Abstract: The present disclosure relates to a device for melting a material without a crucible and for atomizing the melted material in order to produce powder, comprising: an atomizing nozzle; an induction coil having windings, which become narrower in the direction of the atomizing nozzle at least in some sections; and a material bar at least partially inserted into the induction coil. The induction coil is designed to melt the material of the material bar in order to produce a melt flow. The induction coil and the atomizing nozzle are arranged in such a way that the melt flow is or can be introduced into the atomizing nozzle through a first opening of the atomizing nozzle in order to atomize the melt flow by means of an atomizing gas, which can be introduced into the atomizing nozzle.

Abstract: The invention relates to a device (1) for melting a material without a crucible and for atomizing the melted material in order to produce powder, comprising: an atomizing nozzle (5); an induction coil (4) having windings (4a-d), which become narrower in the direction of the atomizing nozzle (5) at least in some sections; and a material bar (3) at least partially inserted into the induction coil (4). The induction coil (4) is designed to melt the material of the material bar (3) in order to produce a melt flow (16). The induction coil (4) and the atomizing nozzle (5) are arranged in such a way that the melt flow (16) is or can be introduced into the atomizing nozzle (5) through a first opening (20) of the atomizing nozzle (5) in order to atomize the melt flow (16) by means of an atomizing gas (19), which can be introduced into the atomizing nozzle (5).

Abstract: The invention relates to a spinneret for spinning threads from a spinning mass—in the form of a melt or solution of natural or synthetic origin—comprising a rotationally symmetrical spinneret. The rotationally symmetrical spinneret inner part is surrounded at least partially by a rotationally symmetrical outer part, wherein in the longitudinal direction between the spinneret inner part and outer part an insulating chamber is formed, in which a gas, preferably air, is received in order to form an insulating gas layer. The invention further relates to a spinning device for spinning threads from a spinning mass, comprising a spinneret part and a gas nozzle part arranged at a distance from the spinneret part. A plurality of spinnerets according to the invention are inserted in the spinneret part and project from the spinneret part, facing the gas nozzle part, and the gas nozzle part comprises a plurality of gas nozzles associated with the spinnerets.

Abstract: The invention relates to a spinneret for spinning threads from a spinning mass—in the form of a melt or solution of natural or synthetic origin—comprising a rotationally symmetrical spinneret. The rotationally symmetrical spinneret inner part is surrounded at least partially by a rotationally symmetrical outer part, wherein in the longitudinal direction between the spinneret inner part and outer part an insulating chamber is formed, in which a gas, preferably air, is received in order to form an insulating gas layer. The invention further relates to a spinning device for spinning threads from a spinning mass, comprising a spinneret part and a gas nozzle part arranged at a distance from the spinneret part. A plurality of spinnerets according to the invention are inserted in the spinneret part and project from the spinneret part, facing the gas nozzle part, and the gas nozzle part comprises a plurality of gas nozzles associated with the spinnerets.

Abstract: The invention relates to a method and a device for producing substantially endless fine threads from polymer solutions, especially spinning material for lyocell, wherein the spinning material is spun from at least one spinning hole or a spinning slot. The spun thread or film is drawn by high-speed accelerated gas flows using a Laval nozzle whose narrowest cross-section is located beneath the point where the spinning material exists. The threads are arranged on a strip in the form of a non-woven or are taken up in the form of a yarn and are subsequently separated in spinning baths by means of solvents.

Abstract: A spinning apparatus for producing fine threads by splicing, which comprises a plurality of protruding spinneret jets disposed in a spinneret jet portion and having spinning orifices from which the spinning dopes exit as monofils and having a plurality of acceleration jets, in particular Laval jets, whose cross section reduces, only to widen downstream of the smallest cross section, which are assigned to the spinning orifices is proposed to be provided with means for feeding gas streams which surround the monofils and are accelerated by the acceleration jets. The acceleration jet, in an at least partially plate-shaped gas jet portion, is constructed as a funnel-shaped depression into which the spinneret jet reaches to form gas flow channels.

Abstract: A strengthened nonwoven is made at least in part of spun microfibers that are strengthened by hydrodynamic needling, alone or together with other fibers such as also staple fibers and/or endless fibers. The microfibers are spun from a polymer melt of only one certain polymer from a plurality of spinning apertures, and the spun filaments are drawn by gas streams accelerated to high velocity by an accelerating nozzle such as a Laval nozzle and, due to further production conditions, each fiber receives before solidification an internal hydrostatic pressure that is higher than the ambient gas pressure so that each fiber cracks in the longitudinal direction and splits up into a plurality of fine endless filaments.

Abstract: The invention relates to a method and a devise for pulversing liquids using gas flows. According to the invention, the liquid is guided through an outlet into a pulverisation chamber and is pulverised in fine droplets. The liquid jet leaving the outlet of a liquid channel is accelerated by a laminar gas flow which is continuously accelerated by means of a Laval nozzle, until the increasing pressure inside the liquid jet and the decreasing pressure in the gas flow leads to the explosion of the liquid jet and to the formation of droplets.

Abstract: The invention relates to a method for producing polylactic acid, comprising the steps of obtaining lactic acid from starchy agricultural products by fermentation, ultrapurification of the lactic acid by ultrafiltration, nanofiltration and/or electrodialysis, concentration of the lactic acid and production of a prepolymer, cyclizing depolymerization to dilactide, purification of the dilactide, ring-opening polymerization of the dilactide and demonomerization of the polylactide.

Abstract: An apparatus comprises a spinning head connected to a feeder for the melt, a spinneret assembly which is held in the spinning head and comprises a spinning bore and which spins a melt monofilament, a plate which is located below the spinning head and which comprises a Laval nozzle arranged in a fixed geometrical relationship. Between plate and spinning head a closed first space is formed provided with a supply of gas and below the plate a second space is provided. The throughput of the melt per spinning bore, the temperature of the melt and the pressure in the first and second spaces are adjusted in such a way that the spun melt monofilament after leaving the Laval nozzle before solidification thereof attains a hydrostatic pressure which is greater than the gas pressure surrounding it, such that the thread bursts and splits into a plurality of fine threads.

Abstract: Non-wovens from water-entangled continuous split fibres and such fibres produced by the meltblown method are known per se. Split fibres are composed of several polymers and are expensive to produce. The drawing air which must be heated to high temperatures in the meltblown method impairs the resistance of the fibres, which are often tom forming staple fibres. The non-wovens or parts of the non-wovens are preferably made from continuous fibres, which burst in a longitudinal direction during production due to high hydrostatic pressure inside the fibre, forming monofilaments with a diameter of approximately 2 &mgr;m, whereby fine, resistant continuous filaments are produced. Non-wovens produced using said thin fibres are bonded using hydrodynamic needling in order to obtain abrasion-resistant wipe non-wovens.

Abstract: The invention relates to a method and a device for the production of essentially continuous fine threads made of meltable polymers. The polymer melt is spun from at least one spin hole (5) and the spun thread is attenuated using gas flows which are accelerated to achieve high speeds by means of a Laval nozzle (6). As a result of the specific geometry of the melt hole (4) and the position thereof in respect to the Laval nozzle (6), the temperature of the polymer melt, the throughout per spin hole and the pressures determining the velocity of the gas flow upstream and downstream from the Laval nozzle (6) are controlled in such a way that the thread reaches an internal hydrostatic pressure before solidifying, whereby said thread bursts into a plurality of fine threads.

Abstract: The invention relates to a method and a device for producing substantially endless fine threads from polymer solutions, especially spinning material for lyocell, wherein the spinning material is spun from at least one spinning hole or a spinning slot. The spun thread or film is drawn by high-speed accelerated gas flows using a Laval nozzle whose narrowest cross-section is located beneath the point where the spinning material exists. The threads are arranged on a strip in the form of a non-woven or are taken up in the form of a yarn and are subsequently separated in spinning baths by means of solvents.

Abstract: A method and device for recovering linear polyesters, such as PET and PBT, from polyester waste of the most varied form, in a continuous manner, in which undried or not dried-through waste is melted, the polymer chains being hydrolytically degraded by adhering moisture, and in which diol, corresponding to the basic constitutional unit of the polymer, is added to the melt resulting in glycolytic degradation, and the melt so treated is further condensed to the desired degree of polymerization.

Abstract: The invention relates to a device for manufacturing spun-bonded webs with a nozzle arrangement which spins out warps of yarns. The device according to the invention has a longitudinally-extended duct for generating a gas current which transports the yarns in the duct, and a depositing chamber with an air-permeable deposit belt for deposition of the yarns. The deposit chamber (9) surrounds the conveyor belt (2) in the deposition area of the yarns, and is in the form of a gas-tight casing (9), the width of which is greater than the width of the deposit belt. By means of the casing, a greater degree of vacuum may be used to generate the gas current, and thus the yarns are more intensively drawn. Furthermore, undesirable turbulence of the yarns at the edges of the deposit belt is reduced, and an improvement is achieved in the web structure in these areas.

Abstract: An apparatus for delivering and depositing groups of continuous threads or filaments, which are conveyed by means of a gas flow and which are introduced substantially parallel into a passage having a corresponding cross-section is proposed, the gas flow accompanying the threads upon entering the upper part of the passage is accelerated to high speed and is then decelerated and the threads are deposited on a moving depositing surface. The gas flow delivering the threads flows at high speed through the passage preferably provided with parallel walls and then is decelerated by the suction of part of the gas in the lower passage area laterally through openings in the passage walls.

Abstract: A reactor for highly viscous media with a horizontally oriented reactor casing having an inlet and an outlet in which a cage-like rotor is mounted in a rotary manner by means of stub shafts. To the cage-like rotor are fixed elements, e.g., rings, which are immersed in and thoroughly mix the media. A stripping rotor is provided coaxially with the cage-like rotor. Both rotors rotate within one another and mix and deliver the media and thereby form free surfaces. In addition, they also clean one another through a scraping action.

Abstract: This invention relates to a process for carrying out continuous demonomerization and postpolymerization of Polyamide 6 melts and a reactor for carrying out this process. The reactor of this invention has a cylinder with a horizontal axis around which an interior rotor shaped like a cage rotates. The reactor can be partially filled with polymer melt. There is a multitude of elements along the periphery of the rotor which partly dip into the melt and serve to convey the melt through the reactor, generate new surfaces and mix and homogenize the melt as the polymer melt undergoes demonomerization and postpolymerization under vacuum.

Abstract: Described are a process and an apparatus for the aftercondensation of polycondensates, wherein moist and amorphous polymer in a granular or powderous form is continuously introduced from above into a single reactor. The granulate flows downward under gravity, with a hot gas being caused to flow in counter-current relation thereto. The reactor is formed as a continuous shaft or column which has positioned in the upper portion thereof an agitating element acting to prevent agglutination of the granulate. The granulate is crystallized and pre-dried in the upper portion of the shaft or column. In a further (subsequent) portion of the shaft or column, drying and aftercondensation take place without separation from the remainder of the shaft or column.

Abstract: This invention relates to a process for carrying out continuous demonomerization and postpolymerization of Polyamide 6 melts and a reactor for carrying out this process. The reactor of this invention has a cylinder with a horizontal axis around which an interior rotor shaped like a cage rotates. The reactor can be partially filled with polymer melt. There is a multitude of elements along the periphery of the rotor which partly dip into the melt and serve to convey the melt through the reactor, generate new surfaces and mix and homogenize the melt as the polymer melt undergoes demonomerization and postpolymerization under vacuum.