Securing and centering devices for a split mechanical seal

摘要

A split mechanical seal (10), for mounting to a stationary housing (14) that contains a rotating shaft (12), including first (20) and second (30) seal ring assemblies, at least one resilient biasing element and at least one axial biasing element. The first and second seal ring assemblies each include a seal ring having two segments (22,32) that are resiliently supported in the seal. The segments (22,32) have an outer surface and a pair of segment sealing faces (21,31) disposed at opposite ends of the segments (22,32). The resilient biasing (200) element is concentrically disposed about and in intimate contact with the outer surface of one of the seal rings, for applying a first radially inward force that biases the sealing faces (21,31) of the seal ring segments (22,32) into sealing contact with each other. The mechanical seal (10) includes a pair of resilient biasing elements disposed about each seal ring, and the resilient biasing element (132) is preferably an elastomeric member. The axial biasing element (200) is associated with at least one seal ring (33) for generating and applying, in cooperation with the elastomeric member (132), a second radially inward force;the second force operating to bias the segment sealing faces (21,31) together when the mechanical seal (10) is exposed to a selected pressure condition. The axial biasing element (200) is an abutment, integrally formed with the segments (22,32) of both seal rings, that has a radially outwardly slanted outer surface. When the mechanical seal (10) is exposed to a selected pressure condition, the elastomeric member (132) is disposed in intimate contact with the abutment (192), and applies an axial force thereto. The abutment (192) transforms the axial force into an axial force component and a second radially inward force component. This second radially inward component also operates to bias the sealing faces (21,31) of the seal ring segments (22,32) into sealing contact with each other. The seal further includes integrally formed screw housings (80,82) that have formed therethrough a fastener-receiving aperture (84). The aperture (84) has a tapped smaller-diameter portion and an untapped larger diameter portion. The aperture (84) mounts a screw (90) that has a screw-head (96) and a shaft (92). The shaft (92) has a tapped larger-diameter distal end and a smaller-diameter proximal end. The screw (90) when mounted within the aperture, is positively maintained therein. The seal (10) further includes a centering mechanism. In one embodiment, the centering mechanism is a centering strap (240), seated within a transverse bore formed through the screw housings (80,82), that has a handle (248) and a pair of elongate flexible segments (250,252). In another embodiment, the centering mechanism is composed of a number of spacers (240) attached to an outer wall of the holder assembly.