Fluid flow control valve - has separate shut-off seat which can be reground without affecting flow characteristics

摘要

The fluid control valve has a conical seat (9) to match the bevelled portion (12) of the valve head (10). The head has an extension (20) of paraboloid form which penetrates into a second orifice (4) below the valve seat and so varies the cross-sectional area of the flow as the valve head is raised. When the valve seat becomes worn it can be reground to restore its sealing effectiveness without affecting the flow control characteristics which are determined by the paraboloid extension.