USA As Represented by Secretary of the Navy

Mark E Shiffler

Luke W Loy

Joseph H Morris

An unmanned marine surface vehicle (UMSV) featuring structural incorporation of the hull of a typical commercially distributed, recreationally enjoyed personal watercraft (PWC). The intrinsic qualities of the PWC hull, especially as pertains to superior seaworthiness and smaller size, avail the UMSV and UMSV system according to this invention. A contoured upper casing which is coupled with the PWC hull serves not only to further the fluid-dynamic integrity of this invention's UMSV but also to house electrical or mechanical components which are designed for effectuating specific military or civilian missions. This invention's UMSV is small, compact, lightweight, durable, rugged, uncomplicatedly direct-driven and quite seaworthy, and hence offers possible advantages over vessels conventionally considered for autonomous or semi-autonomous operations, particularly in terms of cost-effectiveness, expendability, deployability, recoverability, maneuverability and versatility.

Unmanned sea surface vehicle having a personal watercraft hull form

A fluid flow control device is defined by a plurality of flow control sta mounted on a rod. Each of the flow control stages includes a support brace providing sliding support of the rod, an end plate fixably mounted on the rod, and an elastomeric element mounted on the rod between the support brace and the end plate. The elastomeric element defines an annular cavity around an inside perimeter of the tube. The elastomeric element expands between the end plate and support brace in accordance with axial movement of the rod in order to adjust the size of the annular cavity.

Multi-stage fluid flow control device

A fluid flow control device includes a support brace fixably mounted in a uid flow tube. An actuator rod is slidably supported by the support brace. A plurality of conical washers are mounted in sliding engagement on the rod between a stop mechanism on the rod and the support brace. The conical washers are arranged along the rod in an abutting configuration such that adjacent conical washers abut alternately at an apex or base of the conical washers. In operation, the rod is moved so that a compressive force is applied to the conical washers. In this way, the conical washers expand in a radial fashion to reduce the fluid flow area between the device and the tube.

A throttle or fluid control valve uses at least one compressible multi-wave asher as a fluid control element. The apertures formed by the multi-wave washer are short and of low aspect ratio when the valve is fully open to limit pressure drop across the valve, thus substantially preventing cavitation and flow-related noise to high flow velocities. As the valve is closed, the aspect ratio of the apertures increases but surfaces of the apertures remain angled to each other to provide noise cancellation and damping. Several multi-wave washers spaced by sliders are preferably used to further limit pressure drop in any stage and to form a serpentine path in the general direction of flow to provide further noise cancellation and damping. The sliders also enhance the self-purging action of the valve structure. A closure structure is also provided for assuring full closure of the valve.

Multistage variable area throttle valve

A rotary servo or throttle valve comprises a housing defining a chamber and discharge port in fluid communication with the chamber, a rotary valve spool for delivering fluid into the chamber, and a system for delivering pressurized fluid passing from the outlet opening of the valve in the chamber to the discharge port in the housing in which non-cavitating technology can be readily incorporated. The outlet opening of the valve spool is a wedge shaped groove formed in its periphery, the groove having opposed, arcuately diverging sidewalls. The diffusing system comprises an elongated member which may be rotated in the chamber to align a plurality of flow paths with the discharge port and the outlet opening. The elongated member and valve spool may be rotated independently in opposite directions to obtain faster flow rate changes.

Rotary hydraulic servo or throttle valve

A high-pressure pump for electro-rheological fluids in which the pump coments operate with relatively large clearances and rely on the electro-rheological fluid effect for sealing. Preferably, the electro-rheological effect is induced in the fluid only in the region where a seal between relatively merging pump parts is required to generate a fluid pressure increase.

High pressure pump for electro-rheological fluids

In accordance with the present invention, an improved variable breadth imler for use in a variable capacity centrifugal pump and a method for adapting a variable capacity centrifugal pump to produce a specific predetermined shutoff head are provided. The variable breadth impeller is a two piece unit comprising an impeller element having a plurality of radially extending impeller vanes thereon and an axially movable shroud having a plurality of radially extending grooves therein for receiving the impeller vanes in a meshing relationship. The movable shroud further includes a plurality of axially extending grooves in its outer peripheral surface which act as a supplemental pumping means between minimum flow rate condition and shutoff condition. The operation of the improved variable breadth impeller results in a specific predetermined pressure head being attained and maintained at pump shutoff operating condition.

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Annapolis, MD, United States of America

Mark E Shiffler