摘要 |
<p>The butterfly valve has a metal valve seat and a metal vane, providing fluid-tight metal-to-metal sealing. The valve seat is annular and has an inner circular line surface for engagement with the metal vane. The vane is a conical angle-transported disc, the upper face of the disc being angle-transported between 20 deg. and 40 deg. with respect to the lower face. Both faces are true circles, as is every section of the vane parallel to the faces. When the vane mates with the valve seat, true circular line contact sealing results, the valve seat only being very slightly deflected by the vane to effect sealing.</p> |