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Patent 7987805 Click For Printable Version of This Patent
Patent Information:  USPTO Site Listing

Patent Number: 7987805
Case ID: 0
Patent Title: Neutrally buoyant submerged system using lesser density ballast fluid
Status: ACTIVE
Status Date: 11/30/2011 11:07:57 AM
Issue Date: 8/2/2011
Filed Date: 5/28/2009
Serial #: 2/473,485
Assignee Name: The United States of America as represented by the Secretary of the Navy (Washington, DC)
Inventor(s): Buescher, James , Sullivan, Peter , Bratten, Aaron
Lab Information:  View Lab Profile

Lab Name: SPAWAR Systems Center, Pacific
Location: 53560 Hull Street
San Diego, CA 92152-5001
Contact: Contact Lab About This Patent

This application is related to pending patent application Ser. No. 12/469,827, filed May 21, 2009, entitled NEUTRALLY BUOYANT SUBMERGED SYSTEM USING GREATER DENSITY BALLAST FLUID (NC 99596), assigned to the same assignee as the present application, and the details of which are hereby incorporated by reference.


Previous methods for modifying the attitude of submerged objects have involved (a) the shifting of non-fluid mass within the submerged object to alter the position of the center of mass, or by (b) dynamic lifting surfaces or thrusters which require relative velocity of the submerging fluid to exert external forces on the object and change its attitude. Alternatively (c) inflatable or floodable volumes may be used to displace or ingest quantities of submerging fluid from a submerged object, thus changing the object''s total volume, center of buoyancy, and attitude.

Of the above . . . . More
The invention provides a means by which the attitude or orientation of a submerged object can be changed or altered using a fixed quantity of transferable ballast fluid which has a density less than that of the surrounding fluid in which the object is submerged. In one embodiment, the process utilizes a static negatively buoyant material (which could be a lead weight) to offset the net negative buoyancy of the transferable ballast fluid. In this way, the total overall buoyancy of the system does not change, but by transferring ballast fluid into expandable reservoirs which are physically separated from the static negatively buoyant material, the separation between the center of buoyancy and the center of mass of the object can be changed, and thus the attitude or orientation of the object, if it is unrestrained, may be changed.
What is claimed is:

1. Apparatus for changing the attitude of a submerged object immersed within a surrounding fluid comprising a first expandable reservoir collocated with a fixed, negatively buoyant mass, a second, separate expandable reservoir, a flexible fluid conduit for transferring a ballast fluid between the first and second reservoirs, the reservoirs and conduit buoyantly supported by the surrounding fluid and containing only a fixed volume of the ballast fluid which is lesser in density than the surrounding fluid, the object having a passively stable orientation and having an initial center of mass and buoyancy and a net neutral buoyancy, a controllable pump mechanism for controllably transferring the ballast fluid between the reservoirs via the fluid conduit to provide another passively stable attitude of the object with a new center of mass and buoyancy but with an unchanged net neutral buoyancy, thereby controllably changing the attitude of the immersed object.  . . . . More