| 摘要 |
<p>FLAPPER VALVE Disclosed is a subsurface valve for use in a well and having a flapper closure element. The hinge for the flapper closure element is not adversely affected by the violent forces which frequently occur during movement of the flapper closure element. Instead, these forces are absorbed by other components of the valve in a nondestructive manner. This abstract is neither intended to define the scope of the invention, which, of course, is measured by the claims, nor is it intended to limit the invention in any way.</p> |
