Control valve with elastically loaded cage trim

Claim 1

In a control valve, in combination, a valve body; means forming a fluid passage through said body; an intermediate partition interiorly dividing said passage; a port opening through said partition; compressible sealing means engaged at said partition and around said port opening; an access opening through the wall of said body opposite said port opening; a bonnet closing over said access opening; means manipulable for adjustably clamping said bonnet to said body; tubular valve means received through said access opening, engaged to said partition, and overlying said compressible sealing means, said tubular valve means extending from said partition axially of said port opening to a determined small spacing below said bonnet; opposed, annular, closely spaced, axial-thrust-bearing surfaces on said bonnet and valve means; and spring means engaged between said bonnet and valve means surfaces, said spring means constructed and arranged to be axially loaded over the range of variation of the spacing of said surfaces resulting from different rates of heating of, and from different coefficients of thermal expansion of, said valve body and tubular valve means; said thrust bearing surfaces being parallel, inclined surfaces; said spring means being a metal ring of flat, rectangular section, said ring supported on one of said parallel, inclined surfaces at one side of its inner periphery and supported on the other of said parallel, inclined surfaces at the other side of its outer periphery, whereby said ring is twisted out of flat to dished form by the manipulating of said means for clamping said bonnet; said metal ring having a small thickness of from about 0.376 inches to about 0.535 inches; and said metal ring being constructed of a stainless steel alloy which has high strength and elasticity properties, which has been cold worked to retain said properties over long-term use subject to high and repeated twistloading, and which, in said thicknesses and in valve sizes of from about 6 inches to about 16 inches, has a small deflection of from about 0.058 inches to about 0.183 inches, and withstands maximum loads ranging from about 24,000 pounds to about 50,000 pounds.