Device for spinning materials forming threads

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.

1 . An apparatus comprising a spinning head connected to a feeder for the melt, a spinneret assembly which is held in the spinning head and comprises at least one 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 to the spinning bore, wherein between plate and spinning head is formed a closed first space provided with a supply of gas and below the plate is provided a second space, and wherein 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 carried by the flow of gas in or 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.  
   
   
       2 . The apparatus according to  claim 1 , wherein the spinneret assembly is insulated from the first space in the region of the at least one spinning bore by an insulating assembly and/or is heated in the region of the at least one spinning bore.  
   
   
       3 . The apparatus according to  claim 1 , wherein the pressure ratios in the first and second spaces are adjusted in such a way that the gas flow in the Laval nozzle attains speeds up to the speed of sound and over.  
   
   
       4 . The apparatus according to  claim 1 , wherein the second space is at ambient pressure or a few mbar over.  
   
   
       5 . The apparatus according to  claim 1 , wherein the supplied gas is at ambient temperature or the temperature of its feeder.  
   
   
       6 . The apparatus according to  claim 1 , wherein the outlet opening of the at least one spin hole in the region of the Laval nozzle is located at the level of the upper edge of the plate, a few mm above the upper edge of the plate, or extends a few mm into the Laval nozzle.  
   
   
       7 . The apparatus according to  claim 1 , wherein the spinning nozzle assembly comprises a plurality of spinning bore which are if occasion arises provided with nipples and which form a row or several parallel rows.  
   
   
       8 . The apparatus according to  claim 1 , wherein the plate comprises at least one elongate Laval nozzle.  
   
   
       9 . The apparatus according to  claim 1 , wherein the plate comprises a plurality of rotationally symmetrical Laval nozzles.  
   
   
       10 . The apparatus according to  claim 1 , wherein a delivery belt is provided for deposition of the threads and formation of a non-woven fabric.  
   
   
       11 . The apparatus according to  claim 1 , wherein a winding device is provided for winding the threads.  
   
   
       12 . The apparatus according to  claim 1 , wherein the Laval nozzles are designed to provide for a gas flow around the at least one thread which is laminar.  
   
   
       13 . An apparatus comprising 
 a spinning head connected to a feeder for a melt,    a spinneret comprising at least two plate-like parts arranged over one another, and at least one melt supply bore and distribution conduits for distributing the melt, and a plurality of spinning bores, wherein electrical heating conductors are arranged in the region of a boundary surface of the at least two plate-like parts in a manner such that they surround the distribution conduits and compensate heat losses to the outside,    a Laval nozzle arranged in a fixed geometrical relationship to the spinning bores to provide a gas flow around the spinning bores, wherein the throughput of the melt through the spinneret, the temperature of the melt is adjusted in such a way that a spun melt monofilament exiting a spinning bore is carried by the flow of gas in or after leaving the Laval nozzle before solidification thereof and 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.    
   
   
       14 . The apparatus according to  claim 13 , wherein the supplied gas is at ambient temperature or the temperature of its feeder.  
   
   
       15 . The apparatus according to  claim 13 , wherein the arrangement comprises at least one elongate Laval nozzle.  
   
   
       16 . The apparatus according to  claim 13 , wherein the arrangement comprises a plurality of rotationally symmetrical Laval nozzles.  
   
   
       17 . The apparatus according to  claim 13 , wherein a delivery belt is provided for deposition of the threads and formation of a non-woven fabric.  
   
   
       18 . The apparatus according to  claim 13 , wherein a winding device is provided for winding the threads.  
   
   
       19 . A device for spinning materials forming threads, from melts or solutions at temperatures above the ambient temperature, with a spinneret comprising at least two plate-like parts arranged over one another, and at least one melt supply bore and distribution conduits for distributing the melt, and a plurality of spinning bores, wherein electrical heating conductors are arranged in the region of the boundary surface of the at least two plate-like parts in a manner such that they surround the distribution conduits and compensate heat losses to the outside.  
   
   
       20 . A device according to  claim 19 , wherein the distribution conduits comprise melt channels which at the boundary surface are machined into the surface at least of one of the plate-like parts.  
   
   
       21 . A device according to  claim 19 , wherein the distribution conduits comprise a melt distribution space which is arranged in the region of the boundary surface.  
   
   
       22 . A device according to  claim 19 , wherein one of the plate-like parts is designed as a spinneret's lower part with the spinning bores, wherein the spinneret's lower part comprises a holed plate which is applied into a recess and which is applied over the spinning bores.  
   
   
       23 . A device according to  claim 19 , wherein three plate-like parts are provided, wherein electrical heating conductors are arranged in the region of the respective boundary surface between two plate-like parts.  
   
   
       24 . A device according to  claim 19 , wherein the electrical heating conductors are arranged parallel to the respective boundary surface.  
   
   
       25 . A device according to  claim 19 , wherein the electrical heating conductors are designed in an annular manner.  
   
   
       26 . A device according to  claim 19 , wherein at least one groove is incorporated in the region of the respective boundary surface, into which the respective tubularly formed heating body is applied or pressed.  
   
   
       27 . A device according to  claim 19 , wherein further electrical heating conductors for increasing the temperature of the melt are arranged in the region of the spinning bores transverse to their longitudinal directions.  
   
   
       28 . A device according to  claim 19 , wherein the electrical heating conductors are formed as cartridges which are applied into bores or fittings.  
   
   
       29 . A device according to  claim 28 , wherein several cartridges are applied behind one another over the length of the arrangement of the spinning bores.  
   
   
       30 . A device according to  claim 29 , wherein the cartridges have different heating outputs.  
   
   
       31 . A device according to  claim 19 , wherein the spinning bores are formed in a web which is connected to the plate-like spinneret's lower part as one piece, wherein the electrical heating conductors are arranged on both sides of the web transversely to the spinning bores.