| 摘要 |
A control valve well-suited for controlling the flow of particulate solids comprises a valve body having a flow passageway comprising inlet and outlet passages extending transversely to a slide chamber. A plug member having a flow orifice is mounted for movement within the slide chamber to seal the flow passageway when the flow orifice is out of register therewith and to connect the inlet and outlet passages in flow communication when registered therewith. One of the inlet passage and the flow orifice has a cross section including a tapered slot portion which terminates in an apex defining an angle of from about 45 to 90 degrees and an associated polygonal base portion or circular arc base portion subtending from 225 to about 270 degrees of arc. The other has a peripheral shape which includes a leading edge disposed substantially perpendicular to the direction of travel of the plug member. This arrangement provides valves of enhanced rangeability with a unique logarithmic flow characteristic which, for most flow rates, is intermediate to linear and equal percentage flow characteristics.
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