Composite heat source comprising metal carbide, metal nitride and metal

• US 5,146,934 A
• Filed: 05/13/1991
• Issued: 09/15/1992
• Est. Priority Date: 05/13/1991
• Status: Expired due to Term

• Current Assignee: Philip Morris Incorporated (Altria Group, Inc.)
• Original Assignee: Philip Morris Incorporated (Altria Group, Inc.)
• Inventors: Deevi, Sarojini, Hajaligol, Mohammad R., Deevi, Seetharama C., Houghton, Kenneth S.
• Primary Examiner(s): Millin, V.
• Application Number:
  US07/699,490
• Time in Patent Office: 491 Days
• Field of Search: 131/359, 131/352, 131/364, 44/504, 44/520, 44/521, 44/522, 44/16 R, 44/17
• US Class Current: 131/359
• CPC Class Codes: A24B 15/165 comprising as heat source a carbon fuel or an oxidized or thermally degraded carbonaceous fuel, e.g. carbohydrates, cellulosic material
• CPC Class Codes: A24D 1/22 Cigarettes with integrated combustible heat sources, e.g. with carbonaceous heat sources

Abstract

This invention relates to a heat source comprising a mixture of metal carbide, metal nitride and metal which undergo a staged ignition process, particularly useful in smoking articles. The metal carbide/metal nitride/metal mixtures making up the heat source have ignition temperatures that are substantially lower than conventional carbonaceous heat sources, while at the same time provide sufficient heat to release a flavored aerosol from a flavor bed for inhalation by the smoker. Upon combustion the heat source produces substantially no carbon monoxide or nitrogen oxides.

Claims

1. A heat source comprising a first component with an ignition temperature in the range of between about 150°

C. and about 380°

C. and a combustion temperature in the range of between about 350°

C. and about 650°

C.;

a second component with an ignition temperature in the range of between about 340°

C. and about 600°

C. and a combustion temperature in the range of about 500°

C. and about 800°

C.; and

a third component with an ignition temperature in the range of between about 500°

C. and about 900°

C. and a combustion temperature in the range of between about 700°

C. and about 1500°

C.

2. A heat source comprising a first component /with an ignition temperature in the range of between about 150°

C. and about 380°

C. and a combustion temperature in the range of between about 500°

C. and about 650°

C.; and

a second component with an ignition temperature in the range of between about 500°

C. and about 900°

C. and a combustion temperature of between about 700°

C. and about 1500°

C.

3. A heat source for use in a smoking article comprising a first component with an ignition temperature in the range of between about 150°

C. and about 380°

C. and a combustion temperature in the range of between about 350°

C. and about 650°

C.;

a second component with an ignition temperature in the range of between about 340°

C. and about 600°

C. and a combustion temperature in the range of about 500°

C. and about 800°

C.; and

a third component with an ignition temperature in the range of between about 500°

C. and about 900°

C. and a combustion temperature in the range of between about 700°

C. and about 1500°

C.

4. The heat source of claim 3, wherein the second component has an ignition temperature in the range of between about 450°

C. to about 550°

C. and a combustion temperature in the range of between about 600°

C. to about 700°

C.

5. The heat source of claim 3, wherein the third component has an ignition temperature in the range of between about 600°

C. to about 700°

C. and a combustion temperature in the range of between about 750°

C. to about 900°

C.

6. The heat source of claim 3 wherein the second component is selected from the group consisting of a commercial iron carbide and zirconium nitride or a combination of the above.

7. The heat source of claim 3 wherein the third component is selected from the group consisting of a commercial iron nitride, zirconium nitride or a zirconium or a combination of the above.

8. The heat source of claim 3, wherein the first component is iron carbide, the second component is commercial iron carbide and the third component is commercial iron nitride and commercial zirconium nitride.

9. The heat source of claim 8 wherein the ratio by weight of iron carbide to commercial iron carbide to commercial iron nitride to commercial zirconium nitride is 1:

1;

1;

1.

10. A heat source for use in a smoking article comprising a first component with an ignition temperature in the range of between about 150°

C. and about 380°

C. and a combustion temperature in the range of between about 500°

C. and about 650°

C.; and

a second component with an ignition temperature in the range of between about 500°

C. and about 900°

C. and a combustion temperature of between about 700°

C. and about 1500°

C.

11. The heat source of either claims 3 or 10, wherein the first component has an ignition temperature in the range of between about 200°

C. to about 300°

C. and a combustion temperature in the range of between about 450°

C. to about 550°

C.

12. The heat source of claim 10 wherein the second component has an ignition temperature in the range of between about 500°

C. to about 700°

C. and a combustion temperature in the range of between about 750°

C. to about 900°

C.

13. The heat source of either claims 3 or 10, wherein the first component is selected from the group consisting of iron carbide and iron nitride or a combination of the above.

14. The heat source of claim 10 wherein the second component is selected from the group consisting of a commercial iron nitride, zirconium nitride and zirconium or a combination of the above.

15. The heat source of claim 10, wherein the first component is iron carbide and the second component is iron nitride and commercial zirconium.

16. The heat source of claim 15, wherein the ratio by weight of iron carbide to iron nitride to zirconium is 1:

1;

1.

17. The heat source of claim 15, wherein the ratio by weight of iron carbide to iron nitride to zirconium is 10:

5;

1.

18. The heat source of either of claims 3 or 10, wherein the heat source is substantially cylindrical in shape and has one or more fluid passages therethrough.

19. The heat source of claim 18, wherein the fluid passages are formed as grooves around the circumference of the heat source.

20. The heat source of claim 18, wherein the fluid passages are formed in the shape of a multipointed star.

21. The heat source of either of claims 3 or 10, wherein the heat source contains at least one burn additive.

22. The heat source of claim 21, wherein the burn additive is selected from the group consisting of perchlorate, permanganate, chlorate, or nitrate.

23. The heat source of either of claims 3 or 10, wherein the component particles have a size of up to about 700 microns.

24. The heat source of either of claims 3 or 10, wherein the component particles have a size in the range of about submicron to about 300 microns.

25. The heat source of either of claims 3 or 10, wherein the component particles have a B.E.T. surface area in the range of about 1 m² /g to about 400 m² /g.

26. The heat source of either of claims 3 or 10, wherein the component particles have a B.E.T. surface area in the range of about 10 m² /g to about 200 m² /g.

27. The heat source of either of claims 3 or 10, wherein the heat source has a void volume of about to about 85%.

28. The heat source of either of claims 3 or 10, wherein the heat source has a pore size of about submicron to about 100 microns.

29. The heat source of either of claims 3 or 10, wherein the heat source has a density of about 2.0 g/cc to about 10.0 g/cc.

30. The heat source of either claims 3 or 10, wherein the heat source contains at least one catalyst.

31. The heat source of claim 30, wherein the catalyst is iron oxide coated with gold.

32. The heat source of claim 30, wherein the catalyst comprises 0.5% to 10% gold/Fe₂ O₃ by weight.