Methods and equipment for gathering fibres

Patent metadata

Field	Value
Publication number	US-12004558-B2
Application number	US-202217590139-A
Country	US
Kind code	B2
Filing date	Feb 1, 2022
Priority date	Oct 5, 2016
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

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entrained fibres may be directed into the enclosure, a fibre outlet from which an assembly of gathered fibres may be withdrawn from the enclosure and an exhaust outlet through which gas may pass out of the enclosure.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

First claim

The invention claimed is:

1. Equipment for gathering fibres entrained in a gas stream, the equipment comprising
an enclosure having an inlet through which a gas stream carrying entrained fibres may be directed into the enclosure,
a conveyor onto which entrained fibres are deposited within the enclosure,
a fibre outlet from which gathered fibres may be withdrawn from the enclosure on the conveyor, and
an exhaust outlet through which gas may pass out of the enclosure,
wherein the enclosure being constructed to provide a pathway for the fibres through the enclosure from the inlet to the fibre outlet, to separate surplus gas in the gas stream from the entrained fibres and to direct the surplus gas to the exhaust outlet,
wherein the fibre outlet comprises an outlet orifice that discharges into an open channel extending in a direction of movement of the gathered fibres deposited on the conveyor, and
wherein a baffle is arranged at the outlet orifice in a position above the gathered fibres and the conveyor to direct surplus gas emerging from the orifice away from a direction of movement of the fibres and away from the conveyor to reduce a pressure in a region above the gathered fibres on the conveyor.

2. Equipment according to claim 1 wherein the enclosure is constructed to direct gas and fibres into the inlet and surplus gas outside the enclosure.

3. Equipment according to claim 1 constructed to gather the fibres together into a web.

4. Equipment according to claim 1 comprising a transport system arranged to move the fibres along part of the pathway.

5. Equipment according to claim 4 wherein the transport system comprises a conveyor.

6. Equipment according to claim 5 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.

7. Equipment according to claim 5 wherein the transport system is arranged to move the fibres in a different direction from the direction of the gas stream.

8. Equipment according to claim 5 wherein the inlet is arranged to receive the gas stream in a direction at right angles to the direction of movement of the transport system.

9. Equipment according to claim 5 wherein the transport system comprises a conveyor constructed to allow the passage of gas from the gas stream whilst supporting fibres thereon.

10. Equipment according to claim 1 wherein the enclosure is configured to direct substantially all the surplus gas within the enclosure to the exhaust outlet.

11. Equipment according to claim 1 wherein the enclosure is configured to direct a minor proportion of the surplus gas within the enclosure to the fibre outlet to the exhaust outlet.

12. Equipment according to claim 1 wherein the enclosure includes one or more baffles positioned in the pathway to direct surplus gas away from the gas stream.

13. Equipment according to claim 12 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 conveyor, and surplus gas in the gas stream gas away from the transport surface.

14. Equipment according to claim 1 in which the enclosure comprises a baffle positioned in the path of the gas stream and arranged to direct fibres from in the gas stream into a primary passage, and surplus gas from the gas stream into an auxiliary passage separate from the primary passage.

15. Equipment according to claim 14 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 lies alongside the main passage, has an entrance adjacent the inlet, and is arranged to receive gas from the periphery of the gas stream, and an exit directed to one side of the first region.

16. Equipment according to claim 15 wherein the lateral width of the primary passage decreases towards the first region.

17. Equipment according to claim 15 wherein the lateral widths of the auxiliary passages increase towards the second region.

18. Equipment according to claim 14 wherein at least one baffle is provided with louvres.

19. Equipment 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.

20. Equipment according to claim 19 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.

21. Equipment 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.

22. Equipment according to claim 1 further comprising melt blowing equipment for generating fibres of plastics material entrained in a gas stream, and arranged to direct the gas stream into the enclosure.

23. Equipment according to claim 1 further comprising rod forming equipment arranged to receive a web of fibres from the transport surface and to form the web into a continuous rod.

24. An enclosure for use in equipment according to claim claim 1 , the enclosure defining an inlet, through which a gas stream carrying entrained fibres may be directed into the enclosure, a fibre outlet from which gathered fibres may be withdrawn from the enclosure, and an exhaust outlet through which gas may pass out of the enclosure, wherein the enclosure provides a pathway for the fibres through from the inlet to the fibre outlet and is constructed to direct surplus gas in the gas stream away from the entrained fibres.

25. A method of forming an assembly of gathered fibres comprising:
entraining fibres in a stream of gas;
directing the stream of gas and entrained fibres into a wholly or partially enclosed space;
gathering the fibres together in the enclosed space and depositing the entrained fibres on a conveyor;
withdrawing the gathered fibres from the enclosed space on the conveyor through an outlet orifice; and
discharging the gas from the enclosed space at the outlet orifice;
wherein surplus gas is separated from the gas stream and diverted in a direction away from a direction of movement of the gathered fibres at the outlet orifice and away from the conveyor to reduce a pressure in a region above the gathered fibres on the conveyor.

26. A method according to claim 25 wherein the entrained fibres are directed into the enclosed space, and surplus gas is directed outside the enclosed space.

27. A method according to claim 25 wherein the surplus gas is diverted from the periphery of the gas stream.

28. A method according to claim 25 , wherein the fibres are gathered by directing the stream of gas and entrained fibres on to a collecting surface, and causing relative movement between the collecting surface and the gas stream.

29. A method according to claim 25 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 surplus gas on the periphery of the gas stream is diverted laterally away from the direction

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