Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D4/00—Spinnerette packs; Cleaning thereof
  • D01D4/08—Supporting spinnerettes or other parts of spinnerette packs
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
  • D01D4/00—Spinnerette packs; Cleaning thereof

Definitions

• Nozzle plate holder and spinning beam for melt spinning endless threads are provided.
• the invention relates to a nozzle plate holder and to a spinning beam for melt spinning endless threads made in particular of thermoplastic materials (melt).
• the spinning beam comprises, for example, a heating box into which melt lines, melt pumps and nozzle pots (also called “nozzle packages”) which end in nozzle plates protrude.
• the nozzle pots can form vertical indentations of the heating box and can be fastened in bell-shaped receptacles with a vertical, central melt channel which opens into a melt inlet of the nozzle pots.
• the nozzle plate holder forms part of a nozzle pot.
• the temperature control of the melt from the extruder to the outlet from the spinneret is of fundamental importance in melt spinning. It is particularly important to ensure that the melt has the same thermal history for all threads, both in temperature and in the dwell time. Slight deviations of, for example, only 2 ° C. can already lead to visible staining differences or increased capillary breakage rates.
• the product lines and the spinning beams are currently generally heated by condensation.
• the condensation heating enables a very precise temperature control, since this principle in particular intensively heats the points of the room to which saturated steam is applied which have a lower temperature than the condensation temperature of the saturated steam. The result is a very even temperature distribution on the condensation surfaces.
• This heating principle thus enables temperature control of the entire melt distribution system that is accurate to the degree with relatively simple means.
• the melt is again filtered and homogenized in the nozzle packs. These have to be removed from the spinning beam for cleaning purposes or when changing the product to a different number of filaments. Removal and installation of the nozzle packs should be as simple as possible in order to keep the effort for this to a minimum. For this reason, the nozzle packs cannot be directly washed by the saturated steam.
• the heat supply to the nozzle packs therefore only takes place via heat conduction at the contact surfaces between the nozzle pack and the spinning beam and the melt supplied.
• a nozzle package must simultaneously meet many other requirements. For example: - be easy to replace,
• connection to a carrier in the spinning beam is established at the upper (inner) end of the nozzle package (see, for example, DE-C-1246221, DE-A-1660697 and US 4,696,633). This even applies if the package has to be inserted from above or from the side into the designated receptacle (e.g. according to US 3,655,314 or US 3,891,379).
• a "good heat transfer" due to the surface pressure of the nozzle plate holder and a carrier should also be achieved according to DE-C-1529819. However, this requires a special design of the carrier, which impairs effective heating of this part.
• a known spinning beam can be found, for example, in DE-Gb 84 07 945. With this spinning beam, the holder for the nozzle pot (the nozzle package) is welded into the heating box and is therefore practically part of the heating box.
• the arrangement of the nozzle cup in the receptacle is such that a layering, consisting of nozzle plate, filter housing and nozzle cup bottom, is screwed to the base of the receptacle, by means of bolts penetrating the receptacle, which fit into a nut thread in the base of the receptacle are screwed in.
• the screws have to be loosened, after which the nozzle pot can be pulled vertically downwards out of the receptacle. Since the nozzle pots have to be cleaned frequently, sometimes daily, what depends on the mass to be processed, there is considerable wear of the bolts in the area of the nut thread in the base of the receptacle. The bolts must be tightened strongly due to the pressures of about 120 to 350 bar, which are usually present in the nozzle pot, which is to avoid Damage to the bolts and the thread must be done with a torque wrench. Usually, at least four bolts are required to fasten a nozzle pot, so that each time the nozzle pot is cleaned, there is also a significant amount of work involved.
• the nozzle pot has a hollow cylinder which, with an inwardly projecting shoulder, carries the nozzle plate on which the filter housing is mounted via an annular seal.
• a piston with a central through hole that is axially movable in the hollow cylinder and, when the nozzle cup is not filled, is supported over the rim of the plate by a membrane in the manner of an inverted plate.
• a space between the filter housing and the membrane is filled with melt, which in this case presses the membrane away from the filter housing via a cross section that corresponds practically to the piston cylinder and thus the piston.
• the piston stroke is limited during this movement by a sealing ring surrounding the central recess, which is supported against a threaded ring which is fastened by means of bolts to a rigid pump block arranged in the heating box.
• the hollow cylinder with an internal thread is screwed onto the threaded ring provided with an external thread, with which the nozzle pot carried by the hollow cylinder with its shoulder is fastened to the heating box.
• the hollow cylinder must be unscrewed from the threaded ring.
• the invention has for its object to facilitate the assembly and disassembly of the nozzle pots with reduced stress on the seal, in particular to accelerate it.
• the sealing disks with a central through hole are expediently bell-shaped, and in the installed state they rest on the bottom of the receptacles with their bottom surrounding the through hole and the outer edge of the sealing disks is supported on an annular shoulder in the nozzle cup. Due to this design of the sealing washers, when the nozzle cup is filled under the pressure of the melt, the pressure on the one hand presses against the bottom of the receptacle, whereby the sealing effect between the nozzle pot in the area of the central through hole of the sealing washer and the bottom of the receptacle automatically adapts to the prevailing pressure .
• the nozzle pots are expediently designed such that the nozzle plate, a filter housing and a threaded ring forming the nozzle pot base with a central recess are layered in a hollow cylinder of the nozzle pot, the hollow cylinder carries the nozzle plate with a shoulder and the threaded ring in a nut thread of the hollow cylinder is screwed in while compressing the layered components, the annular shoulder pressing the sealing disk arranged on the filter housing against a conical inner surface of the threaded ring presses in such a way that the sealing disk, with its area surrounding its through hole, protrudes slightly from the central recess of the threaded ring.
• the sealing washer is centered by the conical inner surface of the threaded ring, so that after assembly of the nozzle cup it can be fastened in the receptacle with the correct position of the sealing washer by means of the above-mentioned bayonet catch.
• the sealing disc then immediately presses in its correct position against the base of the receptacle, with which the nozzle cup is sealed and prepared for filling with the mass to be processed.
• the filter housing is expediently designed in such a way that, when the nozzle cup is assembled, the filter housing lies against the nozzle plate with a cylindrical projection and the projection surrounds an annular recess in the filter housing in which a Sealing ring is inserted.
• the cylindrical projection on the filter housing settles against the nozzle plate, with the result that the ring-like recess formed by the claim is limited within the projection to the height of this projection.
• the sealing ring inserted into the recess cannot be squeezed together excessively.
• the sealing effect of the sealing ring is determined automatically by the pressure prevailing in the nozzle pot, since this pressure presses the sealing ring outwards against the projection and automatically closes a possible gap between the projection and the opposite surface of the nozzle plate, which offers a projection further the advantage that through him the entire height of the nozzle pot is determined, which therefore has a defined dimension when installed.
• the shoulders arranged on the receptacles and the supports provided on the nozzle pots are expediently designed in the manner of a bayonet catch. This results in a connection between the nozzle pot and the receptacle that can be closed and released in a particularly simple manner, namely only by a rotation of at most about 90 °. Accordingly, there is practically no wear and tear on the bayonet catch even if the nozzle pot is removed frequently.
• the design of the receptacles with the shoulders projecting inwards, which are matched by corresponding supports on the nozzle pots, and the arrangement of the sealing washers with support against the base of the receptacles can advantageously be used in combination, with both measures being quicker and more secure installation or add disassembly.
• 7A and 7B are schematic representations of the conditions in the area of the melt feed.
• Fig. 1 shows the heat flows on a nozzle package.
• a carrier is indicated with the reference number 50 and the nozzle pack with 52.
• the carrier 50 is part of a heating box which is normally heated today by means of diphyl steam (e.g. according to DE-Gb 9313586.6 of September 7, 1993).
• the package is received in a receptacle (the "nozzle throat") 54 in the carrier.
• the package 52 u in particular includes a nozzle plate 56 and a holder 58.
• the holder 58 has a cavity 60 which contains further elements of the package, as will be described below with reference to FIG. 5. However, these elements are superfluous for the schematic representation of the heat balance according to FIG. 1 and are not described individually in connection with the figure.
• the essential heat flows are indicated in Fig. 1 as follows:
• melt Arrow 5 Heat flow from the nozzle pack through heat radiation from the nozzle plate.
• the melt Due to the process, the melt here accounts for the largest part of the heat supply as well as the heat dissipation. Ideally, the two heat flows are equal in amount. This would mean that the melt has a constant temperature until it emerges from the nozzle. To ensure this, the remaining heat flows would have to be balanced.
• the heat losses of the nozzle plate present particular difficulties. Since it cannot be insulated, a large part of the heat is emitted to the environment in the form of radiation and convection. This amount of heat must now be conducted as far as possible from the spinning beam over the nozzle package to the nozzle plate in order to reduce the cooling of the melt to a minimum.
• the temperature difference to the diphyl temperature is a measure of the amount of heat that is withdrawn from the melt.
• the melt is cooled by an average of approx. 0.5 ° C in production.
• the temperature distribution in the stationary state can now be calculated and displayed with the FEM program under the given boundary conditions.
• 3 shows the temperature distribution calculated in this way in the nozzle packet with a nozzle diameter of 90 mm.
• a temperature difference (A &) of approximately 30 ° C. was calculated between the diphyl vapor space and the nozzle plate. Depending on the design (air gap, wall thickness, etc.), this value can also differ by a few degrees. Measurements on the test plant confirm the result of these calculations. This means that, to compensate for this temperature difference, so much heat is removed from the melt that it is cooled by approximately 1.5 ° C. until it emerges from the nozzle. However, this temperature difference cannot be regarded as constant across all nozzles.
• FIG. 5 shows a section of a spinning beam with a nozzle package (in particular a nozzle plate holder) according to this invention.
• the spinning beam comprises a heating box 1, into which melt lines and melt pumps, not shown, protrude, as is shown, for example, in the figures of DE-Gmb 84 07 945 mentioned above.
• the receptacle 2 is inserted into the heating box 1, for example by welding, which consists of the wall 3, which is closed off inwards by the base 4.
• the receptacle 2 encloses the cylindrical interior 5, in which the nozzle pot 6 is inserted.
• the interior 5 merges into the exterior via the cylindrical opening 7, the bottom 4 is penetrated by the melt channel 8, which is connected to a melt pump (not shown).
• the nozzle pot 6 is a rotating body, it is shown in the figure like the receptacle 2 in section.
• the nozzle pot 6 consists of components stacked on top of one another, namely the nozzle plate 9, the filter housing 10 and the threaded ring 11. These three components are inserted into the hollow cylinder 12 which carries the nozzle plate 9 with its shoulder 13.
• the hollow cylinder 12 On the side of the threaded ring 11, the hollow cylinder 12 is provided with the internal thread 14, into which the threaded ring 11 is screwed with its external thread 15.
• the threaded ring 11 is provided with the blind holes 16 and 17, into which a suitable hook wrench fits.
• the threaded ring 11 is screwed into the hollow cylinder 12 by the cylindrical projection 18 on the nozzle plate 9 facing side of the filter housing 10 limited. If the projection 18 abuts the surface 19 of the nozzle plate 9 when the threaded ring 11 is screwed in, the entire length of the nozzle cup 6 is determined. Within the cylindrical projection 18 there is an annular recess which is filled by the sealing ring 20. The sealing ring 20 is pressed outwards against the cylindrical projection 18 by the pressure of a mass to be processed, which thereby fills the intermediate space 21 between the surface 19 and the lower surface 22 of the filter housing 10, as a result of which the effect is exerted this pressure automatically results in a seal adapted to the pressure between the filter housing 10 and the nozzle plate 9.
• the shoulders 23 are components of the insert pieces 25, which are inserted into the wall 3 of the receptacle 2 and screwed tightly to the wall 3 by means of the bolts 26.
• the shoulders 23 and the supports 24 together form a bayonet catch, which the nozzle pot 6 axially locked. At the same time, the bayonet catch forms a direct thermal bridge over the shoulders 23 and the supports 24, via which the nozzle plate 9 is heated directly.
• the connection between the receptacle 2 and the nozzle pot 6 is released.
• the nozzle pot 6 can then be removed from the receptacle 2 through the cylindrical opening 7 and dismantled into its parts, for example for cleaning the filter housing 10 and the nozzle plate 9.
• the sealing disk 27 comes into effect, which is inserted essentially in a conical design into the threaded ring 11, which has a conical inner surface 28 for receiving the sealing disk 27.
• the outer edge 29 of the sealing disk 27 is supported on the annular shoulder 30, which is part of the melt distributor 31 resting on the filter housing 10.
• This melt distributor 31 is here a component of the nozzle pot 6, it serves to cheaply distribute the melt flowing in via the melt channel 8 inside the nozzle pot, which is discussed in more detail below.
• the sealing washer 27 is supported with respect to the ring shoulder 30, whereby it abuts vertically upwards into the bottom 32, which is the through hole, by contacting the conical inner surface 28 of the threaded ring 11 Surrounds 33, which is aligned with the melt channel 8.
• the bottom 32 of the sealing washer 27 protrudes slightly from the surface 34 of the threaded ring 11, so that when the bayonet catch 24/25 is closed, the bottom 32 bears firmly against the lower surface 35 of the base 4 of the receptacle 2.
• the seal between the base 4 of the receptacle 2 to the nozzle pot 6 which is penetrated in front of the melt channel 8 is thus produced, using the pressure prevailing inside the nozzle pot 6 which presses the sealing disk 27 depending on the level of this pressure presses against the lower surface 35 and the conical inner surface 28 of the threaded ring 11.
• the melt flow proceeds as follows: The melt passes from the melt channel 8 through the through hole 33 to the melt distributor 31, over which the melt flows and into the channels 37, only two of which are shown. In the illustrated embodiment, about 24 such channels are available. The melt then flows through the filter 38, which is closed at the bottom by the grating 39. The channels 40 are also introduced into the filter housing 10 (approx. 50 such channels are present), from where the melt reaches the intermediate space 21. The melt now passes through the nozzle plate 9, specifically through the bores 41 which end in capillaries in the lower boundary surface 42 of the nozzle plate 9. The individual filaments then emerge here and are then combined to form individual threads.
• the dashed curve A represents the heat-up behavior (temperature profile over time after installation in the spinning beam - without polymer) of a conventional nozzle packet in the middle of the nozzle
• the dashed curve B shows the corresponding behavior in the edge part of a conventional one Package shows.
• Curve C shows that Warm-up behavior in the middle of the nozzle of a package according to this invention (for example according to FIG. 5), while curve D (which largely coincides with curve C) represents the warm-up behavior of the edge area of the novel package.
• the new nozzle package with the improved heat flow reaches the final temperature much earlier than the conventional conventional nozzle package. Furthermore, the final temperature of the new nozzle package is approximately 10 ° C higher, which corresponds to the calculations. The temperature difference between the center of the nozzle and the edge of the nozzle is already negligibly small in the case of a conventional design nozzle package, but could be improved by the last nuance in the new nozzle package. The test thus confirms the calculated results, according to which the cooling of the melt in the new nozzle package is approximately 0.5 ° C lower than that of the conventional design nozzle package. Although this value appears to be very low, it is of crucial importance for the quality of the yarn produced, particularly in the production of microfilaments.
• the receptacle itself has an axial surface 100 which is directed in the spinning direction. This surface faces an end face 102 of the nozzle packet after the packet is in its operating position, with a gap 104 being present between them.
• the distance between the end face 102 and the contact surfaces of the support can be determined during the manufacture or assembly (ie during the construction) of the package without having to take into account the manufacturing tolerances of the heating box.
• a flexible sealing lip 106 extends from the upper end of the package in order to touch the surface 100. The hardness, bending strength and dimensions of the flexible lip are selected in such a way that surface-to-surface contact according to FIG. 7A occurs is coming. Ideally, the lip conforms to unevenness in the surface 102.
• the risk of leakage between the lip and the surface 102 is small when the melt first enters through the access channel, since the melt pressure is low until the chamber in the package has been filled under the lip. Until this occurs, the lip is additionally pressed against the surface 102 by the melt, which counteracts the risk of leakage.
• the contact conditions before the melt enters are important, as the incorrect construction according to FIG. 7B is intended to illustrate.
• the spring force of the lip has been chosen too large in an upward direction.
• the lip edge accordingly bends down again, which leaves a wedge gap between the edge and the surface 102 open.
• This results in an attack surface for the incoming melt which can lead to the "peeling" of the lip from the surface 102 and to leakage.
• a leak can of course also result from the fact that the spring force that presses the lip against the surface 102 is chosen too low, so that the melt that enters can penetrate into the remaining gap between the lip and the surface 102.
• the lip is provided on a sealing body which is "embedded" in the package so that the body is supported by the package against the melt pressure and only the lip has to deform under the melt pressure.
• the lip is preferably formed in one piece with the body.
• the body can advantageously be formed or arranged such that it can perform additional sealing functions in the package itself.
• the sealing element (the lip) can be plastically deformable under the operating pressure, the element then having to be replaced after the package has been removed from the throat before being introduced again.
• the material of the element can, however, be selected such that the element is elastically deformable even under the operating pressure and is therefore reusable, for example if chrome steel is used.
• the seal is preferably elastically deformable.
• the sealing element (the sealing lip and the sealing body) are exposed to the melt during operation. It is therefore necessary to choose a sealing material that will not react with the melt.
• a metal is preferred, with aluminum and steel being suitable in most cases.
• a seal according to Fig. 5 (with a lip and a one-piece body part) with the conical body part in contact with a conical support surface in the package may e.g. through a. Deep-drawing processes or by metal pressing.
• a sheet thickness of up to approx. 3 mm e.g. for steel approx. 1 mm and for aluminum 1.5 to 2 mm can be used.
• the package is preferably provided with a stop which fixes its angular position about a vertical axis in the operating position of the package.
• the arrangement of the holes in the nozzle plate with respect to the cooling shaft can be predetermined.
• the connection to the carrier is achieved by means of a bayonet lock
• at least one element of the lock can perform the function of the stop.
• a multi-course bayonet lock could be used, although measures must then be taken to distribute the surface pressure over the supports of the lock. This will normally require tighter manufacturing tolerances. Since the radial dimension of these supports strongly influences the division (the mutual distance) of the packets in the spinning beam, this dimension should be kept as small as possible, because a minimal division is generally desirable.
• the radial distance between the outer surface of the package and the outer end of each support is preferably not greater than 10 mm. In the case of a multi-start closure, this dimension can be kept smaller than 5 mm. There are preferably no more than three runs per course.
• the invention in its first aspect (connection at the lower end of the package) results in the shortest possible flow paths for the heat between the heating box and the nozzle plate.
• This aspect of the invention is not restricted to use in combination with a sealing lip, although it is preferably used in combination with a seal which develops its full sealing effect due to the melt pressure.
• Such seals are also known for example from US 4645444.
• the new type of seal is itself an advantage, regardless of the connection between the nozzle package and the heating box - for example, it can be the piston seal according to DE-C-12 46 221 or DE-C-15 29 819 or US-4 Replace 696 633.
• the cylindrical outer surface of the nozzle package is indicated by M.
• This area must have a slightly smaller diameter than the inner surface of the nozzle pharynx in order to allow the package to be inserted into the pharynx without any problems.
• the distance A between the bottom of the Cushions and the more distal end face of the package is chosen to be slightly smaller than the depth of the throat in order to ensure the insertion of the package without touching the end surfaces of the throat.
• the radial dimension of the edition is indicated with D.
• connection at the lower end of the package naturally requires the appropriate design of the lower end of the jet throat. This can be done by the design of the heating box itself, but preferably a support frame for the package is formed separately and attached to the heating box, for example by means of screws, as shown in FIG. 5.
• the frame is preferably interchangeable, which means that the fastening means can be released without destroying parts.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Textile Engineering (AREA)
• Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
• Spinning Or Twisting Of Yarns (AREA)
• Preliminary Treatment Of Fibers (AREA)
• Nonwoven Fabrics (AREA)

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• 1993
  • 1993-06-21 CH CH01853/93A patent/CH688044A5/de not_active IP Right Cessation
• 1994
  • 1994-06-20 DE DE59410185T patent/DE59410185D1/de not_active Expired - Fee Related
  • 1994-06-20 WO PCT/CH1994/000123 patent/WO1995000684A1/fr active IP Right Grant
  • 1994-06-20 EP EP98122845A patent/EP0931863B1/fr not_active Expired - Lifetime
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