| 摘要 |
PURPOSE:To adjust the valve gap always in a suitable range by detecting a variation in seal pressure in a fluid seal part formed in the outer peripheral section of a rotary valve so as to adjust the axial position of a tapered valve inner. CONSTITUTION:In a rotary valve in which a valve inner 13 is rotated so as to open and close gas passages 14 through 16, fluid fed into a small chamber 25 from a fluid source 27 flows into recessed grooves 17a, 17b through a valve gap 32 so as to constitute a fluid seal part having a seal pressure which varies depending upon a clearance of the seal gap 32. Accordingly, even though the valve gap 32 is changed due to expansion of a valve outer 11 and a valve inner 13 or the like, it may be readjusted in such a way a seal pressure which is detected by a pressure sensor 28 through the small chamber 25 is maintained to be constant by displacing the valve inner 13 in the axial direction by a motor 29 and an adjusting member 30, thereby it is possible to always maintain the valve gap 32 at an optimum value. |
