Apparatus for making spunbond from continuous filaments

Patent metadata

Field	Value
Publication number	US-2018282926-A1
Application number	US-201815939753-A
Country	US
Kind code	A1
Filing date	Mar 29, 2018
Priority date	Mar 31, 2017
Publication date	Oct 4, 2018
Grant date	—

Abstract

An apparatus for making spunbond from continuous thermoplastic filaments has a spinneret for spinning the continuous filaments and advancing them in a filament-travel direction, a cooler for cooling the filaments, a stretcher for stretching the filaments, a depositing device including a foraminous belt extending in a machine direction transverse to the filament-travel direction for deposition of the filaments as a nonwoven web and conveyance away from the stretcher, a diffusor between the stretcher and the foraminous belt so that filaments and primary air from the stretcher enter into the diffusor, and a suction device for extracting air through the foraminous belt at an extraction region underneath the diffusor outlet and having a width b in a machine direction that is greater than a width B of the diffusor outlet. The diffusor forms upstream and downstream secondary air-inlet gaps at opposite ends through which secondary air is aspirated into the diffusor.

First claim

We claim:

1 . An apparatus for making spunbond from continuous thermoplastic filaments, the apparatus comprising:
a spinneret for spinning the continuous filaments and advancing them in a filament-travel direction; a cooler for cooling the filaments; a stretcher for stretching the filaments; a depositing device including a foraminous belt extending in a machine direction transverse to the filament-travel direction for deposition of the filaments as a nonwoven web and conveyance away from the stretcher; a diffusor between the stretcher and the foraminous belt so that filaments and primary air from the stretcher enter into the diffusor in the filament-travel direction, the diffusor forming upstream and downstream secondary air-inlet gaps at opposite ends of the diffusor through which secondary air is aspirated into the diffusor, the secondary air-inlet gaps being oriented such that the secondary air flows in at an inflow angle α of less than 100° with respect to the filament-travel direction or with respect to a longitudinal central plane of the depositing device or of the diffusor, the diffuser having walls forming a downstream section diverging toward the depositing device and forming a diffusor outlet having a width B in the machine direction; and a suction device for extracting air or process air through the foraminous belt at an extraction region underneath the diffusor outlet and having a width b in a machine direction that is greater than the width B of the diffusor outlet.

2 . The apparatus defined in claim 1 , wherein the width b of the extraction region is at least 1.2 times the width B of the diffusor outlet.

3 . The apparatus defined in claim 1 , wherein the extraction region projects in the machine direction downstream of the deposition region of the filaments by an extraction section beyond the diffusor outlet and/or wherein the extraction region projects relative to the machine direction upstream of the deposition region of the filaments by an extraction section beyond the diffusor outlet.

4 . The apparatus defined in claim 1 , wherein the extraction by the suction device takes place such that at least in the region of the diffusor outlet tertiary air flows along outer surfaces of the diffusor walls toward the deposition device or the depositing foraminous belt and the tertiary air flows are substantially parallel to the mixed flow of primary air and secondary air flowing toward the diffusor outlet inside the diffusor, the tertiary air also being extracted through the foraminous belt by the suction device.

5 . The apparatus defined in claim 1 , wherein the volume flow VT of tertiary air extracted with the suction device is at least 25% of the volume flow of the extracted primary and secondary air.

6 . The apparatus defined in claim 1 , wherein a subassembly comprising the cooler and the stretcher is closed such that apart from a supply of cooling air in the cooler, no further fluid medium or air flows into this closed subassembly.

7 . The apparatus defined in claim 1 , wherein at the secondary air-inlet gaps, a ratio VP/VS of the volume flows of primary air and secondary air is less than 5:1.

8 . The apparatus defined in claim 1 , wherein in the flow direction of the filaments the diffuser has an upstream convergent diffusor section downstream or underneath the upstream secondary air-inlet gap.

9 . The apparatus defined in claim 8 wherein the diffuser forms a constriction in the flow direction of the filaments between the convergent upstream diffusor section and the downstream diffusor section.

10 . The apparatus defined in claim 9 , wherein a length l K of the convergent diffusor section is 5 to 50% of a length L of the entire diffusor in the filament-travel direction.

11 . The apparatus defined in claim 9 , wherein a ratio l K /l D of a length l, of the convergent diffusor section to a length l D of the divergent diffusor section is 0.1: to 1:1.

12 . The apparatus defined in claim 1 , wherein an outlet angle β of the diffusor with respect to a longitudinal central axis M of the diffusor is a maximum of 30°.

13 . The apparatus defined in claim 1 , wherein the distance of the diffusor or a lower edge of the diffusor from the foraminous belt is 20 mm to 300 mm.

Assignees

• Reifenhaeuser Masch

Inventors

• Frey Detlef
• Neuenhofer Martin
• Sommer Sebastian

Classifications

• D01D5/092

  in shafts or chimneys · CPC title

• D01D4/02

  Spinnerettes (alloys therefor C22C) · CPC title

• D04H3/033 Primary

  reorientation immediately after yarn or filament formation · CPC title

• D04H3/16 Primary

  with bonds between thermoplastic filaments produced in association with filament formation, e.g. immediately following extrusion · CPC title

• D04H1/56

  in association with fibre formation, e.g. immediately following extrusion of staple fibres · CPC title