The present invention makes it possible to fix the ball carrier to the valve body without hindering insertion of the ball, by providing projections on the inner wall surface of the valve body. Ball ValvesIn particular, the ball originally has the shape of a sphere, but when a bore is made in the ball, the ball has a shape in which the sphere is symmetrically cut-away on both sides as a result of the bore or circular flow passage which extends diametrically therethrough. When the ball is viewed in the axial direction of the valve body at the time of being inserted in the valve body, the ball has cut-away portions comprising chordal segments on both sides. Thus, if the projections are formed on the inner surface of the valve body within the range of the chordal segments, the projections can be used to fix the seat carrier to the valve body without hindering insertion of the ball.Ball Valves In the present invention, therefore, the projections are formed on the inner surface of the valve body, and the projections are restricted within the range of the chordal segments, each of which has a chord extending parallel to the stem axis and has a length approximately equal to the diameter of the bore in the ball. BALL VALVESIt may be defined more precisely that each of the chordal segments is, in the cross-section of the valve body, an arched area surrounded by the circle indicating the inner surface of the valve body and by a chord extending parallel to the stem axis and passing two points at which the circle indicating the contour of the ball intersects with two straight lines which are tangents of a circle having the diameter of the bore in the ball and perpendicular to the stem axis. Further, the seat carrier is partly cut-away on the outer surface thereof, and the cut-away portions are located at diametrically opposed positions, extended slightly in the axial direction of the seat carrier to form recesses and to form grooves extending in the circumferential direction. The seat carrier is inserted in the valve body, then while the projections of the valve body are positioned in the recesses of the seat carrier, the seat carrier is further advanced in the valve body, thereafter the seat carrier is rotated to fit or engage the projections in the grooves, and thus, the seat carrier is fixed to the valve body.

MORE NEWS