 175.5
℃ and the temperature Ty at the outlet of the second heater
2 becomes 183.5°C.

Using the above relationship for the first contact heater at a temperature of 400°C, increasing the contact length by 1 cm increases the outlet temperature by 1.6°, while substantially increasing the temperature at the twist fixation temperature of 225°C. Using the smoothing heater, the yarn increases the exit temperature by only 0.25° C. by increasing the contact length as well.

Similarly, the first non-contact heater has a length of 0.75 m and a temperature of 650°C, and the contact smoothing heater is immediately downstream thereof and has a length of 0.25 m and a temperature of 225°C. Consider the case of Considering heating by a mixture of radiation and air convection using a computer model,
The yarn temperature exiting the outlet of the non-contact heater and entering the inlet of the contact heater is expected to be 176°C. By using the above relationship for the second heater, the yarn temperature at the exit of the second heater is 183.7°C.

The smoothing heater 31 forms a substantially linear yarn path, and this yarn path is connected to the non-contact first heater 3.
The path of the thread 13 passing through the thread guide 2 is aligned with the path of the thread 13. As a result, a substantially linear state in which twisting is substantially good in all of the twisting regions from the false twisting device 17 to the twisting guide 23 is achieved, however, compared to the conventionally known device shown in FIG. The overall length has been reduced.

A temperature detection device 33 is provided near the outlet of the first heater 32 and detects the temperature when the yarn 13 leaves the heater 32 and transfers to the smoothing heater 31. The sensor 33 emits an output signal proportional to the yarn temperature, and the signal is supplied to the control means 34, if the yarn temperature is 85% of the above-mentioned predetermined twist fixing temperature of the yarn 13.
If it is outside the above mentioned range of between ~98%,
The control means 34 controls the temperature of the first heater 32 by adjusting the electrical input supplied to the first heater 32.

As explained above, the conventional arrangement and the arrangement according to the invention heat the yarn in contrast, but the total length of the heating area (
1 m) is clearly shorter than the length of the former (conventional) case (2.25 m). In addition to the advantages of reduced machine size and price mentioned above,
The arrangement of the present invention allows operators and maintenance personnel to easily access the inlet end of the heating zone by using a trolley instead of a ladder or overhead walkway as required in prior art systems. be able to. Furthermore, two heaters according to the invention, namely a first heater with a high temperature and a smoothing heater with a substantially fixing temperature for twisting the yarn;
The yarn temperature at the exit of the yarn can be controlled much more precisely than with conventional high temperature heaters alone.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view of a conventional false twisting machine equipped with a plate type heater.

FIG. 2 is a schematic front view of an embodiment of the present invention in which the plate heater of the apparatus shown in FIG. 1 is replaced with a relatively short plate heater using a non-contact type heater.

[Explanation of symbols]

10 Thread processing machine 11 Creel 12 Supply package 13 Thread 14 First feeding device 16 Cooling plate 17 False twisting device 23 Twisting device 30 Thread processing machine 31 Smoothing heater 32 First heater 33 Yarn temperature detection device

Claims (10)

[Claims] 1. A first heating means that is maintained at a temperature exceeding a predetermined twist fixing temperature of the yarn (13) and capable of heating the yarn (13) to a temperature below the predetermined twist fixing temperature. 32
) and downstream of the first heating means, the yarn (1
3) A yarn heating device provided in a twisting region, comprising a smoothing heater (31) capable of heating the yarn to substantially the predetermined twisting fixing temperature. 2. The twisting region is a twist stopper (23).
Yarn heating device according to claim 1, characterized in that it extends between the false twisting means (17) and the false twisting means (17). 3. The first heating means (32) heats the yarn (13) to a temperature of 85% to 85% of the predetermined twist fixing temperature of the yarn.
The yarn heating device according to claim 1 or 2, wherein the yarn heating device is capable of heating to a temperature of 98%. 4. Yarn temperature detection means (33)
The yarn heating device according to claim 3, wherein the yarn heating device is provided near the outlet end of the heating means (32). 5. When a signal is received from the yarn temperature detection means (33) and the yarn temperature is out of the range, the temperature of the first heating means (32) can be controlled in accordance with the signal. Yarn heating device according to claim 4, characterized in that control means (34) are provided. 6. The first heating means (32) is maintained at a temperature exceeding the melting temperature of the yarn (13). Yarn heating device. 7. The yarn heating device according to claim 6, wherein the first heating means (32) is a non-contact heating means capable of heating the yarn (13) by radiation. 8. The smoothing heater (31) comprises a plate forming a substantially straight yarn path substantially aligned with the path of the yarn (13) passing through the first heating means (32). The yarn heating device according to any one of claims 1 to 7, characterized in that: 9. The yarn heating device according to claim 1, wherein the smoothing heater (31) is maintained at a temperature of 180° C. to 280° C. 10. characterized in that said first heating means (32) is substantially 0.75 m long and said smoothing heater (31) is substantially 0.25 m long. The yarn heating device according to any one of claims 1 to 9.