Ball closure device with preset clearances

摘要

A ball closure device (1) movable to close an orifice (8) comprises a closure ball (10) retained in a chamber (12) defined by the body (2) of the device the ball (10) being self-centering with respect to the orifice (8) as a result of the ball (10) having radial and axial working clearances (JR and JA) within the chamber (12). The radial clearance (JR) results from a difference between the diameters of the chamber (12) and the closure ball (10). The axial clearance (JA) is obtained by means of a push-rod (16) mounted in a passage within the body (2) so that the closure ball (10) acts on one end (21) of the push-rod and the other end (22) of the rod (16) acts through a deformable ball (20) on a small contact area (S2) at the end of the passage, a predetermined pressure applied to the closure ball (10) causing a permanent deformation of the body in the region of the contact area (S2) to form the axial clearance (JA).