A valve cage consists of a stackable planar structure design with paths that are azimuthally cut out and connected radially. The pattern causes the flow to move azimuthally and impinge on each other when moving to the next path, thereby reducing the fluid momentum and energy that reduces the erosion capability. The maze-like structure is easy to machine with standard machining techniques.

An example of a valve cage in a co-annular flow system. The valve on the left is closed, and the valve on the right is half-open.
In addition, the use of non-planar disk designs was implemented, which can increase the flow length for a given delta radius, and redirect the flow from the radial direction to the axial direction in counter or co-flow directions. A variety of non-planar disk shapes are apparent that can both increase the flow length, and redirect the flow from the radial direction to the axial direction or conversely. In addition, depending how the cage is oriented, the inlet flow to the main line can be directed counter to the main flow, or co-linear with the main flow.

The valve cage can be used to reduce erosion due to high-pressure jet flows, reduce cavitation by increasing the flow areas in a smooth manner, and reduce valve noise associated with pressure surge. The control features that allow for fine tuning the output pressure and flow velocity include azimuthal, radial, and axial paths in the plates; impinging flows; constricting and dilating flow surfaces; redirecting flow counter and inline with main flow; and redirecting radial to axial, or azimuthal, or vice-versa. These are achieved by adjusting the width of channels, the number of channels, the angular extent of each barrier, misalignment of openings, non-planar geometry of the stackable rings, using variable shaping of the geometry of the obstructing elements that make up the individual layers, and the direction of exit flow from the plate.

This design specifically addresses the problems associated with shutting off a high-pressure valve; namely, potential pressure surge, high-pressure jets, and potential cavitation, all of which can cause damage to the valve body or to the outflow or inflow pipes.

This work was done by Stewart Sherrit, Mircea Badescu, Xiaoqi Bao, and Yoseph Bar- Cohen of Caltech for NASA’s Jet Propulsion Laboratory.

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:

Innovative Technology Assets Management
JPL
Mail Stop 321-123
4800 Oak Grove Drive
Pasadena, CA 91109-8099
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Refer to NPO-48745.


This Brief includes a Technical Support Package (TSP).
Planar and Non-Planar Multi-Bifurcating Stacked Radial Diffusing Valve Cages

(reference NPO48745) is currently available for download from the TSP library.

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This article first appeared in the May, 2015 issue of NASA Tech Briefs Magazine.

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