A valve comprising a valve seat, between an inlet and outlet, and a spherical valve seal 40, which is selectively seated and unseated from the valve seat. The sealing ball 40 is urged in to a sealing position by a valve member 34 which reciprocates along an axis 14. The valve stem 34 terminates in a tip face 38a which has a first recess 38b which takes the form of a concaved spherical frustum with a radius R38b greater than that of the ball R40. A second recess 38c extends into the valve member from, and form in a line of intersection with, the first recess. The ball engages the line of intersection when the valve member is in the open position. The arrangement allows lateral movement of the valve seal with respect to the valve seat during sealing whilst minimising oscillation, and hence noise, when the valve is open. A fixed valve seal is not required nor are additional noise cancelling elements. A common rail using such a valve is also disclosed.
展开▼
