BALL VALVE WITH SEAT LOADING MECHANISM

摘要

A top-entry ball valve 10 comprising a valve body 12 having a valve chamber 13 and fluid flow passages 14, 15, a ball valve element 20 rotatably mounted in the chamber for movement between open and closed positions relative to the flow passages. and a pair of valve seat assemblies 50 disposed in seat pockets 35 formed about the flow passages at opposed sides of the ball and which may be readily loaded for sealing engagement with the ball or readily disengaged therefrom. Each seat assembly 50 comprises a seat ring 51 having a reduced diameter rear portion 51a, an enlarged diameter portion 51b and a radial shoulder 51c formed at the junction of the two portions and an annular sealing element 59 in the face of the seat ring adapted for sealing engagement with the ball element. These projecting pins 65 are mounted in the seat ring 51 in preferred equiangular spaced relation to extend from the shoulder 51c of the seat ring in substantially coaxial relation with the ring axis. A spacer ring 53 is sleeved about the reduced diameter portion 51a of the seat ring 53 and is provided with recesses 68 which are arranged to be adapted to receive the pins 65 therein. The spacer ring 53 is mounted for movement on the seat ring 51 between a first position where it is engaged by the tips of the pins 65 in spaced relation to the seat shoulder 51c and a second position controlled by rotational orientation of the spacer ring to the seat ring wherein the pins 65 are received in the recesses 68 and the spacer ring engages the shoulder 51c of the seat ring. A spring assembly 66 between the spacer ring 53 and a shoulder 42 of the seat pocket continuously urges the spacer ring towards the shoulder 51c of the seat ring and the seat assembly towards sealing engagement with the ball element 20. To facilitate rotation of the spacer ring on the seat ring, a projecting pin 71 is provided on the spacer ring 53 which, when the cover plate 28 of the valve is removed, may be engaged by a pry bar to force relative rotary movement between the spacer ring 53 and seat ring 51 and move the spacer ring to either its first or second positions. The pry bar may also be used to separate the spacer ring from the seat ring shoulder 51c and re-orient the spacer ring to its first operational position so the seat ring assembly is in loaded sealing relation with the ball element and the valve is in operational condition. Placing the spacer ring 53 in its second position, causes a retraction of the seat assembly from the ball element and adapts the valve for in-line removal of the ball and seat assemblies.