Process for treating tobacco

• US 6,082,369 A
• Filed: 07/22/1998
• Issued: 07/04/2000
• Est. Priority Date: 10/19/1995
• Status: Expired due to Term

• Current Assignee: Impex Process Equipment Limited
• Original Assignee: Imperial Tobacco Limited (Imperial Tobacco Group PLC)
• Inventors: Matthews, Keith A., Henneveld, Clifford H., Nevett, Robert, Chard, Brian C.
• Primary Examiner(s): Silverman, Stanley S.
• Assistant Examiner(s): Ruller, Jacqueline A.
• Application Number:
  US09/051,461
• Time in Patent Office: 713 Days
• Field of Search: 131/276, 131/290, 131/291, 131/296
• US Class Current: 131/290
• CPC Class Codes: A24B 3/182 Puffing

Abstract

Tobacco is treated using the following series of steps:

(1) subjecting in a chamber the tobacco to a reduced pressure of not greater than 70 mbar (7 kPa);

(2) impregnating the cell structure of the tobacco with isopentane vapor at a temperature in the range of from 70° C. to 90° C. and maintaining the tobacco in contact with isopentane vapor at a pressure of at least 4 bar (400 kPa) for up to 30 minutes to cause impregnation of the tobacco;

(3) removing excess isopentane vapor from the impregnated tobacco by evacuating the chamber, the pressure change being effected adiabatically;

(4) contacting the impregnated tobacco with steam to expand the tobacco; and

(5) subjecting the expanded tobacco to a reordering process.

Claims

1. A process for treating tobacco comprising a series of steps:

(1) subjecting in a chamber the tobacco to a reduced pressure of not greater than 70 mbar (7 kPa);

(2) impregnating the cell structure of the tobacco with isopentane vapour at a temperature in the range of from 70°

C. to 90°

C. and maintaining the tobacco in contact with isopentane vapour at a pressure of at least 4 bar (400 kPa) for up to 30 minutes to cause impregnation of the tobacco;

(3) removing excess isopentane vapour from the impregnated tobacco by evacuating the chamber, the pressure change being effected adiabatically;

(4) contacting the impregnated tobacco with steam to expand the tobacco to produce expanded tobacco; and

(5) subjecting the expanded tobacco to a re-ordering process.

2. A process according to claim 1, wherein in step (1) the tobacco is subjected to a reduced pressure in the range of 40-70 mbar (4-7 kPa).

3. A process according to claim 1, wherein in step (2) the tobacco is maintained in contact with the isopentane vapour at a pressure in the range of 4000-4500 mbar (400-450 kPa) for about 30 minutes.

4. A process according to claim 1, wherein in step (4) the steam is introduced into the chamber to raise the pressure to a value of from 1000 to 1400 mbar (100-140 kPa).

5. A process according to claim 4, wherein the introduction of steam into the chamber is discontinued when the temperature of exhaust steam allowed to leave the chamber reaches 90-95°

C.

6. A process according to claim 1, wherein the re-ordering process comprises subjecting the expanded tobacco to vacuum drying at reduced pressure in the range of from 180-220 mbar (18-22 kPa).