Methods and equipment for gathering fibres

Patent metadata

Field	Value
Publication number	US-11272733-B2
Application number	US-201716339568-A
Country	US
Kind code	B2
Filing date	Sep 18, 2017
Priority date	Oct 5, 2016
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

A method of, and equipment for gathering fibres (12) entrained a gas stream, for example by melt blowing, comprises an enclosure (50) having an inlet (57), through which a gas stream carrying entrained fibres (12) may be directed into the enclosure (50), a fibre outlet (58) from which an assembly of gathered fibres (12) may be withdrawn from the enclosure (50) and an exhaust outlet (41) through which gas may pass out of the enclosure (50). The enclosure (50) is constructed to provide a pathway for the fibres (12) from the inlet (57) to the fibre outlet (58) in which surplus gas in the gas stream is separated from the entrained fibres (12) and directed to the exhaust outlet (41), thereby reducing turbulence in the fibres (12) in the enclosure (50) which may affect the quality of the finished assembly.

First claim

The invention claimed is:

1. Apparatus comprising:
melt-blowing equipment for generating fibres of plastics material entrained in a gas stream, the melt-blowing equipment comprising a die-head having an outlet from which fibres entrained in a gas stream emerge from the melt-blowing equipment, and
equipment to receive the fibres entrained in a gas stream emerging from the die-head of the melt-blowing equipment, and for gathering said fibres,
wherein the equipment for receiving and gathering said fibres entrained in a gas stream
comprises an enclosure having an inlet through which the fibres entrained in a gas stream are
directed into a primary passage within the enclosure, a fibre outlet from which gathered
fibres are withdrawn from the enclosure, and an exhaust outlet through which the entrained gas separated from the gathered fibres in the primary passage passes out
of the enclosure, the enclosure being constructed to provide a pathway for the fibres through the enclosure from the inlet to the fibre outlet,
wherein the melt-blowing equipment and the equipment to receive the fibres entrained in a gas stream and to gather them is
spaced such that a first portion of surplus gas in which the fibres are entrained is
separated from said entrained fibres as said entrained fibres are directed to the inlet of the enclosure and before the fibres entrained in said gas stream enter the enclosure,
said first portion of surplus gas being exhausted to atmosphere outside of the enclosure, and
wherein the enclosure comprises a baffle extending in the direction of the gas stream and the
pathway for the fibres and which defines an auxiliary passage alongside the primary passage within the enclosure, the baffle being arranged to direct fibres entrained in the gas stream into the inlet of the primary passage,
and a second portion of surplus gas from a
periphery of the gas stream into said auxiliary passage as said entrained fibres are directed to
the inlet, wherein said exhaust outlet includes an outlet from the auxiliary passage to exhaust said second portion of surplus gas to atmosphere outside of the enclosure.

2. Apparatus according to claim 1 , comprising a transport system arranged to move the fibres along part of the pathway, preferably in a different direction to the direction of the gas stream, and wherein the transport system has an upstream portion disposed in alignment with the inlet to collect entrained fibres from the gas, and arranged to move fibres deposited thereon through the enclosure towards the fibre outlet.

3. Apparatus according to claim 2 , wherein the transport system comprises a conveyor constructed to allow gas to pass therethrough to separate a third portion of the surplus gas from entrained fibres on the conveyor.

4. Apparatus according to claim 1 , further comprising a transport surface arranged to move the fibres along part of the pathway, and at least one baffle positioned so as to direct fibre in the gas stream on to the transport surface, and surplus gas in the gas stream gas away from the transport surface.

5. Apparatus according to claim 1 , wherein the primary passage has an entrance adjacent the inlet arranged to receive fibres and an exit arranged to direct fibres to a first region within the enclosure; and the auxiliary passage has an entrance adjacent the inlet and an exit directed to one side of the first region.

6. Apparatus according to claim 5 , wherein the exit directed to one side of the first region directs gas to a second region within the enclosure, and the lateral widths of the auxiliary passages increase towards the second region.

7. Apparatus according to claim 1 , wherein the enclosure comprises a conduit having an elongated section of substantially uniform cross sectional shape through which fibres may pass towards the fibre outlet.

8. Apparatus according to claim 7 , wherein the enclosure further comprises a guide through which fibres may pass into the conduit, the guide having a cross section that tapers towards the elongated section of the conduit.

9. Apparatus according to claim 1 , wherein the fibre outlet comprises an outlet orifice that discharges into an open channel extending in the direction of movement of the gathered fibres.

10. Apparatus according to claim 9 , further comprising a baffle arranged to direct gas emerging from the orifice away from the direction of movement of the fibres.

11. Apparatus according to claim 1 , wherein the enclosure includes an exhaust chamber arranged to receive the surplus gas, and the gas outlet is positioned in communication with the exhaust chamber.

12. Apparatus according to claim 1 , wherein at least one baffle is provided with louvres.

13. A method of generating fibres of plastics material entrained in a gas stream and for gathering said fibres comprising:
generating fibres of plastics material entrain in a gas stream using melt-blowing equipment having a die-head with an outlet such that fibres entrained in a gas stream emerge from the melt-blowing equipment through said outlet,
gathering the fibres entrained in the gas stream in equipment to receive the fibres entrained in a gas stream emerging from the die-head of the melt blowing equipment,
wherein the equipment for receiving and gathering said fibres entrained in a gas stream comprises an enclosure having an inlet, and the fibres entrained in a gas stream are directed into a primary passage within the enclosure through said inlet, and are withdrawin from the enclosure through a fibre outlet, and an exhaust outlet through which the entrained gas separated from the gathered fibres in the primary passage passes out of the enclosure, the enclosure being constructed to provide a pathway for the fibres through the enclosure from the inlet to the fibre outlet,
spacing the melt-blowing equipment and the equipment to receive the fibres entrained in a gas stream and to gather them such that a first portion of surplus gas in which the fibres are entrained is separated from said entrained fibres as said entrained fibres are directed to the inlet of the enclosure and before the fibres entrained in said gas stream enter the enclosure, said first portion of surplus gas being exhausted to atmosphere outside of the enclosure, and
providing the enclosure with a baffle extending in the direction of the gas stream and the pathway for the fibres to define an auxiliary passage alongside the primary passage within the enclosure, the baffle being arranged to direct fibres entrained in the gas stream into the inlet of the primary passage, and a second portion of surplus gas from a periphery of the gas stream into said auxiliary passage as said entrained fibres are directed to the inlet, and
exhausting said second portion of surplus gas to atmosphere outside of the enclosure from said auxiliary passage.

14. A method according to claims 13 , wherein the fibres are gathered by directing the entrained fibres on to a collecting surface, and causing relative movement between the collecting surface and the gas stream.

15. A method according to claim 14 , wherein the gas stream is funnelled in its direction of flow into a region of smaller cross-sectional area as it approaches the collecting surface and a second portion of surplus gas on the periphery of the gas stream is diverted laterally away from the direction of flow.

16. A method according to claims 15 , wherein the second portion of surplus gas adjacent the gathered fibres is diverted away there from the web to facilitate separation of the gathered of the web from the collection surface.

Assignees

• British American Tobacco Investments Ltd
• Tobacco Res & Dev Inst Pty Ltd

Inventors

• Fallon Gary
• Richardson John
• King Ian
• Le Roux Gerhard Malin
• Herholdt Arnold Leslie

Classifications

• A24D3/0229 Primary

  Filter rod forming processes (A24D3/0275 takes precedence) · CPC title