A butterfly valve assembly, of the type to be connected within a flow line, comprising:
- a housing including first and second housing sections, said housing sections including aligned bores defining a flow passage axially therethrough and said housing sections being axially separable, each housing section comprising:
- first and second diametrically opposed recesses disposed such that when said housing sections are in abutting relationship, said first and second recesses define alinged, radially extending journal openings communicating with said flow passage;
- said journal openings each including a first annular portion and a second annular portion, said second annular portion disposed radially outwardly of said first annular portion and being of smaller diameter than said first annular portion;
- and
- a radially inwardly projecting lug extending circumferentially around said flow passage from one journal opening to the other;
- a liner formed of flexible resilient material and mounted in said housing, said liner including a base portion and flange portions disposed at axial ends thereof, said base portion comprising:
- a pair of diametrically opposed collars having openings therethrough aligned with said journal openings, said collars being received in said first portions of said journal openings;
- each collar including a radially inwardly facing annular surface surrounding the opening therethrough;
- two pairs of axially spaced, radially outwardly open, annular grooves extending circumferentially around the outer periphery of said base portion from one collar to the other;
- said annular grooves receiving said annular lugs of said housing sections;
- a pair of seating surfaces extending circumferentially around the inner periphery of said base portion from one collar to the other, said seating surfaces being located intermediate said flange portions;
- said seating surfaces and said annular surfaces surrounding said collars being of spherical configuration;
- said flange portions being tapered, and narrowing in a direction outwardly from the axial outer ends of said base portion and being received in said annular recesses in said end walls of said housing sections, the greatest thickness of said flanges being larger than the depth of said annular recesses so as to project outwardly thereof in an uncompressed state;
- a pair of bushings bonded within said collars;
- said bushings being received in said annular portions of said journal openings;
- and
- a gate rotatably mounted in said housing, said gate comprising integral one-piece closure, stem and stub shaft portions formed of hard plastic material, and a metallic reinforcing shaft extending longitudinally completely therethrough;
- said stem and stub shaft portions being aligned and rotatably received in said bushings, said stem and stub shaft portions each carrying a sealing ring which sealingly engages its associated bushing;
- said stem being rotatable to move said disc portion between passage-opening and passage-closing positions;
- said closure portion including diametrically opposed wing portions and diametrically opposed bearing portions;
- said bearing portions each including a bearing surface in engagement with a respective one of said annular surfaces of said collars;
- said wing portions each including an outer peripheral sealing edge surface extending from one bearing surface to the other, said sealing surfaces being engageable with said sealing surfaces of said liner;
- said sealing surfaces and said bearing surfaces being continuous and of spherical configuration whose center of curvature is essentially co-extensive with the center of curvature of said sealing surfaces and said annular surfaces;
- said bearing portions each having a substantially cylindrical lip extending radially outwardly from said bearing surfaces, the ends of said bushings being seated against flat ends of said lips;
- said stem including a first section of substantially constant diameter rotatably mounted in one of said bushings, a second section rotatably mounted in a third bushing in said housing located outwardly of said first section, said second section being of substantially constant diameter smaller than that of said first section;
- and a tapered section extending between said first and second sections.