Methods and equipment for forming tubes of fibrous material

Patent metadata

Field	Value
Publication number	US-11945178-B2
Application number	US-201816496612-A
Country	US
Kind code	B2
Filing date	Mar 15, 2018
Priority date	Mar 24, 2017
Publication date	Apr 2, 2024
Grant date	Apr 2, 2024

Abstract

Equipment for forming a tubular rod of fibrous material comprises: a gathering station constructed to receive a continuous supply of fibres and to gather the fibres into a bundle as the fibres advance through the equipment; a divider arranged in the path of the fibres through the equipment and constructed to from a cleft along the length of the bundle as it advances through the equipment; a mandrel positioned in the path of the bundle of fibres in alignment with the divider and constructed to form the cleft into a passage through the bundle of fibres as the bundle of fibres advances over the mandrel; and a die constructed and arranged to cooperate with the mandrel to form the fibres in a tubular configuration around the mandrel.

First claim

The invention claimed is:

1. A method of forming a tubular rod of fibrous material using equipment for forming a tubular rod of fibrous material, the equipment including gathering equipment constructed to receive a continuous supply of fibers from said fiber supply module,
a divider arranged in a path of a plurality of fibers emerging from a fiber supply module,
a mandrel assembly comprising an open-ended tubular casing configured to receive the bundle of fibers, and a mandrel mounted in the casing and positioned downstream of the divider, the mandrel having a mandrel support including a divider plate that carries the mandrel and which extends between the mandrel and the casing, the divider plate being located downstream of the divider, and
a die constructed and arranged to cooperate with the mandrel, wherein the die is positioned downstream of the casing of the mandrel assembly, wherein the method comprises:
producing a plurality of fibers using a melt-blowing process in said fiber supply module,
gathering said fibers into an elongated bundle using said gathering equipment constructed to receive a continuous supply of fibers from said fiber supply module,
parting the fibers using the divider to form a cleft along a length of the bundle as the bundle advances through the gathering equipment,
introducing the mandrel into the cleft so that the mandrel and the die cooperate to close the fibers of the bundle around the mandrel in a tubular configuration,
keeping the cleft formed in the bundle by the divider open as the bundle of fibers passing through the casing over the mandrel by aligning the divider plate of the mandrel assembly with the divider,
forming the fibers in a tubular configuration around the mandrel by passing the bundle of fibers through the die, and
separating the fibers from the mandrel as a tubular rod.

2. A method according to claim 1 , wherein the cleft is formed as a recess extending partially through the bundle.

3. A method according to claim 1 , wherein the cleft is formed to extend radially from a periphery of the bundle to the center of the bundle.

4. A method according to claim 1 , wherein the cleft is formed to extend 50%, 60%, or 70% of thickness of the bundle.

5. A method according to claim 1 , wherein the cleft divides the bundle into two parts.

6. A method according to claim 1 , wherein a treatment fluid is delivered to the bundle of fibers as the bundle passes over the mandrel.

7. A method according to claim 6 , wherein the treatment fluid is delivered from within the mandrel.

8. A method according to claim 1 , wherein the fibers are supplied from a feedstock of fibrous material.

9. A method according to claim 1 , wherein the fibers are supplied by a continuous manufacturing process.

10. A method according to claim 1 , wherein the bundle of fibers is treated to fix the bundle in a tubular configuration.

11. A method according to claim 10 , wherein the bundle of fibers is advanced through a constriction that defines a desired circumferential profile for the bundle of fibers, and a treatment fluid for curing the fibers is introduced into the bundle as the fibers enter the constriction.

12. Equipment for forming a tubular rod of fibrous material from a plurality of fibers produced by a fiber supply module using a melt-blowing process comprising:
gathering equipment constructed to receive a continuous supply of fibers from said fiber supply module and to gather the fibers into a bundle as the fibers advance through the gathering equipment;
a divider arranged in a path of the fibers through the gathering equipment and constructed to form a cleft along a length of the bundle as the bundle advances through the gathering equipment;
a mandrel assembly comprising an open-ended tubular casing configured to receive the bundle of fibers, and a mandrel mounted in the casing and positioned in the path of the bundle of fibers downstream of the divider, the mandrel comprising a mandrel support including a divider plate that carries the mandrel and which extends between the mandrel and the casing, the divider plate being in alignment with the divider to keep the cleft formed in the bundle by the divider upstream of the divider plate open as the bundle of fibers passes through the casing and advances over the mandrel; and
a die positioned downstream of the casing of the mandrel assembly, the die being constructed and arranged to cooperate with the mandrel to form the fibers in a tubular configuration around the mandrel.

13. Equipment according to claim 12 , wherein the gathering equipment comprises a forming cone having an inlet for receiving the fibers, an outlet from which a web of fibers may be withdrawn as a bundle, and the forming cone defines a longitudinally extending passage of tapering configuration between the inlet and the outlet.

14. Equipment according to claim 13 , wherein the divider comprises a projection in the passage of the forming cone extending between the inlet and the outlet.

15. Equipment according to claim 12 , wherein the mandrel comprises a passage for delivering a treatment fluid to the bundle of fibers as the bundle passes over the mandrel.

16. Equipment according to claim 12 , wherein the die is constructed and arranged to form the fibers around the mandrel into a tubular external shape.

17. Equipment according to claim 16 , wherein the die comprises a body having a central passage therethrough, and the mandrel comprises a rod mounted within the central passage to define a tubular space between the body and the mandrel.

18. Equipment according to claim 12 , further comprising a treatment station in which the fibers may be cured whilst supported on the mandrel.

19. Equipment according to claim 18 , wherein the treatment station comprises a housing defining a chamber into which a treatment fluid may be introduced, and the die is positioned within the housing and is provided with one or more conduits for delivering the treatment fluid from the chamber to the fibers.

Assignees

• British American Tobacco Investments Ltd

Inventors

• Fallon Gary
• Herholdt Arnold
• Le Roux Gerhard
• Richardson John

Classifications

• B29C70/523 Primary

  and impregnating the reinforcement in the die · CPC title

• A24D3/0291

  for hollow tipped filters, e.g. recess filters · CPC title

• B29B15/122

  with a matrix in liquid form, e.g. as melt, solution or latex · CPC title

• A24D3/0237 Primary

  by extrusion · CPC title

• B29C70/521

  and impregnating the reinforcement before the die · CPC title