Patent attributes
A severe service condition pressure reduction valve that is resistant to damage by debris carried by high-pressure process fluid stream and operates at acceptable noise levels includes a first stage annular member in the form of a tube or sleeve that is closely fitted into the axial annular opening of a disk stack trim or drag valve, the first stage member having a plurality of radial openings extending through the wall of the tube or sleeve that are aligned with, and correspond in radial and axial or longitudinal spacing to the flow paths in the disk stack valve. The external surface of the first stage member is provided with axially-spaced circumferential raised areas or rings that engage the internal surface of the disk stack annulus to prevent axial flow along the exterior surface of the sleeve.
