The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 04, 1987
Filed:
Nov. 30, 1986
William S Melvin, Huntsville, AL (US);
Porter H Mitchell, Fayetteville, AL (US);
Abstract
The mixing of high solids loaded propellants is accomplished under reduced viscosity conditions by employing near critical liquid (NCL) carbon dioxide as the processing fluid in a volume amount from about 10 to about 20 percent of the volume of the propellant ingredients. A typical propellant composition contains about 88 percent solids portion by weight comprised of ammonium perchlorate, aluminum powder, ballistic modifiers, and bonding agent and about 12 percent liquid portion by weight comprised of liquid polymers, plasticizers, and curatives. NCL carbon dioxide facilitates low viscosity mixing of propellant ingredients in a completely inert processing fluid. The method allows the entire mixing procedure to be conducted under reduced temperature conditions (e.g., 90.degree. F. vs 140.degree. F.), and thereby, provides for extended propellant pot life. Pressure mixing in a range of 760 psig to 1000 psig enables carbon dioxide to be maintained as a NCL to assist propellant mixing. When propellant mixing is completed, depressurization of the mixing chamber enables the NCL carbon dioxide to undergo a phase change to its gaseous state. Venting to ambient conditions, releases the gas from the propellant composition. Residual amounts of dissolved carbon dioxide can be completely removed under vacuum prior to propellant casting. If desired, the gaseous carbon dioxide can be contained and recycled for further use.