Aqueous foam generating system and method for generating foam having long wet-to-dry transition times

• US 6,371,384 B1
• Filed: 05/16/2000
• Issued: 04/16/2002
• Est. Priority Date: 05/16/2000
• Status: Expired due to Fees

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Garcia, Felipe
• Primary Examiner(s): Scherbel, David A.
• Assistant Examiner(s): Nguyen, Dinh Q.
• Application Number:
  US09/571,881
• Time in Patent Office: 700 Days
• Field of Search: 239/310, 239/303, 239/304, 239/308, 239/316, 239/318, 239/349, 239/10, 169/13, 169/14, 169/15, 169/44, 252/8.05, 252/3, 252/8
• US Class Current: 239/10
• CPC Class Codes: A62C 5/02 of foam

Abstract

An aqueous foam generating system and method are provided. A first solution has particles of a carbomer resin encapsulated within an anhydrous, non-polar, organic hydrophobic surfactant. A second solution, capable of ionizing the carbomer resin, is pumped into an eductor which draws a volumetric portion of the first solution to form a mixture that is sprayed from an aerator to form an aqueous foam having long wet-to-dry transition times.

Claims

1. An aqueous foam generating system comprising:

a first solution of particles of a carbomer resin encapsulated within an anhydrous, non-polar, organic hydrophobic surfactant;

a second solution of a neutralizing liquid having a ph in the range of approximately 5-11, said second solution being capable of ionizing said carbomer resin;

an eductor having a primary input, a secondary input and an output coupled to said primary input and said secondary input, said secondary input being coupled to said first solution;

a pump for pumping said second solution into said primary input of said eductor, wherein a volumetric portion of said first solution is drawn into said second solution being pumped into said primary output, and wherein a mixture of said first solution and said second solution exits said eductor at said output; and

an aerator coupled to said output of said eductor for spraying said mixture wherein an aqueous foam is formed by said mixture so-sprayed.

2. An aqueous foam generating system as in claim 1 wherein said carbomer resin has a molecular weight between approximately 450,000 and 4,000,000 grams/gram-mole.

3. An aqueous foam generating system as in claim 1 wherein said second solution comprises water mixed with a base material.

4. An aqueous foam generating system as in claim 3 wherein said base material is selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonium hydroxide, amines and alkanolamines.

5. An aqueous foam generating system as in claim 1 wherein said second solution has a ph of approximately 7.

6. An aqueous foam generating system as in claim 1 wherein said second solution comprises approximately 420 grams of sodium hydroxide per 100 liters of water.

7. An aqueous foam generating system as in claim 1 wherein said first solution has a surfactant-to-carbomer resin weight ratio of approximately 10 to 1.

8. An aqueous foam generating system as in claim 1 wherein said volumetric portion comprises approximately 5% by volume of said mixture.

9. A method of making an aqueous foam, comprising the steps of:

providing a first solution of particles of a carbomer resin encapsulated within an anhydrous, non-polar, organic hydrophobic surfactant;

providing a second solution of a neutralizing liquid having a ph in the range of approximately 5-11, said second solution being capable of ionizing said carbomer resin;

pumping said second solution through an eductor that is coupled to said first solution, wherein a volumetric portion of said first solution is drawn into said second solution, and wherein a mixture of said first solution and said second solution exits said eductor; and

passing said mixture through an aerator wherein said mixture is sprayed therefrom to form an aqueous foam.

10. A method according to claim 9 wherein said carbomer resin has a molecular weight between approximately 450,000 and 4,000,000 grams/gram-mole.

11. A method according to claim 9 wherein said second solution comprises water mixed with a base material.

12. A method according to claim 11 wherein said base material is selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonium hydroxide, amines and alkanolamines.

13. A method according to claim 9 wherein said second solution has a ph of approximately 7.

14. A method according to claim 9 wherein said step of providing said second solution comprises the step of mixing approximately 420 grams of sodium hydroxide per 100 liters of water.

15. A method according to claim 9 wherein said first solution has a surfactant-to-carbomer resin weight ratio of approximately 10 to 1.

16. A method according to claim 9 wherein said volumetric portion comprises approximately 5% by volume of said mixture.