| 摘要 |
A butterfly valve is provided having a rotary disc (22) in a housing (60,62) having a valve seat (24) of resilient material. The seat (24) has an outer wall and an aperture therein. A shaft (26,34) affixed to the disc (22) extends through the aperture. A ring (36) surrounds the seat (24) and prevents deformation of the outer wall. The ring (36) is of material much stronger and more rigid than the seat (24) and includes a lip defining an aperture therein in line with aperture. A cylindrical collar (42,44) surrounds the shaft (26,34) and is positioned within the cylindrical lip and supported thereby. The collar (44) provides a bearing surface for the shaft (26,34). The valve seat (24) further includes a pair of flanges (50,52) on the axial ends thereof projecting outward from the outer wall. The ring (36) is positioned between the flanges (50,52) and spaced therefrom creating a groove (54,56) on each side of the ring (36). The disc (22), the seat (24), the shaft (26) and the ring (36) form a unitary valve assembly. The housing is in two sections (60,62), each including projections (64,66) mating with grooves (54,56) to hold the unitary valve assembly within the housing (60,62). The shaft (26) has one end (28) affixed to a hub (29) on the disc (22) by splines which interfere with the hub (29) by a maximum dimension of .030 inch. The hub (29) has a stress less than 20,000 p.s.i. The shaft (26) and the disc (22) are joined by machining the hub (29) with a hole having a diameter slightly smaller than that of the shaft (26). The shaft (26) is pressed into the hole, such that the splines cut grooves in the hole. A retaining ring (108) frictionally engages the shaft (26) and abuts a bearing (106) to ensure that fluid leaking along the shaft (26) past a seal (102) does not eject the bearing (106) and cause injury. |
