Methods of preparing gas generant formulations

• US 5,731,540 A
• Filed: 07/01/1996
• Issued: 03/24/1998
• Est. Priority Date: 01/10/1994
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Innovation Systems, Inc. (Northrop Grumman Corporation)
• Original Assignee: Thiokol Corporation (Howmet Aerospace, Inc.)
• Inventors: Flanigan, David A., Mancini, Vincent E., Harper, Michael R.
• Primary Examiner(s): Jordan, Charles T.
• Assistant Examiner(s): CHI, ANTHONY
• Application Number:
  US08/674,152
• Time in Patent Office: 631 Days
• Field of Search: 149/109.6, 264/3.1
• US Class Current: 149/109.6
• CPC Class Codes: B01J 2/10 in stationary drums or troughs, provided with kneading or mixing appliances
• CPC Class Codes: B01J 2/16 by suspending the powder material in a gas, e.g. in fluidised beds or as a falling curtain
• CPC Class Codes: C06B 21/0066 by granulation, e.g. flaking
• CPC Class Codes: C06B 21/0091 Elimination of undesirable or temporary components of an intermediate or finished product, e.g. making porous or low density products, purifying, stabilising, drying; Deactivating; Reclaiming; porous inert particles or chemicals compounded for these purposes C06B23/00
• CPC Class Codes: C06D 5/06 by reaction of two or more solids

Abstract

Novel methods for processing gas generant compositions to produce feed stock are disclosed. The methods of the present invention include utilizing a binding agent and other additives in a mixture of ingredients of gas generant compositions in sufficient quantities that the ingredients of the gas generating material will agglomerate to form granules as the ingredients are mixed. Processing methods, including roll coating, continuous mixing, static mixing, freeze drying, solvent extraction, emulsification, azeotropic distillation, spray drying, fluidized bed processing and particle grinding are also disclosed for use in preparing feed stock for final gas generant products. The methods of the present invention are particularly useful in processing gas generating materials having a non-azide based fuel.

Claims

1. A method for preparing gas generant feed stock, comprising the steps of:

obtaining a desired quantity of ingredients measured in predetermined ratios according to the composition of a gas generating material having a non-azide based fuel;

introducing the ingredients into an inlet end of a fluidized bed;

supplying fluid media through the fluidized bed to mix the ingredients together;

introducing a solvent into the ingredients while continuing to mix the ingredients to cause the ingredients to agglomerate;

urging the ingredients to a drying zone; and

removing the solvent from the ingredients after sufficient agglomeration has occurred.

2. A method for preparing gas generant feed stock as defined in claim 1, wherein the solvent comprises water.

3. A method for preparing gas generant feed stock as defined in claim 2, wherein the water is introduced at a temperature of from about 60 to about 100 degrees centigrade.

4. A method for preparing gas generant feed stock a as defined in claim 3, wherein the water is introduced at a temperature of from about 60 to about 85 degrees centigrade.

5. A method for preparing gas generant feed stock as defined in claim 2, wherein the step of removing the solvent from the ingredients comprises preheating the fluid media and supplying it into the fluidized bed at the drying zone.

6. A method for preparing gas generant feed stock as defined in claim 1, further comprising the step of lowering the pressure at which the fluid media is supplied into the drying zone.

7. A method for preparing gas generant feed stock as defined in claim 1, further comprising the step of including a binding agent in the mixture in sufficient quantities that the ingredients of the gas generating material will agglomerate to form granules as the ingredients are mixed.

8. A method for preparing gas generant feed stock as defined in claim 1, further comprising the step of including a flow agent in the mixture.

9. A method for preparing gas generant feed stock, comprising the steps of:

obtaining a desired quantity of ingredients measured in predetermined ratios according to the composition of a gas generating material having a non-azide based fuel;

introducing the ingredients into an inlet end of a fluidized bed;

supplying fluid media through the fluidized bed to mix the ingredients together;

introducing a solvent into the ingredients while continuing to mix the ingredients to cause the ingredients to agglomerate;

urging the ingredients to a drying zone; and

removing the solvent from the ingredients after sufficient agglomeration has occurred,

wherein the step of introducing the ingredients into an inlet end of a fluidized bed comprises introducing the ingredients in a dry state.

10. A method for preparing gas generant feed stock as defined in claim 9, wherein the solvent comprises water.

11. A method for preparing gas generant feed stock as defined in claim 10, wherein the water is introduced at a temperature of from about 60 to about 100 degrees centigrade.

12. A method for preparing gas generant feed stock as defined in claim 11, wherein the water is introduced at a temperature of from about 60 to about 85 degrees centigrade.

13. A method for preparing gas generant feed stock as defined in claim 10, wherein the step of removing the solvent from the ingredients comprises preheating the fluid media and supplying it into the fluidized bed at the drying zone.

14. A method for preparing gas generant feed stock as defined in claim 9, further comprising the step of lowering the pressure at which the fluid media is supplied into the drying zone.

15. A method for preparing gas generant feed stock as defined in claim 9, further comprising the step of including a binding agent in the mixture in sufficient quantities that the ingredients of the gas generating material will agglomerate to form granules as the ingredients are mixed.

16. A method for preparing gas generant feed stock as defined in claim 9, further comprising the step of including a flow agent in the mixture.

17. A method for preparing gas generant feed stock, comprising the steps of:

obtaining a desired quantity of ingredients measured in predetermined ratios according to the composition of a gas generating material having a non-azide based fuel;

introducing the ingredients into an inlet end of a fluidized bed;

supplying fluid media through the fluidized bed to mix the ingredients together;

introducing a solvent into the ingredients while continuing to mix the ingredients to cause the ingredients to agglomerate in the fluidized bed;

urging the ingredients to a drying zone of the fluidized bed;

removing the solvent from the ingredients while in the fluidized bed, said removing step being conducted after sufficient agglomeration has occurred; and

discharging the agglomerated ingredients from an outlet of the fluidized bed.

18. A method for preparing gas generant feed stock as defined in claim 17, wherein the step of introducing the ingredients into an inlet end of a fluidized bed comprises introducing the ingredients in a dry state.

19. A method for preparing gas generant feed stock as defined in claim 17, wherein the solvent comprises water.

20. A method for preparing gas generant feed stock as defined in claim 19, wherein the water is introduced at a temperature of from about 60 to about 100 degrees centigrade.

21. A method for preparing gas generant feed stock as defined in claim 20, wherein the water is introduced at a temperature of from about 60 to about 85 degrees centigrade.

22. A method for preparing gas generant feed stock as defined in claim 19, wherein the step of removing the solvent from the ingredients comprises preheating the fluid media and supplying it into the fluidized bed at the drying zone.

23. A method for preparing gas generant feed stock as defined in claim 17, further comprising the step of lowering the pressure at which the fluid media is supplied into the drying zone.

24. A method for preparing gas generant feed stock as defined in claim 17, further comprising the step of including a binding agent in the mixture in sufficient quantities that the ingredients of the gas generating material will agglomerate to form granules as the ingredients are mixed.

25. A method for preparing gas generant feed stock as defined in claim 17, further comprising the step of including a flow agent in the mixture.