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Patent 7984685 Click For Printable Version of This Patent
Patent Information:  USPTO Site Listing

Patent Number: 7984685
Case ID: 0
Patent Title: Neutrally buoyant submerged system using greater density ballast fluid
Status: ACTIVE
Status Date: 11/30/2011 11:07:56 AM
Issue Date: 7/26/2011
Filed Date: 5/21/2009
Serial #: 2/469,827
Assignee Name: The United States of America as represented by the Secretary of the Navy (Washington, DC)
Inventor(s): Buescher, James
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

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 described previous methods, (a) is impractical for very large or non-rigid submerged objects because of the practical issues of re-positioning non-fluid mass within the object. Further, objects which are not large enough to internally house repositionable masses are limited by that approach. Method (b) is impractical for objects which are or must remain static in t . . . . More
The system provides a means by which the attitude or orientation of a submerged object can be changed using a fixed quantity of transferable ballast fluid which has a density greater than that of the surrounding fluid in which the object is submerged. In one embodiment, the process utilizes a static flotation shell 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 fluid into expandable reservoirs which are physically separated from the static flotation shell, 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 an object immersed in a surrounding fluid comprising a first expandable reservoir, a second, separate expandable reservoir, the second expandable reservoir contained within a fixed volume of a static flotation shell, the shell being initially flooded with surrounding fluid to provide initial static flotation of the object having a passively stable orientation and having an initial center of mass and buoyancy and a net neutral buoyancy, a flexible conduit for transferring a ballast fluid which is greater in density than the surrounding fluid between the first and second reservoirs, the first and second reservoirs and the flexible conduit containing only a fixed quantity of the ballast fluid, a pump mechanism for controllably transferring the ballast fluid between the first and second reservoirs via the flexible conduit to provide another passively stable orientation of the object with a new center of mass and buoyanc . . . . More