CPC F16K 11/0708 (2013.01) [F15B 1/26 (2013.01); F15B 13/0402 (2013.01); F15B 15/20 (2013.01); F16K 11/0712 (2013.01); F15B 2013/008 (2013.01)] | 17 Claims |
1. A spool configured to be movable in a longitudinal bore of a valve, the spool comprising:
a shaft varying in diameter along a length of the shaft; and
a plurality of annular lands formed on the shaft and spaced-apart by respective reduced diameter annular neck portions, wherein the plurality of annular lands comprise at least one annular metering land, and wherein the at least one annular metering land comprises:
a plurality of sine notches, wherein the entirety of each sine notch of the plurality of sine notches is formed as a portion of a sine wave, and
a plurality of additional notches having a different shape from the plurality of sine notches, wherein the plurality of sine notches and the plurality of additional notches are disposed in a circular array about a circumference of the at least one annular metering land, and wherein the plurality of sine notches are interleaved with the plurality of additional notches, such that each sine notch is circumferentially-interposed between two additional notches of the plurality of additional notches.
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