Patent Number: 6,293,517

Title: Ball valve having convex seat

Abstract: A valve includes a valve ball and a convex metal valve seat ring that abut along a circle in a metal-to-metal seal. At very high contact forces, the valve ball and/or the valve seat elastically deform to increase the contact area between them and thereby lower the contact pressures applied to the valve ball and valve seat. The valve ball and valve seat are made of materials that do not pressure weld under a wide range of contact pressures. In one embodiment, the valve ball is a stainless steel alloy having a hardness of at least Rockwell 44C and the valve seat is Stellite having a hardness of at least Rockwell 50C. In another embodiment, the valve ball and seat ring are steel alloys having hardnesses above Rockwell 50C.

Inventors: Cunningham; James A. (St. Mary Parish, LA)

Assignee: McKnight; John D.

International Classification: F16K 5/20 (20060101); F16K 5/00 (20060101); E21B 34/00 (20060101); F16K 005/06 (); F16K 005/00 (); E21B 034/14 ()

Expiration Date: 09/25/2018